How fish oils work

For years, epidemiologists and nutritionists have known that a diet high in the v-3 fatty acids found in fish oil correlates with a decreased risk of colon cancer. On page 915, Murray et al. explain why.

As colon carcinogenesis is accompanied by an increase in the expression of the lipid-dependent protein kinase CβII (PKCβII), the authors reasoned that ω-3 fatty acids might inhibit PKCβII signaling. Analysis of rat colonic epithelia and PKCβII transgenic mice demonstrated that ω-3 fatty acids block PKCβII activation and reduce the pro-carcinogenic effects of PKCβII in vitro and in vivo. PKCβII appears to repress the expression of transforming growth factor β receptor II (TGFβRII), desensitizing cells to the growth-inhibiting effects of TGFβ.

The results suggest that ω-3 fatty acids inhibit PKCβII, thus relieving the inhibition of TGFβRII expression. This...