Is there a role for plant science in underpinning the objective of global nutritional security?

The challenges of achieving global food security have become more demanding as scientists have realized that not only calorie content but also food composition and colonic microbial content impact our health and well-being, dramatically. The ways that the nutrients we consume affect our health are highly complex due to the diversity of what we eat, the varying digestibility of what we eat, the changing composition and functioning of each individual’s gut microbiota, the differences in absorption and bioavailability of the nutrients we eat, the differences in responses between individuals to what they eat and the multi-fold mechanisms of action that nutrients have on our health.

Summary diagram of the processes impacting plants and plant-based foods in the diet.
Summary diagram of the processes impacting plants and plant-based foods in the diet. Processing of foods impacts their chemistry, physical properties and digestibility. Once ingested, maceration and digestion by amylases, proteases, lipases, etc., impact the bioavailability of macronutrients, micronutrients and phytonutrients. Dietary nutrients may impact the composition and functioning of the GI microbiota, which predominantly resides in the colon. Changing microbiota functionality may impact the further digestion of food, nutrient absorption, nutrient metabolism in the colon, removal of toxins and pathogens and signalling, especially satiation. Nutrients, or their metabolites, will be absorbed through the gut and enter the bloodstream, where they may have a wide range of physiological effects. Some material, particularly insoluble fibre, will be excreted. Undigested nutrients will also be excreted and may limit the calories and nutrients redeemable from foods. The panel on the right shows the complexity of the different bacterial phyla in the microbiota of mice using a circular phylogenetic tree colour-coded for the different phyla. The bars above the genera summarize the impact of diets enriched in regular tomatoes (red), high anthocyanin and flavonol tomatoes (dark blue), high resveratrol tomatoes (orange) and high anthocyanin, flavonol and resveratrol tomatoes (purple) compared to the standard diet (grey) on the composition of the microbiota. A large bar of the colour of the supplemented diets above each bacterial group that was particularly enriched by specific polyphenol-rich diets is shown (from Scarano et al., 2017).

It has been accepted for more than 50 years that diets rich in plants, particularly fruit and vegetables, protect health, and yet diets have declined, with lower fruit and vegetable content and much more cheap, sugary, oily, processed foods, over the same period. These dietary shifts have had a marked impact on the incidence of chronic diseases; obesity, metabolic diseases, type2 diabetes and cardiovascular diseases. Martin argues that greater support for research into the ways that plant-based foods impact health will be essential for changing dietary patterns to protect health and to achieve global nutritional security.

Reference List

Martin, C. (2018). A role for plant science in underpinning the objective of global nutritional security? Annals of Botany, 122(4), 541–553. https://doi.org/10.1093/aob/mcy118