A recent study, which was conducted by scientists from the Iowa State University (Brown. 2011), scientists investigated the effect of a "balanced nutritionally complete diet" (31% energy from lipid, 13% from protein, and 54% from carbohydrate) with either high (1.17 g/d) or low (0.35 g/d) CLA content on various health parameters of 18 healthy women aged between 20 to 39 years over a 8 weeks period. These are the results:
The CLA diet did not result in any differences in insulin sensitivity, body composition, circulating blood lipids, or other measured disease risk factors as compared with the control diet.Accordingly, the scientists concluded "that a diet naturally enriched with over a 3-fold increase in CLA from pasture-fed cattle "did not provide a health benefit when compared to "a similar diet composed of foods from grain-fed cattle."
While these results stand in line with the generally equivocal findings on possible health benefits from CLA supplementation in human beings, it remains questionable whether with a "nutritionally less complete [from a government standpoint]" diet, i.e. a diet with less carbohydrate content and a consequently higher meat consumption, the results would not have been totally different.
|Figure 1: Fatty acid composition of grass-fed vs. conventional meats.|