Sunday, February 6, 2011

Yes, Diet Affects Attention. Really.

This past week CNN's health blog ran a post by Sonjay Gupta, MD called "Does ADHD Come From Food?" While it's great that CNN and its well-known doctor have given this important issue such a visible platform, it is more than a little disconcerting that the link between diet and attention is presented as a new and unproven concept. The link is fairly well documented in the scientific literature, including this landmark study in The Lancet that was the basis for the strict EU food labelling laws that I've written about previously. All in all, there is a lot of evidence that while not all attention issues are due to foods, some probably are. 

The Feingold Association, which has been around for decades, was one of the first groups to organize around this issue. I encourage you to poke around that organization's web site, look at the evidence and read the "real life" stories. I especially like the story called Taylor's Fuzzy Brained Mice, in which a kid trained four mice to run a maze, then gave two of the mice small amounts of yellow food dye in their water. The results are pretty astonishing - the rats with the dye in their water took longer to run the same maze that they previously completed with times similar to the mice who drank regular water. Further, this confusion was reversed once the colored water was switched back to normal.

Of course, individual stories (called anecdotal evidence in scientific parlance) do not true evidence make. Therefore, the Feignold site also lists many well-conducted scientific studies evaluating the effects of the Western diet on ADHD and other health concerns. It's pretty damning.

And it's not just artificial colorings, flavorings, and preservatives that are suspicious. Nutritionists and dietitians also speculate that the hydrogenated oils found in many processed foods compete with the good fats, like those found in fish and nuts, for valuable real estate in the body. In what is probably an oversimplification of complex brain chemistry, here is one possible scenario: the neurons in your brain are sheathed in fat, which allows electrical impulses to efficiently travel from one neuron to another, resulting in smoothly functioning nervous system. The substitution of hydrogenated oils for the good fatty acids creates a different type of coating of fats around those neurons - replacing the supple, conducive covering provided by good fats - thus interfering with clear thinking and focused attention. Nutritionist Kelly Dorfman explains it all here.

Unfortunately, what is emerging is that eating optimally is not as simple as choosing fruits and vegetables. An article published last year in the journal Pediatrics (the journal of the American Pediatric Association), showed that even moderate exposure to certain pesticides was associated with ADHD. Time magazine wrote about the article here. The authors of the article hastened to point out that eating conventionally grown fruits and vegetables is still preferable to eating junk food. But it does raise the issue of health equity: if organic produce is truly superior, a healthy diet is out of reach for many people for financial reasons. This pushes the issue from one of choice to one of social justice.

In the past few years there have been a slew of reliable studies on the effects of diet on behavior, learning, and attention. The only thing that's remarkable here is the slowness of the medical profession to get on board with this concept.  It's time to move past the endless debate of cause and effect (which is kept alive by the deep pockets of the food industry, its lobbying leverage, and consumers' appetites for poor-quality food) to actually doing something about it. There are many important avenues to explore: why some people are more susceptible to food impurities than others and how those individuals can be screened; what alternatives exist to current colorings, flavorings, stabilizers, etc; and of course, restricting the presence of those impurities in our foods. That's what the Center for Science in the Public Interest is trying to do by lobbying the US Congress to ban certain artificial colorings used in foods. But until then, consumers can do something on their own: make wise food choices. Voting with your checkbook is a time-tested way to bring about change.


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