The typical American diet, rich in calories and fat, is often poor in minerals, the inorganic elements our bodies need. According to dietitians, minerals perform an amazing number of functions, helping to build bones, regulate metabolism, fire nerves, and maintain overall health. But a number of studies reveal that many women do not get enough calcium and iron, and most people get too little magnesium and zinc. The same studies likewise confirm that most people also consume too much sodium and not enough potassium (together, these electrolytes help maintain fluid balance and regulate muscle and heart function).
We know that in almost anything, too much can be as harmful as too little. For instance, if you are diagnosed with iron deficiency, your doctor may recommend an iron supplement; however, if you take one when you don’t need one, you may increase your risk of heart disease and cancer. Some minerals, such as selenium, are toxic in large amounts. And too much of certain minerals can affect levels of another. One study showed that just 18 to 25 milligrams (mg) of zinc – a tad over the recommended 9 mg for women and 12 mg for men – may lower blood levels of copper, another essential mineral. Another study of postmenopausal women found that increasing daily calcium intake from 750 mg to 1,400 mg reduced the absorption of zinc. Experts say that the solution is not to skip calcium supplements if you need them but to add a multivitamin/mineral supplement. Choose one with no more than 100 percent of the recommended nutrient intake.
There are seven key minerals that many of us don’t get enough of:
1. Calcium – Builds strong teeth and bones; prevents and treats some cases of high blood pressure. Sources include low-fat milk and dairy, broccoli, fish with soft bones, and tofu. Be aware, though, that large doses can interfere with the absorption of iron and zinc.
2. Chromium – Allows insulin to metabolize sugar; also needed for metabolizing carbohydrates and fats. Sources include brewer’s yeast, wheat germ, whole grains, meat, and cheese. Be aware, though, that little evidence that supplements, such as chromium picolinate, help people lose weight or gain muscle.
3. Iron – Needed for the production of red blood cells; deficiency can cause weakness, fatigue, pallor, and dizziness. Sources include red meat, liver, eggs, peas, beans, nuts, leafy green vegetables, and fortified grains. Be aware, though, that iron overload can cause liver damage. Don’t take a supplement unless one is prescribed by your doctor. Iron supplements can poison children.
4. Magnesium – Maintains strong bones and regulates blood pressure; may help balance insulin and blood-sugar levels. Sources include leafy green vegetables, grains, beans, fish, eggs, bananas, nuts, and apricots. Be aware, though, that supplements can be dangerous to people with kidney disease and may cause severe diarrhea.
5. Potassium – Helps heart and kidneys function; may lower high blood pressure in some people. Sources include fruits, vegetables, beans, fish, meat, and milk. Be aware, though, that supplements may be dangerous to people with kidney disease and those taking certain medications.
6. Selenium – This trace mineral, needed in only tiny amounts, may help prevent cell damage that leads to cancer. Sources include fish, whole grains, Brazil nuts, asparagus, mushrooms, and garlic. Be aware, though, that high doses (above 200 micrograms a day) can be toxic.
7. Zinc – Needed for cell growth, wound healing, and possibly for proper immune-system function. Sources include liver, eggs, milk, poultry, brewer’s yeast, seafood, wheat germ, and beans. Be aware, though, that too much can impair absorption of copper. High levels (50 to 75 mg a day) may reduce "good" cholesterol.
Nutritionists say that the best strategy is to eat a balanced diet centered on fruits, vegetables, beans, and whole grains. Doing this will provide most people with all the minerals the body needs.