The body stores of folate are adequate for only about 4 months although those with higher folate stores could take longer to become frankly deficient. Individuals who are chronically in negative folate balance may only require a brief “nudge”—from superimposition of an associated illness that leads to hemolysis, anorexia, or folate malabsorption—to “tip” them into frank folate deficiency. This is particularly common in resource-limited countries, where decreased seasonal availability of folate-rich foods, poverty, consumption of a poorly balanced, monotonous, cultural/ethnic diet (of wheat, maize, rice, and well-cooked lentils/beans and vegetables), is further com promised by prolonged cooking which destroys folate. Collectively, these factors contribute to the development of folate deficiency.
Folate deficiency varies among countries and even within different regions of a country and is influenced by the economic status and net folate content of the ethnic diet consumed by the population under study. Before folate fortification of food, about 20% of the US population had low-folate status. In African countries, the prevalence of folate deficiency ranged from a low of 20% in Benin, to 30% in Zimbabwe, to nearly 60% in Sudan; these differences are likely due to the variable masking of folate deficiency by associated cobalamin deficiency and/or hemolysis. In Sri Lanka, one-half of schoolchildren had low-folate status, and in India 60% to 80% of women of childbearing age have nutritional folate deficiency.
In Western countries, food faddism, alcoholism, or unbalanced slimming diets usually lead to decreased folate intake in young to middle-aged individuals.16 Edentulous or infirm persons or neglected older adults who are too ill to prepare their meals, and patients with psychiatric problems, are at risk for nutritional folate deficiency.
Folate fortification of foods in the West has led to widespread elimination of folate deficiency and related anemia, leading to questions of whether testing for folate deficiency is even justified. However, vigilance must be exercised particularly among women on low carbohydrate diets (not using folate supplements) and the elderly who are still at risk for both folate and cobalamin deficiency.
