A new study is showing that flaxseed is NOT associated with a significant reduction in hot flashes for women with menopausal symptoms or breast cancer survivors taking anti-estrogen drugs.
MedPage Today reported that flaxseed “will not ease hot flashes for women with menopausal symptoms or breast cancer survivors taking anti-estrogen drugs,” according to findings presented at the American Society of Clinical Oncology meeting.
Researchers randomized “188 postmenopausal women” to eat a “fiber bar daily that contained either 410 mg of the active flaxseed lignans or 2 g protein as a placebo for six weeks.”
According to results, mean “vasomotor symptom scores dropped 33% with flaxseed-spiked fiber bars, but also fell 29% with placebo fiber bars without a significant difference between groups. … The ‘disappointing’ randomized trial results showed why clinical trials are necessary, noted Mark G. Kris, MD, of Memorial Sloan-Kettering Cancer Center in New York City, who chaired” the ASCO press conference.
Despite this single study, the Natural Medicines Comprehensive Database (NMCD) still rates flaxseed as “possibly effective” for menopausal hot flashes. They say:

Clinical research shows that taking flaxseed orally 40 grams per day significantly reduces symptoms of hot flashes by about 35% and night sweats by about 44% compared to baseline in women with mild menopausal symptoms.
In one clinical trial, flaxseed was comparable to hormone therapy for reducing symptoms. However, in another trial, flaxseed was no better than wheat germ.
Other clinical research, using a lower dose of flaxseed, 25 grams daily, providing 50 mg lignans, shows that this dose of flaxseed does NOT significantly improve hot flashes or measures of quality of life in postmenopausal women.

It should be noted that this study was published as an abstract and presented at a conference. Therefore, these data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
And, until it is published, it will not be considered in the NMCD recommendations.
If you should decide to try flaxseed, remember that it should be taken with an adequate amount of fluid in order to prevent potential bowel obstruction.
Here are some of my past blogs on the topic:

• Natural Medications (Herbs, Vitamins, and Supplements) for Menopausal Symptoms
• Isoflavones reduce postmenopausal insomnia, hot flashes
• Antidepressant eases menopausal hot flashes
• 8 Tips for Eating Healthy During Menopause
• Weight loss may help reduce menopausal hot flashes in overweight or obese women
• St. John’s wort may cool the hot flashes of menopause

More information:

• The U.S. National Women’s Health Information Center has more about treating menopause symptoms here.