Osteoporosis FAQ: How Nutrition and Diet Affect Your Bone Health

Sources of Calcium

Certainly dairy, but make sure to go with low-fat or fat-free versions of yogurt, cheese, and milk. Nondairy sources include soybeans and tofu, bok choy (Chinese cabbage), broccoli, and green, leafy vegetables such as collards, kale, mustard greens, and turnip greens. Salmon and sardines canned with their soft bones are good sources, as well as shellfish, almonds, Brazil nuts, and dried beans.

• Milk, nonfat, 1 cup, 302mg calcium
• Yogurt, plain, low-fat, 1 cup, 300mg calcium
• Baked beans, 1 cup, 142mg calcium
• Cottage cheese, 1 percent milk fat, 1 cup, 138mg calcium
• Broccoli, raw, 1 cup, 90mg calcium
• Tofu, (processed with a calcium salt solution), 1/2 cup, 138mg calcium

Not significantly so. There is slightly more calcium in skim milk because the fat has been removed, leaving more room for other components of the milk and, therefore, more calcium.

They do not "deplete" calcium absorption; however, they contain oxalate or oxalic acid, both of which combine with calcium to form calcium oxalate and thus prevent its absorption, says Kaur. In fact, "Calcium in spinach is absorbed at a very low efficiency (about 5 percent) compared to 30-60 percent absorption of calcium from other sources," adds Teegarden.

One of the biggest problems is that soft drinks replace intake of milk, which is a good source of calcium. Additionally, carbonated drinks have a high phosphate content, "which binds calcium in the bowel and reduces the absorption," says Freeman. Phosphate also forms acid in the bloodstream. "Calcium is then released from the bone to maintain the calcium-phosphate balance and to counteract the acid in the bloodstream," says Kaur.

Charles Stuart Platkin is a nutrition and public health advocate, founder of DietDetective.com, the health and fitness network and author of The Diet Detective's Calorie Bargain Bible (Simon & Schuster, 2007). Copyright 2007 by Charles Stuart Platkin. All rights reserved.

Reprinted with permission from www.dietdetective.com, May 2008.