Science Proves the Dangers of Trans Fats

The emerging lesson in the trans fat saga is an old one. Like other biological processes, the metabolism of fat in the body is profoundly complicated, and we should respect the wisdom of nature. Traditionally, dietary fat was viewed as a positive: a dense source of calories and nutrients, a way to ward off famine. When margarine was first introduced to the public in the 1940's, its use was considered a wartime sacrifice, not a nutritional positive. In the intervening years, dietary fat has become demonized (as, ironically, Americans grow fatter and fatter).

In nature, trans fats are a rare occurrence, produced naturally by the bacteria in the gut of ruminant animals such as cows, sheep and goats. Trans fats make up 2-3% of the milk from these animals, depending on the fatty acid content of their feed. But since World War II, the food processing industry has made trans fats into a common and insidiously increasing element of the modern diet. Exactly how much trans fat the average American consumes is unclear, because the FDA does not require manufacturers to document trans fat quantities on food labels. However, they are a major component of many processed foods, especially baked goods and "diet" products. Margarine and Crisco both contain considerable percentages of trans fats.

To understand what a trans fatty acid is, one has to understand the chemical makeup of a fatty acid. Fatty acids are chains of carbon with a carboxyl group (COOH) at one end that can combine with another molecule. When fatty acids are in solid fats or oils they are combined with glycerol molecules in the proportion of three fatty acids to one glycerol (triglycerides). Fatty acids come in different chain lengths ranging from three to twenty-four carbons long. These fatty acids are either "saturated" with hydrogen atoms and chemically stable or "unsaturated" (missing hydrogen atoms) and chemically unstable. If a fatty acid is missing at least two hydrogens, the adjacent carbons "double bond" to each other. Double bonds in naturally occurring plant oil fatty acids are curved with a "cis" configuration, so they can't pack into a crystal configuration at normal temperatures and remain in a liquid form. Saturated fatty acids have a straight configuration and are therefore solid at room temperature.

Trans fatty acids are also solid at room temperature, giving them the "smooth" mouth feel of saturated fat products such as butter and lard. This allows manufacturers to substitute trans fats in recipes where butter or other solid animal fats would traditionally be used.

Trans fatty acids are created using a hydrogenation process. In this process, vegetable oil is reacted under pressure with hydrogen gas at 250-400 degrees Fahrenheit in the presence of a catalyst such as nickel or platinum. This process can't control where along the chain the hydrogen atoms wind up. Randomly adding hydrogen atoms to oils converts the natural food into many compounds, which are not normally found in nature. Some of these altered compounds are "trans" fatty acids. Trans fatty acids are the same length and weight as the original "cis" fatty acids they were formed from, but are shaped differently in space. Because they have a different shape, they react differently in the body, literally clogging up the cell's machinery by inhibiting the function of membrane related enzymes.

Several adverse health effects are associated with excessive intake of trans fats. Some reports show that trans fats lower the amount of "good" (HDL) cholesterol in the diet and raise the "bad" (atherogenic) LDL cholesterol and total blood cholesterol levels. Trans fatty acids may promote cancer by inducing alterations in the mixed function oxidase cytochromes, which normally metabolize environmental carcinogens, limiting their adverse effect on the body. Trans fatty acids decrease the response of red blood cells to insulin, thus having a potentially undesirable effect on diabetics. Preliminary animal research shows that trans fatty acids may adversely affect immune response by lowering the efficiency of B cell responses and increasing the proliferation of T cells. Trans fatty acids may also interfere with proper function of the reproductive system. They lower the percentage of cream in human breast milk, which is critical to the baby's developing nervous system.

On the other hand, some saturated fats, such as stearic acid (found in beef and chocolate) have been found to be not nearly as unhealthy as originally assumed, having surprisingly beneficial effects on blood cholesterol levels. I do not recommend that people start eating huge amounts of animal fat. However, I would recommend eating small amounts of butter or even bacon fat instead of their trans fat substitutes. Eating whole foods instead of processed ones is the best way to avoid excessive and possibly dangerous intakes of trans fat. McDonalds announced in September that they are reducing the amount of trans fats in their french fries by 48% (total fat content remains the same). Whoopie-dink! I would like to see statistics on the percentage of trans fat in their other products, such as the bun, shake, and special sauce.

One interesting wrinkle in the trans fat debate is the recent emergence of CLA supplements. CLA is made from a mixture of conjugated linoleic acids, similar to the trans fats normally found in small quantities in cow, sheep, and goat milk (commercially they are produced from vegetable oil). Some research indicates that CLA promotes the conversion of food to muscle (instead of fat), aids in the control of diabetes, and slows the buildup of atherosclerotic plaque. However, achieving these effects requires supplementation way beyond the natural levels of CLA found in milk.

I do not recommend taking these supplements. Significantly more research is needed to prove their efficacy and safety. Also, there is not enough assurance that the commercially made product is identical in effect to the natural one. Perhaps, after more research and refinement of the product, CLA may be a useful adjunct in the treatment of diabetics.