KNOW YOUR FATS

Knowing which fats raise LDL cholesterol and which ones don't is a critical step in lowering your risk of heart disease. Saturated fat, trans fatty acids and dietary cholesterol raise blood cholesterol. Monounsaturated fats and polyunsaturated fats don’t. Some studies suggest they might even help lower LDL cholesterol slightly.

- Saturated fats -
Saturated fat is the main dietary cause of high blood cholesterol. The American Heart Association recommends that you limit your saturated fat intake to 7—10 percent of total calories (or less) each day. If you have coronary heart disease or a high LDL cholesterol level, your doctor may recommend the American Heart Association’s diet. It recommends no more than 30 percent of calories from fat, with less than 7 percent coming from saturated fat. Saturated fat is found mostly in foods from animals.

Foods from animals - These include beef, beef fat, veal, lamb, pork, poultry fat, butter, cream, milk, cheeses and other dairy products made from whole or 2% milk. These foods also contain dietary cholesterol.

Foods from plants - These include coconut oil, palm oil and palm kernel oil (often called tropical oils), and cocoa butter.

- Hydrogenated fats -
During food processing, fats may undergo a chemical process called hydrogenation. This is common in margarine and shortening. Recent studies suggest that these fats may raise blood cholesterol. The saturated fat content of margarines and spreads is printed on the package or Nutrition Facts label.

- Polyunsaturated and monounsaturated fats -
Polyunsaturated and monounsaturated fats are the two unsaturated fats. They're often found in liquid oils from plants.

Polyunsaturated fats - These include safflower, sesame and sunflower seeds, corn and soybeans, some nuts and seeds, and their oils.

Monounsaturated fats - These include canola, olive and peanut oils, avocados, peanut butter, and sunflower oil. Monounsaturated fats are also typically high in Vitamin E.

Both polyunsaturated and monounsaturated fats may help lower your blood cholesterol level when you use them in place of saturated fats in your diet. But a moderate intake of all types of fat is best. Use polyunsaturated or monounsaturated oils – and margarines and spreads made from them – in limited amounts.

- Trans fatty acids -
Unsaturated fatty acids can be in one of two shapes-"cis" and "trans." These terms refer to the physical positioning of hydrogen atoms around the carbon chain. The cis form is more common than the trans form. Trans fatty acids (TFA) are found in small amounts in various animal products such as beef, pork, lamb and the butterfat present in butter and milk. TFA are also formed during the process of hydrogenation, making margarine, shortening, cooking oils and the foods made from them a major source of TFA in the American diet. Partially hydrogenated vegetable oils provide about three-fourths of the TFA in the U.S. diet.

How are trans fatty acids harmful?
In clinical studies, TFA or hydrogenated fats tend to raise total blood cholesterol levels but not as much as more saturated fatty acids. TFA also tend to raise LDL ("bad") cholesterol and lower HDL ("good") cholesterol when used instead of cis fatty acids or natural oils. These changes may increase the risk of heart disease.

Because there are no standard methods, it's difficult to estimate the TFA content of food items. It's also difficult to estimate intake, especially long-term intake. The four most important sources of TFA in one large group of women studied included margarine; beef, pork or lamb as the main dish; cookies (biscuits); and white bread.

As of January 2006, the FDA requires transfat to be listed on the nutrition label .

Is butter better than margarine?
Recent studies on the potential cholesterol-raising effects of TFA have raised public concern about the use of margarine and whether other options, including butter, might be a better choice. Some stick margarines contribute more TFA than unhydrogenated oils or other fats.

Because butter is rich in both saturated fat and cholesterol, it's potentially a highly atherogenic food (a food that causes the arteries to be blocked). Most margarine is made from vegetable fat and provides no dietary cholesterol. The more liquid the margarine, i.e., tub or liquid forms, the less hydrogenated it is and the less TFA it contains.

What can I do to regulate my intake of trans fatty acids?
The American Heart Association's Nutrition Committee strongly advises that healthy Americans over age 2 limit their intake of saturated fat to less than 1 percent of total fat intake.

On the basis of current data, the American Heart Association recommends that consumers follow these tips:

• Choose diet rich in fruits, vegetables, whole-grain, high-fiber foods and fat free and low-fat dairy most often.
• Keep total fat intake between 25-35% of calories, with most fats coming from sources of polyunsaturated and monounsaturated fats
• Use naturally occurring, unhydrogenated oil such as canola, sunflower, safflower, or olive oil when possible.
• Look for processed foods made with unhydrogenated oil rather than hydrogenated or saturated fat.
• Use margarine as a substitute for butter, and choose soft margarines (liquid or tub varieties) over harder, stick forms. Look for "0" grams of transfat on nutrition labels.
• French fries, doughnuts, cookies and crackers are examples of foods that are high in TFA. Avoid these foods.
• Limit the fat in your diet. If you don't eat a lot of fat, you won't be consuming a lot of TFA.
• Limit commercially fried foods and commercial baked goods. Not only are these foods very high in fat, but that fat is also likely to be very hydrogenated, meaning a lot of TFA.