Balancing Omega-3 and Omega-6 fats
Most people know about omega-3 fatty acids, the polyunsaturated fats in fish (and some plants) that help protect the heart and may have other benefits. Some research suggests, however, that it isn’t just the amount of omega-3s that’s important, but also their proportion to omega-6 fatty acids. These are another type of polyunsaturated fat, found in many vegetable oils (notably corn, soybean, sunflower, and safflower) and foods that contain these oils, such as margarines, salad dressings, baked goods, and processed snacks.
What our ancestors ate
According to physician and researcher Artemis Simopoulos, MD, and some other experts on fatty acids, humans have evolved from a diet where the ratio of omega-6 to omega-3 fats was probably about 1-to-1; that is, our early ancestors ate as much omega-3s as omega-6s. But the typical American now eats far more omega-6s than omega-3s—by about 16-to-1, on average—due to changes in agricultural practices and food processing over the last 100 years or so. Though omega-6s are considered “good” fats because they lower LDL (“bad”) cholesterol, high amounts or very high ratios of omega-6s to omega-3s may increase inflammation in the body, which in turn may contribute to heart disease, cancer, asthma, rheumatoid arthritis, and other chronic health problems.
Evidence to support this theory, however, has been inconsistent. A few studies have linked a higher omega-6 to omega-3 ratio to an increased risk of depression and bone loss, for example. Other studies suggest that decreasing the ratio does not reduce the risk of heart disease or prostate cancer. It’s true that people who eat a lot of omega-3s relative to omega-6s, as in Crete and Japan, have lower rates of cardiovascular disease, but this could be due to other dietary, lifestyle, or genetic differences. And though early humans had a different diet, that doesn’t mean that such a diet is necessarily the best way for us to eat today.
Boosting omega-3 intake
Some experts think a healthier balance between omega-6s and omega-3s is 4-to-1 or lower. But the idea that this will protect against illness is still unproven. In its official recommendations for dietary intakes, the Institute of Medicine says that “based on limited studies,” a “reasonable” ratio of omega-6s to omega-3s is between 5-to-1 and 10-to-1.
What is clear is that most people could benefit from more omega-3s, which would automatically lower the ratio. That means eating more fatty fish (salmon and sardines, for example). Flaxseeds, walnuts, and canola oil contain alpha-linolenic acid, an omega-3 fat related to those in fish.
Another way to shift the balance is to consume more monounsaturated oils (such as olive, canola, sesame, and avocado oil), which have lower levels of omega-6s, in place of some polyunsaturated oils. Monounsaturated fats may have an even more favorable effect on blood cholesterol than polyunsaturated fats—in particular because they are less likely to lower HDL (“good”) cholesterol.