Reaching Nutritional Adequacy Does Not Necessarily Increase Exposure to Food Contaminants: Evidence from a Whole-Diet...

Dietary guidelines are designed to help meet nutritional requirements, but they do not explicitly or quantitatively account for food contaminant exposures.

In this study, we aimed to test whether dietary changes needed to achieve nutritional adequacy were compatible with acceptable exposure to food contaminants.

Data from the French national dietary survey were linked with food contaminant data from the French Total Diet Study to estimate the mean intake of 204 representative food items and mean exposure to 27 contaminants, including pesticides, heavy metals, mycotoxins, nondioxin-like polychlorinated biphenyls (NDL-PCBs) and dioxin-like compounds. For each sex, 2 modeled diets that departed the least from the observed diet were designed: 1) a diet respecting only nutritional recommendations (NUT model), and 2) a diet that met nutritional recommendations without exceeding Toxicological Reference Values (TRVs) and observed contaminant exposures (NUTOX model). Food, nutrient, and contaminant contents in observed diets and NUT and NUTOX diets were compared with the use of paired t tests.

Mean observed diets did not meet all nutritional recommendations, but no contaminant was over 48% of its TRV. Achieving all the nutrient recommendations through the NUT model mainly required increases in fruit, vegetable, and fish intake and decreases in meat, cheese, and animal fat intake. These changes were associated with significantly increased dietary exposure to some contaminants, but without exceeding 57% of TRVs. The highest increases were found for NDL-PCBs (from 26% to 57% of TRV for women). Reaching nutritional adequacy without exceeding observed contaminant exposure (NUTOX model) was possible but required further departure from observed food quantities.

Based on a broad range of nutrients and contaminants, this first assessment of compatibility between nutritional adequacy and toxicological exposure showed that reaching nutritional adequacy might increase exposure to food contaminants, but within tolerable levels. However, there are some food combinations that can meet nutritional recommendations without exceeding observed exposures.