What do we really know about the health effects of natural sources of trans fatty acids?

Authors: Baer, David

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2011
Publication Date: 2/1/2012
Citation: Baer, D.J. 2012. What do we really know about the health effects of natural sources of trans fatty acids? American Journal of Clinical Nutrition. 95:267-268.

Interpretive Summary: N/A

Technical Abstract: While the food industry remains actively engaged in the development of alternatives for partially hydrogenated vegetable oils in order to reduce intake of trans fatty acids, intake of these fatty acids from natural sources remains as a small part of our diet. The question remains, are there differences in the health effects between the trans fatty acids derived from partially hydrogenated vegetable oils and those naturally produced by ruminant animals, and if so, do the differences matter? Studies of vaccenic acid or dairy fats enriched in vaccenic acid and other trans fatty acids show no effect on LDL cholesterol concentration or show an increase in LDL cholesterol concentration at higher intakes of vaccenic acid. Effect of these treatments on HDL cholesterol concentration is inconsistent, with some studies showing an increase, some showing a decrease, and some showing no effect. To date, few women have been included in intervention studies (about 11% of those studied are women), and since there is some suggestion that men and women may respond differently there may be a gender bias in the literature. Recently, a new intervention study of women using enriched vaccenic acid butter as a dietary sources of ruminant trans fatty acids has been conducted. In this well-controlled feeding study, there was no effect of vaccenic acid on LDL cholesterol concentration. However, there was a significant 5.2% decrease in HDL cholesterol in women with a BMI = 25 kg/m2 but not a significant effect among women with a BMI < 25 kg/m2. It is still difficult to draw definitive conclusions about the role of rTFA in modulating risk for cardiovascular disease as mediated through changes in LDL and HDL cholesterol.