Study Shows Fish Oil Supplements May Cut
Risk of Invasive Ductal Breast Cancer
July 8, 2010 -- Taking fish oil supplements may help reduce breast cancer risk, shows
a preliminary study in Cancer Epidemiology, Biomarkers &
Prevention.
In the study of 35,016
older women with no history of breast cancer, those who reported
currently taking fish oil supplements on a regular basis had a 32%
reduced risk for developing invasive ductal breast cancer, compared with
women who did not take fish oil supplements.
"There is some limited evidence from my study and others that
fish oil may be good for preventing
breast cancer, but there is not sufficient evidence to make a
public health recommendation right now," cautions study researcher Emily
White, PhD, an epidemiologist at the Fred Hutchinson Cancer Research
Center in Seattle. "If you are taking fish oil now for other reasons,
this is reassuring that it may have beneficial effects beside what you
are taking it for," she says. Many people currently take fish oil
supplements to decrease their risk for heart disease.
In the study, 880 women developed breast cancer during six years
of follow-up. The use of fish oil was linked to lower risk of invasive
ductal breast cancer. Ductal breast cancer is the most common type of
breast cancer and forms in the milk ducts. Lobular breast cancer forms
in the milk glands. Researchers did not have information on the doses of
fish oil that were taken by women in the study.
Exactly how fish oil may affect breast cancer risk is not fully
understood, but it may be related to its strong anti-inflammatory
properties. Some research suggests that inflammation plays a role in the
development of breast and other cancers. Other studies have not found a
link between eating more fatty fish and breast cancer risk, but it may
be that the amount of omega-3 fatty acids in fish oil supplements is
much higher than what is typically found in the diet.
Other supplements were not linked to breast cancer risk in the
new study, including black
cohosh, dong quai, soy, and St. John's wort, which are often taken
to relieve some of the symptoms
of menopause.
The new research is part of the Vitamins and Lifestyle (VITAL)
study, which included data from women 50 to 76 years old from Washington
state.
Second Opinion
"This study is one of the largest studies that have come out
showing that there may be role for fish oil in the prevention of cancer,
specifically breast cancer," says Lorenzo Cohen, MD, director of the
Integrative Medicine Program and chief of the section of integrative
medicine in the department of general oncology at the University of
Texas M.D. Anderson Cancer Center in Houston.
"It is most likely useful for cardiovascular risks, and the jury
is still out on whether it helps in the prevention of breast cancer, but
it's not going to hurt," he says.
Second Opinion continued...
It's buyer beware when it comes to choosing fish oil supplements,
he says.
"Some products may be
contaminated with heavy metals," he says. "If you are not going to get
fish oil from the fish itself, do appropriate homework to make sure you
choose a reputable product," he says.
Peiying Yang, PhD, an assistant professor of integrative medicine
at M.D. Anderson, recently received a grant to study how fish oil
supplements affect lung cancer risk. "Fish oil, in general, is
a very good anti-inflammatory agent, and inflammation plays a role in
cancer development," she says.
The new findings are "interesting and provocative," says Bette
Caan, DrPh, a senior research scientist at the Kaiser Permanente
Northern California Division of Research in Oakland. "I would not
recommend that people start taking fish oil specifically to prevent
breast cancer because the data is just not there yet, but if they are
taking it for other reasons, they should continue."
