Trans fatty acids and cardiovascular health: research completed?

This review asks the question if further research on trans fatty acids and cardiovascular health is needed. We therefore review the evidence from human studies on trans fatty acids and cardiovascular health, and provide a quantitative review of effects of trans fatty acid intake on lipoproteins. The results show that the effect of industrially produced trans fatty acids on heart health seen in observational studies is larger than predicted from changes in lipoprotein concentrations. There is debate on the effect of ruminant trans fatty acids and cardiovascular disease. Of special interest is conjugated linoleic acid (CLA), which is produced industrially for sale as supplements. Observational studies do not show higher risks of cardiovascular disease with higher intakes of ruminant trans fatty acids. However, CLA, industrial and ruminant trans fatty acids all raise plasma low-density lipoprotein and the total to high-density lipoprotein ratio. Gram for gram, all trans fatty acids have largely the same effect on blood lipoproteins. In conclusion, the detrimental effects of industrial trans fatty acids on heart health are beyond dispute. The exact size of effect will remain hard to determine. Further research is warranted on the effects of ruminant trans fatty acids and CLA on cardiovascular disease and its risk factors.