Combatting multiple micronutrient deficiencies: A great challenge

Abstract

Maintenance of proper health and resistance to disease requires, in addition to sufficient supplies of energy and the essential macronutrients, provision of adequate intakes of micronutrients ─ vitamins and minerals. It is known that such sub-clinical deficiency symptoms of various micronutrients as fatigue, impaired immunity, irritability, pains, etc. maybe non-specific and, consequently, difficult to diagnose. Hence, comprehensive policy-making, adoption of strategies, preventive measures and interventions at the population level would be a great challenge.

Deficiencies of micronutrient imperil health of man in various forms: slow growth and development; impaired immunity, vision and wound healing; bleeding; anemia; bone disorders; etc. At least two billion people ─ different age/sex groups ─ suffer from deficiencies of essential vitamins and minerals, termed “hidden hunger”. Based on the Hidden Hunger Index, strongly inversely associated with the Human Development Index, preschool children in at least twenty countries in Asia and Africa suffer from multiple micronutrient deficiencies, as well as stunting (1). It has also been reported that in Mangolia 78% of children are at risk of at least two coexisting micronutrient deficiencies, while 14.5% are stunted and wasting, which is one of the forms of child malnutrition prevalent in many countries, is not a problem (2). Preliminary findings of national micronutrient surveys in IR Iran, too, show that multiple micronutrient deficiencies may be common in some vulnerable groups. In this issue of our journal Samadpour and colleagues also emphasize micronutrient deficiencies among young Iranian children.

Inadequate intakes and deficiencies of vitamins and minerals have been found even in generally well-nourished populations such as, for example, Canada, where the daily B-vitamins and zinc intakes of some women were below the respective estimated average requirements ─ between 25% and 39% (3). In the European countries, too, sections of the population have low intakes of several micronutrients, namely, iodine, magnesium, iron, vitamin D, calcium, selenium, thiamin and riboflavin (4), and in USA, 5.7% of the population are reported to be at risk of at least two vitamin deficiencies (5).

Another important point to consider is that metabolic disturbances related to obesity, a disease and a risk factor for several other diseases, currently quite prevalent and on the increase globally, could be a cause, as well as an undesirable consequence, of deficiency of several vitamins, including vitamins C, B12, folate, and the fat-soluble vitamins. It has been reported that the risk of deficiency of these vitamins may increase in obese individuals (6). Athletes, too, may be at risk of oxidative stress if they do not receive sufficient amounts of micronutrients ─ some of the B-vitamins and minerals ─ involved in energy production.

Strategies to combat micronutrient deficiencies include dietary diversification, dietary supplementation, mass food fortification and home food fortification. As regards vitamin and mineral supplements, now very popular in many countries, it is to be noted that even individuals who are on adequate diets will be at a lower risk of deficiency when they take multivitamin-multimineral supplements. Also, the risk of pregnant women giving birth to low-birth weight and small-for-gestational-age babies will decrease when they receive iron and folic acid supplements during pregnancy. In India, where deficiencies of some micronutrients are prevalent, salt fortified with iron and vitamin A, was found to improve the status of these two micronutrients among children in Tamilnadu (7).

In conclusion, considering that multiple micronutrient deficiencies are widespread globally,   national health and nutrition policy-makers and planners should attempt to adopt policies, design and implement strategies and programs, aiming at combating multiple micronutrient deficiencies rather than concentrating on one single micronutrient, for example, iron or vitamin D alone. That is to say, the emphasis should be on reducing the overall burden of micronutrients deficiencies.