Can you take too much omega 3 fish oil

CORVALLIS, Ore. - A new review suggests that omega-3 fatty acids taken in excess could have unintended health consequences in certain situations, and that dietary standards based on the best available evidence need to be established.

"What looked like a slam dunk a few years ago may not be as clear cut as we thought," said Norman Hord, associate professor in OSU's College of Public Health and Human Sciences and a coauthor on the paper.

"We are seeing the potential for negative effects at really high levels of omega-3 fatty acid consumption. Because we lack valid biomarkers for exposure and knowledge of who might be at risk if consuming excessive amounts, it isn't possible to determine an upper limit at this time."

Previous research led by Michigan State University's Jenifer Fenton and her collaborators found that feeding mice large amounts of dietary omega-3 fatty acids led to increased risk of colitis and immune alteration. Those results were published in Cancer Research in 2010.

As a follow-up, in the current issue of the journal Prostaglandins, Leukotrienes & Essential Fatty Acids,Fenton and her co-authors, including Hord, reviewed the literature and discuss the potential adverse health outcomes that could result from excess consumption of omega-3 fatty acids.

Studies have shown that omega-3s, also known as long chain polyunsaturated fatty acids (LCPUFAs), are associated with lower risk of sudden cardiac death and other cardiovascular disease outcomes.

"We were inspired to review the literature based on our findings after recent publications showed increased risk of advanced prostate cancer and atrial fibrillation in those with high blood levels of LCPUFAs," Fenton said.

Omega-3 fatty acids have anti-inflammatory properties, which is one of the reasons they can be beneficial to heart health and inflammatory issues. However, the researchers said excess amounts of omega-3 fatty acids can alter immune function sometimes in ways that may lead to a dysfunctional immune response to a viral or bacterial infection.

"The dysfunctional immune response to excessive omega-3 fatty acid consumption can affect the body's ability to fight microbial pathogens, like bacteria," Hord said.

Generally, the researchers point out that the amounts of fish oil used in most studies are typically above what one could consume from foods or usual dosage of a dietary supplement. However, an increasing amount of products, such as eggs, bread, butters, oils and orange juice, are being "fortified" with omega-3s. Hord said this fortified food, coupled with fish oil supplement use, increases the potential for consuming these high levels.

"Overall, we support the dietary recommendations from the American Heart Association to eat fish, particularly fatty fish like salmon, mackerel, lake trout or sardines, at least two times a week, and for those at risk of coronary artery disease to talk to their doctor about supplements," he said.

"Our main concern here is the hyper-supplemented individual, who may be taking high-dose omega-3 supplements and eating four to five omega-3-enriched foods per day," Hord added. "This could potentially get someone to an excessive amount. As our paper indicates, there may be subgroups of those who may be at risk from consuming excess amounts of these fatty acids."

Hord said there are no evidence-based standards for omega-3 intake and no way to tell who might be at health risk if they consume too high a level of these fatty acids.

"We're not against using fish oil supplements appropriately, but there is a potential for risk," Hord said. "As is all true with any nutrient, taking too much can have negative effects. We need to establish clear biomarkers through clinical trials. This is necessary in order for us to know who is eating adequate amounts of these nutrients and who may be deficient or eating too much.

"Until we establish valid biomarkers of omega-3 exposure, making good evidence-based dietary recommendations across potential dietary exposure ranges will not be possible."

Sanjoy Ghosh from University of BC-Okanagan, Canada and Eric Gurzell from Michigan State University also contributed to this study, which was supported by grants from the National Institutes of Health and the Canadian Diabetes Association.

Fish oil comes from many types of fish. It is rich in two important omega-3 fatty acids called eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

The benefits of fish oil seem to come from its omega-3 fatty acid content. Fish that are especially rich in these oils include mackerel, herring, tuna, and salmon. The body doesn't produce many of its own omega-3 fatty acids. Omega-3 fatty acids reduce pain and swelling, and also prevent the blood from clotting easily.

Some fish oil products are approved by the FDA as prescription medications to lower triglycerides levels. Fish oil is also available as a supplement. Fish oil supplements do not contain the same amount of fish oil as prescription products, so they cannot be used in place of prescription products. Fish oil supplements are sometimes used for heart health and mental health, but there is no strong evidence to support most of these uses.

Do not confuse fish oil with EPA, DHA, cod liver oil, flaxseed oil, krill oil, or shark liver oil. See the separate listings for these topics.

