Environmental pressures and pesticide exposure associated with an increase in the share of plant-based foods in the diet.

Diets rich in plant-based foods are encouraged for human health and to preserve resources and the environment but the nutritional quality and safety of such diets is debated. This study aimed to model nutritionally adequate diets with increasing plant food content and to characterise the derived diets using a multicriteria approach including, nutrients intake, environmental pressures and exposure to pesticides. Using data of the NutriNet-Santé cohort (N = 29,413), we implemented stepwise optimization models to identified maximum plant-food content under nutritional constraints. Environmental indicators at the production level were derived from the DIALECTE database, and exposure to pesticide residues from plant food consumption was estimated using a contamination database. Plant-based foods contributed to 64.3% (SD = 10.6%) of energy intake in observed diets and may reach up to 95% in modelled diets without jeopardizing nutritional status. Compared to the observed situation, an increase in plant-based foods in the diets led to increases in soy-based products (+ 480%), dried fruits (+ 370%), legumes (+ 317%), whole grains (+ 251%), oils (+ 144%) and vegetables (+ 93%). Animal products decreased progressively until total eviction, except for beef (- 98%). Dietary quality (estimated using the Diet Quality Index Based on the Probability of Adequate Nutrient Intake) was improved (up to 17%) as well as GHGe (up to - 65%), energy demand (up to - 48%), and land occupation (- 56%) for production. Exposures to pesticides from plant-based foods were increased by 100% conventional production and to a much lesser extent by 100% organic production. This study shows that shifting to nutritionally-adequate plant-based diets requires an in-depth rearrangement of food groups' consumption but allows a drastic reduction environmental impact. Increase exposure to pesticide residues and related risks can be mitigated by consuming foods produced with low pesticide input.

Plant to animal protein ratio in the diet: nutrient adequacy, long-term health and environmental pressure.

Background: Animal and plant protein sources have contrasting relationships with nutrient adequacy and long-term health, and their adequate ratio is highly debated. Objective: We aimed to explore how the percentage of plant protein in the diet (%PP) relates to nutrient adequacy and long-term health but also to environmental pressures, to determine the adequate and potentially optimal %PP values. Methods: Observed diets were extracted from the dietary intakes of French adults (INCA3, n = 1,125). Using reference values for nutrients and disease burden risks for foods, we modeled diets with graded %PP values that simultaneously ensure nutrient adequacy, minimize long-term health risks and preserve at best dietary habits. This multi-criteria diet optimization was conducted in a hierarchical manner, giving priority to long-term health over diet proximity, under the constraints of ensuring nutrient adequacy and food cultural acceptability. We explored the tensions between objectives and identified the most critical nutrients and influential constraints by sensitivity analysis. Finally, environmental pressures related to the modeled diets were estimated using the AGRIBALYSE database. Results: We find that nutrient-adequate diets must fall within the ~15-80% %PP range, a slightly wider range being nevertheless identifiable by waiving the food acceptability constraints. Fully healthy diets, also achieving the minimum-risk exposure levels for both unhealthy and healthy foods, must fall within the 25-70% %PP range. All of these healthy diets were very distant from current typical diet. Those with higher %PP had lower environmental impacts, notably on climate change and land use, while being as far from current diet. Conclusion: There is no single optimal %PP value when considering only nutrition and health, but high %PP diets are more sustainable. For %PP > 80%, nutrient fortification/supplementation and/or new foods are required.

Identifying the most Efficient Detailed Trajectories toward Healthy Diets-A Graph-Based Analysis.

BACKGROUND: Much effort has been devoted to defining healthy diets, which could lower the burden of disease and provide targets for populations. However, these target diets are far removed from current diets, so at best, the population is expected to move slowly along a trajectory. OBJECTIVE: Our aim was to characterize the different possible trajectories toward a target diet and identify the most efficient one for health to point out the first dietary changes being the most urgent to implement. METHODS: Using graph theory, we have developed a new method to represent in a graph all stepwise change trajectories toward a target healthy diet, with trajectories all avoiding risk of nutrient deficiency. Then, we have identified and characterized the trajectory with the highest value for long-term health. Observed male and female average diets are from the French representative survey INCA3, and target diets were set using multicriteria optimization. The best trajectories were found using the Dijkstra algorithm with the Health risk criteria based on epidemiological data. RESULTS: Within ∼2.6M diets in the graphs, we found optimal trajectories that were rather similar for males and females regarding the most efficient changes in the first phase of the pathways. In particular, we found that a 1-step increase in the consumption of whole/semirefined bread (60 g) was the first step in all healthiest trajectories. In males, the subsequent decrease in red meat was immediately preceded by increases in legumes. CONCLUSIONS: We show simple practical dietary changes that can be prioritized along an integral pathway that is the most efficient overall for health when transiting toward a distant healthy diet. We put forward a new method to analyze dietary strategy for public health transition and highlight the first critical steps to prioritize.

Plant-based meat substitutes are useful for healthier dietary patterns when adequately formulated - an optimization study in French adults (INCA3).

