Mineral utilization from foods, factors

Recent review articles (, 104-109) have described general factors that affect mineral utilization from foods. General factors such as the digestibility of the food that supplies the mineral, chemical form of the element, dietary levels of other nutrients, presence of mineral chelators, particle size of the food or supplemented minerals and food processing conditions all play a role in the ultimate mineral bioavailability (104). Many unit food processing operations can be shown to directly or indirectly alter the level or chemical form of minerals or the association of minerals with other food components. 

One of the most active areas of research on foods in the last few years has been the investigation of factors that effect human and animal mineral utilization from plant foods. 

Although 12 oz (360 ml) of beer furnishes only about 9% of the estimated allowance for chromium, few foods other than brewers yeast supply this mineral in such a readily utilized form, since all of the chromium in beer is alcohol extractable. Recent research has shown that the biological activity of chromium is associated with an alcohol soluble factor which appears to promote better utilization of carbohydrates by the body. Hence, certain chromium-deficient people with diabeticlike tendencies might benefit from drinking beer. 

Mineral imbalances and toxicities— There is still considerable controversy regarding the optimal amounts of various essential mineral elements because dietary excesses of certain elements may interfere with the utilization of others. Eur-thermore, almost every one of the nutritionally essential minerals has potential toxicity at high levels. However, these toxicities are not as likely to result from eating unfortified foods, as they are from special circumstances such as (1) the taking of mineral supplements (2) contamination of food and water by environmental factors such as containers, piping, and airborne dusts and/or (3) fortification of foods with minerals. 

Food Additives. Many natural and synthetic substances are added to foods to improve their color, odor, texture, and taste. The U.S. Food and Drug Administration has established strict regulations governing food additives so that there is little likelihood of any direct toxic effects resulting from the proper use of such ingredients. However, some of these substances affect the utilization of certain minerals. Such effects may not Ite important to people who eat a little of everything, but they may be responsible in part for mineral deficiencies or toxicities in people whose diets are narrowly limited by choice, economic circumstances, or other factors. Therefore, some effects of various food additives on mineral metabolism follow ... 

---