How Micronutrient Status May Affect Eating Behavior-Hypothesis and Perspectives.

The importance of micronutrient status in human food choice remains a fundamental issue needing further investigation. The objectives of the present paper are to present and discuss historic and current research together with a general model incorporating this interaction and to suggest future research to address the questions this poses. By definition, essential nutrients must be consumed in sufficient amounts to meet an individual's requirements. While data indicate that complex neuroendocrine mechanisms provide negative-feedback control of energy and protein intake to support homeostasis, corresponding mechanisms controlling micronutrient intake are less well studied. In some contexts, they are explicitly assumed to be absent, specifically for models evaluating safety and risks of deficiencies. However, it may be hypothesized that for at least some micronutrients, mechanisms exist that aid attainment of requirements by altering preference for micronutrient-rich foods so as to increase ingestion of foods containing them, similar to how being thirsty increases the appeal of watermelon compared with dry food. If this hypothesis is correct, it may hold important implications for understanding the types and quantities of foods ingested. Greater appeal in foods richer in essential nutrients may reduce the risk of malnutrition. However, by extension, it may be posited that the use of supplements could confound the most healthful food choices. For example, obtaining vitamin C from supplements or fortified foods could then causally reduce the dietary intake of vegetables and fruits by reducing the appeal of these foods. The unintended consequence may be a lower intake of fiber, nitrate, and phytochemicals, food constituents that may contribute to health without being essential nutrients themselves. This hypothesis can and should be tested empirically, for example, through randomized placebo-controlled supplementation trials. If clear causal effects are documented, clinical and public health guidance will require critical evaluation and possible modification.