Again - news on that fish and fish oils are good for you!

Women with certain polymorphisms get twice the breast cancer-preventing punch of eating fish rich in fatty acids. University of Southern California researchers who in 2004 found that certain fish oils appear to reduce breast-cancer risk now have discovered that the oils may especially benefit women with a particular genetic makeup.

The protective effects of fish oils – called marine omega-3 fatty acids – are linked to the cancer-fighting properties of the oils’ byproducts, say investigators from the Keck School of Medicine of USC and the National University of Singapore. Women whose bodies do a poor job of flushing the fish-oil byproducts benefit most from consuming them, the researchers believe. This insight may help scientists better understand exactly how fish oils deter cancer.

“We found that women with certain common DNA patterns experienced more breast cancer protection from marine omega-3 fatty acids than women with other common patterns,” says Keck preventive medicine researcher Manuela Gago-Dominguez, lead author of the study published in the journal Carcinogenesis.

Findings came from the Singapore Chinese Health Study, a prospective investigation of diet and cancer risk in more than 63,000 Chinese men and women in Singapore.

The researchers had already found that among postmenopausal women in this group, those who ate the most omega-3 fatty acids – present in fish like salmon and mackerel – were 34 percent less likely to be diagnosed with breast cancer than women who ate the least omega-3 fatty acids from fish.

“Through this study, we have identified a novel gene-environmental interaction between certain genotypes and omega-3 fatty acids on breast cancer development,” says Keck School researcher Mimi C. Yu, principal investigator of the Singapore Chinese Health Study.

Scientists suspected that lipid peroxidation products – substances produced when the fatty acids break down – were behind the protection. Gago-Dominguez says certain enzymes in the body known as glutathione S-transferases (GST) help the body get rid of these lipid peroxidation products. Each person has certain genes that carry the recipe for making GST.

But these genes can be found in slightly different varieties – called polymorphisms – in the population. The differences between the genes can mean the difference between GST that clears substances efficiently out of the body and GST that works a little slower.

The researchers looked at the genetic makeup of study participants and grouped them according to which polymorphisms they had. They found that postmenopausal women who had low-activity versions of genes associated with GSTs (known as GSTM1, GSTT1 and GSTP1) had a lower risk of breast cancer.

Women with a combination of the lowest-activity forms of GSTM1 and GSTP1 had 64 percent lower risk of the cancer; and women with a combination of the lowest-activity forms of GSTT1 and GSTP1 had a 74 percent lower risk of the cancer. Among both pre- and postmenopausal women with high-activity versions of GST-related genes, fish oils don’t seem to reduce breast cancer risk.

In an earlier study, the researchers had looked at consumption of omega-6 fatty acids – found in such foods as cereals, eggs, poultry, most vegetable oils, whole-grain breads, baked goods and margarine. They concluded that, overall, eating more of these acids had no effect on risk. However, the scientists found that women who consumed little omega-3 fatty acids from fish and a lot of omega-6 fatty acids actually had an increased risk of breast cancer.

So, that means more sushi and less… eh cake(?) for us girls!

Link to original article - USC