A recent study on the effect of plant-based diets on children in Poland was published in The American Journal of Clinical Nutrition. Findings suggest differences in cardiovascular health profiles, bone density and growth factors when comparing vegetarian, vegan and omnivorous diets.
Plant-based foods already dominate most omnivorous diets, yet trends in vegetarian and vegan lifestyles lead to increasing dominance of plant-based foods on our plates. The choices of consuming less products derived from animals are underpinned by a variety of reasons, from ethical to perceived improved human and environmental health. Such choices flow down from parent to child, but the research is limited on the health and development effects these diets have on our younger generations.
The present study explored the effect vegan and vegetarian diets had on growth, body composition and cardiovascular and nutritional metrics in children 5 to 10 years old, with the control being an omnivorous diet. A vegan diet was associated with a healthier cardiometabolic risk profile, but with increased risk of nutritional deficiencies, lower heights and lower bone mineral content. Vegetarian diets saw less pronounced nutrient deficiencies but a less favourable cardiometabolic risk profile.
Nutrient adequate vegetarian and vegan diets are possible for individuals who have the financial means to eat well, supplement where necessary and address risks of nutrient deficiencies. This study highlighted that supplementation to address nutrient deficiencies in Vitamin B12 and D is possible. Through doing so, individuals may see benefits by way of a healthier cardiovascular risk profile – reducing the risk of one of the deadlier diseases of the modern world. However, an alarming finding from the study was the low bone density associated with veganism. Increased risk of breaks and injuries and a less favourable health status when entering later life was highlighted by the authors.
Further research is required in the area of vegetarian and vegan diets and their health implications, especially in younger and elderly people to determine long term affects. As our knowledge in this area grows it will allow us to make more informed decisions on what a sustainable diet is: one that is both good for the planet, our health, and our children’s health.
Results of the SNi DELTA Model have this week been published in the Journal of Nutrition. The paper details the construction of the model, the scope of its use, and some key results that challenge widely repeated ideas in the food system.
As detailed in the paper, the DELTA Model is an online tool that allows users to design global food system scenarios (in terms of production, waste and use) and see the outcomes for human nutrition. For example, a user can design a scenario with increased food production and decreased food waste, which the model will then use to calculate the nutrients available to the global population. This value is then compared to the nutrients that the population requires, calculated using demographic data coupled with age and gender specific nutrient requirements.
How does the model work?
DELTA was developed using publicly available datasets from international organisations, complemented with key information from the scientific literature. It takes global food production totals and runs them through a calculation pipeline:
Allocation: food items are allocated to their uses. This includes use as animal feed, processing into other food or non-food commodities, seed for following growing seasons, and non-food use (such as sugar crops for biofuel production). The amount wasted along the supply chain is also deducted.
Consumer use: a substantial amount of food matter is not consumed, either because it is considered non-edible (such as animal bones and vegetable peel), or it is simply thrown away uneaten.
Conversion to nutrients: food composition data are used to convert the total amount of food consumed into a total amount of nutrients consumed. 29 essential nutrients are included.
Bioavailability scaling: specific nutrients are scaled for bioavailability, i.e. the ability of the body to utilise these nutrients when consumed in certain foods.
The total amount of bioavailable nutrients is then compared to the requirements of the global population. This can either be today’s population, or a forecast population in the future, and DELTA considers the demographic makeup of these populations when calculating nutrient requirements, because not all individuals have the same nutrient needs.
What are the results of the model?
In this paper, the DELTA Model was used to address a number of different questions.
Where are the gaps in our current food production system?
Using 2018 data, it was found that there was sufficient availability of most nutrients to feed the global population. The only exceptions were calcium and Vitamin E. There was even sufficient macronutrients (e.g. protein, energy, fat) to nourish the 2030 population. This demonstrates that the problems of undernutrition present in the world are partly due to the inequitable distribution of food.
What about food waste?
The DELTA Model found that even completely removing food waste doesn’t solve all our nutritional problems. There still wouldn’t be enough calcium or Vitamin E for the global population. This is because we waste different amounts of different nutrients, so reducing waste has a varied impact on nutrient availability.
Comparison between levels of waste for each nutrient considered by the DELTA Model in 2018. The bars show total nutrient waste and loss as a percentage of target daily intake. Nutrient waste is dominated by waste of plant foods, and varies greatly between nutrients.
What foods should we be producing in the future?
The DELTA Model wasn’t designed to be prescriptive, so no optimal food production system is given. Instead, a few example future scenarios are discussed, each of which fails to meet nutritional needs in some way.
