Omega, the final letter of the Greek alphabet, is often used to signify the last of something or the end. When applied to dietary fats, though, omega represents a healthy beginning. Two families of polyunsaturated fats, the omega-3 and the omega-6 fats, are good for the heart and the rest of the body.
Excessive amounts of omega-6 polyunsaturated fatty acids (PUFA) and a very high omega-6/omega-3 ratio is found in today's Western diets. These diets promote the pathogenesis of many diseases, including heart disease, cancer, and inflammatory and autoimmune diseases. Increased levels of omega-3 PUFA (a lower omega-6/omega-3 ratio) exert suppressive effects on these illnesses. Dietary omega-3 fatty acids are involved in the prevention of heart diseases, and in some neuropsychiatric disorders, particularly depression, as well as in dementia, notably Alzheimer's disease.
Chemistry of omega-3 and omega-6
Omega-6 and omega-3 fatty acids are called polyunsaturated fats because they have many double bonds. The terms omega-3 and omega-6 describe the position of the first carbon-carbon double bond in the fat's backbone. This influences the shape of a fat molecule which, in turn, affects its function in the body. Our body does not have the enzymes to produce them, so we must get them from our diet. These fatty acids are biologically active and have important roles in processes like blood clotting and inflammation. Omega-6s are pro-inflammatory, while omega-3s are anti-inflammatory. Chronic inflammation may be one of the leading drivers of the most serious modern diseases, including heart disease, metabolic syndrome, diabetes, arthritis, Alzheimer's and many types of cancer.
Scientists have hypothesized that a diet high in omega-6s but low in omega-3s increases inflammation, while a diet that includes balanced amounts of each reduces inflammation.
Those who follow a Western diet are typically eating way too much omega-6s relative to omega-3s. Many believe this is a serious health problem. An omega-6 to omega-3 ratio that is too high may contribute to excess inflammation in the body, potentially raising the risk of various diseases.
Benefits of eating more omega-3 fats
Many benefits can be derived from omega-3 fats, which can be found in fatty fish and plant sources like flaxseeds and walnuts. Omega-3 fats help protect the heart from lapsing into potentially deadly erratic rhythms. They ease inflammation. They inhibit the formation of dangerous clots in the bloodstream. They also lower levels of triglycerides, the most common type of fat-carrying particle in the blood. To improve the ratio of omega-3 fats to omega-6 fats, eat more omega-3s, not fewer omega-6s.
The main charge against omega-6 fats is that the body can convert the most common one, linolenic acid, into another fatty acid called arachidonic acid, and arachidonic acid is a building block for molecules that can promote inflammation, blood clotting, and the constriction of blood vessels. But the body also converts arachidonic acid into molecules that calm inflammation and fight blood clots. Omega-6 fats, which we get mainly from vegetable oils, are also beneficial. They lower harmful LDL cholesterol and boost protective HDL. They help keep blood sugar in check by improving the body's sensitivity to insulin. Yet these fats don't enjoy the same sunny reputation as omega-3 fats.
The balance between n-3 and n-6 PUFAs is essential for metabolism and maintenance of the functions of both classes. The availability of n-3 long-chain PUFAs plays a major role in regulating both fat accumulation and its elimination by the liver.
The critics argue that we should cut back on our intake of omega-6 fats to improve the ratio of omega-3 to omega-6s. Omega-6 fats are not only safe but they are also beneficial for the heart and circulation. What scientists found is that the body converts very little linolenic acid into arachidonic acid, even when linolenic acid is abundant in the diet. Eating more omega-6 fats did not aggravate inflammation. Instead, eating more omega-6 fats either reduced markers of inflammation or left them unchanged. Many studies showed that rates of heart disease went down as consumption of omega-6 fats went up. Replacing saturated fat with omega-6 fats can reduce the risk of heart attacks and other coronary events. Replacing saturated fats with polyunsaturated fats (including omega-6 and omega-3 fats) reduced heart disease rates more than did replace them with monounsaturated fats or carbohydrates.
Sources of omega-3 and omega-6 fat
- Good sources of omega-6 fats include safflower oil, sunflower oil, corn oil, soybean oil, sunflower seeds, walnuts, pumpkin seeds. For omega-3 fats, good sources include oily fish such as salmon, herring, mackerel, and sardines; fish oil and flaxseed oil; flaxseeds, walnuts, and chia seeds. One effective way to increase your omega-3 intake is to eat seafood once or twice per week. Fatty fish like salmon are particularly good sources.
