Coffee may help some women reduce cancer risk

Some at breast-cancer risk get coffee break
Java improves odds for those with rare genetic mutation, Canadian study says

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By ANDRÉ PICARD
Friday, January 6, 2006
PUBLIC HEALTH REPORTER

Women who drink six or more cups of coffee a day can slash their risk of developing breast cancer by a startling 75 per cent -- but only if they have a genetic mutation that places them at extremely high risk of developing cancer in the first place, according to new Canadian research.

The study shows that women with the BRCA1 mutation, who have about an 80-per-cent risk of developing breast cancer before age 70, saw that risk fall to about 20 per cent if they were heavy coffee drinkers.

"The results are dramatic," said Steven Narod, Canadian Research Chair in Breast Cancer and principal author of the study.

However, in an interview, he cautioned that the findings apply only to a very specific subset of women. About one in 500 women in Canada carry the BRCA1 mutation, and an equal number carry the BRCA2 mutation. (The study results were unclear on whether they, too, benefited from coffee consumption.)

"I wish we saw these effects in every woman, but we don't," Dr. Narod said.

"Still, this provides some important information for women with the mutation," he said.

The new research, published in yesterday's edition of the International Journal of Cancer, involved 1,690 women with BRCA1 and BRCA2 mutations.

Less than 5 per cent of the women in the study habitually drank six or more cups of coffee daily, but their risk reduction was by far the greatest.

Those who drank four to five cups a day saw their risk fall by 25 per cent, while those who drank one to three cups (the large majority) had a relative risk reduction of 10 per cent compared with women who drank no coffee.

Only women who drank caffeinated coffee derived any benefit. Women with the genetic mutation who drank decaf actually saw their risk increase slightly.

Parviz Ghadirian, a professor in the department of nutrition at the University of Montreal and co-author of the paper, said caffeine has a demonstrated effect on hormones, and the hormone estrogen in particular. (Excessive estrogen is known to cause breast cancer.)

He said caffeine helps the body metabolize (or break down) estrogen. Coffee is also an important source of phytoestrogens, which may have protective effect against cancer.

At the same time, caffeine can rob the bones of important minerals and hasten osteoporosis.

"It's a bizarre situation," Dr. Ghadirian said. "You don't want to suggest that people drink this much coffee -- six cups a day is a lot -- but for gene carriers, this is one thing we can tell them that is beneficial."

Some of these women have undergone mastectomies (and had their estrogen-producing ovaries removed) because they are so worried about getting breast cancer.

A less radical prevention option would likely be welcomed by those who carry the high-risk gene.

At the Centre for Research in Women's Health at Sunnybrook and Women's College Health Sciences Centre, where Dr. Narod practices, women with genetic mutations that predispose them to breast cancer are given a long list of dietary and lifestyle practices that can help them reduce risk.

Despite the new data, the researcher said he is unlikely to recommend enormous quantities of coffee.

Rather, Dr. Narod said he will continue to urge women to seek other sources of phytoestrogens (such as green leafy vegetables including broccoli and Brussels sprouts, and soy) and supplements such as DIM (Diindolylmethane, a broccoli extract sold in pill form).

The BRCA1 and BRCA2 mutations are seen principally in women of Ashkenazi (Eastern European) Jewish heritage who have a first-degree relative (parent, sibling, child) with breast or ovarian cancer. Women who are not of Ashkenazi descent, but have a first-degree relative diagnosed with breast cancer before age 50 or a male relative with breast cancer, are also at higher likelihood of carrying the breast-cancer gene.

Dr. Narod said all women of Jewish descent should undergo genetic testing, as should anyone with a strong family history of breast or ovarian cancer.

In 2005, an estimated 21,600 women and 150 men were diagnosed with breast cancer, according to the Canadian Cancer Society. An estimated 5,300 women and 45 men died of breast cancer last year.

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