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

Fasenra (benralizumab) receives US FDA approval fo…

AstraZeneca and its global biologics research and development arm, MedImmune, announced that the US Food and Drug Administration (FDA) has approved Fasenra (benralizumab)...

Alzheimer's disease might be a 'whole body' proble…

Alzheimer's disease, the leading cause of dementia, has long been assumed to originate in the brain. But research from the University of British Columbia and Chinese scie...

Cancer cells destroyed with dinosaur extinction me…

Cancer cells can be targeted and destroyed with the metal from the asteroid that caused the extinction of the dinosaurs, according to new research by an international col...

Novartis confirms leadership in multiple sclerosis…

Novartis today announced it will present 54 scientific abstracts from across its multiple sclerosis (MS) research portfolio at the 7th Joint European and Americas Committ...

Amgen and Novartis announce expanded collaboration…

Amgen (NASDAQ:AMGN) and Novartis announced an expanded collaboration with the Banner Alzheimer's Institute (BAI) to initiate a new trial - the Alzheimer's Prevention Init...

Transplanted hematopoietic stem cells reverse dama…

Researchers at University of California San Diego School of Medicine report that a single infusion of wildtype hematopoietic stem and progenitor cells (HSPCs) into a mous...

Novartis announces the planned acquisition of Adva…

Novartis announced today, that it has entered a memorandum of understanding with Advanced Accelerator Applications (AAA) under which Novartis intends to commence a tender...

'Precision Medicine' may not always be so precise

Precision Medicine in oncology, where genetic testing is used to determine the best drugs to treat cancer patients, is not always so precise when applied to some of the w...

China's out of control 'silent killer' affects one…

More than one-third of adults in China have high blood pressure - often dubbed the "silent killer" for its lack of symptoms - but only about one in 20 have the condition ...

New tissue-engineered blood vessel replacements on…

Researchers at the University of Minnesota have created a new lab-grown blood vessel replacement that is composed completely of biological materials, but surprisingly doe...

New US study reveals key reasons why millions of p…

Few of the more than 90 million Americans(1) with obesity are seeking and receiving long-term obesity care, according to new data from the Awareness, Care and Treatment I...

Efficacy and safety maintained in patients who swi…

Boehringer Ingelheim today announced one-year data from VOLTAIRE®-RA, a pivotal Phase III clinical trial comparing Cyltezo® (adalimumab-adbm) and reference product Humira...

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 ]