Saturated and unsaturated fatty acids are the two classifications of fat. Saturated fats, which are solid at room temperature, are very detrimental to heart health because they contribute to high levels of cholesterol in the body. Unsaturated fats (mono- and polyunsaturated), which are liquid at room temperature, have many positive health outcomes. An inappropriate balance of essential, polyunsaturated fatty acids can contribute to the development of disease while a proper balance helps maintain and even improve health. This article will focus on providing the difference between the two most popular polyunsaturated fats, omega-6 and omega-3 and their associated health benefits.
Omega-6 and omega-3 fatty acids are essential polyunsaturated fatty acids (PUFAs), which cannot be made from scratch by body cells, nor can the cells convert one to the other. They must be provided by the diet.
Essential fatty acids (EFAs) have many very important functions, most notably as acting like hormones, regulating blood pressure, blood clot formation, blood lipids, the immune response, and the inflammation response to injury and infection. In addition, EFAs also serve as structural parts of cell membranes, constitute a major part of the lipids of the brain and nerves and are essential to normal growth and vision in infants and children.
Omega-6 vs Omega-3 Fatty Acids
The omega-6 fatty acid, linoleic acid, is found in many popular vegetable oils (see table below) and is consumed in excess in our society. This could lead to significant health problems because a high consumption of linoleic acid can lead to an increase in the production of eicosanoids that are involved in inflammatory, cardiovascular and immunological diseases.
The omega-3 fatty acid, alpha-linolenic acid, is not as abundant as linoleic acid, but it is readily available in most health food stores (see the below table for sources). Unfortunately, because it is not as easy to locate as linoleic acid, alpha-linolenic acid is not consumed in large amounts in today’s society. This omega-3 fat has very positive health outcomes including some of the following:
- Decreasing risk for coronary artery disease
- Decreasing hypertension
- Improving insulin sensitivity for individuals with Type 2 diabetes
- Reducing tenderness in joints with individuals with rheumatoid arthritis
- Assisting with proper development of the brain cerebral cortex
- Assisting with proper retina formation for proper vision
- Decreasing inflammatory disorders
- Protecting against stroke caused by plaque buildup and blood clots
- Lowering triglycerides and raising HDL levels
Biochemistry of Omega-6 and Omega-3 Fatty Acids
The omega-6 fat, linoleic acid, is converted to arachadonic acid in the body. The omega-3 fat, alpha-linolenic acid, is converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA, found primarily in cold-water fish such as tuna, salmon, and mackeral, are the byproducts of alpha-linolenic acid oxidation that produce the positive health outcomes mentioned previously.
Omega-6 and omega-3 essential fatty acids are best consumed in a ratio of 3:1 to maximize positive health benefits. Unfortunately, the ratio that exists in modern Western diets ranges from 10-30:1. The reason such a low ratio is important is because the omega-6 fatty acids compete with the omega-3 fatty acids for the same desaturation and elongation enzymes. And because Western culture diets include so many omega-6 fats compared to omega-3 fats, very little omega-3 fats are converted into the healthy EPA and DHA compounds.
It is best if the body has more alpha-linolenic (omega-3) fatty acids in order to produce more EPA and DHA and less linoleic (omega-6) fatty acids, which produces arachadonic acid and overpowers the conversion of EPA and DHA.
Eating cold water fish three to four times per week and increasing the consumption of flaxseed oil is recommend. Beware of taking fish oil supplements as the research does not provide a clear message regarding their safety. Omega-3 fatty acids are among the most vulnerable of the lipids to damage by oxidation, and researchers are investigating whether individuals taking fish oil supplements may experience an increase in the potentially harmful oxidative reactions. Supporters of taking fish oil supplements recommend taking between three to 10 grams per day for cardioprotective benefits.
Concentrate on educating clients about the differences between omega-6 and omega-3 fatty acids and more importantly, where to find each and how to best incorporate them into existing eating patterns. Whether it is through supplementation or food is the individual’s end decision.
The below table displays popular oils that contain omega-6 and omega-3 fatty acids. (Approximate EFA content in grams per 100 grams.)
- Shils, Olson, Shike, and Ross. Modern Nutrition in Health and Disease. 9th Edition.
- Sizer and Whitney. Nutrition Concepts and Controveries. 9th Edition.