Omega-3 fatty acids in fish oil may have benefits beyond potentially boosting heart health -- they could also benefit the immune system, according to a new study in mice.


Researchers from Michigan State University and East Carolina University found that feeding fish oil high in the omega-3 fatty acid compound DHA (docosahexaenoic acid) seemed to boost activity of a white blood cell called a B cell, a vital part of the body's immune response. And because of the particular way the DHA-rich fish oil worked in the mice, the researchers noted the finding could have special applications for people with compromised immune systems.


The findings, which are published in the Journal of Leukocyte Biology, included comparing two groups of mice -- one that was fed a control diet, and one that was fed a diet that included DHA-rich fish oil. After five weeks, researchers took B cells from the mouse tissue and then examined them in the lab for B cell activation.


Omega-3 fatty acids are most commonly naturally found in fish, as well as some plant sources, according to the University of Maryland Medical Center. They've been shown in research to improve cognitive health and decrease risk of heart disease and cancer. Omega-3-rich foods are also prevalent in the Mediterranean diet, which has been linked with a lower risk of heart disease and increased longevity.


But the effects of fish oil in supplement form on heart health has not been totally conclusive, with some studies suggesting it has protective benefits, while others show no effect at all. A recent review of studies, published in the Archives of Internal Medicine, showed no difference in heart attack or stroke risk between people who take fish oil supplements and those who don't, Health.com reported. However, experts noted that the jury is still out as to who exactly could benefit from fish oil, as there weren't uniform DHA or EPA (eicosapentaenoic acid, another main compound in omega-3s) levels used in all the studies included in the review.


Currently, the Dietary Guidelines for Americans recommends people eat around two to three servings of fish a week to get a good amount of dietary omega-3s, TIME reported. To make it even more worth your while, a recent study from Harvard and the University of Washington showed that the biggest fish-eaters (calculated by blood levels of omega-3s) also live more than two years longer, on average, than people with low omega-3 levels.


Don't eat fish? Click through the slideshow for some vegetarian sources of omega-3s, from our partners at Blisstree.com:






  • Flaxseed Or Flaxseed Oil


    Flaxseed is one of the most highly-recommended plant sources for omega-3s. Ground flaxseed is a staple in my kitchen -- it keeps for a long time in the freezer, and because flaxseed is virtually tasteless, I throw it in all sorts of things -- cereal, oatmeal, smoothies -- to boost my omega-3 intake. You can use ground flaxseed goo as an egg substitute in vegan baking. Flaxseed oil has <a href="http://www.krispin.com/omega3.html#Supplementing" target="_hplink">7980 mg omega-3's per 1-tbsp serving</a>.

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    <em>Flickr photo by <a href="http://www.flickr.com/photos/alishav/3462217890/" target="_hplink">Alisha Vargas</a></em>




  • Chia Seeds


    Chia seeds are another plant source of omega-3's that I like to sneak into my diet. You can throw chia seeds into stir fry, salads, seitan, dips and more. Like ground flaxseed, chia seeds have a mild -- if any -- taste. But they'll add a dose of omega-3's and a slight crunch wherever they're added.


    <em>Flickr photo by <a href="http://www.flickr.com/photos/notahipster/4998594527/" target="_hplink">little blue hen</a></em>




  • Hemp Seeds


    Vegan and gluten-free, hemp seeds also have the most essential fatty acids of any nuts or seeds and a perfect 3:1 <a href="http://today.msnbc.msn.com/id/16637630/ns/today-food/t/nutty-hemp-hot-food-trend/" target="_hplink">ratio of omega-3 to omega-6</a>.

    They're also high in protein, minerals and rare polyunsaturated fatty acids like gamma-linolenic acid (GLA) and stearidonic acid (SDA). Like flax and chia seeds, you can sprinkle hemp seeds into lots of different things. Store in the freezer to keep them from going bad.


    <em>Flickr photo by <a href="http://www.flickr.com/photos/restlessglobetrotter/3425782783/" target="_hplink">Jason Rogers</a></em>




  • Perilla Oil


    Perilla oil comes from the seeds of the herb perilla. Over 50 percent of perilla oil consists of ALA, with about <a href="http://www.krispin.com/omega3.html#Supplementing" target="_hplink">8960 mg omega-3 fatty acids</a> per tablespoon (compared to 1680 mg omega-6's).




  • Cauliflower


    "Many people are not aware that cauliflower contains a good amount of omega-3 essential fatty acids, making this veggie great for heart health," says nutritionist Margaux Rathbun. "In addition to the omega-3, cauliflower contains other heart-friendly nutrients including potassium, magnesium and niacin."

    <a href="http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2390/2" target="_hplink">One cup contains about 37 mg of omega-3's</a>. To retain the nutrients in cauliflower, Rathbun recommends steaming it for no more than five to six minutes, then adding lemon juice and cold-pressed extra-virgin olive oil.


    <em>Flickr photo by <a href="http://www.flickr.com/photos/wordridden/4626951567/" target="_hplink">Jessica Spengler</a></em>




  • Hummus


    "Hummus is a vegan source of omega-3's," with about 300 mg in a one-cup serving, explains Charis Freiman-Mendel, author of "Cook Your Way Through the S.A.T.". That's because hummus is made with tahini, which is made from omega-3-packed sesame seeds. "Delicious, healthy, great brain food," says Freiman-Mendel.


    <em>Flickr photo by <a href="http://www.flickr.com/photos/alga/3122887625/" target="_hplink">Albertas Agejevas</a></em>




  • Purslane


    Purslane is a salad or cooking green with a slightly peppery taste. It's got <a href="http://www.health.com/health/gallery/0,,20487719_5,00.html" target="_hplink">400 mg of omega-3's per serving</a>. It's also high in <a href="http://nutritiondata.self.com/facts/vegetables-and-vegetable-products/2604/2" target="_hplink">vitamin A</a>, calcium, potassium and iron.




  • Brussels Sprouts


    One serving of Brussels sprouts contains about 430 milligrams of alpha-linolenic acid -- more than one-third of the <a href="http://www.nal.usda.gov/fnic/DRI//DRI_Energy/energy_full_report.pdf" target="_hplink">daily ALA amount recommended</a> by the National Academy of Sciences.

    "These tasty little green veggies are loaded with nutrients, including omega-3 fatty acids," says nutritionist Margaux Rathbun. "They're the perfect food for promoting healthy and beautiful skin. Try steaming them for about five minutes to keep all of the health-promoting nutrients intact."

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    <em>Flickr photo by <a href="http://www.flickr.com/photos/39975765@N05/6399983389/" target="_hplink">Mallory Dash</a></em>




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