PNP NUTRITION BASICS: Lesson 5 - Trans Fats

Trans fats are fats produced by the hydrogenation or partial hydrogenation of liquid vegetable oils, which chemically alters them to become solid. They are commonly found in processed foods, including cookies, baked goods, popcorn, margarine, shortenings, crackers, doughnuts, chips, frozen waffles, and french fries. 

Trans fats are artificially altered versions of essential fat molecules that play a key role in metabolism. Often, a small change in an essential molecule leads to the transformation into a new molecule with an opposite biological effect. Recent studies confirm that trans fats increase the risk of heart attack and have other adverse effects.

Health Risks of Trans Fats

Initially, the evidence linking trans fat intake to heart disease was indirect and not convincing.  Recent studies, however, have shown that as little as 1.3 grams a day can negatively affect health. A unique study used trans fatty acid levels in red blood cells as a marker of the participant’s trans fat intake, as opposed to relying on food questionnaires or food diaries, which often suffer from poor recall.

The Nurses’ Health Study, one of the longest-running major women’s health investigations, looked at the trans fat consumption of 166 participants who developed heart disease between 1989 and 1995, and 327 women who did not. The women were divided into four groups based on their trans fats consumption. Those who consumed an average of 2.0 grams of trans fats per 1,000 calories a day were at the highest risk for heart disease. Even those eating as little as 1.3 grams per 1,000 calories a day were at risk. Considering that a serving of french fries has 5 grams of trans fats, a danish has more than 3 grams, and even microwave popcorn has 1.1 grams, this is concerning.

Other studies have shown an increase in LDL (bad cholesterol) and a decrease in HDL (good cholesterol) with trans fat consumption, unlike with saturated fats. The change in the ratio of LDL to HDL cholesterol, which best predicts heart disease, was about twice as bad on a high trans fat diet than as that of a high saturated fat diet. Evidence has clearly shown that trans fats increase the risk of heart disease, and more recent findings suggest they may also cause type 2 diabetes.