Why are omega-3 fatty acids so important?
Now, that's the omega-3-thousand-dollar question. Omega-3 fatty acids are a type of polyunsaturated fat, and researchers still are in the midst of discovering a lot about them. So far, the evidence weighs heavily in favor of diets richer in omega-3s than most Americans get.
Typically, the American diet contains about 20 times as much omega-6 fatty acid as omega-3 fatty acid. Although both "healthy" polyunsaturated fats, they play very different roles. Scientists believe we'd be better off if the ratio of omega-6 to omega-3 in our diet was closer to 2 to 1 instead of 20 to 1.
Both omega-6 and omega-3 fatty acids give us essential fats -- "essential" because we must get them from our diet (our bodies can't make them on our own). Among playing other functions in the body, an excess of omega-6 fatty acids tends to increase inflammation and blood clotting, while omega-3s tend to decrease both.
Diets with a better ratio of omega-3 fatty acids appear to have numerous benefits, including fewer risks related to cardiovascular disease, arthritis and autoimmune diseases. In addition, an Ohio State University study recently published in the journal Psychosomatic Medicine indicates that more omega-3s may be associated with lower levels of depression and stress. In that study, psychology and nutrition researchers teamed up to study 43 middle-aged to elderly adults, about half of whom were caring for relatives with Alzheimer's or other type of dementia. They found that participants who had much higher levels of omega-6 than omega-3 fatty acids in blood samples also reported more symptoms of depression. While results are preliminary (a larger study is planned), the findings echo other research that indicates such a link.
People consume omega-6 fatty acids all the time, without even knowing it. They're abundant in many oils, such as sunflower, corn, soybean and peanut oil. People only need the equivalent of about one tablespoon of oil rich in omega-6 fatty acids each day to get what they need -- easily consumed in the form of salad dressing, mayonnaise, margarine, baked goods, eggs and other foods.
Omega-3 fatty acids are less abundant. While some types of oils, such as canola and soybean, contain a small but significant amount of omega-3s, others have much less. A great source is fish -- that is, fatty fish such as salmon, halibut, herring, lake trout, bluefish, tuna, and Atlantic mackerel. Other good sources include flaxseed and walnuts.
Fish oil supplements generally aren't recommended unless you're under a doctor's care. Besides, foods rich in omega-3s also tend to be good sources of lean protein, fiber, or other healthful ingredients.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or firstname.lastname@example.org.
Editor: This column was reviewed by Martha Belury, professor of human nutrition in the College of Education and Human Ecology and a researcher with the Ohio Agricultural Research and Development Center. She was one of the researchers in the Ohio State study mentioned in this column. For more information, see the news release at: http://researchnews.osu.edu/archive/omega-3.htm