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United States Department of Agriculture

Agricultural Research Service

OMG- OMeGa-3s!
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Matt Picklo

You see the word "omega-3" on food labels from walnuts to fish to peanut butter to fish oil pills. What are omega-3s?  And what do they do for your health?

Omega-3s are fatty acids (components of fats).  The name comes from their characteristic structure, with double-bonded carbon atoms located three positions from the end of their chain.  Omega-3s are found in plants and animal products, but in differing levels and of different types. For example, flax seed and walnuts contain the simple omega-3, alpha-linolenic acid (ALA).  Salmon and tuna contain high levels of larger, more complex omega-3s, eicospentaenoic acid (EPA) and docosahexaenoic acid (DHA).

The buzz about omega-3s concerns the recognition that they are important for good health. DHA is essential for the development of the brain.  For that reason, many infant formulas are supplemented with it.  The adult brain also needs DHA, which after consumption becomes concentrated in the nerve endings that relay information from cell to cell.  There is some evidence that lack of omega-3s may contribute to depression in adults.

Clinical studies have shown that supplementing diets with DHA and EPA reduces risk of heart attacks and strokes. Researchers have found that omega-3s can reduce arrhythmias (irregular heartbeats), lower blood pressure, and lower triglyceride levels in the blood.  Other evidence indicates that omega-3s can reduce inflammation.

Omega-3s work to promote heart health and reduce inflammation in different ways. After being consumed, EPA and DHA become part of the membranes of our cells where they affect proteins regulating heart rhythm. They can be converted to potent anti-inflammatory agents called resolvins and protectins.  In addition, they can bind in the cell nucleus to affect the expression of genes.

How much omega-3s are needed by adults?  Research shows that an intake of 250 mg/day (about 2 grams/week (only 18 calories) of EPA and DHA reduces risk for cardiovascular disease.  Unfortunately, the diets of many Americans do not provide this amount. 

Including salmon and tuna are excellent ways to increase your omega-3 intake.  Each is a good source of EPA and DHA.  Just 4 ounces of Atlantic salmon provides more than 1 gram of these omega 3s. Walnuts and flaxseed contain ALA; but the body only converts 10% of ALA to EPA and DHA.  Some margarines and peanut butters are now being enriched with omega-3s through ALA fortification.  In addition, fish oil supplements are rich in both DHA and EPA.

Scientists at the Grand Forks Human Nutrition Research Center are performing cutting edge research on omega-3s!  We recently demonstrated that baking salmon to the recommended internal temperature of 145 °F preserves the levels of EPA and DHA.  We also found the conversion of ALA to EPA and DHA to be greatest when eating a diet low in fat.   We are currently recruiting volunteers for a study to determine the efficacy of formulations of omega-3s designed to be well absorbed. 

What does this research mean for us and our families? Omega-3 foods are an important part of healthy diets.  Most of us need to reduce our total fat intakes, but we also need to include more omega-3 sources in our diets.

To create a personal plan, or to track foods and nutrients eaten, USDA provides a free interactive tool called SuperTracker at:  https://www.choosemyplate.gov/SuperTracker/

After entering foods eaten, consumers can also use the "Food Details Report" to select individual nutrients they wish to track-including how much dietary alpha-linolenic acid (ALA), omega-3 EPA and omega-3 DHA they consumed.


Last Modified: 5/17/2012