PURPOSE: We studied to what extent plant-based meat substitutes could improve the nutritional adequacy and healthiness of dietary patterns, depending on their nutrient composition. METHODS: From diets observed in French adults (INCA3, n = 1125), modeled diets were identified by allowing various dietary changes, between and within food categories, when two plant-based meat substitutes were made available: an average substitute (from 43 market substitutes) and a theoretical nutritionally designed substitute, fortified or not with zinc and iron at 30% or 50% of Nutrient Reference Values. Under each scenario, healthier but acceptable modeled diets were identified using multi-criteria optimization, by maximizing a health criteria related to Dietary Guidelines while minimizing deviation from the observed diets, under constraints for nutrient adequacy. RESULTS: Without fortification, the average substitute was hardly introduced into modeled diets, whereas the optimized substitute was preferentially introduced, in large amounts, yet together with a moderate reduction of red meat (- 20%). The comparative advantages of the optimized substitute were its higher contribution to vitamins B6 and C, fiber and α-linolenic acid (ALA) intakes, and its lower contribution to sodium intake. When fortified with iron and zinc, substitutes were introduced in larger amounts into modeled diets, with much higher red meat reductions (down to - 90%). The optimized substitute continued to be preferred, leading to healthier modeled diets that deviated less from the observed. CONCLUSION: Plant-based meat substitutes can be levers for healthy diets only when well nutritionally designed with enough zinc and iron for a substantial red meat reduction.

Nutritional issues and dietary levers during gradual meat reduction - A sequential diet optimization study to achieve progressively healthier diets.

BACKGROUND & AIMS: Reducing meat consumption is a current trend and a strong prospect for the future in Western countries, but its dietary modalities and nutrient challenges remain poorly documented. Using diet optimization under a broad set of constraints, we tried to identify a sequential meat reduction transition and analyze its nutrient issues and dietary levers. METHODS: Based on the consumption of French adults (INCA3, n = 1 125, 18-64 years old), we modeled a transition towards a nutritionally adequate healthy dietary pattern under the constraint of a gradual reduction in meat consumption in successive 10% steps. Using a multi-criteria optimization procedure, the diet modeled at each meat reduction step was to be healthier but close to the previous diet. RESULTS: The most significant changes occurred early in the modeled transition process, with drastic reductions in processed and red meats in favor of poultry, which rapidly became the predominant meat before gradually decreasing from 50% to 100% meat reduction. At the same time, whole grain products, fruits and vegetables consumption increased rapidly to reach a plateau from 50% meat reduction onwards. Some nutrients were limiting, in particular bioavailable iron and zinc, and vitamin A, but sufficient intakes were achieved by restructuring diets based on food groups other than meat. Other nutrients mainly supplied by meat such as vitamin B6 and B12, protein and indispensable amino acids, were never limiting. CONCLUSION: Healthy and nutritionally adequate food patterns can be identified throughout a transition to complete meat reduction. After a 50% reduction in meat consumption, poultry is almost the only meat remaining and its further reduction makes the diet only marginally healthier.

Nutritionally adequate and environmentally respectful diets are possible for different diet groups: an optimized study from the NutriNet-Santé cohort.

BACKGROUND: Research has shown that vegetarian diets have a low environmental impact, but few studies have examined the environmental impacts and nutritional adequacy of these diets together, even though vegetarian diets can lead to nutritional issues. OBJECTIVES: Our objective was to optimize and compare 6 types of diets with varying degrees of plant foods (lacto-, ovolacto-, and pescovegetarian diets and diets with low, medium, and high meat content) under nutritional constraints. METHODS: Consumption data in 30,000 participants were derived from the French NutriNet-Santé cohort using an FFQ. Diets were optimized by a nonlinear algorithm minimizing the diet deviation while meeting multiple constraints at both the individual and population levels: nonincrease of the cost and environmental impacts (as partial ReCiPe accounting for greenhouse gas emissions, cumulative energy demand, and land occupation, distinguishing production methods: organic and conventional), under epidemiologic, nutritional (based on nutrient reference values), and acceptability (according to the diet type) constraints. RESULTS: Optimized diets were successfully identified for each diet type, except that it was impossible to meet the EPA (20:5n-3) + DHA (22:6n-3) requirements in lacto- and ovolactovegetarians. In all cases, meat consumption was redistributed or reduced and the consumption of legumes (including soy-based products), whole grains, and vegetables were increased, whereas some food groups, such as potatoes, fruit juices, and alcoholic beverages, were entirely removed from the diets. The lower environmental impacts (as well as individual indicators) observed for vegetarians could be attained even when nutritional references were reached except for long-chain n-3 (omega-3) fatty acids. CONCLUSIONS: A low-meat diet could be considered as a target for the general population in the context of sustainable transitions, although all diets tested can be overall nutritionally adequate (except for n-3 fatty acids) when planned appropriately.This trial was registered at clinicaltrials.gov as NCT03335644.

The potential effects of meat substitution on diet quality could be high if meat substitutes are optimized for nutritional composition-a modeling study in French adults (INCA3).

