Other issues of Nutrition Advisor

All fats are not created equal

Are you fat phobic? There's no need to be fearful of fat. This vital nutrient plays many important roles in your body. First of all, fat is a source of energy. It insulates the body, which helps to maintain your body temperature. Fat assists in the absorption of certain vitamins and it helps the brain and nervous system function properly.

The fat in food takes longer to digest, so as a result, you'll feel full longer. When it comes to cooking, fat is also responsible for adding flavor. But don't run out to buy those donuts just yet! Not all fats are created equal.

Essential fats
“Healthy” fats contribute to overall health and may even prevent certain diseases. Some fats are even vital to the human body, these are linoleic and alpha-linolenic acids (also know as “essential fatty acids”) because the body cannot make them on its own. Without these building blocks of fat, a person could develop essential fatty acid deficiency, which could lead to growth retardation, skin lesions, reproductive failure, fatty liver, excess thirst, reduced learning and impaired vision.

Essential fatty acids may even play an important role in protecting you from certain diseases. Therefore, it may not be enough to simply avoid deficiency, but to ensure that your intake of these fatty acids is sufficient. They are found in a wide variety of foods. Linoleic acid naturally occurs in vegetable oils and poultry. Alpha-linolenic acids is found in soy oil, nuts and seeds.

Types of fat
Regardless of the type of fat we consume, all fats are made of fatty acids and glycerol. When it comes down to science, fatty acids consist of chains of carbon, hydrogen and oxygen. The terms, saturated and unsaturated refer to how many hydrogen atoms are connected to each carbon.

Saturated fats
This type of fat is generally solid at room temperature. Saturated fats are known to increase total blood cholesterol and LDL cholesterol, also known as the “bad” cholesterol. This type of fat is primarily found in animal products, such as butter, lard and the fat in dairy products and meats. Tropical oils, such as palm and coconut, are also classified as saturated fats.

Monounsaturated fats
Monounsaturated fat contains one (mono) double bond on its carbon chain. This is what differentiates it from a saturated fatty acid, which has no double bonds. This staple of the Mediterranean diet may help protect you from developing heart disease. Research has shown that monounsaturated fat may help prevent heart attacks, reduce bad cholesterol while possibly raising HDL, the “good” cholesterol, and lowering blood pressure. Dietary sources include olive and canola oils, as well as nuts and avocados.

Polyunsaturated fats

• Omega 6 fatty acids are predominantly comprised of linoleic acid. They play an important role in immune function, blood pressure regulation, inflammation and pain perception. These fatty acids tend to increase inflammation if too much is consumed and must therefore be balanced by providing omega 3 fatty acids as well. Omega-6 fatty acids can be found in corn, safflower and soybean oils.
• Omega 3 fatty acids are mostly made up of alpha-linolenic acid, which may be helpful in reducing the risk of heart disease by preventing blood clots. They can be found in fatty fish, such as salmon and albacore tuna, nuts, and soy, canola and flaxseed oils.

Hydrogenated fats
These types of fats are created when an unsaturated fat is chemically altered to create a fat that is more stable at room temperature and can extend the shelf life of some food products. As a result, these fats act like saturated fat and can increase cholesterol levels. They are primarily found in packaged foods, like cookies, crackers and sticks of margarine. Trans fatty acids are one form of hydrogenated fat.

Tips

• Choose lower fat dairy products, such as 1% or skim milk, light yogurt and part-skim cheeses.
• Remove visible forms of fat from meats before cooking. Buy lean beef, skinless poultry and fish. Add fish rich in omega-3 fatty acids to your diet once or twice a week.
• Use monounsaturated fats, such as olive or canola oils when cooking.
• Choose a soft tub margarine instead of stick margarine or butter.
• Sprinkle ground flax on yogurt, shakes and cereal. Flax can be ground in your regular blender; no special equipment is necessary.
• Snack on a handful of almonds, cashews or walnuts. Toast them for extra flavor.
• Toss olives or sunflower seeds onto your salad.
• Make your own salad dressing using olive, canola or flaxseed oil.
• Opt for an occasional avocado-try it on salad or as guacamole.

The Yale-New Haven Nutrition Advisor is created by registered dietitians and dietetic interns who staff the Nutrition Clinic at Yale-New Haven Hospital. For information, contact the Nutrition InfoLine at (203) 688-2422.

For more information on this topic, see

• Know your fats, American Heart Association
• Keep your heart healthy and control cholesterol with food first, American Dietetic Association
• How you can lower your cholesterol levels: Introduction to the heart healthy diet, National Heart, Lung and Blood Institute
• The truth about trans fats, Yale-New Haven Nutrition Advisor
• Yale-New Haven Nutrition Forum (search by keyword)

Other issues addressed by Yale-New Haven Nutrition Advisor:

• The whole truth on whole grains
• Alzheimer’s disease and diet
• Does fast food have to equal fat food?
• The truth about trans fats
• Understanding yogurt
• Thinking about going low-carb?
• What's to drink?
• Obesity—it's not just for grown-ups anymore
• Fruits and vegetables: Always in season
• Calcium: Not just for bones anymore!
• Mercury Rising
• A powerful B vitamin: Folate
• Vegging out
• Manic for organic
• Beta carotene
• Archive

Last revised: June 6, 2005 (mv)

Home page URL: http://www.ynhh.org

All information is intended for your general knowledge and is not a substitute for medical advice or treatment for specific medical conditions. You should seek prompt medical care for any specific health issues and consult your physician before starting a new fitness regimen.