Essential fatty acids are vital for the body’s normal development. They are a necessary component of cell membranes throughout the body; they are also particularly important for development of the brain and the retina. Both omega-3 and omega-6 fatty acids are required for neurons, the information-processing cells of the brain and nervous system, to function properly. They are used to make brain cell membranes as well as neurotransmitters, the chemicals that neurons use to communicate. Deficiencies in essential fatty acids can also cause reduced growth, infertility, and an inability to heal wounds and fight infection.
Deficiencies in omega-3 fatty acids during pregnancy and in babies can cause developmental problems in the nervous system, including the visual system. Breast milk is a good source of essential fatty acids, including omega-3. DHA in particular is important for brain and eye development. For this reason, some baby formulas are now supplemented with essential fatty acids.
A system out of balance
Today’s humans eat less of omega-3 and more of omega-6 fatty acids primarily because they eat less fish and fewer green, leafy vegetables. In addition, modern farming techniques that emphasize mass production of food tend to produce meat, fish, eggs, and vegetables that are lower in omega-3 and higher in omega-6 fatty acids than foods grown in the wild. One reason for this is that farm animals are fed grains, which are high in omega-6.
Too much of omega-6 fatty acids in the diet may lead to inflammation (although some studies indicate that one specific omega-6 fatty acid, GLA, can actually be anti-inflammatory). Inflammation is a response of the immune system that is designed to protect the body against injury or infection, but sometimes it can actually cause or worsen diseases.
Relative decreases in the consumption of omega-3 fatty acids may lead to a number of medical problems, including cardiovascular disease, cancer, osteoporosis, premature birth, cystic fibrosis, depression, asthma, and diabetes. Increasing consumption of omega-3 fatty acids usually reduces consumption of omega-6; this in turn can reduce inflammation and increase blood vessel dilation. These responses may help in the treatment or prevention of many diseases.
The most effective way to eliminate the imbalance of omega-6 and omega-3 is to change one’s diet. Simopoulos states, “The simplest recommendation that anyone can make at this point is to change vegetable oils. In other words, not to eat or cook with corn oil, sunflower, safflower, cottonseed, or soybean oils because they are very high in omega-6 and contain practically no omega-3. Instead, use a combination of olive and canola oils or flaxseed oil or walnut oil.” Simopoulos also recommends eating more green, leafy vegetables, fish, and servings of fruit. She has written a book called The Omega Diet: The Lifesaving Nutritional Program Based on the Diet of the Island of Crete, which describes her recommendations in greater detail. (Also check out “Omega Bites” for more information about how to replace omega-6 fatty acids in your diet with omega-3 fatty acids.)
Omega-3 fatty acids and diabetes
Several studies have provided evidence that omega-3 fatty acids may be good for preventing or treating diabetes. The first piece of evidence comes from studies of people who eat large amounts of fish. These populations, which include residents of Greenland and Alaska, tend to have a lower incidence of diabetes. People who immigrate to India, a country in which fish is not regularly consumed, tend to acquire diabetes at a higher rate than their peers who remain in their native lands. Studies of rats have shown that omega-3 fatty acids suppress the development of insulin resistance in those rats given a high-fat diet.