Dietary fats called omega-3 fatty acids may start protecting a
woman from breast cancer before she is even born. Unfortunately,
most Americans eat far too much omega-6 and too little omega-3
fat, which tends to cancel out the benefits of omega-3s.
Most vegetable oils and products made from common vegetable oils
are big sources of omega-6 fatty acids, while the omega-3 fatty
acids are found in fish oil, green leafy vegetables, flax seeds,
walnuts and cold-water fish such as salmon, mackerel and
A dramatic drop in mammary cancer risk among mice whose mothers
ate diets rich in the omega-3s while pregnant and nursing was
detected in a study presented at the 96th Annual Meeting of the
American Association for Cancer Research this month.
The researchers worked with mice bred to develop breast cancer.
Female mice were fed diets high in either omega-6 fatty acids or
omega-3 fatty acids, both during the gestation period and while
After the daughters were weaned, one group was placed on a high
omega-6 fatty acid diet, while the other was fed predominantly
omega-3 fatty acids.
All female pups exposed only to omega-6 fatty acids had mammary
gland tumors by 6 months of age. But fewer than 60% of the female
offspring nourished with omega-3 fatty acids either before birth
or while nursing formed mammary tumors by the age of 8 months.
Those exposed to omega-3 fatty acids both before and after birth
had a tumor incidence rate of just 13%.
It appears that diets high in omega-6 fatty acids raise maternal
estrogen levels, which in turn are linked to an increased
incidence of breast cancer among female offspring.
“Inadvertently, we may be setting up our daughters to develop
breast cancer 50 years from now,” the lead researcher said.
If you plan to become pregnant, are pregnant, or are nursing,
omega-3 fatty acids are a valuable component of your diet. Visit
our web page to find out more about fish oil.
Source: 96th Annual Meeting of the American Association for
Cancer Research, April 20, 2005