Omega-3 fatty acids are key for normal development and growth. Lack of dietary intake of omega-3 fatty acids and too much intake of omega-6 fatty acids is believed to be a significant contributing factor to many diseases. Since the human body cannot make omega-3 fatty acids, we have to get them from our diet. Omega-3 supplements have become one of the most popular supplements in the U.S. They're used to help prevent and treat a number of serious diseases.
Why do people take omega-3 fatty acids?
Studies show strong evidence that omega-3 fatty acids from fish oil can lower blood pressure and triglyceride levels. There's also good evidence that diets high in omega-3 fatty acids help with rheumatoid arthritis. Past evidence pointed to omega-3 fatty acids reducing risk of heart attacks, strokes and death from heart disease, but recent research has refuted these findings. More specific research is needed to sort this out.
Omega-3 fatty acids have been studied in many other conditions. They include asthma, cancer, depression, psoriasis, and inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. While some of these studies have been promising, they're still inconclusive.
The different types of omega-3 fatty acids can be confusing. There are the fish oils, which contain docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Then there are the plant sources with alpha-linolenic acid (ALA), which is converted into omega-3 fatty acids in the body.
Studies have generally used fish oils as the source for omega-3 fatty acids. While plant sources with ALA may have the same benefits, less is known about them. For now, fish oils with DHA and EPA have the more established benefit.
How much omega-3 fatty acids should you take?
There are no standard doses for omega-3 fatty acids. The American Heart Association (AHA) recommends 1 gram per day of EPA+DHA for people with heart disease. Higher doses -- between 2 to 4 grams per day -- are used to lower triglycerides. If you need to take omega-3 fatty acid supplements, ask your health care provider what dosage you should use. Children shouldn't use omega-3 fatty acid supplements unless a doctor suggests it.
Can you get omega-3 fatty acids naturally from foods?
Good food sources of omega-3 fatty acids include:
- Coldwater fish, like mackerel, tuna, salmon, and sardines
- Cod liver
- Flaxseed and canola oils
- Soybeans and tofu
The AHA recommends that people eat fish at least twice a week to increase their intake of omega-3 fatty acids.
Eating fewer foods with omega-6 fatty acids -- like some meats, eggs, and oils -- can also improve the ratio of omega-3 fatty acids in the blood, effectively raising the concentration or levels in the body. Many people in the U.S. eat diets that have 10-25 times as many omega-6 fatty acids as they do omega-3 fatty acids. This imbalance may play a role in the onset of many diseases. The more appropriate ratio appears to be approximately 3:1 or 4:1.