Waste and losses in the global food system

This Thought for Food article examines the loss of nutrients as a result of food waste. Not all foods are wasted to the same extent, and thus neither are all nutrients. Aggregate numbers for global waste or waste reduction targets mask these important variations.

When considering the impact of changes in the food system, we need to consider the supply of nutrients, as well as the supply of foods. The primary role of the food system is to provide nutrients – in the form of foods – to meet the needs of the global population.

Distinction should be made between food losses and food waste. Losses are the decrease in edible mass along the supply chain prior to retail, and waste the decrease that occurs at the retail and consumer end of the chain. Read More

When demonstrating the impact of food loss and food waste, we should consider the decreases in available nutrients.

When we lose or waste foods containing nutrients that are in abundant supply, this is less critical from a human wellbeing point of view than the loss or waste of foods rich in undersupplied nutrients.

Ways of improving the future food system could include:

  • reducing loss and waste (and potentially lowering production) where we have excess nutrient supply
  • reducing loss and waste (and potentially increasing production) where there are nutrient shortages

So where are the nutrient shortages?

From a macronutrient perspective, current estimates are that nearly 690 million people have insufficient protein and/or energy intakes. However, micro-nutrient deficiencies (hidden hunger) are also an enormous problem: globally, anaemia (iron deficiency) is estimated to impact 43% of 0-5 year olds and 38% of pregnant women; up to 1.8 billion people may have insufficient iodine intake; and 17% of the global population is at risk of zinc deficiency.

The DELTA Model has been created to help people explore future food production scenarios. It uses data on food production, losses, wastes and end uses, coupled with food composition, nutrient bioavailability, population forecasts and nutrient requirements to determine whether a future food system scenario can meet the nutrient needs of the global population. Modelling the food system shows that globally, with equal distribution, we have enough macro-nutrients for all, even carrying current production levels through to feed the 2030 population.

For protein – often cited as a nutrient we need to produce more of to satisfy a growing global demand – there is already enough protein available globally to provide the target intake for the expected 2050 population based on current nutritional guidelines, if it were equitably distributed.

This may seem surprising, but a challenge in discussing the future of food is in separating the nutrition we need, and the nutrition we might want or prefer. Protein is a good example of this. Statements that we “need to expand production by 70%” by 2050 are based on consumer demand rather than requirement. The DELTA Model exposes the differences between demand for specific nutrients such as protein and population requirements.

However, the global story differs for the micronutrients. We are already limited on total supply of Calcium and Vitamin E and will also be limited on Iron, Potassium, Vitamin A and Zinc by 2030 unless changes to the food system are made. That is, even if distributed equally, there is not enough of these nutrients to meet everyone’s needs.

When we look at the distribution of nutrient supply at a country level the picture is worse. The variation in nutrient supply in 2015 shows that a significant proportion of the global population had insufficient access to Calcium, Vitamin E, Iron, Potassium, Zinc, Vitamin A, Riboflavin, Vitamin B12, Fibre, Folate, and Vitamin C.

Relative nutrient supply distribution at a country level in 2015.  All values are normalised to the target intake with the coloured bar showing the global average supply and the error bars showing the range in country level supply from the 10th to the 90th percentile of the global population.

Waste varies with food type, which affects the supply of nutrients in different ways.

Let’s consider a simplified food supply chain: On Farm -> Supply Chain -> Retail -> Consumer

  • On Farm losses are challenging to quantify, as these may include crops or parts of crops not harvested or not used for human food. These quantities are often not recorded either. In many farming systems, waste materials on farm are used to provide food for animals with almost 30% of the global livestock ration coming from crop residues, by-products and coproducts.
  • Once food commodities leave the farm, losses occur along the supply chains that connect farms with retail, including as part of processing into other products. With more expensive commodities there are strong economic drivers to reduce losses through supply chain infrastructure. For less valuable commodities this may not be the case. Well-developed supply chains seek to recover valuable nutrients from by-products and “wastes” by processing into additional foods, animal feeds, or for other uses.
  • At the consumer end of the supply chain, food may be discarded at retail or in-home for its appearance, age, or various other reasons. Consumer waste is generally greater in high income nations where there is the luxury of choice. Individual consumers or households often lack the resources and the incentives to repurpose food waste and inedible material.
Per-capita food waste by country income bracket expressed as Wasted Daily Diets – the number of additional person days of nutrition wasted based on the first limiting nutrient. Data from Chen et al. 2020. 

Across the supply chain economic drivers mean we waste less of what is expensive, which – combined with the perishability of many fruits and vegetables – means food loss and waste is dominated by plant material. Over 20% of fruits, nuts, and vegetables, and their associated nutrients are lost or wasted after leaving the farm gate. Losses of animal products are 7-10%, and losses of more stable plant commodities (e.g. pulses and sugar) are up to 8%. This means that there is less potential to increase the supply of nutrients that are mainly found in animal sourced foods by reducing loss and waste, compared with nutrients common in plant foods. For example, an 50% reduction in all food loss and waste would result in a 16% increase in Vitamin C supply, but only a 6% increase in Vitamin B12.

Overconsumption is a form of waste

The other aspect of waste that needs to be considered is overconsumption. Nutrients consumed in excess of requirements are either excreted in bodily wastes, or in some cases – as with excess food energy intake – accumulated within the body. Once a certain level of supply has been achieved, further intake gives no further benefit to the individual and is thus a form of nutrient or food waste. When we look to the future, reducing overconsumption waste may have a significant impact on global nutrition.

Taking the previous example of Vitamin C, the range in 2015 nutrient supply at a country level was from around 66% of the daily requirement, to more than 2.8 times the target. For Vitamin B12 – sourced almost exclusively from animal foods – the 2015 availability varied from 40% to 1.75 times the target. Reduced waste and more equitable distribution of foods would increase the availability of nutrients to the populations currently below the target.

When considering the question of what to do about food waste, we should also think about the nutrient waste that occurs as part of this. Waste of nutrient rich foods has a greater impact on our ability to nourish populations that waste of nutrient poor foods. Waste occurs at all stages of the supply chain, and there are many forms of consumer waste – including excess intake. Quantifying and addressing how and where we waste important nutrients is a promising route to reducing nutrient deficiencies.

This Thought for Food was written by the SNi team in collaboration with Prof Thom Huppertz and Prof Wayne Martindale.

Glossary

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Your health is what you eat: the role of nutrition in health

This Thought for Food from Professor and researcher in Health Economics at the University of Sao Paulo, Flavia Mori Sarti, focuses on the importance of healthy diets based on regular intake of fruit and vegetables to maintain health and prevent the onset of noncommunicable diseases (NCDs), alongside the potential impacts on health care costs.

In recent decades, advances in nutrition research have been showing the role of diet in promoting health and preventing diseases. A balanced food consumption pattern that includes diverse types of staples, fruits, vegetables, and protein sources provides the energy, macro- and micronutrients to support healthy lifestyles. The consumption of other bioactive compounds may also help prevent certain chronic NCDs such as type 2 diabetes, dyslipidemias, and cardiovascular diseases.

However, the food consumption patterns of many populations around the world have been changing away from more traditional patterns towards modern diets marked by excessive intake of industrialized foods with high content of sugar, trans-fats and salt. The nutrition transition refers to the process of substitution of foods in natura with industrialized foods in different populations. This is often accompanied by a decrease in physical activities during transport, work and leisure, and an increase in sedentary activities.

