Flaxseed may reduce hot flashes

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September 3, 2007  
Filed under Women's health


Mayo Clinic release – Data from a new Mayo Clinic study suggest that dietary therapy using can decrease hot flashes in postmenopausal women who do not take estrogen.

The findings from the pilot study are published in the summer 2007 issue of the Journal of the Society for Integrative Oncology.

What is hot flash? A hot flash is often described as a flush of intense warmth across much of the body that may be accompanied by sweating, reddening of the skin, or, occasionally, cold shivers. Hot flashes occur in varying frequency and duration, even during sleep, and often cause or accompany sleep deprivation, anxiety and irritability.

“Hot flashes are a bothersome issue for women experiencing ,” says Sandhya Pruthi, M.D., Mayo Clinic breast health specialist and the study’s primary investigator. “We hope to find more effective nonhormonal options to assist women, and flaxseed looks promising.”


Although until recently hormone replacement therapy was the most commonly prescribed treatment for hot flashes, unwanted side effects have led to the search for nonhormonal solutions. Several effective nonhormonal drug therapies have been identified, but they are not always effective, and not all women can use them because of side effects. These limitations have led researchers to explore non-drug agents. They have studied a variety of herbal and dietary supplements in randomized, placebo-controlled trials, including vitamin E, black cohosh and soy, but none has shown to produce any significant reduction in frequency or severity of hot flashes.

What is flaxseed used for?

  • Flaxseed is most commonly used as a laxative.
  • Flaxseed is also used for hot flashes and breast pain.
  • Flaxseed oil is used for different conditions than flaxseed, including arthritis.
  • Both flaxseed and flaxseed oil have been used for high cholesterol levels and in an effort to prevent cancer.

How It Is Used

Whole or crushed flaxseed can be mixed with water or juice and taken by mouth. Flaxseed is also available in powder form. Flaxseed oil is available in liquid and capsule form. Flaxseed contains lignans (phytoestrogens, or plant estrogens), while flaxseed oil preparations lack lignans.

What the Science Says

  • Flaxseed contains soluble fiber, like that found in oat bran, and is an effective laxative..
    Studies of flaxseed preparations to lower cholesterol levels report mixed results.
  • Some studies suggest that alpha-linolenic acid (a substance found in flaxseed and flaxseed oil) may benefit people with heart disease. But not enough reliable data are available to determine whether flaxseed is effective for heart conditions.
  • Study results are mixed on whether flaxseed decreases hot flashes.
  • NCCAM is funding studies on flaxseed. Recent studies have looked at the effects of flaxseed on high cholesterol levels, as well as its possible role in preventing conditions such as heart disease and osteoporosis.

The 29 participants in Mayo’s clinical trial were women with bothersome hot flashes who did not want to take estrogen because of a perceived increased risk of breast cancer. They also had not received (in the preceding four weeks) antineoplastic chemotherapy, androgens, hormonal agents, or other herbal supplements, including soy. Some patients did not complete the trial, but full data for six weeks of flaxseed therapy, consisting of 40 grams of crushed flaxseed ingested daily, was obtained from 21 of them.

Participants were asked questions that the researchers translated into a hot flash score — a combined measure of frequency and severity. The frequency of hot flashes decreased 50% over six weeks, and the overall hot flash score decreased an average 57% for the women who completed the trial. Participants also reported improvements in mood, joint or muscle pain, chills and sweating; which significantly improved their health-related quality of life.

“We are quite pleased with the improvements noted by these women in their quality of life,” says Dr. Pruthi. “Not only does flaxseed seem to alleviate hot flashes, but it appears to have overall health and psychological benefits as well.”

Dr. Pruthi’s team chose to research flaxseed because it is a phytoestrogen (plant-based estrogen source). Flaxseed contains lignans and omega-3 fatty acids. Lignans are antioxidants with weak estrogen-emulating characteristics, and have some anti-cancer effects. Flaxseed also appears to have anti-estrogen properties and has been shown in some recent research trials to decrease breast cancer risk. The researchers hypothesized that patients taking flaxseed might gain some relief for hot flashes.

This pilot trial was designed to determine the effectiveness of flaxseed in alleviating hot flashes and identify possible side effects. Dr. Pruthi cautions that the results are preliminary and taking flaxseed may not give relief to every woman suffering hot flashes.

“While results were promising, we have more research to conduct,” she says. “Oftentimes, pilot studies show promising results that upon further study in a large, randomized placebo-controlled study turn out to be much less remarkable.”

Dr. Pruthi’s research team hopes to open a new, larger clinical trial in 2008 evaluating flaxseed against a placebo to better refine the results, and to hopefully confirm flaxseed as a new treatment option for hot flashes in women.

Other Mayo Clinic researchers included Charles Loprinzi, M.D.; Susan Thompson; Paul Novotny; Debra Barton, Ph.D.; Lisa Kottschade; Angelina Tan; and Jeff Sloan, Ph.D. The flaxseed study was supported in part by the Susan G. Komen Breast Cancer Foundation.


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