Omega-3s Reduce Breast Cancer Risk Factors

WASHINGTON, DC – Daily supplementation with high doses of omega-3 fatty acids markedly reduces breast tissue hyperplasia and key biomarkers for breast cancer in pre- and post-menopausal women, according to a report presented at the recent meeting of the American Association of Cancer Research (AACR).

Dr. Carol Fabian, director of the Breast Cancer Prevention Center, University of Kansas presented two small studies evaluating the effect of omega-3s on cytologic hyperplasia fabian-webwith atypia in breast tissue, one in a group of 36 pre-menopausal women, and another in a group of 35 post-menopausal women. In both studies, all women were considered to be at high risk for developing breast cancer.

After 6 months of daily supplementation with 4 g of omega-3s, both groups showed a significant reduction of atypia. Before the study, the incidence of atypia was 70%. By the end of the study period, this had decreased to 44%.

Taking the two study cohorts combined, 2 of the 71 subjects discontinued before conclusion, and 7 reported gastrointestinal side effects of grade two or higher, Dr. Fabian reported.

“Studies of the use of omega-3 fatty acids in human beings are just now getting underway in terms of preventing cancer,” she said, explaining that recent advances in the use of genomics to identify those at high risk for cancer have contributed a great deal to the research.

“There is a huge interest in this area in the research community, because a part of the public would much rather take a natural product or behavioral intervention than get a prescription for a drug. Of women who do not have breast cancer but are at high risk, probably less than 5% will take a pharmaceutical like tamoxifen to help prevent cancer, even though it reduces the risk by 50% in high-risk women,” said Dr. Fabian.

A Two-fer

“On the other hand, they are probably much more likely to take a natural product, but it may only reduce the risk by 15 to 20%. It’s much better if the entire population actually takes something (that reduces the risk by 20%) rather than only 2% of the population taking something that reduces the risk by 50%. And if omega-3s also reduce heart disease, which is very common in older people, that’s a two-fer,” she explained.

She noted that the dose needed to modulate breast cancer risk would very likely confer a cardiovascular benefit. “Omega-3 fatty acids are thought to be helpful in preventing heart disease, when given in doses of up to 500 mg per day, but we think the doses necessary to prevent cancer would be much higher,” said Fabian, who is also presenting an education session on natural products for chemoprevention at this year’s annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago this June.

She admits that the theme of her ASCO session is a bit misleading. “Chemoprevention is actually a bad term. We’re trying to prevent cancers with natural products, as opposed to drugs like Tamoxifen. So this is really primary prevention of cancer.”

Primary Prevention

In addition to reducing pre-cancerous tissue changes in the breast, omega-3 supplementation may also be able to reduce the risk of colon cancer, as was reported in a 2010 study published in the journal, Gut, and a more recent trial in the British Medical Journal in 2012.

Both studies looked at the effect of omega-3s in reducing a condition called familial adenomatous polyposis, a rare disease in which people get many polyps, which are precursors to colon cancer, Dr. Fabian explained.

Other natural products that seem to reduce cancer risk include vitamin D and lignans. “We think taking moderate to high doses may reduce the risk by at least 20% or more,” said Fabian, who noted that the largest study is currently underway. It looks at lignans alone in preventing breast cancer in high-risk pre-menopausal women. Dr. Fabian’s group at the University of Kansas is accruing about 220 patients for this multi-center study that will probably not be complete until 2015.

She believes there is a bright future in the incorporation of natural products for mitigating cancer risk. “We have to define how these things work, the doses, and we need to know the populations in whom they’re going to work best.”


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