The importance of consuming fruits and vegetables

Agriculture remains one of the most important economic activities, generating employment and income for billions of individuals worldwide. There are approximately 250,000 edible plant species known; however, only around 120 species are cultivated for human consumption. In addition, 12 plants and five animal species are responsible for approximately 75% of world food. Yet, plant food sources represent the main source of energy and nutrients, and are the sole contributors to fiber intake in the human diet.

Many health authorities recommend food consumption patterns with increased consumption of fresh fruits and vegetables to ensure sufficient intake of fiber, micronutrients, trace elements and bioactive compounds, also known as phytochemicals.

Dietary guidelines referring to the daily intake of fresh fruits and vegetables seek to promote the supply of nutrients through healthy diets, optimizing body functions and maintaining an individual’s health. Considering variations in cultural habits, several countries and regions publish and update national dietary guidelines based on current nutrition knowledge adapted for their populations (for example, Australia, Brazil, European Union, India, Japan, New Zealand, and the United States).

Nutritional deficiencies, such as a lack of specific vitamins and minerals found at high concentrations in plants, may be prevented through inclusion of diverse fruits and vegetables in daily meals. There is significant evidence that the high consumption of fiber reduces cholesterol and reduces the risk of cardiovascular diseases, diabetes and certain types of cancer. In addition, research on the numerous bioactive compounds that have been identified in plant foods show their contribution to the reduction of risk of NCDs in diverse population groups.

However, not all fruits and vegetables are of equal benefit. The 5-a-day mantra, adopted by authorities in many countries to increase fruit and vegetable consumption, can give the impression that all forms of fruit and vegetables deliver equally positive health consequences. While increased fruit and vegetable consumption is linked to multiple positive health outcomes, it is important to acknowledge the varied nutritional contents of these foods.

For example, there has been much debate on whether fruit juices should count towards achieving intake targets. While fruit juices contain many important micronutrients, they are also a source of sugar while lacking fiber. In developed nations, dietary fruit and vegetable variety is poor, with starchy vegetables making a disproportionately high contribution to vegetable intakes. These foods deliver a high energy intake with low nutrient diversity compared to other vegetables, such as leafy greens. The most desirable increases in fruit and vegetable consumption would be those that deliver high concentrations of micronutrients and fiber without contributing to macronutrient excesses.

Diet-health nexus for reduction of health care costs

Although there is substantial evidence on the protective effects of healthy diets, the consumption of diverse fruits and vegetables in daily diets is usually lower than recommendations in many countries.

The World Health Organization recommendation regarding consumption of fruits and vegetables is to include at least 400 grams per capita per day in the diet. However, according to data from the Food and Agriculture Organization (FAO), only 101 out of 174 countries had sufficient food supply to achieve this recommendation in 2018. Accounting for food waste (approximately 15% to 30% of food supply, depending on the country), the proportion of countries that fulfill the WHO recommendation reduces to approximately 60 out of 174 countries.

On the other hand, 169 out of 174 countries had a food energy supply greater than 2,000 calories per capita per day. Even accounting for food waste, approximately 120 countries still provide excess daily calories for adult individuals with sedentary lifestyles.

Therefore, modern lifestyles lead to a higher prevalence of obesity and related morbidities in many countries. The recent Global Burden of Disease Study 2019 indicated the greatest recorded increase in populations’ exposure to obesity and diabetes was between 1990 and 2019, among other risk factors for early mortality linked with modifiable behaviors. Simultaneously, the low diversity in food consumption patterns provide low intakes of micronutrients and bioactive compounds, characterizing the double burden of diseases, marked by coexistence of undernutrition and obesity related to NCD.

In Brazil, direct costs due to outpatient and inpatient care for treatment of 14 overweight- and obesity-related diseases has been estimated to total US$ 2.1 billion per year between 2008 and 2010. Other estimates pointed to expenditures of approximately 3.45 billion reais (US$ 908 million), attributable to outpatient, inpatient and medication for treatment of hypertension, diabetes and obesity on the national health system in 2018.

A systematic review of literature showed estimates of substantial direct health care costs of obesity and related diseases in 17 studies from developed countries and 6 studies from developing countries. They found that the medical costs associated with obesity and its knock-on effects had been increasing across both the developed and developing world. A previous review indicated that obesity was responsible for approximately 0.7% to 2.8% national health care expenditures in developed and developing countries worldwide. Additionally, individuals diagnosed with obesity usually presented costs 30% higher in comparison with healthy weight individuals due to occurrence of obesity-related NCD.

Conclusion

The reversion of negative nutrition transition trends worldwide depends on changes at individual, social, and policy level: these include gradual modifications of dietary patterns towards greater inclusion of nutrient-dense fruits and vegetables; increased physical activity levels, particularly during transportation and leisure; regulation of food marketing directed at children; adoption of nutrition education strategies; and health promotion actions within primary health care.

The cost-effectiveness of numerous strategies targeting obesity among children, adolescents and adults was assessed through economic evaluation studies in Australia, showing higher effectiveness of actions focusing on lifestyle changes among younger individuals, especially tackling consumption of industrialized foods and beverages, promoting physical activity and encouraging regular consumption of nutritious foods. Primary health care strategies addressing healthy lifestyles through family-based visits and surgical interventions showed reasonable cost-effectiveness.

Besides reducing costs in national health systems, incremental changes in diet associated with adjustments in physical activity level may prevent the onset of diverse NCD and reduce early mortality in different population groups worldwide, thus prolonging healthy life years and maintaining quality of life of individuals. In sum, following dietary guidelines will be a win-win situation for individuals and governments.

The Thought for Food was written by Flavia Mori Sarti, professor and researcher in Health Economics from the University of Sao Paulo, Brazil.

Glossary

Photo courtesy of Flavia Mori Sarti.

The life of your food: A discussion of LCAs

A low impact lifestyle has become desirable as the consequences of our excessive consumption are exposed. However, how do we assess the environmental impacts that our product choices have? Here, we discuss the use of life cycle analyses (LCAs) and the challenges and opportunities these pose in estimating the environmental impact of our food systems.

LCAs are an assessment method used to estimate the environmental impact of items over their lifetime. Such impacts can include water use, land use and greenhouse gas emissions (GHGs). When used correctly, they can be an effective comparative tool between similar items and highlight points in the value chain for improvement.

LCAs have a number of stages, and there are a range of types of LCA. Lifecycle inventories (LCIs) are first collected, which take account of all inputs and outputs within a system. This is followed by LCIAs (lifecycle impact assessment) where the impacts of LCIs are quantified and often differentiated into ecosystem impacts, human impacts and resource depletion. The commonly used term ‘footprint’ can represent a partial or full LCA, but only focuses on one aspect of the system. For example, a water footprint assesses the impact on water availability and quality across the entire life cycle of the product, but this would not include the impact on carbon emissions or land use.

LCAs are recognised as a useful impact assessment tool and as such have standardised methods set by ISO (International Organization for Standardisation). These guidelines have been interpreted differently throughout the literature, especially when applied to a system requiring the allocation of upstream products and inputs that serve in more than one system. For example, water used to irrigate rice paddies would form part of the water footprint of the rice. However, if the rice straw is also used as animal feed, how should the water footprint be allocated between the rice and animal production? Another issue with the methodology when applied to GHGs is that it typically only uses the GWP100 climate change metric, which can misinterpret short lived gas potentials e.g. methane. These limitations highlight the complexities of LCAs and the need for consistent methodology to improve the reliability of the assessment.

Using LCAs for the estimate of a product’s impact provides a landscape where the products can be compared. Although this can see misinterpretation, which will be discussed later, the complexities of this process can also offer up informative results for consumers and producers that may not seem obvious at first glance. This can be best used when comparing products that are similar in their final output (i.e. provide an equivalent user benefit), but may differ in their production chain e.g. competitor products, items produced in different regions and countries, or comparing similar products manufactured by the same company.

