Contrary to previous research, a study published last Sunday showed that flaxseed is ineffective in reducing hot flashes among menopausal women.

“The results were surprising. Pilot study data suggested that flaxseed use was associated with reduction in hot flashes,” wrote study lead author Sandhya Pruthi, associate professor of medicine at the Mayo Clinic in Rochester, Minnesota, US.

“Flaxseed may be a highly touted supplement for many ills, but according to our randomised study results, it is not effective for hot flashes,” Prof. Pruthi wrote.

Hot flashes, which are common symptoms during menopause and also occur following hormonal breast cancer treatment, can have a serious effect on quality of life.

Prof. Pruthi presented the work at the 47th annual conference of the American Society of Clinical Oncology held in Chicago.

More than 30,000 researchers and representatives of pharmaceutical companies are taking part in the forum.

Estrogen therapy is sometimes effective at reducing hot flashes, but many women fear the risks of cancer risks linked to hormonal therapy, Prof. Pruthi said.

Earlier evidence suggested that flaxseed could have some anti-estrogen properties, and a previous pilot study by the authors had shown a 57 per cent drop in hot flashes among women taking flaxseed.

The current study involved 188 postmenopausal women who for six weeks were assigned to eat a daily flaxseed bar that contained 410 mg of lignans – a plant-based compound known to have both estrogenic and anti-estrogenic effects or a placebo protein and fibre bar. Ninety-one of the women studied had a history of breast cancer.

While researchers found little difference between the two groups concerning hot flashes, both groups reported increased bloating, diarrhea and nausea.