Iron deficiency reduces the physicalcapacity to do work, which seems to be less related to the degree of anemia than to theimpaired oxidative metabolism in the muscles dueto the lack of iron-containing rate-limiting enzymesfor oxidative metabolism. This reduced ability to dowork can be reversed with iron administration.Studies of adolescent girls show that iron deficiency without anemia is associated with reducedphysical endurance and changes in mood and ability to concentrate. A study showed a re-duction inmaximum oxygen consumption in iron deficientnonanemic woman unrelated to the decreased oxygen transport capacity of the blood (9). Since the highest prevalence is found ininfants, children, adolescents, and women ofchildbearing age, the burden falls not just on theindividual but on society as a whole. The debilitating consequences include loss of human capitaland reduced work capacity and therefore of productivity in adults. In economic terms, the WorldBank and the US Agency for International Development (USAID) estimated iron deficiency costthe country of India about 5 %of its GNPannually (10) in the mid-1990s. DETERMININGFACTORSWorldwide the most common cause of iron deficiency is nutritional iron deficiency. Does thisimply that the normal diet cannot cover physiological iron requirements? For many years nutritionistshave assumed that all nutrients can be obtainedfrom a diet containing a variety of foods drawnfrom a variety of sources. It has been thought that ifpeople had access to a sufficient quantity and variety of foods, then they would meet their nutritionalneeds. This still may be true, but despite increasesin the availability of a wide variety of foods inalmost every country in the world, the continuedexistence of micronutrient deficiencies, includingiron deficiency anemia, throws this generalassumption into question. Why have improved foodsupplies not necessarily resulted in adequate vitamin and mineral intakes?Factors that determine iron deficiency anemiainclude overall low incomes and poverty thatresult in low overall food intakes and poor monotonous diets low in micronutrient content. Thesemay be compounded by a lack of understandingof the value of a varied diet and the importance offoods rich in micronutrients as well as the role ofdietary inhibitors and enhancers that interferewith the absorption of iron. Illness and infectionssuch as malaria, tuberculosis, and HIV/AIDS arealso contributing factors.Poor dietary intake both in terms of totalquantity of food and of micronutrient rich foodare often the major cause of micronutrient malnutrition. Virtually all traditional dietary patternscan satisfy the nutritional needs of populationgroups so long as the capacity to produce and purchase food is not limited for example by socioeconomic conditions or cultural practices thatrestrict the choice of foods. The erosion of thesepractices due to changing lifestyles and modernization can lead to unhealthy food choices, and
the protection and promotion of those diets that
can provide the nutrients we require need our continued support.
The most affected population groups in need
of improved nutrition generally include vulnerable resource-poor subsistence farmers and landless laborers whose main food supplies come
directly from the land and who often have
restricted access to fortified foods due to low purchasing power and undeveloped distribution
channels. Those who are physiologically vulnerable include those groups with special dietary
problems or nutritional needs, including women
of childbearing age, pregnant and lactating
women, young children and famine-affected populations, who may lack access to a diet that is sufficient in quantity or quality to provide adequate
levels of iron. Special attention is needed to meet
the food and nutrition needs of both these vulnerable groups.
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