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Fish oil benefits the brain and more, but with some warnings

Kathleen Blanchard's picture
Fish oil benefits the brain, but not if there is too much mercury.

The benefits of fish oil are well documented. Now researchers have found the omega-3 fatty acids found in fish oil can help preserve brain volume as we age. Scientists from the University of South Dakota in Sioux Falls and Health Diagnostic Laboratory, Inc., in Richmond, Va say fish oil can help preserve memory with aging, But the Environmental Working Group has highlighted some warnings about mercury in fish that are important for consumers seeking to keep their brains and hearts healthy. Plus, the study is far from conclusive, thought omega-3 fatty acids have been found to have enough health benefits for controlling inflammation in past studies.

The study

For their study, the researchers measured brain volume in addition to levels of omega-3 fatty acids EPA+DHA in red blood cells among 1,111 women who were part of the Women's Health Initiative Memory Study.

The association found between higher levels of omega-3 fatty acids and brain volume was the equivalent of preserving two years worth of brain volume, specifically in the hippocampus that is associated with memory. The oils could help protect against dementia and Alzheimer's disease, the study suggests.

Study author James V. Pottala of the University of South Dakota in Sioux Falls and Health Diagnostic Laboratory, Inc., in Richmond, Va., and colleagues who carried out the study, published online in the journal Neurology, suggest higher levels of the fish oil can be achieved with supplements or diet.

The finding doesn't prove you will protect your brain with fish oil though, but shows some association. The study had some limitations that include other explanations people in the study had more brain volume, other than higher levels of EPA + DPA. Plus there are some warnings about how you get your omega-3s that savvy consumers should know about. Many supplements are contaminated and over-the-counter types may not contain what they say.

Mercury concerns

The study results parallel new warnings from the Environmental Working Group (EWG) that states eating 12 ounces of fish a week that is recommended by government nutrition programs could be dangerous.

Many types of fish high in mercury with low omega-3s

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The EWG calculated that most fish consumed by 90 percent of the population contains very little omega-3 fatty acids found in other seafood – docosahexaenoic acid and eicosapentaenoic acid, often denoted as DHA and EPA - meaning you would have to eat 20 to 100 ounces of fish each week to reap any health benefits.

The group also says pregnant women whose babies are at risk from mercury would need to avoid most of the fish on the market.

A good choice is four to 8 ounces of wild caught salmon each week that can provide enough omega-3s for heart and brain health. The EWG recommends against eating farmed salmon. Other good choices include anchovies, shad, sardines, farmed trout, herring and mussels.

Fish that you want to keep off your plate that contain too few omega-3 fatty acids include:

  • Tilapia
  • Shrimp
  • Scallops
  • Pollock
  • Cod
  • Oysters
  • Crab
  • Clams
  • Catfish

Tuna is affordable and has a long shelf life, but the EWG says mercury in tuna is just too risky. Albacore tuna is highest in mercury. If you choose "light" tuna that contains skipjack and yellowfin you will get less mercury, but fewer omega-3 fatty acids.

The take home message for consumers seems to be that omega-3 fatty acids have multiple benefits. Other findings show the oils can protect against fatty liver disease. The benefits for heart health are well documented.

The most recent study shows the oils could guard the aging brain by preserving brain volume and thus memory; potentially thwarting dementia and Alzheimer's disease. The caveat is to remember that some of the fish we consume could be lacking enough omega-3s to be of benefit, in addition to containing high levels of mercury that can be dangerous for children and pregnant women especially. You can also get omega-3 fatty acids by consuming flaxseed, canola and soybean oil. Walnuts are also a good choice.

Foods studied for their health benefits
Seven dietary guidelines to prevent Alzheimer's disease
Magnesium's role in preventing Alzheimer's disease

Environmental Working Group
"US Seafood Advice Flawed on Mercury, Omega-3s"
January 21, 2014
Sonya Lunder, Senior Analyst, and Renée C. Sharp

"Higher RBC EPA + DHA corresponds with larger total brain and hippocampal volumes"
James V. Pottala, PhD, et al.
January 22, 2014