Flaxseed does not reduce hot flashes among postmenopausal women. These results were presented at the 2011 annual meeting of the American Society of Clinical Oncology.
Menopause—when menstrual cycles end and ovarian hormone production drops dramatically—produces symptoms such as hot flashes and night sweats in up to 80% of women. When these symptoms are severe, they can have a profound effect on a woman’s quality of life and ability to function. Hot flashes are also common in women who have been treated for breast cancer.
Although estrogen (with or without progestin) can relieve menopausal symptoms, treatment with estrogen may not be an option for breast cancer survivors. Studies over the last several years have also raised concerns about the health effects of estrogen treatment in women without breast cancer, prompting interest in nonhormonal approaches to managing menopausal symptoms. Flaxseed—a source of dietary lignans—showed promising efficacy in preliminary studies.
To further evaluate flaxseed in the management of hot flashes, researchers conducted a Phase III clinical trial among 188 postmenopausal women who were experiencing at least 28 hot flashes a week. Roughly half of the women had a history of breast cancer. Study participants received either a daily flaxseed bar or a placebo (a bar made of protein and fiber without flaxseed or lignans). This treatment continued for six weeks.
The flaxseed bars did not affect hot flash frequency or severity. In both study groups (flaxseed and placebo), roughly one-third of women had a 50% reduction in hot flash scores. Both groups also reported increased bloating, diarrhea, and nausea.
These results suggest that flaxseed is not effective against hot flashes in postmenopausal women.
Reference: Pruthi S, Qin R, Terstriep SA et al. The evaluation of flaxseed for hot flashes, results of a randomized, controlled trial, NCCTG study N08C7. Paper presented at: 2011 Annual Meeting of the American Society of Clinical Oncology; June 3-7, 2011; Chicago, IL. Abstract CRA9015.