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.
Vitamin D deficiency in nursing mothers and how it can affect the infants
While human milk is the preferred source of most nutrients for infants during the first year, there has been concern about the adequacy of human milk in providing vitamin D. It has been demonstrated that, if a lactating mother has limited sun exposure and/or limited vitamin D intake, breast milk has very low levels of vitamin D which is significant for newborns with a vitamin D deficiency and for those who are exclusively breastfed for a prolonged period of time. How- ever, there is no consensus on the dosage of vitamin D that needs to be supplemented to pregnant women nor is there robust scientific evidence to support implementation of a vitamin D supplementation program for pregnant and lac- tating mothers.
A new study from Iran suggests that inhaled corticosteroids in combination with vitamin D supplementation could improve airway functions in patients with mild to moderate persistent asthma.
A new US study reports that a supplementation with vitamin C in men with low vitamin C blood levels may improve physical conditions and decrease the incidence and duration of colds.