Definition of a Trace Mineral

Trace minerals can be found in whole grains.

Trace minerals are required by the body to function properly, but only minute amounts are necessary for health. Excessive amounts of trace minerals can even cause harmful effects, notes the University of Delaware Cooperative Extension (UDCE). Animals also require trace minerals for optimal health. For humans, those who eat a healthy, balanced diet are likely to get all the trace minerals they need without supplementation. In animals, supplementation is sometimes called for to offer herbivores such as cattle and horses optimal health.

Types

Two types of dietary minerals exist: macrominerals and trace minerals. They are differentiated by the amount the body requires in order to properly function. Macro, meaning "big" or "large," identifies nutrients the body requires in large amounts, often hundreds of milligrams daily. The term "trace" means a small amount, and this category of minerals is required in daily doses as little as 0.02 mg.

Examples

Iron and zinc are two well-known trace minerals, and they are also the two your body requires the most of, compared to other trace minerals. The recommended daily intake of iron is 10 to 18 mg for adults, while the recommended intake of zinc is 15 mg daily. This is still a tiny--trace--amount, compared to the recommended intake of other minerals (known as macrominerals) such as calcium, which is 800 to 1,200 mg, according to UDCE. Other trace minerals include fluoride, copper and manganese, with recommended daily intakes between 1.5 and 5 mg. The human body requires less than 1 mg per day of the trace minerals selenium, iodine, chromium and molybdenum.

Sources

Whole grain products are an excellent source of several trace minerals, including magnesium, molybdenum, iron and selenium. Meat products provide chromium, selenium and copper. In addition to manually fluoridated water, fluoride can be found in seafood and leafy green vegetables. Nuts contain manganese and copper, while beef, organ meats and oysters are excellent sources of iron.

Benefits

Both zinc and iron contribute to growth: iron in the form of blood cell formation and zinc in the form of bone growth. Copper helps the body use iron and enables other cell functions, such as the ability to use the energy stored in fat. Animal studies suggest a link between cancer prevention and selenium, notes UDCE, but human studies are inconclusive on the matter.

Iodine is essential to thyroid hormone production, which affects metabolism, growth and reproductive function. Manganese helps the body take advantage of the energy in carbohydrates, as does chromium. Molybdenum assists the body in processing the other trace minerals.

Considerations

While healthy, balanced diets generally contain adequate trace minerals, a study by the U.S. Department of Agriculture (USDA) reports that those who follow vegetarian diets may lack essential trace minerals. Vegetarians are less able to absorb dietary iron and zinc than their meat-eating counterparts. Long-term effects of this are inconclusive as of 2010, but the USDA suggests monitoring vegetarian women of childbearing age and children in particular to ensure optimal amounts of trace minerals in the blood.

Excessive amounts of any trace mineral can lead to negative health effects, although this is rarely caused by dietary intake alone, except in individuals with other health concerns, according to the Merck Manual. Copper toxicity can lead to Wilson's disease. Iodine in excessive amounts can lead to hypo- or hyperthyroidism, and excess iron can cause diabetes mellitus. Overdoses of selenium can lead to hair loss and nausea, while zinc can impair immunity in excessive amounts.

References

• University of Delaware Cooperative Extension: Trace Minerals
• University of Florida: Essential Trace Minerals for Grazing Cattle in Florida
• Pub Med: Bioavailability of Iron, Zinc and Other Trace Minerals from Vegetarian Diets
• Kids Health: Minerals
• Merck Manuals: Mineral Deficiency and Toxicity