Brain size matters because a shrinking brain is a sign of Alzheimer's disease.
In fact, the scientists say the brain preservation seen with higher omega-3 levels in the study is equal to preserving one to two additional years of brain health. The protection was largely seen in the brain's hippocampus region, the area where shrinkage is associated with dementia. Older women with the highest EPA plus DHA fish oil levels had a nearly 3 percent larger hippocampus portion of the brain compared to women with the lowest levels. For perspective, others studies have reported that in patients with Alzheimer's disease, the hippocampus is 40 percent smaller than it is in healthy people of the same age.
The preservation of brain size could be made possible by eating fatty fish alone, or through supplementing, the study authors say. "Our findings suggest—don't prove—that a level of EPA plus DHA, the two major 'fish oil' omega-3s, in red blood cells…may be a target for maintaining brain health," explains William Harris, PhD, study coauthor and a senior scientist at Health Diagnostic Laboratory.
But it's not always all good news when it comes to fish oil and brain preservation.
"I am excited about plant and fish omega-3 fatty acids for brain health," explains Mark Moyad, MD, MPH, Jenkins director of complementary and alternative medicine at the University of Michigan Medical Center and author of The Supplement Handbook. "The brain is composed of a large percentage of fatty acids and eating more omega-3s may not only preserve neurotransmitter function but brain volume.
"However, is this enough to recommend utilizing an omega-3 fatty acid dietary supplement to protect brain health? Not exactly, for many reasons," he adds.
The Downside to Fish Oil
Dr. Moyad points out that the less brain size loss in people with the highest fish oil levels in the study were barely significant, adding that although the hippocampus was larger, it wasn't enough to be a better outcome like fewer cases of memory loss or Alzheimer's disease. "Although this study is interesting, it is far from a game changer," he says. "This is what I call the glass is 10 percent full approach to research, where there is no correlation with anything studied except one or two things, and the research focuses on this and not the 90 percent of the empty glass."
One of the biggest downfalls of using fish-based omega-3 products is the recent history of omega-3s in major clinical trials over the past 18 months, Dr. Moyad explains, noting the major failures in past 12 to 18 months. He points to the AREDS2 Trial, which showed omega-3s cannot slow the progression of macular degeneration. This matters because eye and brain health are closely tied. Also, a recent Italian trial appearing in the New England Journal of Medicine looking at fish oil's benefit for heart health found it did not offer protection in healthy people.
The Upside of Fish Oil
Still, there is lots of evidence suggesting fish oil could help protect the brain and delay cognitive decline and/or dementia. More research is needed, but for now Moyad for the most part agrees with the American Heart Association's guidelines to get the equivalent of two omega-3 oily fish meals per week. (More is not necessarily better.)
If you do turn to fish oil supplements, though, Dr. Moyad says there is an unusually high rate of quality control with this particular supplement compared to others. And several studies addressing the Japanese nuclear power plant disaster have found that the Fukushima nuclear reactor event doesn't seem to have posed a radiation threat to fish. The only real concern was in migratory Pacific bluefin tuna (which you shouldn't eat anyway because the species is on the verge of collapse). But even with that species, scientists calculated that the radiation was well below acceptable levels and would result in two additional fatal cancer cases per 10 million similarly exposed people.
"I believe the overall concern is low and the benefits of eating most omega-3 fish far exceed the risk," Dr. Moyad says, noting that one of the largest studies of fish consumption in the U.S from Harvard found that people with the higher fish intakes had lower risk of heart disease, the number one killer of Americans for 100 of the last 101 years. (They enjoyed this heart benefit even though these people had some of the highest amounts of mercury.) "In other words, benefit usually outweighs risk when eating healthy fish," Moyad says.
How to Protect Your Brain
• Work low-mercury oily fish—such as anchovies, sardines, mackerel, and wild-caught salmon—into your diet.
• Don't rely on lean fish like tilapia for omega-3s.
• If you don't want to eat fish or supplement with fish oil, you can get marine-based omega-3s from algae products. After all, it's from eating these that fish have such high levels! Nordic Naturals offers a no-GMO option.
• Work plant-based omega-3s, such as ground flaxseed, into the equation, too. Getting all three omega-3s—ALA from plants and EPA and DHA, primarily from fish and algae, appear to provide a synergy that allows one to maximize the diverse potential benefits, Dr. Moyad says. "Interestingly, many plant sources of omega-3 are high in fiber, but fish is not but has vitamin D and protein, so there is a beautiful synergyhere in recommending both."
• Eat these 21 brain foods.
• Exercise! There's strong evidence that sweating it out regularly can protect your brain.