PURPOSE: While consumer demand for meat substitutes is growing, their varied composition raises questions regarding their nutritional value. We aimed to identify and characterize the optimal composition of a meat substitute that would best improve diet quality after complete meat replacement. METHODS: From an average individual representing the dietary intake of French adults (INCA3, n = 1125), meat was replaced with an equivalent amount of a mostly pulse-based substitute, whose composition was based on a list of 159 possible plant ingredients and optimized non-linearly to maximize diet quality assessed with the PANDiet score (considering adequacy for 32 nutrients), while taking account of technological constraints and applying nutritional constraints to limit the risk of overt deficiency in 12 key nutrients. RESULTS: The optimized meat substitute contained 13 minimally processed ingredients. When used to substitute meat, the PANDiet score increased by 5.7 points above its initial value before substitution (versus - 3.1 to + 1.5 points when using other substitutes on the market), mainly because of higher intakes of nutrients that are currently insufficiently consumed (e.g., alpha-linolenic acid, fiber, linoleic acid) and a lower SFA intake. The meat substitute also mostly compensated for the lower provision of some indispensable nutrients to which meat greatly contributed (e.g., vitamin B6, potassium, bioavailable iron), but it could not compensate for bioavailable zinc and vitamin B12. CONCLUSION: Choosing the correct ingredients can result in a nutritionally highly effective meat substitute that could compensate for reductions in many nutrients supplied by meat while providing key nutrients that are currently insufficiently consumed.

Modeled healthy eating patterns are largely constrained by currently estimated requirements for bioavailable iron and zinc-a diet optimization study in French adults.

BACKGROUND: Healthier dietary patterns involve more plant-based foods than current Western diets rich in animal products containing high amounts of bioavailable iron and zinc. Little consideration is given to the bioavailability of iron and zinc when studying healthy eating patterns. OBJECTIVES: Our aim was to determine whether currently estimated requirements for bioavailable iron and zinc limit the identification of healthier dietary patterns. METHODS: Using dietary data from a representative French survey and multicriteria nonlinear optimization, we identified diets that maximize health criteria based on food-based dietary guidelines and concomitantly depart only minimally from the observed diet while complying with all nutrient reference values either strictly (nonflexible optimization) or by allowing bioavailable iron and zinc below the current reference values, but to a limited extent (flexible optimization). Using a comparative risk assessment model, we estimated the resulting impact on cardiometabolic and colorectal cancer mortality/morbidity and changes to iron-deficiency anemia. RESULTS: Under nonflexible optimization, reference values for bioavailable iron and zinc were the most binding of the 35 nutrient constraints, and modeled diets displayed considerable redistributions within grains and meat. With flexible optimization, modeled diets were healthier as they contained less red meat and more whole-grain products, but would increase iron-deficiency anemia to 5.0% (95% CI: 3.9%, 6.4%). Globally, in terms of disability adjusted life years (DALYs), as the loss due to anemia would represent <30% of the gain otherwise made on chronic diseases, adding flexibility in the iron and zinc reference values would result in a further 18% decrease in the disease burden from 84,768 [95% uncertainty interval (UI): 81,066, 88,470] to 99,689 (95% UI: 95,787, 103,591) DALYs averted. CONCLUSIONS: Currently estimated requirements for bioavailable iron and zinc proved to be critical factors when modeling healthy eating patterns. Considering lower reference values enables the identification of diets that are apparently healthier overall.

Halving food-related greenhouse gas emissions can be achieved by redistributing meat consumption: Progressive optimization results of the NutriNet-Santé cohort.

BACKGROUND: Diet-related greenhouse gas emissions (GHGe) mainly comes from animal-sourced foods. As progressive changes are more acceptable for a sustainable food transition, we aimed to identify nutritionally adequate and culturally acceptable optimized diets ensuring a gradual reduction in GHGe, using observed diet from a large sample of French adults, while considering the mode of food production (organic vs conventional farming) and the co-production link between milk and beef. MATERIAL AND METHOD: Based on the consumption of 257 organic and conventional foods among 29,413 participants (75% women, age: 53.5 ± 14.0y) of the NutriNet-Santé study, we modelled optimal diets according to GHGe reduction scenarios in 5% steps, from 0 to 50% with nutritional, acceptability, and coproduct constraints, for men, premenopausal and menopausal women separately. RESULTS: Gradual GHGe decrease under these constraints led to optimal diets with an overall decrease in animal foods, with marked reductions in dairy products (up to -83%), together with a stable but largely redistributed meat consumption in favor of poultry (up to +182%) and pork (up to +46%) and at the expense of ruminant meat (down to -92%). Amounts of legumes increases dramatically (up to +238%). The greater the reduction in diet-related GHGe, the lower the cumulative energy demand (about -25%) and land use (about -43%). The proportion of organic food increased from ~30% in the observed diets to ~70% in the optimized diets. CONCLUSION: Our results suggest that meeting both nutrient reference value and environmental objectives of up to 50% GHGe reduction requires the reduction of animal foods together with important substitutions between animal food groups, which result in drastic reductions in beef and dairy products. Further research is required to explore alignment with long-term health value and conflict with acceptability, in particular for even greater GHGe reductions.