Trace minerals are inorganic nutrients that are used for many biological functions, such as digestion, growth and hormone regulation. Humans need less than 100mg of trace minerals daily; current research has not yet clearly defined how much are needed because they are difficult to measure.
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Iron: Oxygen Transport
Iron, the most common trace mineral in the body, is needed to carry oxygen in the red blood cells' hemoglobin to all body parts. There are two kinds of iron: heme and nonheme. Heme iron is from animal tissues and is readily absorbed when eaten, whereas nonheme iron is from plants and is difficult to absorb.
Good sources of heme iron include shellfish, red meats, tofu and fish.
Zinc: Enzyme Activities
Zinc is required for about 10 enzyme functions, including nucleic acid synthesis, immune function, would healing, insulin storage and release and sex organ development. Lack of zinc in your diet can cause stunted growth, skin rash, diarrhea and poor wound healing. Excellent sources of zinc include seafood, beef, eggs, whole grains, nuts and beans.
Selenium works with vitamin E as an antioxidant by protecting cells from free radical damage, such as from peroxides. Selenium participates in an enzyme function (glutathione peroxidase) that prevents free radical production by decreasing peroxide concentrations in the cell, while vitamin E can stop the cell-damaging action of free radicals.
Although selenium in small amounts is healthy, too much of this mineral causes liver disease, hair loss and weakness. Too little selenium causes muscle weakness and pain and heart disease.
Good sources of selenium include fish, organ meats, shrimp, whole grains and egg noodles.
Iodide: Thyroid Function
The thyroid gland controls how quickly the body uses energy and makes proteins, and how sensitive the body should be to other hormones. Dietary iodide is required to make thyroid hormones, such as thyroxine (T4), to promote normal thyroid functions. Too little iodide causes goiter, a condition where the thyroid gland is enlarged from too much release of the thyroid-stimulating hormone (TSH) from the pituitary gland. This causes a fall in metabolic rate and increase blood cholesterol.
Sources of iodide include table salt, saltwater fish, crops grown near the ocean, cottage cheese and shrimp.
Chromium: Glucose Uptake
Chromium enhances glucose absorption into the cells and stimulates fatty acid and cholesterol synthesis. Good sources of chromium include mushrooms, organ meats, egg yolks, broccoli, nuts, apples, bananas and spinach.
- "Perspectives in Nutrition"; Gordon Wardlaw and Margaret Kessel; 2002
- Metals in Nutrition