One product may have a variety of impact levels dependent on its origin, where it was purchased, right down to the practices of the individual farmer. Simple consumer choices may significantly decrease an individual’s impact. When choosing a discretionary food like chocolate, the choice of dark chocolate over milk or white chocolate significantly reduces the environmental impact. A difference in the nutritional composition of these products should be noted, although it is not a product we eat for its nutritional benefit. Furthermore, it has also been found using LCAs that a change to using 100% recyclables will result in minor reductions in an individual’s carbon footprint, and rather a focus on simply reducing consumption of packaging would see better results.

One of the most robust uses of LCAs is in the optimisation of company production lines. An internal LCA can pinpoint both the area with the most opportunity to reduce impact (e.g. manufacture, shipping, retail) or highlight one product having less impact than another, signifying its value for the company. Having numerical figures produced by LCAs can also provide tangible options for tracking improvements through regular analyses. For example, following its first LCA in 2009, Nespresso committed to reducing the carbon footprint of a cup of its coffee by 28% by 2020. Through these LCAs, Nespresso also investigated the impact between coffee systems to show the use of Nespresso was equal in carbon footprint with three other common coffee systems, while fully automated coffee systems had the highest carbon footprint. Not only does the direct product hold opportunity for more sustainable consumption choices; so too do the processes used to extract the coffee.

The benefits of the accurate use and awareness of LCAs go further than educating individuals or companies. As the literature on LCAs increases across a broader range of products, processes and end-of-life options, it allows consumers to make informed decisions in their quest for a truly low impact life. This also provides critical data to modelling platforms such as the DELTA Model.

With the complexities of LCAs comes the opportunity for misleading comparisons. This can be through comparing two products that have little similarity in characteristics, comparing different parts of the value chain (cradle-to-farmgate versus cradle-to-grave), or only using one footprint to pull conclusions on an item’s entire impact. These have led to some misconceptions, especially when inappropriately exploited by commercial interests to promote one product over another. For example, plant-based milks being touted by some as better for the environment than dairy.

The environmental impact of bovine milk has shown significant variation between different countries, right down to differences inter-regionally. This variation allows the impact assessment outputs to be picked in favour of marketing claims by competitors. When used to compare bovine milk to plant-based alternatives, LCAs can create oversimplified and misinterpreted conclusions such as assuming nutritional equivalence between products, or using global average impacts not representative of the variation between production systems. More appropriate use of LCAs in milk comparisons would be to compare plant-based milks with one another, or compare different farming systems and practises between countries.

This scenario exemplifies the potential misuse of the tool, and highlights a gap in the literature that LCAs are yet to fill when applied to delivery of nutrition. A focus has been placed on whole products and macronutrients, where LCAs give footprints per kg of product or, less commonly, per kg of protein. Micronutrients are yet to be explored and would be an instrumental addition when considering the entire impact of food. This has become even more critical as deficiencies in specific nutrients when feeding the global population have been suggested by the DELTA Model. This gap can be demonstrated in LCA comparisons of protein sources that claim protein powders are more efficient protein sources than cheeses, grains and beef when considering their environmental impacts. This study does not include the numerous micronutrients also received from the ‘less efficient’ protein sources.

Taking a holistic view, you could argue that given the interconnectivity of complex systems such as the food system, even seemingly unrelated factors can have indirect impacts on one another. LCAs can provide an excellent measurement tool when estimating the impact of products on individual environmental factors. However, the examples of misinterpretation and the opportunity for further research demonstrate how the application of LCAs can fall victim to tunnel vision when estimating a product’s true impact. This absence of a holistic view can produce results misleading for consumers. Narrow LCAs provide one piece of the puzzle and consideration should be made of the broader impacts the product has on our planet, our bank accounts, our health and our livelihoods.

Glossary

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Trading in soil carbon stocks

Soil carbon has become a hot topic, with carbon sequestration in soil a possible method for reducing atmospheric CO2. But this isn’t an easy task, and there’s a lot more to soil carbon than just sequestration. Here, we provide an overview of soil carbon flows and what they mean in the context of the global food system.

The term soil carbon refers to carbon stocks, in various forms, present in the world’s soil. Soil carbon can be organic (e.g. living or decomposing organisms, humus) or inorganic (e.g. carbon-containing minerals such as calcite).

The amount of carbon in the world’s soils is estimated in the region of 2500 gigatons, more than three times that present in the atmosphere and more than four times that in all living organisms. Organic matter in the soil, including soil carbon, is vital to good soil health, improving water and nutrient retention, maintaining soil structure and as nutrient sources for plant and microbial life.

Soil carbon content can be understood as the balance between carbon inputs and carbon losses. A major contributor to soil carbon inputs is photosynthesis. Plants capture atmospheric CO2, which is transferred below the soil surface via the roots. As well as contributing to the structure of the plant, some carbon is passed to rhizobial microorganisms, the microbial populations that live in close association with plant roots. As root structures and microbial populations in the soil grow, so too does the bound soil carbon.

Carbon can also be added to the soil through decomposing plant and animal material. The process of decomposition involves microbial respiration, which releases CO2 into the atmosphere, but some of the carbon in the decomposing material remains in the soil. The net balance between carbon inputs and losses to the atmosphere determine whether the soil carbon concentration increases or decreases.

However, further complexity is added to the system by other, abiotic factors. Soil composition, temperature, water content and erosion all influence soil carbon cycling. Naturally, this means that soil carbon stocks vary enormously between different parts of the world, from less than 1 tonne of carbon per hectare in desert environments to several hundred tonnes in tropical forests. Even within local regions, soil type can result in significant differences in soil carbon concentrations. This variation makes quantifying soil carbon challenging.

Agriculture directly influences soil carbon stocks. Clearing of land for agriculture, and tillage and cropping are generally considered to reduce soil carbon concentrations. However, this is not always the case: in certain systems, conversion of forest to grassland results in increased soil carbon concentrations, but it is uncertain how permanent this change is.

A number of activities exist that can increase carbon sequestration in the soil, or decrease the rate of carbon loss incurred by agriculture. Reducing tillage and soil erosion minimises carbon loss to the atmosphere or to waterways, while organic fertiliser application can add to the carbon input on agricultural land. The use of cover crops, which prevent leaving the soil bare between cropping cycles, can also help to maintain or even increase soil organic carbon.

The benefits of such practices are both local and global. Increased soil carbon benefits soil health, increasing crop yields in some systems. The benefits to soil structure of high soil carbon also allow for better retention of micronutrients, such as iron and zinc. This can result in higher concentrations of these mineral in crops, and thus in our own nutrition.

However, there are challenges in increasing agricultural soil carbon stocks in many areas. It is far easier to add to soil carbon in areas where the current concentration is low than in areas with relatively high existing stocks, which may be close to saturation with carbon. Moreover, it is easier for agricultural interventions to increase carbon concentrations in the upper layers of soil than the deeper layers.

Perhaps the greatest driver of recent interest in soil carbon is for its potential in sequestering atmospheric carbon emissions from human activity. Atmospheric carbon, in the form of CO2, is well known as a greenhouse gas. Thus, the possibility of using soil as a carbon sink is gaining momentum.

The potential of this possibility has recently been demonstrated in Australia. Australia has an existing Carbon Farming Initiative that provides the legislation for obtaining carbon credits by demonstrating increases in soil carbon on owned land. Recently, an Australian cattle farm sold carbon credits to Microsoft to the value of $500,000, obtained entirely from soil carbon sequestration from the management of the farm’s grazing land.

