Trans fatty acids (TFA), an enfant terrible of the food industry, may promote cardiovascular disease by triggering inflammatory processes in the cells lining blood vessels, American scientists report.
TFAs are attractive for the food industry due to their extended shelf life and flavour stability, and have displaced natural solid fats and liquid oils in many areas of food processing.
But scientific reports that trans fatty acids raise serum levels of LDL-cholesterol, reduce levels of HDL-cholesterol, and influence other risk factors for cardiovascular diseases (CVD), has led to a well-publicised bans in New York City restaurants, and other cities, like Boston and Chicago, considering similar measures.
"There is little known about the mechanisms by which TFA exert harmful effects on the cardiovascular system," wrote lead author Kevin Harvey in the British Journal of Nutrition. "The present in vitro study is the first to demonstrate the effects of membrane-incorporated C18:2 TFA on human aortic endothelial cell (HAEC) function."
The study, conducted by researchers from the Methodist Research Institute at Clarian Health in Indianapolis and Indiana University looks to support calls to remove and reformulate foods to improve their health profiles.
Cardiovascular disease (CVD) causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
Harvey and co-workers performed the in vitro study using cells from the lining of the human aorta. They found a two-fold increased incorporation of trans-18:2 fatty acids in the cells than cis-18:2 fatty acids.
In an attempt to understand what effect the increased incorporation would have on the cells, the researchers studied markers of inflammation and signs of dysfunction in the cells that would affect cardiovascular health in the long-term.
Increases of between 1.5 and three-fold were observed for several molecules, such as intercellular adhesion molecule-1 (ICAM), and monocyte chemoattractant protein-1 (MCP-1).
"In conclusion, these in vitro studies demonstrated that TFA play a role in the induction of pro-inflammatory responses and endothelial cell dysfunction," stated the researchers.
Beyond heart disease
At the start of 2008, researchers from Harvard reported that increased intakes of trans-fatty acids may increase the risk of non-aggressive prostate tumours by about 100 per cent.
The Harvard researchers report in the January issue of Cancer Epidemiology Biomarkers & Prevention (Vol. 17, pp. 95-101) that the highest blood levels of trans oleic acid and linoleic acids (18:1n-9t and 18:2t) were associated with a 116 and 97 per cent increase in the risk of non-aggressive prostate tumours, respectively, compared to the lowest levels.
Furthermore, the fats may also raise the risk of breast cancer by 75 per cent, according to data from the French part of the European Prospective Investigation into Cancer and Nutrition. Writing in the American Journal of Epidemiology, Veronique Chajes from the Centre National de la Recherche Scientifique (CNRS) reported that high blood levels of trans fatty acids, but not cis fatty acids, was associated with a significant increase in breast cancer risk.
Source: British Journal of Nutrition
April 2008, Volume 99, Issue 04, pp 723-731, doi: 10.1017/S0007114507842772
"Trans-fatty acids induce pro-inflammatory responses and endothelial cell dysfunction"
Authors: K.A. Harvey, T. Arnold, T. Rasool, C. Antalis, S.J. Miller, R.A. Siddiqui