Are Dairy Products the Answer to Osteoporosis?

Written by Dr. Fuhrman’s colleague Anna Quisel, M.D. for the July 2003 edition of Healthy Times:
As a woman and a breast-feeding mother, I almost feel guilty when someone asks, “You don’t drink milk? How do you get your calcium?” As people learn more about the problems associated with osteoporosis, interest in calcium is skyrocketing. That’s the good news. The bad news is that the dairy industry has done a terrific job of promoting dairy products as the only adequate dietary source of calcium. Dairy products are far from the solution, and may very well be a cause of the problem.

Adequate amounts of calcium are necessary for high-level health. Calcium is necessary for heart muscle contraction, skeletal muscle contraction, the action of most hormones in the body, and bone strength. Because calcium is so crucial to survival, our bodies carefully regulate the amount of it in our blood. We even have a back-up reservoir of calcium available at all times—our bones.

Calcium reservoir
To keep a constant level of calcium in the blood, our bodies are continually adding and removing calcium to the bloodstream. When there is extra calcium in the bloodstream, the body removes some of it and stores it in the bones. When there is too little, the body takes calcium from the bones and adds it to the bloodstream.

It works like this: When serum calcium levels fall, a hormone called parathyroid hormone, produced in four small glands attached to the thyroid gland, stimulates osteoclasts. The osteoclasts break down bone and release calcium. When calcium is plentiful, a hormone called calcitonin, made in the thyroid, stimulates osteoblasts, cells that store calcium by building bones.

For a long time, scientists thought this was the whole story—if you don’t get enough calcium, your body will withdraw calcium from your bones, and eventually you will develop osteoporosis. But the story is turning out to be more complex.

High intake, weak bones
Much to the chagrin of the dairy industry, scientists have discovered that more calcium isn’t better. In fact, the countries around the world with the highest rates of calcium intake—including the U.S. and Canada—have the highest rates of hip fractures among the elderly. The largest source of calcium in these countries is dairy products. In one of the largest studies of diet and health ever undertaken in the U.S., the Nurse’s Health Study, researchers found that high total calcium intake and milk consumption did not protect against osteoporotic fractures.1 In a comprehensive review of all studies of dairy intake and bone strength in 2000, researchers concluded “that the body of scientific evidence appears inadequate to support a recommendation for daily intake of dairy foods to promote bone health in the general U.S. population.”2

Japanese women have lower total calcium intake than U.S. women at about 400-500 mg per day from soy products, vegetables, and small fish bones—yet they have lower rates of hip fracture despite having smaller bones.3 So high calcium intake alone, especially when the source of calcium is dairy products, does not ensure bone strength. Even bone mineral content (the amount of calcium- phosphate in bones) does not necessarily determine risk of fracture. This mineral-content finding is very important because physicians currently assess risk for bone fractures using x-ray measurement of bone mineral content.

Building strong bones
Adopting an Eat to Live-style diet is crucial for strong bones. Vegetables, beans, fruits, and nuts are the best sources of calcium, potassium, vitamin K, magnesium, and vegetable protein, as well as the phytochemicals (such as isoflavones) and micronutrients that are gaining recognition as important for bones. Keep in mind that the current U.S. daily calcium recommendation of 1200 to 1500 mg for postmenopausal women is an attempt to offset the ill effects of the typical vegetable-and nutrient deficient American diet, which is laden with salt, caffeine, and junk-food. Sadly, even this attempt to flood the body with extra calcium to compensate for poor nutrition has not been proven to prevent fractures.4 (Check out Get Some Veggie Calcium for good sources of calcium.)

Weight bearing and resistance exercise are extremely important to bone strength, and can reverse osteoporosis even in postmenopausal women.5 Walking is particularly important to hip bone strength.

Vitamin D might be more important to bone strength than calcium. Vitamin D promotes the uptake of calcium from the intestines and also increases bone building. The sun is probably our best source of vitamin D. Vitamin D needs are probably met with 15 minutes of exposure in the middle of the day three times per week. Many studies have shown that vitamin D supplements increase bone density in postmenopausal women; however, a recent comprehensive review of the subject determined that the efficacy of vitamin D supplements had not been proven.6 If you haven’t had your vitamin D blood levels checked, you might consider it so that you can increase your sun exposure or add a supplement if necessary.

Avoid toxins. The ingestion of animal protein—especially when combined with low vegetable intake, steroids, caffeine, cigarettes, vitamin A (retinol—found only in animal foods, fortified foods, and vitamin pills), and salt all have been associated with weak bones.
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