Fats in the Diet

Fats in moderation add taste and enjoyment to foods. Americans eat foods that contain fat to satisfy their hunger and to enjoy food flavor. According to the 2005 U.S.Dietary Guidelines for Americans, some dietary fat is needed for good health. Fats supply energy and essential fatty acids and promote the absorption of fat-soluble vitamins.

But all fats are not created equal. Experts who specialize in cardiovascular health find monounsaturated and polyunsaturated fatty acids useful in lowering blood cholesterol when used in recommended amounts as a part of a low cholesterol and overall healthy diet.

Nutrition experts continue to recommend that consumers use soft margarine spreads instead of butter to improve the nutritional profile of their diets. This is essential in light of what leading health authorities recommend about reducing total fat, saturated fat and cholesterol intake. Because soft margarine spreads (buttery spreads) are very low in saturated fat and contain no dietary cholesterol, they are the tablespread of choice for a majority of Americans. Most of these products are reduced in total fat, too.

The plain truth is that Americans need to lower overall fat intake, maintain a healthy weight, and exercise to promote good health. Diet is only one of the many risk factors for a variety of diseases, including heart disease. Leading health professional groups continue to advise the public to continue to follow a diet that is low in saturated fat and contains less than 30 percent of calories from total fat.

To help clarify some common questions about fat in the diet, here are some questions and answers, many of which are taken from a Q & A prepared by the Food and Drug Administration (FDA) and are marked with an asterisk (*).

Q: What are fats and fatty acids? *

A: Fats are a group of chemical compounds that contain fatty acids. Energy is stored in the body mostly in the form of fat. Fat is also needed in the diet to supply essential fatty acids, substances essential for growth but not produced by the body itself. The terms fat and fatty acids are frequently used interchangeably.

Q: What are the main types of fatty acids? *

A: There are three main types of fatty acids: saturated, monounsaturated and polyunsaturated. All fatty acids are chains of carbon atoms with hydrogen atoms attached to the carbon atoms. A saturated fatty acid has the maximum possible number of hydrogen atoms attached to every carbon atom. It is therefore said to be "saturated" with hydrogen atoms, and all of the carbons are attached to each other with single bonds.

In some fatty acids, a pair of hydrogen atoms in the middle of a chain is missing, creating a gap that leaves two carbon atoms connected by a double bond rather than a single bond. Because the chain has fewer hydrogens, it is said to be "unsaturated." A fatty acid with one double bond is called "monounsaturated" because it has one gap. Fatty acids having more than one gap are called "polyunsaturated."

The fat in foods contains a mixture of saturated, monounsaturated and polyunsaturated fatty acids. In foods of animal origin, a large proportion of fatty acids are saturated. In contrast, in foods of plant origin and some seafoods, a large proportion of the fatty acids are monounsaturated and polyunsaturated.

Q: How do saturated and unsaturated fat relate to heart disease? *

A: Higher intakes of saturated fat raise low density lipoprotein cholesterol (LDL-C or "bad" cholesterol) in the blood. An elevated LDL-C increases the risk of developing coronary heart disease (CHD). Substituting intake of monounsaturated and polyunsaturated fat for saturated fat decreases LDL-C and the risk of CHD.

Q: What are trans fatty acids? *

A: Trans fatty acids, also known as trans fat, are made during partial hydrogenation of vegetable oils. Usually the hydrogen atoms at a double bond are positioned on the same side of the carbon chain. However, partial hydrogenation reconfigures some double bonds and the hydrogens end up on different sides of the chain. This type of configuration is called "trans" (means "across" in Latin).

A: No. Although some margarines contain more trans fat than butter, the total of trans and saturated fat (the LDL-C raising fats) is always less than the total for butter. The total for butter is much higher because of all the saturated fat that it contains. The chart below shows you the comparisons of the content of these types of fats in butter and in some margarines. It is usually better to eat the softer or liquid margarines that contain lower amounts of saturated and trans fats.

Q: What is the bottom line on trans fat and margarine?

A. When it comes to overall nutrition, even the more traditional stick margarines (those that have 60% or more oil) have a better nutritional profile than butter (even when trans fat is added to the amount of saturated fat). This can be illustrated if one were to add up the amount of trans fat and the amount of saturated fat in each of these products. Even if trans fats do act similarly to saturated fat, margarine wins nutritionally each and every time. Also, the reduced-fat, low-fat and fat-free soft margarine spreads, representing the vast majority of today's margarine products market, provide consumers the opportunity to reduce saturated fat and trans fat even further.

Q. How can consumers be assured that it's OK to eat margarine?

A. Consumers should listen to the advice of leading health authorities such as the American Heart Association, the National Cholesterol Education Program, the U.S. Surgeon General and the American Dietetic Association - all of these organizations stress the need to reduce total fat, saturated fat and cholesterol in the diet. For heart health, leading health groups recommend soft margarine spreads over butter because margarine has no cholesterol (making it ideal for a low cholesterol diet) and much less saturated fat, and many margarine products have less total fat, trans fat and calories as well. These organizations also stress that consumers are still eating way too much saturated fat, and that should be the primary focus of any diet designed to reduce heart disease risk.