The lowdown on fats: the good, the bad and the omegas
By: Les Riess, M.D.
Most of us are probably aware of the health benefits associated with a low fat diet. Low fat does not mean no fat, however. Our bodies require a certain amount of fat in order to stay healthy.
The issue gets more complicated when we talk about good fats and bad fats. How do you know a good fat from a bad one and how fat much is enough? Then you hear about the benefits of essential fatty acids and omega-3s. Where do they fit in?
There are some things that all fats have in common. They all – good and bad – contain nine calories per gram. Fats are a necessary part of your diet, but the American Heart Associations recommends that you limit fats to no more than 25 to 30 percent of the calories that you consume.
One way to keep tabs on the amount of fat in your diet it by reading nutrition labels. Each label lists total fat, saturated fat, trans fat, polyunsaturated fat and monounsaturated fat.
Saturated fats are the bad guys. You want to limit them in your diet. Foods high in saturated fats include butter, lard, hydrogenated vegetable oil, whole milk, cream, bacon, processed meats and processed grain products such as cakes, cookies and muffins.
Trans fats are even worse than saturated fats. They are fats that are created when hydrogenation is used during food processing to solidify liquid oils in order to give the food a longer shelf life. If you could eliminate trans fats completely from your diet, it would be a good thing. In general you want to avoid them whenever possible.
Saturated fats and trans fats can contribute to high cholesterol, which can lead to clogged arteries and decreased blood flow to the heart and brain. When it comes to fats, remember: saturated equals bad.
Both polyunsaturated and monounsaturated fats are members of the good fat group. They can help to lower bad (LDL) cholesterol and increase good (HDL) cholesterol.
In general, monounsaturated fats are liquid at room temperature, but start to turn solid when chilled. Olive oil contains monounsaturated fats. Other foods high in monounsaturated fats are canola oil, peanut oil, sunflower oil, sesame oil, avocados and peanut butter.
Polyunsaturated fats can have a beneficial effect on your health when they are used to replace saturated or trans fats. Essential fatty acids are one type polyunsaturated fats. As their name implies, they are essential for health. The catch is that that our bodies don’t make them, so we have to get these essential fats from the food we eat.
Omega-3 is one essential fatty acid that we hear a lot about. In general, omega-3’s work by encouraging the production of body chemicals that decrease inflammation throughout the body, bringing about some promising health benefits. These include: lowering blood pressure, cholesterol and triglyceride levels; lowering the risk of heart disease and stroke; reducing symptoms of rheumatoid arthritis, depression, asthma, ADHD, certain skin conditions and osteoporosis; boosting prenatal health and brain development. Some studies also indicate that omega-3 may help protect against dementia and Alzheimer’s disease, but the evidence is preliminary at this point.
Omega-3s are not one single nutrient, but a collection of several. Two of the most significant are EPA (eicosapentaenic acid) and DHA (docosahexanoic acid). The main sources for EPA and DHA are cold-water fish – salmon, mackerel, tuna, oysters, anchovies, herring, sardines, sturgeon and lake trout.
Many people avoid eating fish because of concerns about mercury poisoning. The latest FDA recommendations say that consuming up to 12 ounces of a variety of fish each week is safe. The American Heart Association recommends at least two servings (or about six ounces) of fish per week to meet the body’s omega-3 requirements.
A third type of omega-3 is known as ALA (alpha-linolenic acid). The body can take ALA and convert it to EPA and DHA, however the conversion isn’t very efficient. Only about five to 10 percent of ALA gets converted to EPA and DHA. Good sources of ALA are: walnuts, flaxseed, canola oil, olive oil and soybean oil.
A number of food products are fortified with omega-3 fatty acids. Some of the more common items are eggs (chickens are fed grain fortified with omega-3), yogurt, juice, milk, bread, pasta, waffles and baby food. Free-range poultry and beef also contain higher levels of omega-3 than grain-fed animals.
Finally, omega-3 fatty acids are available in fish oil supplements. The jury is still out on supplements; many experts recommend getting essential fatty acids solely from the food you eat. In addition, there are possible side-effects associated with supplements. If you are considering a fish oil supplement, get your physician’s approval before starting.
Omega-3 works in the body to balance the effects of another essential fatty acid: omega-6. Sources of omega-6 include eggs, poultry and vegetable oils. Omega-6 works to support skin health, lower cholesterol and help with blood clotting. It is an essential fatty acid, but most people get more than their minimum dietary requirement. When this happens, blood can clot too easily, increasing the risk of heart attack and stroke.
Most experts believe that the balance between omega-3 and omega-6 should be between one to four parts omega-3 to one part omega-6. Contrast this to the typical American diet, which experts estimate at between one part omega-3 to 10 to 30 parts omega-6. Substituting olive oil for vegetable oil when cooking is one way to decrease dietary amounts of omega-6.
Fat – who would think that one three-letter word could be such a complex topic? In a nutshell: Avoid saturated and trans fats whenever possible. Limit unsaturated fats. Try to fill your fat intake with polyunsaturated fats known as essential fatty acids, with special attention paid to omega-3 fatty acids. If you’ve never developed a taste for tuna, lake trout or salmon, now would be a great time to start.
|Dr. Riess is a board certified family practice physician at Raiter Clinic|