October 2011

Cells on fire: trans fats and the human body

Journal_News_JLRcoverIn 2003, Denmark became the first country to ban all trans fats from food products produced within its borders, and a new study in the Journal of Lipid Research indicates that the move might have been a smart one.

Trans fat, the more common name for unsaturated fat with trans-isomer fatty acids, has been targeted by medical professionals and health departments around the world as the culprit of the growing obesity epidemic.

At the University of Copenhagen, Nathalie Bendsen and her colleagues carried out a 16-week, double-blind clinical trial to determine the effects of industrially produced trans fatty acids, or IP-TFA, on established biomarkers of inflammation, oxidative stress and endothelial dysfunction. (Partially hydrogenated vegetable oil is the primary source of IP-TFA.)

Inflammation occurs when chemicals are produced by the immune system; these chemicals cause damage to the body on a cellular level. Development of cardiovascular disease and type 2 diabetes may be accelerated by oxidative stress, an imbalance of the production of reactive oxygen and the impaired ability of the human body to clear toxic products containing reactive oxygen and to repair cellular damage caused by them. Endothelial dysfunction is the underlying cause of all vascular diseases; these diseases occur when blood vessels don’t work as well as they should.

Consuming IP-TFA already has been positively linked to markers of low-grade inflammation and endothelial dysfunction. In their paper “Effect of industrially produced trans fat on markers of endothelial dysfunction and systemic inflammation: evidence from a randomized trial in overweight women,” Bendsen et al. present the results of their clinical study in which every day they gave healthy, overweight, postmenopausal women IP-TFA partially hydrogenated soybean oil or control oil that contained no IP-TPA incorporated into two bread rolls. Participants underwent fasting blood tests at every clinical visit, 24-hour urine collection and abdominal fat biopsies. The samples were then analyzed.




Levels of tumor necrosis factor alpha (TNFα), an inflammatory marker, increased in the IP-TFA group, whereas the levels decreased in the group that received no IP-TPA. However, there were no significant differences between the two groups when other markers in the blood, such as serum C-reactive protein (CRP), adiponectin and interleukin 6 (IL-6), and serum sE-selectin, a biomarker for endothelial dysfunction, were examined. Analysis of the urine samples indicated that the difference between the two groups in the amount of 8-iso-prostaglandin-F (PGF), a marker for oxidative stress, also was not significant. When examining the biopsy samples, the researchers noticed that in the IP-TPA participants, there was a two-fold increase in the content of specific trans fat isomers present in adipose tissue (where fat is stored in the body) that was not observed in control participants’ samples.

The study’s results support previous research that the link between dietary IP-TFA and cardiovascular disease most likely involves activation of the TNFα system in the body. Partially hydrogenated vegetable oil, the primary source of IP-TFA, might seem harmless on the surface, but it looks like the powers that be in Denmark who decided to ban trans fats are definitely on to something.

Mary L. Chang (mchang@asbmb.org) is managing editor of the Journal of Lipid Research and coordinating journal manager of Molecular and Cellular Proteomics.

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