Flaxseed and Hot Flashes

[Guest guest]

In what the lead investigator called a " surprising " result because it

contradicts preliminary research, the dietary supplement flaxseed did not

significantly reduce hot flashes in postmenopausal women with or without

breast cancer in a phase 3 trial.

The study was presented here at the American Society of Clinical Oncology

2011 Annual Meeting.

Hot flashes are a " common " symptom that women experience during menopause

and during antiestrogen treatments for breast cancer, said lead study

Sandhya Pruthi, PhD, from the Mayo Clinic in Rochester, Minnesota, at a

meeting press conference.

It has been theorized that flaxseed is a possible treatment for hot flashes

because it is a source of dietary lignans, which are phytoestrogens, said

Dr. Pruthi. However, the trial got its start on a less intellectual basis —

in Dr. Pruthi's office at the Mayo Clinic, when a patient told her about

using flaxseed for hot flashes.

In the trial, 188 women were randomized to eat a daily flaxseed bar

containing 410 mg of lignans or a placebo fiber bar; the participants all

reported at least 28 hot flashes per week at enrolment.

After 6 weeks, mean hot flash scores were reduced by 4.9 units in the

flaxseed group and by 3.5 units in the placebo group; the difference was not

statistically significant (*P* = .29).

In both groups, a little over a third of the women experienced a 50%

reduction in their hot flash scores.

" The results were surprising. Pilot study

data<http://www.webmd.com/menopause/news/20070830/flaxseed-may-ease-hot-flashes>\

suggested

that flaxseed use was associated with reduction in hot flashes, "

Dr. Pruthi said in a press statement, referring to a previous 30-patient

study with a different method of flaxseed ingestion.

Dr. Pruthi's reaction was not shared by a nutrition scientist who is a

flaxseed researcher.

" I'm not surprised at the result, " said Lilian , PhD, from the

University of Toronto in Ontario, Canada, who was not involved in the study

and was asked to provide comment.

Several other studies have shown the same thing — namely, compared with

placebo, flaxseed does not significantly reduce hot flashes, she said.

What about the earlier results from the 30-patient study by Dr. Pruthi and

colleagues? " Their pilot study had no placebo control, " Dr.

told *Medscape

Medical News*.

In the pilot study, conducted in 2007, the number of daily hot flashed were

halved in the women taking flaxseed. In addition, the intensity of the hot

flashes dropped by 57%. In that study, the women ate 2 tablespoons of ground

flaxseed twice daily, mixed into their cereal, juice, fruit, or yogurt.

The results of the phase 3 trial are " disappointing, " said Mark Kris, MD,

from Memorial Sloan-Kettering Cancer Center in New York City, who moderated

the press conference. One of the " difficulties " of being a medical

researcher is " dealing with the rollercoaster " of study results, he said.

*Some Participants on Aromatase Inhibitors and Tamoxifen*

There is a need for an alternative to estrogen-plus-progesterone therapy for

hot flashes, Dr. Pruthi explained, because of concerns arising from the

Women's Health Initiative about associated health risks with that treatment.

Of the 178 evaluable women in the study, 91 had a history of breast cancer

and 87 did not. The women with breast cancer were allowed to participate

even if they were taking antiestrogen drugs, such as tamoxifen, raloxifene,

or aromatase inhibitors. But the study protocol required that the women had

to have been on a consistent dose for more than 4 weeks and had to remain on

the medication during the study period. Fifty percent of the participants

were receiving aromatase inhibitors, and 25% were receiving tamoxifen, said

Dr. Pruthi.

Finding a treatment for hot flashes induced by aromatase inhibitors might be

a tall order.

The severity and array of menopause symptoms, including hot flashes, caused

by aromatase inhibitors led one expert at a 2010 cancer prevention meeting

to say that " it appears to be a much worse profile " than originally thought.

" This is like menopause plus <http://www.medscape.com/viewarticle/732366>, "

said Judy Garber, MD, MPH, from the Dana-Farber Cancer Institute in Boston,

Massachusetts, at the cancer prevention meeting.

*Gastrointestinal Adverse Effects*

In the study, the participants completed a daily diary of their hot flashes,

and the researchers measured the differences in hot flashes — in number and

severity — between the start and completion of the study.

Both groups reported increased bloating, diarrhea, and nausea. The

gastrointestinal adverse effects seen in both groups were likely due to the

fiber content in the flaxseed and placebo bars, say the study authors in

their abstract.

Dr. agreed, and said that the symptoms were to be expected because

the treatment bars were packed with a lot of flaxseed and both bars had a

lot of fiber.

Flaxseed is thought to have a variety of potential health

benefits<http://www.webmd.com/diet/features/benefits-of-flaxseed>,

but disappointed the researchers.

" Flaxseed may be a highly touted supplement for many ills, but according to

our randomized study results, it is not effective for hot flashes, "

summarized Dr. Pruthi in the press statement.

*Study was funded by the National Cancer Institute. Dr. Kris reports being a

consultant to Boehringer Ingelheim GmbH, Celgene, Daiichi-Sankyo,

GlaxoKline, Merck, the National Cancer Institute, Novartis, Chugai

Pharmaceutical, EMD Serono, and Syndax Pharmaceuticals.*

American Society of Clinical Oncology (ASCO) 2011 Annual Meeting:

Abstract CRA9015 <http://abstract.asco.org/AbstView_102_77648.html>. To be

presented June 6, 2011.

--

Ortiz, MS, RD

*The FRUGAL Dietitian* <http://www.thefrugaldietitian.com>

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