Schemes like the Carbon Farming Initiative have the potential to spread. However, in order to quantify changes in soil carbon stocks, it is essential to measure changes in soil carbon over time. This can be done by taking soil samples from a number of representative sites and quantifying the carbon present. These measurements can then be repeated to establish changes in soil carbon concentration over time. However, the wide variation in soil carbon even within a small area makes generalisation of carbon concentrations difficult. Currently, work is underway to benchmark New Zealand soil carbon concentrations, with a view to tracking changes in the future. This work will have to contend with the difficulties of varied concentrations, but may ultimately lead to some form of soil carbon credit system in New Zealand.

Study of soil carbon is benefiting from the interest sparked by the need to reduce atmospheric carbon concentrations. However, its importance to the global food system reaches beyond carbon sequestration. Healthy soils play a role in reducing the environmental impacts of agriculture by retaining nutrients and structure, and enabling optimum crop yield and nutrient content. In the future, the drive for carbon sequestration may also influence land management and provide another source of income for food producers.

Glossary

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GMO crops in the global food system

Genetically modified organisms (GMO) are already major contributors to the global food system since their commercial introduction in the 1990s. For example, over 90% of US corn and soy acreage is planted with GMO seeds. Despite this, the use of GMO is still controversial, with many individuals against their use and many authorities strictly regulating their production and consumption. Here, the arguments for and against GMO use in crop production are presented. 

GMO are defined as organisms, and products thereof, that are produced through techniques in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination. 

The process in which GMO are created differs depending on the degree of modification required but generally, a desirable trait is identified in one organism that could be of benefit in another. The trait is studied and, if possible, the gene(s) responsible for the trait are isolated. These genes are then introduced to the target organism, either via bacterial or viral infection, where the microorganism carries the target gene into the organism for uptake, or by bombarding the organism with particles coated in the target gene. 

The outcome of the process is a GMO that expresses the desired trait isolated from the original organism. 

Advantages of GMO  

The ability to transfer desirable traits between distantly related crops that cannot be interbred has obvious benefits. Examples of GMO use include the ability to increase photosynthetic rate, develop crops that are drought-tolerant with increased yields, and produce crops with disease resistance, such as blight-resistant potatoes

Moreover, crops can be developed that have greater nutritional value than conventional varieties. There exists a long list of such biofortified crops, including cassava with increased zinc, iron, protein and vitamin A content, high lysine maize, high provitamin A rice, and corn with increased provitamin A and folate. These crops are of particular value in global regions where nutrient deficiencies are a high priority public health issue. 

One widely used GMO is Bt-maize. This crop takes its name from Bacillus thuringiensis, the bacterium that donated to the maize plant the trait of producing an insecticidal toxin. Thus, Bt-maize is more resistant to pest insects than conventional maize, leading to higher yields and reduced pesticide use. As a result, 82% of the crop grown in the US in 2020 was the Bt variety. 

Disadvantages of GMO  

The arguments against GMO are largely based on health and environmental risks. The approval process for GMO is nationally administered, so differs between countries. Largely, these processes are more rigorous than for conventional foods and assess both the health and environmental risks of the GMO. 

The World Health Organisation states that no negative health consequences of approved GMO have been shown to date. However, concerns and risks do exist. One health concern raised is the possibility of allergenicity being unintentionally transferred between organisms. An example of this was when early GMO researchers, hoping to increase methionine content, found that the main allergen from Brazil nuts retained its allergenicity after transfer into a GMO soybean. As a result, the GMO soybean was never released commercially and allergenicity is now an important consideration when selecting donor crops. 

From an environmental perspective, there is the possibility that the GMO crop itself, or the introduced gene via cross-breeding or gene transfer, could escape the farmed environment and become a pest. The implications of this would depend entirely on the nature of the GMO crop; for example, transfer of a herbicide resistance gene to a non-target organism could lead to difficulties in controlling its growth. Alternatively, GMO crops could outcompete other plants due to the introduced trait, resulting in decreased biodiversity with unknown downstream implications. While the risk of these unintended consequences is low, they should be considered in the design and management of GMO. 

Finally, some express the opinion that GMO are morally wrong, as they involve too great an interference with living organisms. Such a decision can only be weighed by the individual but will likely mean that a proportion of the population will continue to avoid foods containing GMO products. 

This avoidance is challenging given the ubiquity of GMO products in many foods and by the difficulty for a consumer in identifying GMO foods. Different authorities take different stances on GMO labelling. For example, GMO are not specifically labelled in the US, rather foods that contain ‘bioengineered’ ingredients must be labelled as such. However, specific food labelling for certain types of GMO is on the horizon. The EU has stricter rules, with a requirement for GMO ingredients to be listed on food packaging. However, major food retailers have previously been forced to change their GMO policies due to the increasing “risk of finding GM material in non-GM food”. 

Conclusion 

GMO are widespread in the global food system, but not equally distributed.  

Moreover, regulation of GMO production varies and is not always clear and explicit. There are countries, like the US, where GMO crop production is widespread. Contrastingly, 19 member countries of the European Union have previously voted to either partially or fully ban the use of GMO. In New Zealand, no GMO crops are commercially grown. These variations in use and acceptance will certainly limit investment and development of future GMO. However, there is the opportunity for countries that have a GMO-free stance to use this status to market their products at a premium. 

GMO crops generally result in decreased pesticide use, coupled with increased yields and profitability. Moreover, there are those that believe that GMO will be necessary to adequately nourish a growing population and to adapt production to changing climates. The risks of GMO largely relate to unintended and uncertain consequences that must certainly be properly managed if GMO use and development is to increase. 

This Thought for Food was written by Cody Garton, a summer intern from Pūhoro STEM academy

Glossary

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Saturated facts

For nearly 50 years it has been believed that saturated fat is linked to heart disease. However, the scientific evidence does not universally support this assertion and recommendations are being made to change dietary guidelines and public knowledge around saturated fat. 

In response to increasing rates of heart disease in Western populations in the mid-20th century, the results of epidemiological studies comparing diets in different countries suggested that saturated fat intake could be a risk factor. Minimising the intake of saturated fat-containing foods such as red meat, dairy and chocolate was advised as a result. Currently, the NZ and UK dietary guidelines recommend reducing saturated fat intake, while the US and Australian Dietary Guidelines recommend the restriction of saturated fatty acids (SFAs) to less than 10% of total calorie intake in order to reduce the risk of cardiovascular disease (CVD). 

Saturated fatty acids (SFA), colloquially termed saturated fat, are molecules found in many common foods, especially animal fats and certain plant oils. Saturated refers to the molecular structure of the fatty acids, which have only single bonds between the carbon atoms, which cannot bond with any more hydrogen: thus, saturated with hydrogen. 

The claim that saturated fats were linked to negative health outcomes was accepted by public health institutes such as the World Health Organisation and the American Heart Association, and quickly caught on as a widespread belief. This has become so ingrained that, despite evidence to the contrary, it is proving difficult to change nutritional guidelines and the opinions of medical professionals, nutritionists, and consumers.  

A recent study, published in the Journal of the American College of Cardiology (JACC), performed a meta-analysis of randomized trials and observational studies on saturated fat. It was found that there were no beneficial effects of reducing SFA intake on cardiovascular disease and total mortality. While it was found that SFAs do increase cholesterol in most individuals, they increase concentrations of large particles of low-density lipoprotein (LDL) cholesterol, which is less correlated with CVD risk than the small, dense particles.  

