High doses (over 2,500 mg per day) of calcium supplements may increase the risk for kidney stones. (Because many commercial foods are now fortified with calcium, this upper limit may be easier to reach than people think.)
 | Click the icon to see an image of calcium sources. |
Vitamin D. Vitamin D is necessary for the absorption of calcium in the stomach and gastrointestinal tract and is the essential companion to calcium in maintaining strong bones. Some studies suggest that vitamin D protects against osteoporosis only in combination with calcium.
Vitamin D is manufactured in the skin using energy from the ultraviolet rays in sunlight. It can also be obtained from dietary supplements. As a person ages, vitamin D levels decline. They also fall during winters months and when people have inadequate sunlight. Pollution may also contribute to less sunlight and declining vitamin D levels.
 | Click the icon to see an image of vitamin D sources. |
Current adult guidelines recommend:
- 400 IU (10 mcg) for people between ages 50 and 60
- 600 IU (15 mcg) for those over age 70 who do not have sufficient exposure to sunlight
Drinking milk fortified with vitamin D and sunlight exposure supply most people's need for vitamin D. (One cup of whole milk provides about 100 IU of vitamin D.) Oily fish (sardines especially, also salmon, fresh tuna, mackerel) are also important dietary sources of vitamin D.
Alcohol
Effect on the Heart. One drink a day in women who are not at risk for alcohol abuse may be beneficial for the heart. Red wine in particular contains a substance called resveratrol, which is classified as a phytoestrogen and has estrogen-like effects.
Effect on Bones. Alcohol has different effects on bones depending on how much is consumed. A 2004 study found that moderate wine consumption was linked to improved bone mineral density in postmenopausal women. Alcohol, in moderate amounts, may increase estrogen levels. Excessive drinking, however, has been associated with brittle bones.
Effect on Breast Cancer. Women who drink face an increased risk for breast cancer, but the risk associated with mild to moderate drinking is small.
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