The same green leafy vegetables and legumes that provide iron are also good sources of calcium, for the most part, and absorption is typically better from these sources than from dairy products. One common exception is spinach, which has a great deal of calcium, but it's absorption is poor. But broccoli, brussels sprouts, kale, and other common greens have highly absorbable calcium.
If you like, you can also use calcium-fortified products such as breakfast cereals and juices, although these products provide more concentrated calcium than is necessary. It pays to put some thought into keeping your bones healthy. Studies have shown that the following factors are helpful in building and maintaining strong bones:
• Getting plenty of exercise. Studies have concluded that physical exercise is the key to building strong bones (it's more important than any other factor). For example, a study published in the British Medical Journal that followed 1,400 men and women over a fifteen-year period found that exercise may be the best protection against hip fractures and that "reduced intake of dietary calcium does not seem to be a risk factor." And at Penn State University, researchers found that bone density is significantly affected by how much exercise girls get during their teen years, when 40 to 50 percent of their skeletal mass is formed.
• Getting enough vitamin D. If you don't spend any time in the sun (about fifteen minutes on the face and arms each day is enough), be sure to take a supplement or eat fortified foods.
• Eliminating animal protein. For a variety of reasons, animal protein causes calcium losses.
• Limiting salt intake. Sodium tends to cause the body to lose calcium in the urine.
• Eating plenty of fruits and vegetables. People who eat lots of vegetables and fruits are less likely to have bone breaks. Part of the reason may be that they contain vitamin C, which is essential for building collagen, the underlying bone matrix.
• Not smoking. Studies have shown that women who smoke one pack of cigarettes a day have 5 to 10 percent less bone density at menopause than nonsmokers.
3. Is it healthy for a pregnant or nursing mother to eat a plant-based diet? How about kids?
According to the American Dietetic Association:
Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life-cycle including during pregnancy, lactation, infancy, childhood, and adolescence. Vegetarian diets offer a number of nutritional benefits including lower levels of saturated fat, cholesterol, and animal protein as well as higher levels of carbohydrates, fiber, magnesium, potassium, folate, antioxidants such as vitamins C and E, and phytochemicals. Vegetarians have been reported to have lower body mass indices than nonvegetarians, as well as lower rates of death from ischemic heart disease, lower blood cholesterol levels, lower blood pressure, and lower rates of hypertension, type 2 diabetes, and prostate and colon cancer.
—American Dietetic Association position paper on vegetarian and vegan diets
In the seventh edition of Dr. Benjamin Spock's Baby and Child Care—the last edition published during Dr. Spock's