An important finding of this study was that health effects could not be predicted from the SFA nutrient group alone; consideration of the overall macronutrient distribution and food matrix was necessary. Different SFAs have different physiological effects, which are further influenced by the foods they are found in and the carbohydrate content of the diet. Several foods relatively rich in SFAs but also rich in other nutrients, such as whole-fat dairy, dark chocolate, and unprocessed meat, were not associated with increased CVD or diabetes risk. 

There are calls to examine the overall risks of foods containing SFA, rather than SFA themselves. Likewise, the replacement of SFA-containing foods with those containing other fatty acids, often recommended in nutritional guidelines, was found unlikely to reduce CVD events or mortality. The authors of this last publication warned that current recommendations to replace SFA with alternative fatty acids may hinder efforts to get people to adopt more beneficial lifestyle changes, thinking that this single dietary change may be sufficient to reduce their CVD risk. 

One of the studies included in the JACC meta-analysis was the PURE (Prospective Urban Rural Epidemiological) study of 135,000 people from 18 countries on five continents. It found all types of fat (saturated, mono-unsaturated and polyunsaturated) were not associated with CVD, and saturated fat had an inverse association with stroke. Additionally, fat intake was associated with lower risk of total mortality. In contrast, a diet high in carbohydrates was associated with higher overall mortality risk.  

The claims around the negative consequences of fat intake may themselves have caused health problems. Reduction of saturated fat in the diet can lead to excessive consumption of carbohydrates as a replacement. Prevalence of obesity and type 2 diabetes has exploded in recent years, as seen in the chart below. Dr James Muecke, 2020 Australian of the Year, wrote in the Canberra Times“A flawed dietary guideline, which we have obediently and blindly followed for 40 years, is literally killing us. We’ve been encouraged to eat less fat and consume more carbs and yet we’ve never been fatter, our teeth never more rotten, and type 2 diabetes and its complications never more prevalent.” Dr Mueke makes clear the far greater need to prioritise reductions in excess carbohydrate consumption, rather than reductions in fat, to reduce the rate of non-communicable diseases in developed nations like Australia.

Rapidly increasing prevalence of obesity globally over the last 40 years. Source: World Health Organisation

In addition, advice to reduce consumption of nutrient-rich foods such as dairy and meat risks limiting the intake of nutrients such as calcium, iron, zinc, riboflavin and Vitamin B12. The Global Burden of Disease study shows that in the main, global health problems are caused more by what people do not eat – either through poor choice or through lack of choice – rather than an excess of certain foods. With the exception of excess sodium, the highest association of mortality and disability-adjusted life years globally was with insufficient intake of nutrient-rich foods. The study also showed the problems of consuming excess sugars. Consuming calorie-rich but nutrient-poor foods (e.g., sugary drinks) can displace nutrient-rich foods in the diet. The Global Burden of Disease study demonstrates that diets low in nutrient-rich foods are correlated with higher mortality. Importantly, saturated fat intake did not appear with any link to higher burden of disease. 

Number of deaths per 100 000 population attributable to individual dietary risks at the global level in 2017. Reproduced from the Global Burden of Disease study.

It is important for policy makers and health institutes to take all evidence into account when- designing nutritional guidelines. Arbitrary recommended intake levels for saturated fat will be less useful for the prevention of CVD or reduced mortality than targeting excess consumption, particularly of carbohydrates, and micronutrient deficiencies. Foods containing saturated fat, such as meat and dairy, can contribute to a nutritious balanced diet. They certainly should not be removed from the diet due to their saturated fat content, which has inconsistent links to modest impacts on CVD. Replacing these foods with carbohydrates will likely cause greater damage. 


Glossary

Photo by Anna Onishchuk on Unsplash

The requirement for balanced global diets that connect 9 billion consumers


Wayne Martindale, Associate Professor of Food Insights and Sustainability at the University of Lincoln, provides a perspective on sustainable diets and how we should think about them.

The food and beverage system functions globally; we all source our meals from a global marketplace. The responsibility for a nutritious and balanced diet begins with producers and manufacturers before it is presented to consumers. The flow of foods and ingredients in the global food system provides many surprises.  

This article is a viewpoint from Europe and the United Kingdom, where our nation is soon to realise the impact of globally sourcing our food. Sustainability and security are inseparable attributes here and we believe a sustainable diet must provide balanced nutrition and security. This article will develop this relationship using existing evidence and demonstrate that limiting the discussion to a single attribute of sustainability such as greenhouse gas emissions, biodiversity or land use change will only result in polarised debates that will never get us to where we need to be. 

Best practice in the food and beverage industry has been transformed by sustainability. It resonates across industry and consumers as an ideal we should rightly strive to achieve. Much of what we have been aiming for is to reduce the greenhouse gas emissions associated with the production and consumption of foods. Manufacturers are now reporting carbon zero product categories including whole milk and beef, which was unthinkable ten years ago. Our improved understanding of how resources flow through food systems has made carbon zero a reality. Programmes that sought to reduce greenhouse gas emissions ten years ago exposed many gaps in our understanding of food systems.  

The initial debates tended to demonise food and beverage products with higher carbon footprints – namely livestock products and beef (Cederberg et al., 2011). What these studies did not consider was nutritional delivery and consumer experience, both of which are important because without them sustainability will never be delivered (Haddad, 2018). This is because every meal must deliver balanced nutrition and a favourable experience. If it does these two things, it is more likely it will result in optimal health and not be wasted. I was working with CSIRO in Melbourne as a McMaster Fellow when I realised that these relationships were critical. This was in part due to the publication of the Total Well Being Diet (TWD) book by CSIRO (Noakes and Clifton, 2005). What influenced me here was the fact that a formalised and scientifically formulated diet for health – the TWD – could resonate so strongly with consumers that a Government Science Agency publication on dietary change became a best seller! In the UK, this was only achieved by our best celebrity chefs, with the science part often in second place for editorial decision making. The TWD demonstrated the requirement for a healthy diet is clearly resonant with consumers. The notion of what is a sustainable one was less so, but it raised the issue of whether the two are related in any way? 

The issue of sustainability in food has often been associated with carbon footprint. The first studies of crop and livestock production that calculated what we now recognise as a carbon footprint were reported over 20 years ago (Brentrup et al., 2000). These were transformative in that they identified production processes that could reduce greenhouse gas emissions. In the case of agricultural products, their application resulted in reductions in diesel and fertiliser nitrogen used in sustainable farming.  

However, in terms of guiding responsible consumption, carbon footprints can be cumbersome. Such direct measures of carbon footprints for food lead to comparing livestock and plant proteins without considering any dietary requirements. Consumers are often told to not eat specific products, with beef being the main target for such attacks. This leads to a ‘stand-off’ in the sustainability arena, stifling innovation in manufacturing. Nutrition, consumer experience and taste all play an important role in quantifying what is sustainable, and they need to be accounted for when we place carbon footprinting into diets, meals and lifestyles. 

Carbon zero thinking has been transformative in breaking this deadlock and the launch of branded zero carbon livestock products such as whole milk, beef and lamb have shown that food producers and manufacturers are confident in claiming it (read more here). The subsequent re-thinking of carbon footprinting is enlightening because it can be related to achievable and nutritious diets and lifestyles so that responsible consumption is possible.  

Plant products typically have a lower carbon footprint than livestock products. Converting plant protein into livestock protein as efficiently as possible often means an increased carbon footprint. But even here there are exceptions. For example, rice has a greater footprint than whole milk (Clune et al., 2017). This is because of the requirement to flood and drain the soils used to grow rice, resulting in methane emissions (Burney et al., 2010). 

