Edited by Kate Findley, The Great Courses Daily
Omega-3 fatty acids, found in fish and flaxseed, are packed with health benefits. Omega-6s—not so much. Dr. Ormsbee explains the distinction and why the Western diet needs to be rearranged.
Omega-6 and Omega-3 Fats
Omega-6 and omega-3 fats are both polyunsaturated, or essential fatty acids. Omega-6s produce compounds that are involved with inflammation, blood vessel constriction, and immunity. All of these functions are important, and it’s critical that they are well controlled.
Because omega-6 fats lead to inflammation when taken at high levels, they are known as pro-inflammatory agents. Thus, eating too many foods with omega-6 fatty acids, like heated vegetable oils and many boxed and packaged foods, can compromise health and optimal body composition, especially when not balanced with other types of fats like omega-3 fatty acids.
Omega-3 fatty acids are beneficial for health due to their anti-inflammatory effects and effects on decreasing blood clot formation. Some omega-3 fats keep cells less rigid and more fluid. In doing so, they promote blood vessel dilation, which lowers blood pressure and can decrease instances of heart attacks.
Omega-3 fatty acid consumption can also lower blood concentrations of triglycerides, cut the chances of rheumatoid arthritis, and even reduce some behavioral disorders. Some data shows that low omega-3 intake is associated with both poor memory and mood disorders.
More and more evidence is emerging that supports using omega-3 fatty acids in cases of traumatic brain injury to help with immediate and long-term outcomes for these patients.
Essentially, omega-3 fatty acids have the opposite role of omega-6 fatty acids. Because of this, a balanced intake of omega-6 and omega-3 fatty acids is needed for optimal health and physical function.
Re-examining Our Omega Ratios
Americans tend to have very high omega-6 fatty acids consumption in comparison to omega-3 fatty acids because of the high content of omega-6s in many of the pre-packaged foods and vegetable oils that we eat. In fact, the typical Western diet is reported to contain an almost 20:1 omega-6 to omega-3 ratio, while many experts recommend that the ratio should be closer to 2:1 or 1:1 for optimal health.
This is a problem because a high ratio is reported to promote cardiovascular disease, cancer, and inflammatory and immune diseases. A higher intake of omega-3 fatty acids seems to have the opposite effect and reduce the likelihood of cardiovascular disease, cancer, and inflammatory disorders.
If you can’t lower your omega-6 intake, then be sure to reduce the gap in the ratio by eating more omega-3 fatty acids. The balance of the omega-3s in your diet is very important for optimal health, so it’s a good idea to attack this from both sides: decrease the amount of omega-6 fatty acids that you eat, and increase the amount of omega-3 fatty acids that you eat.
The Ills of Trans Fats
Another type of fat found in many packaged foods is trans fat. Recently, the media has focused prominently on the negative consequences of consuming trans fats, and legislation in the United States to completely ban fats from restaurants has been a big issue. Trans fats are called trans due to the chemical structure of the molecule that surrounds the double bonds between the carbons in the fatty acid chain.
Fatty acids that have a degree of unsaturation will have a double bond between the carbon atoms. This provides a chance for the fatty acids to exist in either a cis form, where hydrogen atoms are on the same side of the carbon chain, or in the trans form, where hydrogen atoms are on opposite sides of the carbon chain.
These forms, the cis and the trans, alter the geometric shape of the fat. The transfiguration allows for more stable structure due to equal distribution of hydrogen molecules on both sides of the double bond.
Cis fats, with hydrogen atoms on just one side of the carbon atom chain, tend to fold upon themselves, while trans fats do not fold up very well, and this makes trans fats able to pack tightly together in the cell membranes, which makes them rigid. Most naturally occurring fatty acids in foods are in the cis form, and most trans fats are man-made.
Trans fats are made in an industrial manufacturing process that adds hydrogen to previously liquid vegetable oil, making it a solid at room temperature. This fat is thus artificially hydrogenated.
This is done to give foods a longer shelf life and may make certain foods taste better. Many restaurants will use partially hydrogenated vegetable oils to deep-fry foods because the oil does not need to be changed as frequently as other types of oils, so there is a cost savings for restaurants to consider when they choose the types of oils that they cook with.
Many foods contain trans fats, including baked goods like cookies, fried foods, potato chips, and margarine. A diet high in trans fats may increase your bad low-density lipoproteins (LDL) cholesterol and decrease your good high-density lipoproteins (HDL) cholesterol.
It may also be associated with your risk of developing heart disease. Some trans fat occurs naturally in food, so it is not entirely avoidable. However, you can do your best to avoid trans fats by cooking with whole ingredients and avoiding pre-packaged food as much as possible.
Dr. Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his M.S. in Exercise Physiology from South Dakota State University and his Ph.D. in Bioenergetics from East Carolina University.