Side Effects

When taken by mouth: Fish oil is likely safe for most people in doses of 3 grams or less daily. Taking more than 3 grams daily might increase the chance of bleeding. Fish oil side effects include heartburn, loose stools, and nosebleeds. Taking fish oil supplements with meals or freezing them can reduce these issues.

Consuming high amounts of fish oil from DIETARY sources is possibly unsafe. Some fish are contaminated with mercury and other chemicals. Fish oil supplements typically do not contain these chemicals.

When applied to the skin: There isn't enough reliable information to know if fish oil is safe or what the side effects might be.

Special Precautions and Warnings

Pregnancy and breast-feeding: Fish oil supplements are likely safe when taken by mouth. Taking fish oil does not seem to affect the fetus during pregnancy or the baby while breast-feeding. But shark, swordfish, king mackerel, and tilefish should be avoided during pregnancy, by those who may become pregnant, and while breast-feeding. These fish might contain high levels of mercury and may contain other toxins. Limit consumption of other fish to 12 ounces/week (about 3 to 4 servings/week). Consuming fatty fish in high amounts is possibly unsafe.

Children: Fish oil supplements are possibly safe when taken by mouth. In adolescents, fish oil has been used safely in doses of up to about 2.2 grams daily for 12 weeks. But young children should not eat more than two ounces of fish per week. Consuming fish oil from DIETARY sources in large amounts is possibly unsafe. Fatty fish contain toxins such as mercury. Eating contaminated fish frequently can cause serious adverse effects in children.

Bipolar disorder: Taking fish oil might increase some of the symptoms of this condition.

Liver disease: Fish oil might increase the risk of bleeding in people with liver scarring due to liver disease.

Diabetes: Taking high doses of fish oil might make it more difficult to control blood sugar levels.

Familial adenomatous polyposis: There is some concern that fish oil might further increase the risk of getting cancer in people with this condition.

Conditions in which the immune system response is lowered (including HIV/AIDS): Higher doses of fish oil can lower the body's immune system response. This could be a problem for people whose immune system is already weak.

An implanted device to prevent irregular heartbeat: Fish oil might increase the risk of irregular heartbeat in patients with an implanted defibrillator. Stay on the safe side and avoid fish oil supplements.

Fish or seafood allergy: Some people who are allergic to seafood such as fish might also be allergic to fish oil supplements. There is no reliable information showing how likely people with seafood allergy are to have an allergic reaction to fish oil. Until more is known, advise patients allergic to seafood to avoid or use fish oil supplements cautiously.

Interactions ?

Moderate Interaction

Be cautious with this combination

• Fish oil might lower blood pressure. Taking fish oil along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

• Fish oil is sometimes used to lower triglyceride levels. Birth control pills might reduce this effect if taken with fish oil.

• Orlistat might keep the beneficial fatty acids in fish oil from being absorbed by the body. Taking fish oil and orlistat at least 2 hours apart may keep this from happening.

• Fish oil might increase how much cyclosporine is in the body. Taking fish oil with cyclosporine might increase the effects and side effects of cyclosporine.

• Fish oil might increase how much sirolimus is in the body. This might increase the effects and side effects of sirolimus.

• Fish oil might increase how much tacrolimus is in the body. This might increase the effects and side effects of tacrolimus.

Minor Interaction

Be watchful with this combination

• Fish oil might slow blood clotting. Taking fish oil along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

• Warfarin is used to slow blood clotting. Fish oil might also slow blood clotting. Taking fish oil with warfarin might slow blood clotting too much and increase the risk of bleeding. Until more is known, use cautiously in combination with warfarin. Have your blood checked regularly, as your dose of warfarin might need to be changed.

• Some fish oil products contain a fatty acid that might reduce the effects of some chemotherapy drugs, called platinum agents. But the amount of this fatty acid in most fish oil products is probably too low to be a concern. There is no need to stop taking fish oil if you are also taking platinum agents.

Dosing

Fish oil supplements have most often been used by adults in doses of up to 6 grams daily by mouth for up to 12 weeks. Fish oil products typically provide 180-465 mg of EPA and 120-375 mg of DHA per capsule. Fish oil is also available in prescription drugs, including Lovaza, Omtryg, and Epanova. Fish oil supplements cannot be used in place of fish oil prescription drugs. Speak with a healthcare provider to find out what product and dose might be best for a specific condition.

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2018.

How much omega

Can you overdose on omega

What happens if your omega

How much fish oil should you take per day?