Fish For Brain Health (For Some People)

Researchers at the Rush University Medical Center, Missouri University Research Reactor, and Wageningen University in the Netherlands looked at the autopsied brains of people who had died of natural causes. They found that whether or not a brain had the tangled proteins characteristic of Alzheimer's disease or signs of other diseases that cause dementia depended on genetics, and whether or not the donor of the brain had regularly eaten seafood.

The researchers recruited 544 volunteers in the Chicago area who subsequently died at an average age of 89. These volunteers had "good brains." Despite having grown up in an era in which college education was not the norm, the majority of the volunteers had two years of university-level education or more. Approximately two-thirds were women. Each volunteer was surveyed annually so the researchers could record their dietary choices.The families of 287 of the participants of the study allowed brain autopsies, which revealed striking differences between volunteers who ate seafood and those who did not. Chicago, of course, is an area not known for seafood, and ocean fish and shellfish were not consumed by all of those in the study.

Here's what the researchers discovered:

• The brains of volunteers who ate seafood meals at least once a week had significantly fewer neuritic plaques, which are deposits of toxic proteins in the gray matter.
• The brains of volunteers who ate seafood meals at least once a week had significantly fewer neurofibrillary tangles, which are twisted strings of proteins that form around injured neurons in the brain.
• The brains of volunteers who ate seafood meals at least once a week were significantly less like to show clear physical signs of Alzheimer's disease.
• None of these changes was associated with the use of fish oil supplements, and
• The benefits of fish in the diet for the aging brain was limited to people who had a gene that increases the risk of Alzheimer's called apolipoprotein E (APOE ε4).

However, eating fish has other benefits. The brains of the volunteers who ate fish at least weekly were also less likely to exhibit signs of cerebral macroinfarction, otherwise known as stroke. What protects against stroke seems to be not so much the fatty acids found in fish as the fatty acids found in all kinds of "good fats," both from fish and from health plant oils.

READ Diet High in Fish Can Help You Preserve Bone Density

This is not the first study to find that good diet protects against Alzheimer's in people who have the  apolipoprotein E gene. Over 20 years earlier, a Columbia University named Jose Luchsinger found that people who had the APOE ε4 gene were much less likely to develop Alzheimer's if they simply consumed fewer calories. "Giving your brain a break" from the constant production of free radicals from food, and avoiding protein consumption long enough (18 hours) to facilitate a detoxifying process called autophagy helped preserve brain function for years longer than expected.

Brain Food For Brain Power Throughout The Lifespan

Everything scientists know about brain food isn't about Alzheimer's and other diseases of the aging brain. There is quite a bit you can do at all stages of life to maintain your brain with diet. Let's start with the not yet born.

A fatty acid called docosahexaenoic acid, also known as DHA, is an essential building block of the neurons of the brain and of the retina both before birth and in the first year of life after birth. Babies whose mothers get more DHA during pregnancy, or who get more DHA from formula, grow into children with better verbal skills, better eye-hand coordination, and lower likelihood of ADHD by the age of eight. 

DHA is an omega-3 fatty acid that occurs in both healthy seed oils and in fish and krill oils. It's abundant in microalgae, although microalgae is a relatively expensive source of it, and it's also found in fish oil and fish. In the case of brain development in infants in children, supplements are actually superior to fish or spirulina as a source of adequate amounts of DHA. Fish oil and krill oil are better sources of another fatty acid called EPA (eicosapentaenoic acid), which fights inflammation, but doesn't build brains.

About 20 percent of the population of North America lacks a gene that codes the proteins for an enzyme called tetrahydromethylfolate reductase. This enzyme transforms the B vitamin folic acid into methylfolate which can be used by cells. Without this enzyme, just consuming enough folic acid doesn't do the body a lot of good. Over 90 percent of the folic acid consumed in the diet fails to enter cells. In fact, taking folic acid supplements actually interferes with the ability of cells to use it. This functional deficiency of methylfolate shows up as a tendency toward miscarriage in women, and various brain health issues in both sexes.

The solution for this problem is extraordinarily simple. Just take over the counter methylfolate. Costing less than $10 a month, this single intervention can make a huge difference in how your feel and how sharp you are.

There's some evidence that a high-fat diet acts on the hippocampus in ways that cause:

• Difficulties with forming memories, especially spatial memories (learning a dance step, playing competitive sports, juggling, finding your way through a new neighborhood).
• More of a crash after eating high-sugar foods, because of greater sensitivity to insulin.

Especially in men, even more than in women, reducing the amount of fat in the diet helps brain power, especially the ability to learn new physical skills and to maintain energy all day long no matter what your eat for breakfast or lunch. A healthy, balanced, lower-fat, lower-carb, lower-calorie meal, of course, is optimal for brain health.

READ Eating Fish At Least Two To Three Times A Week Will Decrease Your Risk Of Stroke

Fish, as mentioned earlier, seems to help maintain brain power in old age.

It's a reasonable question to ask whether it's really a good idea to eat fish when so many fish are contaminated with mercury. The brain researchers mentioned earlier in this article actually did find that eating more fish was associated with more mercury in the brain. However, higher mercury levels, at least in this study, were not associated with pathological changes in the brain. As long as you are not eating large amounts of predator fish, such as shark, the benefits of fish outweigh any problems with mercury.