Nutritional risk-benefit assessment of plant-forward diets: what is the balance between the risks of nutrient inadequacy and the benefits of healthier eating patterns?
Résumé
National dietary guidelines in high-income countries and internationally defined reference diets emphasize a higher proportion of energy – and in particular protein – from plants, which is expected to reduce the risks of chronic diseases. On the other hand, there have been warnings about risks of nutrient deficiencies, depending on the level of animal/plant protein in the diet and the type of the dietary pattern. There has been little attempt to address those two sides of the risk-benefit balance together although this is needed if are to get a clearer answer to an ongoing debate. Here, we will review the evidence from the literature with a focus on findings from our team, mostly based on diet modelling and in silico experiments. We will first present the nutrients for which there is – or not – a risk of deficiency in different types of transitions to more plant-based diets, and then assess the risks of inadequate intake and the risks of overt deficiency. We will then make comparisons with the benefits for long-term health that are expected from changes in the dietary patterns. We will show cases when these benefits appear to largely outweigh the risks, and we will also present an example of a refined assessment with an integrated evaluation using a common metric (Disability-Adjusted Life Years, DALYs). We will briefly touch on the possible integration of chemical risk from higher proportion of plants in diets. Finally, the many sources of uncertainty in these risk-benefit assessment frameworks will be discussed.