Scaling up food supply with the population doesn’t resolve nutrient gaps, it just keeps them from growing any larger.
Removing meat and seafood production to achieve a globally vegetarian diet increases the food available to people due to reduced animal feed demand, but leaves gaps for key nutrients for which these foods are major contributors, such as iron, zinc and Vitamin B-12.
Increases in plant food production can help to feed a growing population, but using this technique alone to meet nutrient requirements may come with an excess intake of energy.
Finally, halving waste by 2050 is an admirable goal, but not the whole answer. Doing so would keep macronutrients above requirement, but would leave many micronutrient deficiencies.
What’s novel about DELTA?
There exist several other models for global nutrition which perform a similar role to DELTA (e.g. GENuS, The Global Nutrient Database, Beal et al.). The key points of difference and novelty in DELTA are:
Accessibility: few of the alternative models are openly available for the general public to use to gain a better understanding of global nutrition. Moreover, many of the alternative models use data that is not publicly accessible, making interpretation more challenging.
Bioavailability of nutrients: the DELTA Model takes into account the fact that 100g of a nutrient from one food is not the same as 100g of that nutrient from another food. For example, DELTA scales the availability of protein and the essential amino acids based on protein quality: the ability of the body to obtain and use these nutrients from different sources. The model also scales the iron and zinc requirements of the global population based on the foods available to meet these requirements. Consideration of bioavailability allows for a more realistic comparison between availability and requirement than is possible from considering content alone.
Inclusion of upper and lower safe intake levels for nutrients: we all know about recommended daily intakes for nutrients. However, many nutrients have additional reference values, such as for safe lower and upper intake levels. The DELTA Model displays these in addition to a target intake, to give the user more information about the adequacy of nutrient supply. For example, in several scenarios detailed in the paper, there is sufficient availability of most required nutrients. However, these scenarios also feature energy availability above the safe upper intake level, implying that obtaining the target levels of other nutrients in these scenarios may necessitate excess energy intake.
The future of the DELTA Model
The current DELTA Model has a number of limitations for the SNi team to address in the future. For example, the current version considers 29 nutrients, but this does not include all that are essential to good nutrition. Inclusion of essential fatty acids will be a key next step.
Bioavailability is currently only included for some of the nutrients in the model. This will be developed in the future, but is limited by the availability of data for all nutrients from all foods.
Future versions of the model will also need to calculate the environmental impacts of food system scenarios. At present, it is the user’s responsibility to decide whether their scenario is possible from an environmental perspective. We are currently working on land use sub-models, which will allow the user to see the required land necessary for food production in their scenario. Other environmental impacts will follow.
Under justified scrutiny from an environmental sustainability perspective, the global food system needs to change. However, it is essential that the nutritional implications of any change are not forgotten. The DELTA Model is a tool that allows us to investigate future food system scenarios to see what is possible from a nutrition perspective, to be considered alongside the other aspects of sustainability.
While it may seem a rather squeamish topic, edible insects have been found to provide a healthy source of protein for humans. With a low environmental footprint, insect protein looks to be growing as a favourable alternative protein source for the future.
A recent paper in The American Journal of Clinical Nutrition has found that mealworms provide a high-quality protein source that matches that of milk protein. Through the use of isotope labelling, this research found that the nine essential amino acids in mealworm-derived protein had the same performance on digestion, absorption and stimulation of muscle growth as milk protein.
Milk protein is often considered the “gold standard” for protein quality, with plant-based proteins falling in behind due to their often-incomplete profile of amino acids and lower bioavailability. Although a rich nutrient source, milk is often criticised for its environmental footprint due to methane emissions, water use and quality, and agricultural land use change. Insects on the other hand can be reared at scale with minimal environmental impact, and according to the present study can provide a high-quality protein source for the human diet.
At present, the major non-food uses of insects are in animal feed and fertiliser. However, research like this and others (e.g. EFSA’s safety assessment, FAO paper on benefits of insect-based protein) along with significant market value growth indicates future development in this industry for human food is likely. To unlock the potential of edible insect-derived protein, the negative perceptions of eating insects in the Western World would need to be overcome.
This study highlights the promising benefits of mealworm as an environmentally friendly protein source for the human diet. However, milk provides more than just protein. Arguably more important than being a protein source, dairy foods are an important source of micronutrients often difficult to otherwise adequately source from our diets, including Vitamin B2 and B12, calcium and potassium. The use of milk as a comparison to novel protein sources is useful but before any conclusions can be formed around substitution potential, the entire nutrient profile of foods must be considered to determine other benefits exclusive of protein.
