The researchers looked at trans fatty acids, which are found in hard margarine and deep fried and processed snacks and food, including fast food and commercially baked products. They are similar in structure to saturated fats, and are known to raise levels of "bad" cholesterol and decrease "good" cholesterol levels.
In the United States, people get about 2% of their calories from trans fatty acids. The researchers followed 667 healthy men over age 64 from 1985 to 1995, keeping track of their diet patterns. In 1985, the men got 4.3% of their calories from trans fatty acids, about double the intake seen in the US and other countries. By 1995, this number dropped to 1.9%.
About 98 of the men were diagnosed with heart disease during the 10-year period.
The men who consumed the most trans fatty acid at the beginning of the study had twice the risk of developing heart disease as their counterparts who consumed the least.
In the United States, although the trans fatty acid content of margarine has dropped, people are consuming just as much as ever, the report indicates, because they are getting more trans fatty acids from commercially baked products and fast foods.
The Lancet March 10, 2001;357:732, 746-751
Trans fatty acids from hydrogenated vegetable or fish oils, when consumed in large amounts, increase serum LDL-cholesterol and decrease HDL-cholesterol concentrations. One would expect and increased risk of coronary heart disease from this, so the results are not surprising.
Some researchers use the fact that some animal products also have trans as a justification for discouraging eating animal fat. The editorial cites two studies from showing that beef trans fatty acid (trans-vaccenic acid) intake did not show any significant associations with the risk of heart disease.
I am fond of telling patients that one French fry (full of trans fat) does more to harm your health then on cigarette. This study tends to confirm that impression.
Related Articles:
Health Risks from Processed Foods and The Dangers of Trans Fats