Friday, October 23, 2009
Milk and dairy products are so prevalent in our diet, that milk or dairy products are even listed as a separate food group in the USDA Food pyramid guidelines. That is surprising, since about 2/3 of the world population is lactose intolerant. Lactose intolerance is the inability to digest lactose, the main sugar in milk due to a lack of the enzyme lactase that is needed for digestion of milk. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the NIH (USA) estimates that between 30 and 50 million Americans are lactose intolerant. This includes an estimate of lactose intolerance affecting 75% of African-Americans and 90% of Asian and Native Americans.

Babies can digest milk but lose the enzyme needed to properly digest the lactose in milk as they grow older. Is this a subtle hint that nature gives us that we donĂ¢€™t really need milk as adults? Milk is a rich source of calcium and women especially are very concerned of developing osteoporosis without milk products.

We have been taught all the good things about milk. Here are some counter-arguments:

1. The hunter-gatherer diet of our ancestors was completely free of milk. However, studies of the skeletal remains of Paleolithic show great strength and the total absence of advanced osteoporosis 2. A 12-year Harvard study (Feskanich, Willett, Stampfer, Colditz: Milk, dietary calcium and bone fractures in women: a 12 year-prospective study, Am J Publ. Health, 1997) showed that women consuming two or more glasses of milk per day had a higher incidence of fractures than women consuming less than one glass per week. 3. Osteoporosis rates have been rising in the US. Based on 2000 census data, osteoporosis and low bone mass is a major health risk for an estimated 44 million Americans. This is estimated to climb to over 61 million by 2010. Yet, the US is a country with very high dairy consumption. Osteoporosis rates are lower in countries like Japan with much lower dairy and protein consumption. 4. Milk is very rich in protein and bone loss is accelerated by excessive amounts of protein in the diet. 5. In order to use calcium, the body needs a comparable amount of the mineral magnesium. Milk contains only small amounts of magnesium. 6. Fifty years ago, the average cow produced 2000 pounds of milk per year. Today that number is up to 50,000 pounds per year. The impact of all the drugs, antibiotics, BGH, hormones, feeding plans and specialized breeding on our health is claimed to be safe. 7. Milk naturally contains Insulin-like growth factor (IGF-1) that is identical to the human IGF-1. IGF-1 has been known to increase the risk for premenopausal breast cancer, colon cancer and prostate cancer (Smith, George Davey, et al. Cancer and insulin-like growth factor-I. British Medical Journal, Vol. 321, October 7, 2000, pp. 847-48 (editorial))

What about Vegans and low bone mass?

Luigi Fontana, M.D., Ph.D. of the Washington University School of Medicine in St. Louis investigated the bone health of 18 strict raw-food vegans. Their diet did not contain any animal products but consisted of a variety of uncooked vegetables, fruits, sprouted grains, seeds and nuts. The researchers found that the raw food vegetarians had lower bone mass compared to people on a more typical American diet, but other biological markers indicated that their bones, although light in weight, may be healthy. The vegans had higher-than average levels of Vitamin D, low levels of C-reactive protein (an inflammatory molecule that is becoming linked with the risk of heart disease), diabetes and other chronic disease. Additionally, they had lower levels of IGF-1, a growth factor linked to risk of breast and prostate cancer. One possible explanation for the lower bone mass could have been the lower body weight of the raw-food vegetarians but further studies are needed.

Where can I get calcium?

The current recommended dietary allowance (RDA) for calcium is 1000mg per day for adults between 19 and 50 years and 1200 mg over 50. Below are some vegetarian foods and their corresponding calcium content.

Navy Beans (1 cup cooked): 128mg Tofu (1/2 cup): 120 to 250mg Soymilk fortified (1 cup): 252mg Collard Greens (1/2 cup cooked): 178mg Turnip Greens (1/2 cup cooked): 125 Kale (1/2 cup cooked): 90mg Broccoli (1/2 cup cooked): 89mg Bok Choy (1/2 cup cooked): 79mg


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