Trans fat but not saturated fat may cause heart disease, diabetes mellitus
Abbi Lane-Cordova from University of Iowa in Iowa City, Iowa, United States and colleagues published a study in The FASEB Journal to suggest that trans fat but not saturated fat is a risk factor for heart disease and diabetes mellitus.
Trans fat has been associated with 100,000 deaths from cardiovascular disease annually in the United States, according to Harvard epidemiologists and nutritionists.Trans fat is also implicated in the etiology of type 2 diabetes mellitus.
In the current study, researchers tested three beverages with each having 520 kcal energy, 56 grams of fat and 5 grams of carbohydrate, one with 42% trans fat, one with 88% saturated fat, and a third one with 2 grams of fat and 5 grams of carbohydrate as placebo, in 11 healthy (who did not suffer heart disease nor diabetes mellitus) non-obese men and women at an average age of 47 years.
The researchers confirmed their hypothesis that "a beverage high in TFA (but low in carbohydrate, SFA) would cause a larger acute reduction in endothelial function (brachial artery flow-mediated dilation, FMD) and insulin sensitivity compared with SFA (but low in carbohydrate, TFA)."
Specifically, the beverage with high trans fat, but not the one with high saturated fat nor the placebo reduced FMD at 3 to 4 hours of ingesting the beverage. Also, The postprandial blood sugar level was reduced across groups while the homeostasis model of insulin resistance (HOMA-IR) decreased when drinking beverages with high SFA or placebo, but not with high TFA. Impaired endothelial function leads to deadly cardiovascular disease while insulin resistance is a feature of type 2 diabetes mellitus.
The study concluded that trans fat, but not saturated fat harms the endothelial function and reduces postprandial insulin sensitivity in healthy adults. The results could imply that trans fat but not saturated fat is a risk factor for heart disease and diabetes mellitus.
The Food and Drug Administration has now recognized the toxicity of trans fat and not long ago released a statement to indicate that it plans to ban use of trans fat (partially hydrogenated vegetable oils) in processed food in three years. Currently, the agency allows food processors to use trans fat and to claim a food with zero trans fat if the food does not contain more than 0.5 grams of trans fat per serving. Because the serving size is arbitrary, many foods with trans fat can be labeled as zero trans fat.
Food consumers need to understand that trans fat can be formed during food processing. Natural vegetable oils with polyunsaturated fatty acids can be converted partially into trans fat when they are heated. If trans fat is indeed a risk factor for cardiovascular disease and type 2 diabetes mellitus, one should eat a diet full of raw (unheated) foods in order to reduce the risk of these diseases. (David Liu)