Consideration of production volume can provide a transformative view of the global food system carbon footprint. Production of the ‘big four global commodity crops’: rice (0.7 billion tonnes per year), wheat (0.7 Bn t/yr), maize (1.0 Bn t/yr) and soy bean (0.3 Bn t/yr) account for around 2.8 billion tonnes of production each year (Clune et al., 2017). Three of these crops have a carbon footprint of 0.5 tonnes CO2-equivalent per tonne production, and rice has 2.6 tCO2-e/t, summing to 2.8 Billion tCO2-e associated with the big four each year. The mean or average carbon footprint for beef globally is around 25 tCO2-e/t, some 50 times that of wheat, maize and soybean crops, used for both feed and food. However, only 64 million tonnes of beef are produced globally each year, which accounts for some 1.5 Bn tCO2-e. The GHG ratio of the ‘big three’ (‘big four’ excluding rice) to beef is therefore not 50 but 1.5! If we include rice, beef has half the global carbon footprint of the big four crops. This means we are being mis-led by slavishly following carbon footprint data alone. 

There is also much more here, in that a number of studies on beef for the reported average carbon footprint include the prime production of Wagyu beef under extremely intensive conditions (beer and massages) that holds no resemblance to grass fed and finished beef systems including typical Wagyu systems. The issue of production volume together with variation in carbon footprint data is overlooked in simplistic carbon footprint assessments. If we include variation in livestock production systems, the idea of a typical carbon footprint becomes unrealistic at best! Moreover, the spotlighting effect of carbon footprint will often leave the issue of nutrition aside and this is another reason there is a requirement to look at how carbon footprints of food are measured.

If we were to eat the lowest carbon footprint food group per calorie it would be cake and confectionery alone, because these foods have a carbon footprint of around 80 gCO2-e/100 kcal, whereas fruit and vegetables produce over 400 gCO2-e/100 kcal (Drewnowski et al., 2014). This is surely the opposite to what we are told as consumers. Milk and dairy products are in the middle of this range, lower than meat. And this is only considering calories; considering other essential nutrients such as protein would likely paint a different picture again. The dietary context for carbon footprint clearly needs to be clarified and that is why the Sustainable Nutrition Initiative seeks to find methods of providing robust evidence that will guide realistic, sustainable consumption that provides good health. 

An improved ability to access data has brought energy balance and carbon footprinting into the consumer goods arena and the drive for carbon zero is creating much innovation in food and beverage. It has brought sustainability closer to the consumer in that the consumption of a nutritionally balanced diet can be delivered sustainably even if we do not choose or eat food based on carbon footprints.  

It is important that improvements do not get lost in purely carbon footprinting diets. We are developing models for the UK that identify where critical points and connectivity in the food system control resource flows (Martindale, Duong, et al., 2020). These can be integrated with the nutritional insights of the DELTA Model developed by the Sustainable Nutrition Initiative and build on established indices of food sustainability. New Product Development (NPD) is the operational activity we are focusing on because, if product developers and technologists build in sustainability at the concept stages, there is an increased possibility that the final product will deliver it (Jagtap and Duong, 2019). One of our models – Centreplate – is currently being tested with respect to NPD strategies, improving protein supply and reducing waste (Martindale, Swainson, et al., 2020).  

We are currently at a point where food system insights have the potential to bring sustainability and nutritional datasets together because of two technological advances we would consider most notable. The first is the ability to embed digital technologies into resource packaging so that traceability and analysis of supply chain data can be enabled securely for most food companies (Martindale et al., 2018). The other is the projection of dietary impact of nutrition on populations. This changed forever a generation ago in response to the newly sequenced human genome. What followed was a scramble for therapeutics but the interaction of health and nutrition through our diet was largely overlooked (King et al., 2017). We now have a greater understanding of how genes and metabolism interact with what we choose to eat. It is essential to keep the food system lens, and this is what the Sustainable Nutrition Initiative’s DELTA Model does. Connecting datasets and making sure we speak to each other is becoming increasingly important. This is otherwise known as interoperability in the digital arenas. We have the capability to deliver a net zero sustainable food system, but without interoperability it will not happen. 

Our food future depends on all partners in the global system connecting methods and data that will guide sustainable dietary choices. At present the sustainable diet arena is noisy and confusing for many consumers because polarised views can dominate. This is why actions such as the Sustainable Nutrition Initiative are so important; they lay bare facts and guide routes to sustainable and secure global consumption that still provide the choice and experience that consumers require.

Wayne Martindale directs the Food Insights and Sustainability Service at the National Centre for Food Manufacturing at the University of Lincoln. Wayne has been working in sustainability since 1998, after eight years of doctoral research in biochemistry in the UK, Japan and USA. He started his sustainability practice with the BASIS/FACTS leadership team delivering certification programmes for UK agriculture and has held visiting scientist roles at CSIRO Australia and the OECD in Paris.


Glossary

Photo courtesy of Wayne Martindale.

Protein: we need quality, not just quantity


Getting enough protein in our diets is essential for adequate nutrition. What is less well known is that protein represents a group of nutrients, the amino acids, each of which needs to be consumed in sufficient amounts. Here, we look at how we digest protein, the importance of amino acids, and show that protein quality, not just quantity, is vital.

Protein, alongside carbohydrates and fat, is one of the dietary macronutrients found on the nutrition label of all commercially-produced food. The recommended daily intake (RDI) for protein on these labels varies between authorities, but is usually around 50 g. This allows food companies to easily calculate and display on packaging what percentage of your protein RDI is supplied by their product.

But what is meant by ‘protein’ on these labels? And where do these RDIs come from?

Protein and amino acids

Proteins are a group of molecules essential to all life, distinguishable from carbohydrates and fats by containing nitrogen. The use of proteins in our bodies is broad: they form our tendons and ligaments as collagen, break down our food as digestive enzymes, and protect from infection as antibodies, among many other roles.

Every protein is composed of a string of smaller molecules, amino acids, folded into a functional shape. The amino acids in the string and the folded shape of the protein are specific to the function of that protein.

When we discuss protein as a dietary macronutrient, we are really referring to the supply of amino acids in the foods we eat, rather than the protein per se. The protein content seen on food packaging should really be seen as the sum of the amounts of each amino acid in the food.

Protein digestion and use

Protein is present in the majority of foods we eat. The amount and type of protein varies depending on the food, but all are subjected to the same digestive processes once eaten.

Protein digestion begins in the stomach. The body produces the enzyme pepsin, which starts the breakdown of proteins with the help of the stomach’s acidic conditions. Digestion continues in the small intestine, with the enzymes trypsin and chymotrypsin continuing the breakdown of proteins to individual or very short strings of amino acids (dipeptides and tripeptides).

These small molecules, rather than the original proteins, are absorbed by the intestine and transported around the body in the bloodstream. Once absorbed, amino acids are used to construct the many proteins needed by the body.

Consuming adequate protein in the diet is essential. Our bodies do not store protein in the way we can store fat or carbohydrates. Instead, there is a constant cycling of protein construction, breakdown and excretion. This protein turnover cycle leads to around 250 grams of new protein being produced each day, either using recycled amino acids from body protein breakdown, or from the amino acids derived from newly digested dietary protein. If dietary protein is lacking, this can lead to an overall depletion of body protein over time.

The importance of each amino acid

The most common way of calculating protein RDI is by bodyweight. For example, a frequently heard recommendation is that you should eat 0.8 g of protein each day for each kg of bodyweight. Thus, a 75 kg man should consume 0.8 x 75 = 60 g of protein each day. However, there is a lack of consensus around the value of 0.8 g, with many arguing that intake should be at least 1 g, particularly for athletes and older adults.

