Soy consumption, but not dairy consumption, is inversely associated with fatty acid desaturase activity in young adults

Abstract

Past evidence in animals showed that soy protein consumption suppressed delta-6 desaturase (D6D) activity compared to casein, however the effects of soy protein consumption on fatty acid desaturation remains poorly explored in humans. This thesis investigated the association between the consumption of soy and dairy beverages and foods with plasma fatty acid levels and estimated desaturase pathway activity in a multiethnic Canadian population of young adults. Food frequency data and plasma fatty acid data previously collected for the Toronto Nutrigenomics and Health Study were analyzed. Significant inverse associations (p≤0.05) were found between soy consumption and overall desaturation pathway activity. Plasma levels of omega-6 long-chain PUFAs, as well as various estimates of desaturase pathway activity, were significantly lower in individuals consuming soy compared to individuals consuming only fluid milk and dairy products. Collectively, these findings suggest that soy consumption, but not dairy intake, is inversely associated with desaturase pathway activity.