There is a great deal of confusion on which fats are good or bad. The key to your good health may lie in choosing the right fats to eat and cook with. Here are a few of my thoughts on which ones to use and avoid. I’ll also dispel a few misconceptions about omega-6 fats.
Consume fish and flaxseed oils
You are probably well aware of the many health benefits associated with omega-3 fats. They reduce blood triglycerides, lower inflammation and are associated with lower risk for many chronic diseases like diabetes and heart disease.
There are several different types of omega-3 fatty acids. The most important one found in our cell membranes is DHA, which is made from EPA, which in turn is made from ALA (alpha linolenic acid). Fish, cod liver and krill oil are all good sources of EPA and DHA. Flax seed oil is rich in ALA, which needs to be converted to EPA and then DHA. In humans, the conversion is not particularly efficient—around 10%, so using flax seed oil as a sole source of EPA and DHA is not as effective as consuming a preformed source of EPA and DHA found in fish.
A healthy dose of EPA and DHA is about 500-1,000 mg a day, which is found in 2-3 softgels depending on their concentration level. Take 1-2 tablespoons of flax oil a day, which contains about 7,000 mg of ALA per tablespoon. While flax is not as good at lowering triglycerides, it still helps with things like skin and joint health, a healthy inflammation response, and can counteract an excess of omega-6 fats in your diet.
The omega-6 fatty acids sometimes get a bad rap because they can easily be consumed in excess and contribute to an imbalance with the omega-3s. Generally, you should try to reduce omega-6 intake and increase your omega-3 intake.
Minimize these omega-6s
Minimize your use of cooking oils, salad dressings or snack foods that contain safflower oil, sunflower oil, corn oil or soy oil. These fats are high in LA (linoleic acid), an omega-6 fat.
Emphasize good omega-6s (GLA)
However, specific omega-6 fatty acids have been shown to have health benefits. One of the good omega-6 fats is GLA (gamma linolenic acid). GLA is a precursor to arachidonic acid and has been shown to possess anti-inflammatory properties. In one recent study, GLA helped obese individuals maintain weight after major weight loss. Obese individuals who had successfully lost weight (minimum 26 pounds) were randomized to take a GLA supplement in the form of borage oil (5 g/day containing 890 mg/day of GLA) or an olive oil placebo. After one year of supplementation, the placebo group regained 19 pounds whereas the GLA group only regained 4.8 pounds. How GLA worked remains speculative, but it could likely be a method of maintaining adequate arachidonic levels, which is known to have several positive health effects (e.g., improved insulin sensitivity, decreased fat synthesis).
GLA is found in borage seed oil, evening primrose oil and black currant seed oil. Many of the balanced omega 3-6-9 supplements on the market contain some GLA for these reasons.
CLA (conjugated linoleic acid) is a different type of fat that has consistently been shown to reduce body fat. One study examined the effects of CLA on body fat over a one year period. A total of 180 overweight men and women were randomly assigned in a double-blind fashion to receive either 3.6 g of CLA or a placebo (olive oil). Subjects were not provided with specific diet or exercise instructions, only to take the prescribed supplements. Body composition (using dual energy X-ray absorptiometry) was assessed before and after one year of supplementation to assess fat mass and lean body mass.
In the placebo group, there were essentially no changes in body weight, fat mass, or lean body mass. In the CLA group, there was a small weight loss of 2.4 pounds. There was also a significant 3.7 pound reduction in fat mass for the CLA group as well as a significant 1.5 pound increase in lean body mass. Thus, without any dietary or exercise intervention, simply supplementing with 3.6 grams of CLA a day promoted loss in body weight and fat while increasing lean body mass.
Saturated fats, MCTs and Omega-9s
Saturated fats are neither omega-3 or 6. Their intake is widely understood to promote plaque development and risk of heart disease, but recent evidence has called into question that premise. In fact, all recent meta-analyses have come to the conclusion that increasing saturated fat intake is not associated with increased risk for heart disease.
Coconut Oil (with MCTs)
Most saturated fats are 14 to 18 carbons in length, but medium chain fatty acids (12 carbons or less) are found in some foods. Medium chain fatty acids are unique. They are not stored in appreciable amounts in the body and are promptly burned as fuel. When they are ingested, fat burning increases and so does the production of ketones. Coconut and palm kernel oil are uniquely rich in medium chain fatty acids (more than 50% of total fat). Milk fat (cream and butter) also deliver a decent amount medium chain fatty acids (about 20% of total fat). Emerging research shows they elevate ketones, which
are a clean burning fuel, meaning they don’t generate a lot of free radicals. They also increase antioxidant defense and protect against oxidative stress. Consider cooking or baking with coconut oil or take 1-2 tablespoons a day.
Olive Oil (has Omega-9 Oleic Acid)
Olive oil is primarily an omega-9 monounsaturated fatty acid (55-83% oleic acid). This is a good oil to use in salad dressings to replace high omega-6 fats.
Avoid trans fats
Avoid all trans fats (hydrogenated fats) that are used to prolong the shelf life of foods. They’re typically used for frying (french fries and doughnuts) or are in many processed snacks, crackers and cookies. They can increase unhealthy cholesterol levels (LDL), lower your good cholesterol (HDL) and increase triglycerides. Over time, trans fats can lead to hardening of the arteries and clogged arteries.
By choosing the right fats, you’ll improve many markers of good health. You can even lose excess body fat with some of the specialized fats like CLA.
References: Schirmer MA, Phinney SD. Gamma-linolenate reduces weight regain in formerly obese humans. J Nutr. 2007 Jun;137(6):1430-5.
Jeff S. Volek is a professor in The Human Performance Laboratory at The University of Connecticut, Storrs, CT. He is an R.D. and has a Ph.D. in Kinesiology (Pennysylvania State University). He serves on the editorial boards of Nutrition and Metabolism and the Journal of Strength and Conditioning Research. He has published over 250 scientific articles and chapters.