Excess omega-3 fatty acids could lead to negative health effects

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.

Most Popular Now

FDA approves Roche's OCREVUS™ (ocrelizumab) for re…

Roche (SIX: RO, ROG; OTCQX: RHHBY) announced today that the US Food and Drug Administration (FDA) approved OCREVUS™ (ocrelizumab) as the first and only medicine for both ...

Read more

First collaborative definition of patient centrici…

AstraZeneca announced that BMJ Innovations has published the first collaborative definition of patient centricity for the pharmaceutical industry. The definition was co-d...

Read more

High doses of vitamin C to improve cancer treatmen…

Clinical trials found that it is safe to regularly infuse brain and lung cancer patients with 800 - 1000 times the daily recommended amount of vitamin C as a potential st...

Read more

Deep learning algorithm could boost drug developme…

Artificially intelligent algorithms can learn to identify amazingly subtle information, enabling them to distinguish between people in photos or to screen medical images ...

Read more

Bristol-Myers Squibb enters into separate agreemen…

Bristol-Myers Squibb Company (NYSE:BMY) today announced that it has entered into two separate agreements to license BMS-986168, an anti-eTau compound in development for ...

Read more

Tagrisso (osimertinib) receives US FDA full approv…

AstraZeneca today announced that the US Food and Drug Administration (FDA) has granted full approval for Tagrisso (osimertinib) 80mg once-daily tablets, for the treatment...

Read more

A one-two punch hits pancreatic cancer where it hu…

Australian scientists have uncovered a promising new approach to treating pancreatic cancer, by targeting the tissue around the tumour to make it 'softer' and more respon...

Read more

FDA allows marketing of first direct-to-consumer t…

The U.S. Food and Drug Administration today allowed marketing of 23andMe Personal Genome Service Genetic Health Risk (GHR) tests for 10 diseases or conditions. These are ...

Read more

Novartis to strengthen R&D pipeline by in-lice…

Novartis has exercised an option to in-license ECF843 for ophthalmic indications worldwide (outside Europe). The closing of the deal is subject to customary closing condi...

Read more

New drug delivery system shows promise for fightin…

A new cancer-drug delivery system shows the ability to exploit the oxygen-poor areas of solid tumors that make the growths resistant to standard chemotherapy and radiatio...

Read more

Towards a safe and scalable cell therapy for type …

More than 36 million people globally are affected by type 1 diabetes (T1D), a lifelong disorder where insulin producing cells are attacked and destroyed by the immune sys...

Read more

XELJANZ® (tofacitinib citrate) receives marketing …

Pfizer Inc. (NYSE:PFE) announced today that the European Commission (EC) has approved XELJANZ® (tofacitinib citrate) 5 mg twice daily (BID) oral tablets in combination wi...

Read more

Pharmaceutical Companies

[ A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Z ]