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Dairy Products and Bone Health
By Susan Levin, M.S., R.D.
This letter was published in the January 2007 edition of the Journal of the American Dietetic Association
To the Editor:
In their review, “Is Calcium and Vitamin D Supplementation Overrated?,” Lee and Majka ask a critically important question. However, their answer ignored key scientific evidence (1). Their recommendation to consume three 8-oz glasses of vitamin D–fortified milk per day to meet the minimum requirements for calcium and vitamin D is especially problematic, since most research shows that dairy products are not beneficial to bone health.
The Nurses’ Health Study (2), which followed more than 75,000 women for 18 years, showed no protective
effect of increased milk consumption on fracture risk. Similarly, a 1994 study of elderly men and women in Sydney, Australia, showed that higher dairy product consumption was associated with increased fracture risk. Those with the highest dairy product consumption had approximately double the risk of hip fracture compared with those with the lowest consumption (3).
The high rate of osteoporosis in the United States has more to do with excessive protein consumption, along with a sedentary lifestyle and tobacco and alcohol use, than with any “deficiency” of cow’s milk. Acidic animal protein leads to urinary excretion of calcium and the consequential loss of calcium from the bone. Because of
this major influence of protein on calcium balance, the World Health Organization makes two sets of recommendations: one for people consuming a typical Western diet high in animal protein, and a second for those consuming a diet that is lower in animal protein. For the former, 1,000 mg of calcium is recommended for
females from 19 years of age to menopause; for the latter, 750 mg of calcium is recommended (4).
Healthful, plant-based sources of calcium include kale, broccoli, and other green leafy vegetables that contain
readily absorbable calcium. A recent report found that “greens such as kale can be considered to be at least
as good as milk in terms of their calcium absorbability” (5).
An elevated risk of prostate cancer has been associated with dairy consumption (6,7), and the same may be true for ovarian cancer (8). Lactose intolerance, a commonly overlooked condition, affects an overwhelming majority of many minority populations, as well as about 15% of whites (9).
Just as cow’s milk is fortified with vitamin D, so are dairy alternatives, including soy and rice milks and some juices. Exposure to sunlight will also provide the vitamin D necessary for strong bones.
Milk and dairy products are not necessary in the diet and can, in fact, be harmful. By consuming a healthful
diet of grains, fruits, vegetables, legumes, and fortified foods, including cereals and juices, one can meet calcium
and vitamin D requirements with ease—and without the health risks associated with dairy products.
1. Lee C, Majka DS. Is calcium and vitamin D supplementation overrated? J Am Diet Assoc. 2006;106:1032-1034.
2. Feskanich D, Willett WC, Colditz GA. Calcium, vitamin D, milk consumption, and hip fractures: A prospective
study among postmenopausal women. Am J Clin Nutr. 2003;77:504-511.
3. Cumming RG, Klineberg RJ. Casecontrol study of risk factors for hip fractures in the elderly. Am J Epidemiol.
4. Joint FAO/WHO Expert Consultation on Diet, Nutrition, and the Prevention of Chronic Diseases. WHO
Technical Report Series 916. Geneva, Switzerland: World Health Organization; 2003.
5. Heaney RP, Weaver CM. Calcium absorption from kale. Am J Clin Nutr. 1990;51:656-657.
6. Chan JM, Stampfer MJ, Ma J, Gann PH, Gaziano JM, Giovannucci E. Dairy products, calcium, and prostate cancer risk in the Physicians’ Health Study. Am J Clin Nutr. 2001;74:549-554.
7. Chan JM, Gann PH, Giovannucci EL. Role of diet in prostate cancer development and progression.J Clin Oncol. 2005;23:8152-8160.
8. Cramer DW, Harlow BL, Willet WC. Galactose consumption and metabolism in relation to the risk of ovarian cancer. Lancet. 1989;2:66-71.
9. Bertron P, Barnard ND, Mills M. Racial bias in federal nutrition policy, part I: The public health implications
of variations in lactase persistence. J Natl Med Assoc. 1999;91:151-157.
Susan Levin, M.S., R.D., is a dietitiatn for the Physicians Committee for Responsible Medicine.