It seems like there's a new study relating nutrition and brain development every week. Sometimes, health experts tell us to eat grilled tuna, high in omega-3s, to ward off Alzheimer's disease -- and then, a new report on mercury levels reveals just how risky tuna can be for brain health. Clinical studies that have tried to administer certain nutrients to promote better neurological health have almost always failed. The haziness of all this data makes it hard to place your faith in any one diet.
Oregon Health & Science University's Dr. Gene Bowman has a theory about the source of the confusion. He thinks that the reason past studies have failed to produce satisfactory results is that they're getting their information from the wrong place. Most studies on long-term nutrition and health rely on dietary surveys, which ask studies' participants to remember everything they've eaten over the past few weeks. That's a tall order when you’re talking to people at risk for -- or even in the early stages of -- dementia.
"People with advanced age have more problems remembering what they've eaten," Bowman told The Huffington Post.
But Bowman thinks he has a better way to do things. Instead of asking people what they've eaten over the past few weeks, he looks at nutrient levels in their blood and finds out for himself.
It's not 100 percent foolproof, and it works better for some nutrients than others, but Bowman has published several studies that have demonstrated that blood levels of many nutrients are well correlated with a subject's diet over a period of about a year.
He said the model could be adapted to suit studies of any number of nutrition-related diseases, which all currently rely on dietary studies. But in his own neurological research, he's focused on nutrients that are known to be found at relatively high levels in spinal fluid and brain tissue.
"If the nutrients don't get into the brain, then it's a harder case to prove," he explained. "Maybe if some nutrients are damaging or improving the blood-brain barrier, without actually getting into the brain, that could have an impact on brain development ... but basically, we focus on nutrients that we've found at high levels in the brain itself, like vitamin C."
And this past week, for the first time, he released the first big findings produced by this new method. His latest study, "Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging," published in the Dec. 28 issue of Neurology, found some striking patterns relating what people eat to how their brains function.
Two of his positive findings have already attracted substantial notice. Bowman found that people with high plasma levels of B vitamins and vitamins D, E and C had more total brain volume and better overall cognitive functioning. Additionally, people with higher levels of marine Omega-3 fatty acids running through their bloodstreams were found to have better executive function.
Bowman was quick to note that the study was conducted using data from just 100 people, all elderly, all living in Oregon, and all Caucasian. And he stated these positive trends were relatively minor.
Another trend isolated in the study, though, was not minor. Bowman said that the most striking correlation found in the study was that people with high levels of trans fats in their blood had significantly worse cognitive performance and less total brain volume. In other words, the study indicated that eating foods high in trans fats -- mostly junk food, like processed pastries and fatty red meats –- may cause brain damage.
The pattern was so striking that Bowman said it was worth taking seriously despite the size of the study.
"It's clear that trans fats are bad -- both for your heart and now, we see, for your brain," Bowman said. "So I would recommend that people stay away from all trans fats. If you aren't sure whether something has them, just look at the ingredients; if there's vegetable shortening, partially hydrogenated anything... just put it down. That’s the big message here."
It's a good thing, then, that the tide has turned against trans fats in recent years. Places as far flung as New York and Switzerland have banned restaurants from featuring menu items with high levels of trans fats, and many major companies have tried to remove them from products. Though, as a HuffPost Healthy Living post from earlier this month demonstrated, there are still a lot of foods out there that contain trans fats.
The other patterns were also solid enough that scientists have said they warrant further study.
The eventual hope is that this sort of research will allow neurologists to develop individualized dietary therapies for better brain functioning. But the next step will be to find out whether or not blood nutrient levels today can predict brain development down the line. If they can –- if say, Bowman and his colleagues can determine that ingesting more vitamin E can help support the structural integrity of the hippocampus, the seat of memory -– then someday, a visit to a neurologist may be a lot like a visit to a dietician.
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