This calculation around protein RDI hides the more specific amino acid requirements of the body. There are 20 common amino acids, 9 of which are essential. Essential means that the body cannot effectively make these amino acids itself, so must obtain them from the diet.

There are RDIs for each essential amino acid, based on the amount required for body protein production. However, these RDIs are not displayed on food products, as this would be difficult to calculate for each food and make understanding nutrition labels more difficult. Instead, the protein RDI approximates what is needed based on the amino acid content of an average diet. This approximation was designed for a population that consumes a diverse diet over time. It is less fitting for day-to-day protein consumption of the individual, particularly those who consume only a limited range of protein sources. As an individual, it’s important you obtain enough of each essential amino acid each day.

What happens if we don’t get enough of a certain amino acid?

The result of deficiency in amino acids is best explained through an analogy.

Imagine you are assembling toy cars. The process involves painting the body of the car green, and then putting on the wheels. You have a box of car bodies, a pot of green paint, and a box of wheels.

As you are assembling these cars, you come to a point where you still have car bodies and wheels, but you have run out of green paint. However, with a little more effort, you can make more green paint by mixing some blue and yellow paint you have. With this newly made green paint, the assembly process can continue.

However, if you come to a point where you have car bodies and paint, but have run out of wheels, you cannot continue to assemble the cars. No matter how much of the other two components you have, the wheels are essential, so car assembly must stop until you have more wheels.

The construction of the toy cars from components is analogous to the construction of a protein in the body from individual amino acids. In the assembly of a protein, several different amino acids are required. Like the green paint, if the body runs out of a non-essential amino acid, then it can produce more from other amino acids, although less efficiently. However, if the body runs out of an essential amino acid (those that must be derived from the diet), protein synthesis is halted – much like running out of wheels in the toy car assembly.

If you do not obtain sufficient essential amino acids from your diet, synthesis of necessary proteins can be halted. The wheels in the toy car analogy are the ‘first limiting’ component in car assembly. In humans, it is often the amino acid lysine that is the first limiting amino acid to protein synthesis. This is because lysine is required in a large number of proteins and is not always readily available from the diet. A person can be protein deficient by being deficient in just one essential amino acid, regardless of the amount of the other amino acids they consume. And since the body is unable to store protein, an excess of unused amino acids consumed will be wasted by the body when it cannot immediately use them. Getting enough of each essential amino acid is required for optimal health.

How do I ensure I get enough of each amino acid?

Different foods contain different distributions of amino acids. For example, chickpeas are higher in lysine than oats, but the reverse is true for the amino acid cysteine. Plant foods are more often limited in certain essential amino acids than animal foods, due to the similar proteins required by animals and our own bodies. If plant-sourced foods are your main source of protein, it is important to understand their amino acid profile. Plant foods with complementary amino acid profiles can be consumed together to make up for their individual deficiencies.

Another important consideration is amino acid bioavailability; the percentage of the total amino acid that is available to the body from different food protein sources. The efficiency of the protein digestion process varies depending on the structure of the protein consumed and the food matrix proteins are contained in. Extensive research has been performed on the bioavailability of each amino acid in human foods. The table below gives a summary of bioavailability values for some selected foods.

FoodAmino acid bioavailability
(% of total consumption that is absorbed)
Roasted beef94 – 99  
Fish81 – 94
Cooked kidney beans64 – 100
Oats70 – 88
Potatoes47 – 66
Rice75 – 99
Skim milk78 – 97
Cooked soyabeans71 – 90

Bioavailability of amino acids can vary widely between foods. Therefore, it is useful to have a score for each food reflective of the overall amino acid availability, commonly referred to as protein quality. The DIAAS score (Digestible Indispensable Amino Acid Score) is recommended by the UN Food and Agriculture Organisation for this purpose. The digestibility of each essential amino acid in a food is calculated and compared to a reference protein, and the DIAAS is the lowest of these calculated values. The score is thus reflective of the digestibility of the most limiting essential amino acids in the food.

A DIAAS score of 100 or more indicates excellent protein quality, with high digestibility of all the essential amino acids. Scores between 75 and 100 are considered good sources of protein, but consuming complementary proteins would improve their profile. Scores below 75 are of lower quality. Some example foods with their DIAAS are given below.

FoodDIAASLimiting amino acid(s)
Beef (roasted)99Leucine and Valine
Pea protein concentrate82Methionine and Cysteine
Rice (cooked)60Lysine
Skim milk powder105Methionine and Cysteine
Soya protein isolate84Methionine and Cysteine
Wheat45Lysine

Generally, animal-sourced foods have higher DIAAS scores than plant-sourced foods. This means that the profile of amino acids is better suited to human digestion and to fulfilling our needs for protein synthesis.

At a global scale, producing enough of each amino acid is critical to the ability of the food system to meet nutrient needs. When considering possible future scenarios, the DELTA Model predicts the supply and bioavailability of essential amino acids, as well as total protein.

Take home message

The single macronutrient protein consists of a group of essential nutrients: the amino acids. These molecules are what is needed in our diet to construct the diverse body proteins, essential to bodily function, health and life.

Getting enough protein in your diet is not just about reaching the protein RDI. Instead, you need to reach the RDI for each essential amino acid. This is most easily achieved by eating high-quality protein, or combinations of protein sources with complementary amino acid contents.


Glossary

References for DIAAS values: 1, 2, 3, 4

Green car photo by MW on Pixabay. All other photos courtesy of the Riddet Institute.

Microbiomes and Sustainable Nutrition


Did you know that around 10% of your daily energy intake is supplied by intestinal microbes? Or that many plants and animals that we rely on for food are dependent on microbes for their survival? Although the connections between the microscopic world and the global scale of sustainable nutrition are not obvious, microbes play a significant role in the way our food is produced, processed and digested.

The term microbiome refers to a collection of microbes in a certain location. For example, the human gut microbiome consists of the microbial population living in our intestinal tract, which is receiving increasing attention as we recognise its importance in human health.

Microbiomes exist in diverse locations, many of which form part of the global food system. The role of these microbiomes in delivering sustainable nutrition for the global population is increasingly clear.

Cereal crops are a staple food source for the global population, providing predominantly energy and protein. These crops rely on soil nutrients, such as nitrogen, to grow and produce the protein we then consume. Often these nutrients are applied to cropland as fertiliser, produced either industrially or from animal sources. Management of fertiliser application is essential to avoid environmental damage caused by excess nutrients in soils and waterways.

Nitrogen can also be captured directly from the air by soil and root microbiomes, and microbes associated with roots can increase the availability of micronutrients to the plant. These microbes also increase the resistance of crops to soil pathogens. Moreover, soil microbes play a role in reducing soil erosion by producing products that bind the soil together. Current soil microbiome research is tackling the problem of reduced crop yields due to microbiome depletion and working to understand how the beneficial impacts of soil microbes can be harnessed. Learn more

In addition to plant-sourced food products, microbiomes are essential in the production of animal-sourced foods. An example of this is the rumen microbiome. Much of the forage consumed by ruminants cannot be digested by the animal’s own digestive enzymes; instead, the action of rumen microbes converts resistant plant matter, such as cellulose, to nutrients that can be absorbed by the animal’s digestive tract. These microbial products form the majority of energy intake for many domesticated ruminants. The action of the rumen microbiome is thus an important step in converting inedible plant material into animal-sourced food products in our own diet.