A recent review has analysed the current indices, metrics and models for the nutritional quality and environmental sustainability of foods and diets. Such indicators must capture the all of important aspects of both these perspectives, without losing clarity.
The authors found that 50 dietary quality indices have been proposed over the last 30 years, many of which have limitations that lead to unrealistic recommendations for food substitutions that are not nutritionally interchangeable.
For environmental indices, the review found that most diet-related impact assessments use only a few environmental indicators in their analyses. These are commonly related to greenhouse gas emissions, land use and/or freshwater use. Other indicators are occasionally used, but no standardised procedure for dietary life cycle analysis exists.
The review also encompasses socioeconomic factors related to healthy sustainable diets. This is an omission of most environmental studies on sustainable diets, which the authors state leads to recommendations that are empirically unfeasible.
The authors address a number of key misconceptions that persist in sustainable healthy diet indices. Several of these relate to nutrients, foods or food groups that have been labelled as detrimental to health, while the scientific evidence around them calls for more nuance. Similarly, the nutritional requirements of different population groups are not always included in calculations. Degree of processing often features in indices, despite not describing or quantifying a clear effect on health.
On the environmental side, the authors address the rare inclusion of aspects such as seasonality or transport of food. They use the example of in-season locally grown vegetables having a substantially lower carbon footprint than greenhouse grown, and also point to the trade-offs: conventionally grown vegetables that are imported will often have a lower footprint than locally grown greenhouse vegetables.
The review concludes with an extensive list of nutrition, health, environmental and socioeconomic indicators that should be included in the assessment of sustainable healthy diets. The nutritional indicators include demographically adjusted nutrient intake requirements and a wide range of essential nutrients to be considered – approaches also taken by the DELTA Model. The development of an all-inclusive index for sustainable healthy diets would be a daunting task requiring extensive and detailed data for any foods or diets addressed. However, this is necessary if we wish to reliably quantify the contribution of foods to such diets, as selective use of indicators will lead to bias.
Many parts of the developing world are transitioning from traditional animal-sourced foods to lower diversity, higher production animals. In parts of the Amazon, this includes transitions from capture fisheries to aquaculture and chicken production. These transitions are often supported by international development organisations to increase food security, but new research has examined what this transition means for human nutrition in a Peruvian population.
The authors found that increasing chicken production at the expense of capture fisheries increased the number of individuals who could meet their protein and zinc requirements, but decreased the number meeting iron, calcium and fatty acid requirements. These changes would be particularly impactful on young children and adult women due to their nutrient requirements. Similar, but less drastic changes, were found for the replacement of capture fisheries with aquaculture.
The authors make a number of recommendations looking to the future. Diversity of animal production and consumption should be maintained, as both the traditional and novel production systems have benefits for nutrition. Fishery protection to ensure continued availability of traditional food sources is a priority, as should be the production of diverse species in aquaculture systems.
The approach taken by these authors is similar to that of the DELTA Model, emphasising the need to consider the availability of all essential nutrients resulting from proposed changes to a 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.
The World Health Organization (WHO) European Office for the Prevention and Control of Noncommunicable Diseases have released a fact sheet on their workstreams around healthy and sustainable diets. This work is intended to guide European national policy on shifts towards more sustainable diets.
Many public health authorities and governments use WHO recommendations as a basis to guide decision making. The outlined workstreams indicate WHO’s interest in nutrient profiling, processed foods and beverages, digital marketing and sustainable food systems. Below are some details on individual workstreams:
Food profiling model for healthy and sustainable diets
Current food profiling tools (that score foods on nutritional and environmental factors) will be reviewed and used to develop a new standardised tool. This tool will then be used to inform the creation of sustainable food labelling.
Data platform for modelling healthy and sustainable dietary patterns
An open-access data platform that will allow governments to assess their national dietary intake data and model diets to meet local nutrition needs and sustainability goals.
Guidelines on ultra-processed plant-based foods
Investigating the nutritional composition of ultra-processed plant-based foods (such as vegan burgers) sold in retail and restaurants. This will be used to inform guidelines on ultra-processed plant-based food intake.
Healthy digital food environments
An online platform, called FoodDB, that compiles nutrition data from online food retailers, with the intent of making healthy online food choices easier.
These projects will have important ramifications for the treatment of sustainable nutrition by European authorities. Quantifying the nutritional composition of novel foods is essential in understanding their benefits and risks. It is to be hoped that this project will extend to consideration of the bioavailability of the nutrients in the novel foods.
