NOT all trans fats are bad for health. At least not the natural ones found in ghee, butter and cheese. Scientists have found that naturally occurring trans fats in milk and meat products obtained from ruminant animals like cows and buffaloes do not increase the risk of cardiovascular diseases the way industrial trans fats do.
Trans fat is short for trans fatty acid. Industrial trans fats like those in vanaspati are formed during the addition of hydrogen atoms to products to increase their shelf-life. The fats are associated with serious health problems, ranging from diabetes to heart diseases to cancer. They have been banned in a few European countries, such as Denmark and Switzerland, and in some of the cities in the US.
The levels of natural trans fats vary between three and eight per cent of total fats in the natural products. Though these trans fats are chemically different from the industrial ones they are generally clubbed together.
Scientists from France, Canada and Denmark analysed the effects of natural trans fats on health in three different studies. In the first study, a group of researchers from France and Canada, led by J M Chardigny of French National Institute of Agricultural Research, compared 13 studies conducted to study the effect of ruminant trans fatty acids (R-TFAs) intake on cardiovascular health of men and women. The volunteers in these studies were fed varying amount of R-TFAs which contributed between 0.12 to 4.19 per cent of their total daily energy consumption. The results showed that consumption of R-TFAs did not pose any serious threat to cardiovascular health. “There is no association between natural trans fats intake and cholesterol-dependent cardiovascular risk factor,” says Chardigny.
In another study, M U Jakobsen, professor of public health at Aarhus University in Denmark and his team reviewed research papers which had analysed association between the intake of trans fatty acids from ruminant sources and the risk of coronary heart diseases. They concluded that increased risks of coronary heart diseases are linked only to the intake of industrially produced trans fatty acids.
The third study by researchers from University of Alberta in Canada analysed the effects of natural trans fats on rats. It showed that ruminant trans-11 vaccenic acid, the predominant naturally occurring trans fatty acid, actually improved fat breakdown and inhibited enlargement of heart muscles.
“There is increasing evidence that these (natural trans fats) are good fats and could be health-enhancing. They should not be an unintended target of the bid to rid the diet of trans fats,” says Spencer Proctor, director of the metabolic and cardiovascular diseases laboratory at the University of Alberta.
The findings were presented at the 10th congress of the International Society for the Study of Fatty Acids and Lipids, which concluded on May 30 at Vancouver. Seema Gulati, head of National Diabetes, Obesity and Cholesterol Foundation, a non-profit, says though natural trans fats are different from industrial, one should wait for final conclusions. “The discussion on their health impacts is still on,” she adds.