Rumen microbiome research currently has a strong focus on minimising the production of methane, a greenhouse gas and by-product of digesting plant material, by the rumen microbiome. This research is unpacking what causes certain microbiomes to produce less methane than others, and what the impact of different animal feeds is on methane production. Learn more

Continuing along the food supply chain, microbes are responsible for the production of common fermented foods. Fermented foods include cheeses, yoghurts, kimchi, sourdough and fermented meats, and are produced via the introduction of microbial populations to the raw food material. Apart from changing the taste, texture and appearance of these foods, the fermentation process enables perishable foods to be stored for longer periods, which can reduce food waste. The nutritional value of fermented foods is also enhanced in many cases. For example, the fermentation of cabbage to sauerkraut results in vitamin B12 synthesis, a nutrient not available in unfermented cabbage. There is also the probiotic capacity of fermented foods: their consumption can introduce beneficial bacteria to the human gut microbiome. Learn more

Microbiomes continue to play a role in the food system even after food is eaten. Although there are microbiomes in different sections of the human digestive system, the gut microbiome is intensively studied for its impacts on human nutrition and health. The make-up of our microbiome is in part determined by our diet, which forms the major food source for intestinal microbes. Just as our own ten trillion human cells require the nutrients we eat to carry out their function, so too do our equally numerous microbial cells. Current research is demonstrating increasing links between gut microbiome composition and various outcomes for human nutrition and health. This includes links to energy and nutrient yield from the diet, roles in intestinal disease and even impacts on brain function and mood. It is now recognised that we cannot have a full appreciation of human nutritional health without consideration of the gut microbiome. Learn more

A sustainable food system is one that ensures food security and nutrition for all, without compromising the future of the economic, social and environmental bases that the system depends on. Microbiomes are a critical element of a sustainable food system. Soil microbiomes enable and enhance crop growth, while playing a protective role in minimising the environmental damage of farming. Animal microbiomes are essential for the conversion of inedible plant material to animal-sourced foods, essential for food security in many developing parts of the world. Fermented foods are an integral constituent of the diet in many cultures and provide a means of preserving perishable foods, as well as adding nutritional and financial value. Finally, the human microbiome in part determines the nutrition we obtain from the foods we eat.

Microbiomes are present throughout the food system, and touch on all aspects of sustainability. As such, designing sustainable food systems for the future must involve consideration of the microbial element.


Glossary

Photo by Science in HD on Unsplash

Build a food system from nutrient rich foods first


The philosophy of the Sustainable Nutrition Initiative (SNI) is to help create a better understanding of our food systems and identify opportunities for improvement. This is to ensure that in the future we can sustainably feed the global population. SNI has developed a modelling approach to test any range of possible scenarios that could contribute to globally sustainable food systems; The DELTA Model. This Model is unique because it explores the ability of different food production scenarios to provide the bioavailable nutrients needed to adequately feed the global population. The Model does not try to identify or prescribe options for diets for individuals, as there are many ways individuals, particularly those with money and access to different food types, can meet their nutrient requirements. Rather, it enables the creation of scenarios to inform discussions about possible future food production systems that meet the nutrient requirements of the entire population.

A critical feature of a sustainable food system is that the food produced is sufficient to provide the bioavailable nutrients required by the global population. However, there are imbalances in the production and consumption of these nutrients, causing a range of health issues. There is also sub-optimal use of resources, including environmental resources, to produce and distribute food. Globally, the current food system provides sufficient energy and macro-nutrients, but not sufficient micro-nutrients and trace elements, to meet global requirements. Therefore, production and consumption of nutrient-rich foods, particularly those that address micro-nutrient and trace element deficiencies, should be a priority.

There is an increasing challenge to feed the world within global resource constraints

The target of the global food system is to meet nutrient requirements of the global population. This includes all nutrients that humans must obtain from their diet to survive and thrive; energy, macro-nutrients – including essential amino acids as part of overall protein, micro-nutrients and trace elements. However, the earth has limited resources. There is a limit to the amount of food that can be produced before we run out of land, water and other resources. Not all food production scenarios are practical within these constraints. It is therefore a challenge to use resources optimally to ensure all nutrient requirements are met.

The global food production system produces enough energy to feed the world, but problems arise from lack of choice or poor choice

The current food system already has sufficient, even an abundance of energy and macro-nutrients to feed the global population. According to FAO, the world produces around 2,900 calories, 83 grams of protein, and 84 grams of fat per person, per day. This is more than enough to meet the average human requirements. There are however imbalances in the production and consumption of such nutrients. The reason that 11% of the world is undernourished is because of the inequality in access to food (distribution and affordability), rather than production scarcity. Other health issues caused by an under or over consumption of energy arise from a lack of choice or poor choice.

There is not enough production of some micro-nutrients to feed the world

While there is evidence that global food production can feed the world on a calorific basis, the micro-nutrient and trace element requirements of the global population may not be able to be met, even with perfect distribution and zero waste.

According to WHO, an estimated 2 billion people have a micro-nutrient or trace element deficiency (including clinical and sub-clinical deficiencies). Micro-nutrient and trace element deficiencies are common contributors to poor growth, intellectual impairments, and increased risk of morbidity and mortality. This is often referred to as ‘hidden hunger’; it doesn’t always cause death in the way protein-calorie hunger does. Instead it often results in individuals ‘surviving but not thriving’. Long-term consequences occur not only at the individual level but have detrimental impacts on national economic development and human capital. The most common deficiency is iron which affects a quarter of the global population. In some cases, these deficiencies are due to poor dietary choice, but others are due to a lack of choice resulting from limited access.

The DELTA Model shows that if all food that is currently produced was distributed evenly globally, there would still be shortages against requirements for some micro-nutrients and trace elements such as calcium, iron and zinc. In other words, the global food production system currently cannot provide sufficient micro-nutrients and trace elements to feed the world. This indicates resources are not being used to produce food that is optimal for meeting human requirements.

The food system should prioritise nutrient-rich foods

To ensure that the food we produce has sufficient nutrition to feed the global population, while still staying within the constraints of planet earth, nutrient-rich foods should be prioritised. The food system should be built from foods that deliver highly bioavailable quantities of micro-nutrients. This is particularly important for the nutrients in short supply (like calcium, iron and zinc), but as part of an overall nutrient-rich profile.

For example, the richest and best-absorbed source of calcium is cow’s milk and its derivatives. Other foods show high concentrations of calcium; however, bioavailability is variable. Milk is an efficient source of calcium in the food system. But the real benefit lies in dairy being a balanced source, rich in multiple nutrients other than calcium, including high-quality protein, zinc, vitamin B12 and riboflavin.  

For iron, the best sources come from animal-sourced foods, including red meat. This is because the bioavailability of haem iron from animals is much greater than non-haem iron from plant sources. Haem iron also helps the absorption of non-haem iron. Therefore, it is important to have sufficient red meat, alongside plant-sourced foods in the system to meet global iron requirements.

Of course, animal-sourced foods are not the richest source of every micro-nutrient and trace element. For example, vitamin C is best sourced from plants. The key is that starting with foods rich in bioavailable nutrients helps to ensure the global nutrient requirements are met, while using the limited production resources in the most efficient way.

If the food system is built up from the most nutrient rich foods first, energy as well as other macro-nutrients will naturally be met, as these are inherent in food groups. For example, milk also contains fat and protein, as well as the micro-nutrients and trace elements as explained above. Therefore, improvement and optimisation of food systems should place priority on nutrient rich foods.


Glossary

Photo by Louis Hansel @shotsoflouis on Unsplash