The safety of micronutrients – Part 1: fat-soluble vitamins
Excessive intake of high-energy macronutrients and their potential consequences for people’s health are a problem in many industrial nations. In the case of micronutrients, however, epidemiological data suggests that over-supply is the exception rather than the rule across the globe. Many people are therefore concerned that their dietary habits are failing to provide them with a sufficient supply of essential nutrients such as vitamins and carotenoids. Given that intakes of some nutrients are below officially recommended levels, it might at first sight appear unnecessary to set upper intake levels for micronutrients. However excessive intake of food supplements and fortified foods in addition to normal diets could conceivably lead to intake levels which could potentially be considered harmful. It may be sensible to define an upper daily intake level at which the risk of adverse effects on health is unlikely, particularly in the case of fat-soluble vitamins which are stored in small quantities in the body.