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Ask the Doctor
 How do dairy products cause cancer? And if you don't drink milk,
how do you get all the calcium you need?
Recent
scientific studies have suggested that specific components in dairy
products may be linked to an increased risk for ovarian, breast,
and prostate cancers. For ovarian cancer, galactose, a component
of the milk sugar lactose, has been under study as a possible culprit.
A recent analysis of studies examining a relationship between dairy
product consumption (skim, low-fat, and whole milk, yogurt, cheese,
and total lactose) and ovarian cancer risk found that for every
10 grams of lactose consumed—the amount in one glass of milk—ovarian cancer risk increased by 13 percent.
Although dairy
is often touted as a good source of calcium, it may actually provide
an excessively high calcium load, resulting in a lowering of blood levels of
activated vitamin D. In the case of prostate cancer, where vitamin D is thought
to be protective, high intake of dairy could therefore have a harmful effect.
This is supported by findings from the Physicians Health Study, a Harvard University
study that followed the diets of over 20,000 male physicians. In that study,
men who consumed more than 600 mg per day of calcium from dairy products had
a 32 percent higher risk of developing prostate cancer than men who consumed
less than 150 mg.
In addition, dairy product consumption has been shown to increase
levels of insulin-like growth factor I (IGF-I) in the body, a potent
stimulus for cancer cell growth. High IGF-I levels are linked to
increased risk of prostate cancer and breast cancer.
Replace cow’s
milk in your diet with healthier alternatives, such as rice milk,
almond milk, oat milk, and soymilk. There is even nondairy
ice cream, cheese, cream cheese, and yogurt readily available in
grocery stores. As you eliminate dairy products from your diet,
you may notice an improvement in digestion, a reduction in arthritis
pain, and fewer symptoms of seasonal and/or other allergies.
What
about calcium? A moderate amount from a variety of plant sources
is best. There’s plenty of easily absorbed calcium in dark
leafy greens, such as bok choy, kale, mustard greens, collard greens,
and turnip greens, as well as in broccoli, dried beans, figs, almonds,
calcium-fortified juices, and nondairy milks. Plus, these foods
contain other cancer-fighting nutrients that aren’t
present in dairy products.
Gordon Saxe, M.D., Ph.D.
Assistant Professor
University of California, San Diego
Department of Family and Preventive Medicine
Moores UCSD Cancer Center
Have a question for the doctor? Send it to newsletter@CancerProject.org.

The Cancer
Project News, Spring 2006
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