11/12/2022 0 Comments Best trace minerals on market![]() The availability of iron in the food supply has increased since 1909, chiefly because of the enrichment of flour and cereal products. BEST TRACE MINERALS ON MARKET HOW TOThe publication Recommended Dietary Allowances (NRC, 1980) provides directions on how to calculate available iron. Food composition data provide no indicators concerning the efficiency with which the body absorbs iron from a given food. Ascorbic acid facilitates the absorption of nonheme iron, but dietary fiber, phytates, and certain trace elements may diminish it. Heme iron is present in meats, poultry, and fish and is more efficiently absorbed than inorganic (nonheme) iron, which is found in plant as well as animal foods. Iron absorption is affected by many factors. Since the need for iron is greater during periods of rapid growth, children from infancy through adolescence, as well as pregnant women, may fail to consume sufficient iron to meet their needs. diet provides only 6 to 7 mg of iron per 1,000 kcal. Women have difficulty achieving this high intake, because they generally have a relatively low caloric intake, and the usual U.S. Therefore, the Recommended Dietary Allowance (RDA) for women 11 to 50 years of age is 18 mg/day, but for men 19 years and older is only 10 mg/day. Because of iron losses during menstruation, women in their reproductive years require higher iron intakes than men. As a component of hemoglobin and myoglobin, it functions as a carrier of oxygen in the blood and muscles. The committee identifies such gaps in knowledge and suggests directions for research. Data from animal feeding experiments are also incomplete. Furthermore, most of the evidence is not related to dietary exposure but focuses, for example, on inhalation exposure in the workplace. Most such studies have focused on cadmium, chromium, and selenium. Interactions between the various trace elements are also briefly considered.Įpidemiologic data on the relationship between many of the trace elements and the incidence of diseases such as cancer, cardiovascular disease, and hypertension are incomplete. Also discussed are aluminum, cadmium, mercury, arsenic, and lead these elements have not been demonstrated to be essential for humans but were reviewed by the committee because they are frequently ingested as contaminants in food or water. This chapter is a summary of the role of the following essential trace elements in the etiology and prevention of chronic diseases: iron, zinc, fluoride, selenium, copper, chromium, iodine, manganese, and molybdenum. The difference between toxic intakes and optimal intakes to meet physiological needs for essential trace elements is great for some elements but is much smaller for others. Iron, as a constituent of hemoglobin and myoglobin, also plays a vital role in the transport of oxygen.Īll trace elements are toxic if consumed at sufficiently high levels for long enough periods. Trace elements function primarily as catalysts in enzyme systems some metallic ions, such as iron and copper, participate in oxidation-reduction reactions in energy metabolism. Some of them are known to be nutritionally essential, others may be essential (although the evidence is only suggestive or incomplete), and the remainder are considered to be nonessential. Trace elements (or trace metals) are minerals present in living tissues in small amounts. ![]()
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