Monday, September 7, 2009

Go To Health: Flaxseed

Flax has been grown since the beginnings of civilization, initially in Babylon & Egypt. It was used to make linen for clothing, fishnets, and to wrap mummies. In the 8th century, Charlemagne commanded his subjects to eat flaxseed to maintain good health. In the 12th century, Abbess Hildegard von Bingen used flaxseed poultices to treat boils. Throughout history it has been used to treat constipation, as a bulking agent, combined with plenty of water. While it is still used today to make linen and as a healthy human food, flax is also made into industrial linseed oil, linoleum, and animal feed.

*Flaxseed oil: The oil in flax seeds contains alpha-linolenic acid (ALA), an essential omega-3 fatty acid like fish oil. ALA may not have the same benefits as fish oil (see my blog on omega-3 fatty acids), as it is more difficult for the body to efficiently convert ALA to a form of omega-3 fatty acids that it can readily use –the EPA and DHA in fish oil. However, ALA is a good choice for vegetarians. Flaxseed oil should come in a dark and opaque container and be refrigerated; add it to salad or foods after cooking. It cannot withstand high heat.

*Flaxseed Meal: When you buy whole flax seeds, grind a week’s supply and refrigerate the flax meal. You can eat it on salad, cereal or in smoothies. By eating the whole ground flax seed you are getting the oil as well as beneficial compounds known as lignans. Lignans are plant compounds similar to estrogen that also act as antioxidants. Lignans may lower estrogen in humans by inhibiting enzymes that are involved in estrogen production; the exact mechanisms are not known. There is interest in flaxseed because of the potential for plant estrogens to act differently from the body’s natural estrogen. In animal and preliminary human studies, flax seeds have been shown to inhibit tumors.

Breast Cancer: Researchers at the University of Minnesota studied the effect of flaxseed supplementation in a group of 28 postmenopausal nuns - chosen because of their strict dietary practices. The volunteers were given daily dietary supplements of either zero, five or ten grams of ground flaxseed for seven week cycles over the course of a year. A heaping tablespoon of ground flax weighs about 10 grams. Consumption of five or ten grams of flax significantly decreased blood levels of certain types of estrogen that are characteristic of postmenopausal women. Since previous studies have shown that increased levels of these estrogens (estrone sulfate and estradiol) may increase a woman’s risk of developing breast cancer, reducing levels of these hormones is thought to be advantageous. This study does not show that flaxseed prevents cancer, the researchers caution. Further studies are needed to work out how the supplement lowers estrogen and also to see if flaxseed may inhibit cancer. Besides lignans, the fiber and omega-3 fatty acids in flaxseed could also be protective.

Prostate Cancer A recent study at The M.D. Anderson Cancer Center looked at prostate cancer patients at least 21 days before surgery, and found that proliferation (cancer cell division) was significantly lower in men given supplemental flax seed – 3 tablespoons daily. These findings suggest that flaxseed is safe for men and is associated with biological alterations that may protect against prostate cancer. Previous studies had shown that ALA might not be advisable for men with prostate cancer. Further studies would be helpful on this important subject.

Blood Fats: An international review of studies on the effects of flaxseed meal on cholesterol found that flax significantly reduced total and LDL cholesterol, with the greatest effects seen in people with high cholesterol readings and in post-menopausal women.

Hot Flashes A study at the Mayo Clinic looked at 29 women with bothersome hot flashes who did not want to take estrogen because of the possible increased risk of breast cancer. After six weeks of ground flaxseed therapy, 2 tablespoons daily, their frequency of hot flashes decreased 50 percent, and the overall hot flash intensity decreased an average 57 percent. Participants also reported improvements in mood, joint or muscle pain, chills and sweating; which significantly improved their quality of life. This is an example of the ability of plant estrogens to act as an estrogen as well as an anti-estrogen.

Sadja Greenwood MD, MPH –back issues on this blog

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