Is Iron Really the Most Common Nutritional Deficiency in the World?
Iron is said to be the most common nutritional deficiency in the World today. This is not surprising in developing countries as the access to red meat is low, and the bioavailability of iron from plant sources is not high. Interestingly, iron deficiency anaemia and other clinical disorders of poor iron status are common in developed nations despite access to cheap food. The most well known physiological role for iron is in the process of hematopoiesis, the formation of new red blood cells, although iron is also used as a cofactor in certain enzymes, most notably tyrosine and tryptophan hydroxylase. Folic acid (folate is the reduced form of folic acid) is an important component of tetrahydrofolate, which is important in 1-carbon metabolism. Folic acid is also required for hematopoiesis, although the prevalence of folic acid deficiency in the diet is not as well reported as for iron. However, studies have investigated the iron and folic acid levels in humans, and shown that certain groups are at risk of developing deficiencies.
For example, in one study1, researchers assessed the folic acid and iron status of a number of adolescent and mature pregnant women. This research was interesting because the women in the study were from a poor socioeconomic background and research suggests that such individuals are at higher risk of nutritional deficiencies. Of the subjects, 40 % had low haematocrit levels, which remained relatively constant throughout the three trimesters of pregnancy. In addition, 48 % of the subjects had low serum folacin (folate) of between 3 and 6 ng/mL and 15 % had deficient folacin below 3 ng/mL. Of all the subjects 29 % were at high risk and 11 % at medium risk of poor pregnancy outcomes based on the very low (<140 ng/mL) and low (140 to 160 ng/mL) red blood cell folacin concentrations. In terms of serum iron, 4 % had low serum iron and 12 % had low transferrin saturation. However, generally the serum iron was lower in the older women compared to the adolescent women.
These results are interesting because they show that in pregnant women from low socioeconomic backgrounds, folic acid deficiency is more common that iron deficiency This raises the question as to whether iron is really the most common nutritional deficiency in the World? It is the opinion of this author that iron is certainly the most reported nutritional deficiency in the World, but this may relate more to the prioritisation of its measurement over other nutrients. In other words, iron is the most reported nutritional deficiency in the World because other nutrients are simply not measured to the same extent. This in turn likely relates to a broader understanding of the functions of iron in human nutrition compared with other trace minerals such as chromium, selenium or zinc. That the prevalence of iron deficiency is surpassed by folic acid deficiency in this group of women lends weight to the argument that general nutrient deficiencies are prevalent throughout the World and are a major cause of supposed idiosyncratic disease.
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