If you’re taking 4,000 mg of calcium per day, you’re taking much too much, and I urge you to reduce the amount immediately. We all need calcium to regulate nerve and muscle functions and build strong bones. You can get adequate amounts from your diet if you eat a lot of cooked greens (collards have most), molasses, sesame seeds, broccoli, and tofu (be sure to read package labels to make sure calcium was used in its preparation), as well as calcium-fortified soy milk, orange juice and, of course, dairy products.
For women who don’t think they are getting enough of these foods, I recommend a supplement of 500 to 700 mg daily in divided doses with meals. Women concerned about osteoporosis should be aware that supplemental calcium alone will not correct the problem, which is related to heredity, lifestyle and diet, and is accelerated by hormonal changes at menopause. Weight-bearing aerobic exercise (walking, jogging or aerobics) and weight lifting should be part of your prevention program. Because high protein diets also cause bones to lose calcium, keep your daily protein intake low (limit it to no more than 10 to 15 percent of total calories). Avoid soda, excessive caffeine intake, and smoking, all of which promote calcium loss in the urine.
An adequate daily intake of calcium (1,000-1,200 mg) along with magnesium and potassium works to control blood pressure by helping to regulate the amount of sodium your body retains. Most of us get all the potassium we need from fresh fruits (especially bananas) and vegetables. (Don’t take potassium supplements unless a doctor has prescribed them.) Taking too much calcium (three to four times the usual dose) can lead to such side effects as constipation, dry mouth, a continuing headache, increased thirst, irritability, loss of appetite, depression, a metallic taste in the mouth, and fatigue.
Of the many calcium supplements available, I recommend calcium citrate, because it is more easily assimilated than other forms, especially by older people with less stomach acid. Calcium carbonate is more easily available and less expensive but not as well absorbed. It is OK to use calcium supplements containing vitamin D. In fact, I recommend taking 2,000 IU of vitamin D a day to insure proper absorption and use of calcium. Along with your calcium supplements, be sure to take magnesium (half the dose of your calcium supplement); without it you may find that the calcium is constipating.
Andrew Weil, M.D.