Trans Fatty Facts You Need to Know
by Dana Denis, MSPH., RD (topic expert: nutrition)

You thought you were following a heart-healthy diet by switching from butter to margarine and now you find out that may have posed more harm than benefit due to trans fatty acids. The new fat to avoid is trans fat or trans fatty acids.

What Are Trans Fatty Acids?

Trans fatty acids are the product of the hydrogenation of fats and oils. Food manufacturers use this procedure to turn liquid oil into the solid form that we see in stick margarine and vegetable shortening. These hydrogenated or partially-hydrogenated products are also used in the production of crackers, snack foods, baked goods, frozen meals and fast foods.

Trans fatty acids also naturally occur in meat and dairy products; however, this form does not usually pose the significant consequences of the commercially produced trans fatty acids. A study of the U.S. population found that Americans consume an average of 5.3 grams of trans fat per day, or about 2.6% of total calories. In light of recent evidence the recommendation is to try to reduce this amount to "as low as possible while consuming a nutritionally adequate diet."

How Do Trans Fatty Acids Affect Health?

Trans fatty acids increase LDL-cholesterol (bad cholesterol) and reduce HDL-cholesterol (good cholesterol). Saturated fat increases LDL-cholesterol, but also increases HDL-cholesterol. Therefore, trans fatty acids are associated with a greater risk for cardiovascular disease than saturated fat!

Other Fat Facts

When saturated fat in the diet was replaced with monounsaturated fat (found in olive, safflower and canola oils, nuts and olives) a 30% reduction of coronary heart disease (CHD) was observed.

When saturated fat was replaced with polyunsaturated fat (found in corn, soybean, and sunflower oils) there was an even greater reduction in risk of CHD as well as potential benefits on insulin sensitivity in type 2 diabetics.

Omega 3 fatty acids, from fish oils and plant sources, have also been found to reduce risk of CHD by reducing both triglycerides and the formation of blood clots.

Simply reducing the total fat in the diet does not appear to be associated with a reduced risk of heart disease. Replacing calories from fat sources with calories from carbohydrate may actually increase risk. Carbohydrate reduces LDL and HDL cholesterol, as well as increases triglycerides.

Labeling

As of Jan. 1, 2006, the FDA required the amount of trans fatty acids to be listed on the Nutrition Facts Label of foods and supplements. It is on a separate line under saturated fat content. This new labeling requirement enables consumers to make more informed decisions when choosing products. It has already prompted food manufacturers to look for healthier alternatives in food processing that are free of trans and saturated fats.

Recommendations

Replacing trans fatty acids with mono- or polyunsaturated fatty acids is the single most effective change you can make in your diet to improve your blood lipid (fat) profile. Watch for products that contain hydrogenated or partially hydrogenated oils. Include foods high in omega-3 fatty acids. As always, increase intake of fruits, vegetables and whole grains and choose lean protein sources and low-fat dairy products.