The greater availability of nutritional data to researchers and policy-makers should allow for more evidence-based decisions on food policy shifts. However, the challenge of creating food profiling tools that can fully capture the nutritional and environmental aspects of different foods is clear: nutrition and environmental impacts are very broad topics, and unifying data from both of these fields in order to compare different foods directly will not be straightforward.
Moreover, there is a difference between healthy, sustainable diets and a globally sustainable food system. A diet that meets health, nutrition and sustainability goals for an individual may not be feasible for feeding the global population. For example, increasing the production of a certain food that contributes to one individual’s healthy, sustainable diet may result in less sustainable production of that food. It is essential to consider both what is healthy for individuals and what the global food system can sustainably produce for the global population.
The Riddet Institute is this week hosting an event to bring together food system stakeholders and decision makers for accessible evidence-based discussion of the key global issues and the local decisions that we need to make.
Sustainably feeding a growing population is a global problem, but also one for New Zealand to consider. Where does our reputation for high quality, premium food products fit in a hungrier world? How can kiwi innovation and ingenuity make a difference to the global future of food?
The event will explore the current conversation of sustainable food, bringing moderation and balance to what is often a debate of extremes. National and international experts in the fields of nutrition, food waste, food systems, life cycle analysis and consumer science will speak on these important issues, with open discussion from the attendees.
This dialogue will inspire our future decisions and put New Zealand at the front of the sustainable food systems debate.
A recent study on dairy’s role in cardiometabolic health has added further nuance to the topic by indicating the different outcomes total dairy and individual dairy products have on biomarkers of disease.
Cardiometabolic diseases including cardiovascular disease, diabetes and chronic renal failure are now the number one cause of death in our aging population. The main cause of these diseases is an unhealthy lifestyle. A broad range of biomarkers (indicators of a disease that can be found in the blood) have been identified and can be used to determine onset. Some studies have linked dairy intake with increased risk of individuals developing cardiometabolic disease. The present study tested these associations to further understand how dairy products can influence cardiometabolic health by measuring biomarkers.
The cross-sectional study included over 35,000 women aged 50 to 79, spanning 40 clinical centres across the US. Concentrations of 20 different biomarkers were compared.
The key findings were:
Lower triglyceride (type of fat associated with cardiometabolic disease) was associated with greater intake of total dairy. This was driven by full-fat dairy products
Greater total milk and yoghurt intake were associated with lower concentrations of total cholesterol, while greater butter intake was associated with higher cholesterol concentrations
Greater total dairy, total and full-fat cheese and yoghurt were consistently associated with lower concentrations of glucose, insulin and C-reactive protein (all of which are biomarkers of cardiometabolic disease).
These findings do not support conclusions of dairy playing a role in cardiometabolic disease, and more specifically the health benefit for low-fat dairy product varieties over full-fat, as promulgated by some health authorities. The challenge in finding consistent outcomes for the role of dairy in the onset of cardiometabolic disease calls for further research in the area. What has been made obvious is the critical role that nutrition plays in the health of our populations and that individual products, rather than food groups, should be considered.
An integrated technique has been used to find the multiple benefits of introducing legumes to crop rotations in a recent Frontiers study. Not only are these promising findings for developing sustainable food systems, but also a step forward in holistic life cycle analysis measurement.
Adding legumes (beans, peas, lentils) to crop rotations has been shown to increase the nutritional value for livestock and humans while reducing environmental impacts and resource costs. In one example, introducing a legume crop into a typical rotation in Scotland reduced external nitrogen requirements by almost half, with no detriment to the crop’s human nutrient output.
The benefits of legumes range from environmental to nutritional. Unlike many other crops that require additional nitrogen to grow, legumes obtain sufficient nitrogen from the air around them without the need for additional fertilizers. This occurs through a symbiotic relationship with root bacteria that transforms nitrogen in the air to a useable form for plants. Legumes also reduce the need for fertiliser in future crops as they enrich the soil with nitrogen. In terms of human nutrition, legumes are rich in protein, fibre, folates, iron, potassium, magnesium and vitamins.
The novelty of this study was in its comprehensive comparisons across ten crop sequences, 16 impact categories, lengthy timeframes and various European locations. The authors went beyond simple footprinting techniques that only consider the environment or nutrition in isolation. Instead, they considered the footprint of delivering a specific quantity of nutrition. This provides a welcome and realistic perspective on the value of the whole system, with inter-crop effects and overall efficiency of cropping sequences considered.
This work has shown that the choice of functional unit has an important influence on the apparent efficiency of different crop rotations. It also indicates a need for further research using functional units that represent the multiple nutritional attributes of crops for livestock feed. The results of this study illustrate the benefit of using whole-system thinking when designing interventions to drive sustainable food systems.
