Thursday, July 15, 2010

Hyperactivity and Diet

Here's the title to a June 2009 article in the Harvard Mental Health Letter: "Diet and Attention Deficit Hyperactivity Disorder - Can some food additives or nutrients affect symptoms? The jury is still out."

Hmmm. That sounds very noncommittal. Let's start instead with the 2007 Southampton Study. Published in the Lancet, Britain's premier medical journal, this was a well-designed nutritional study! We're talking a randomized, placebo-controlled, crossover study. That's enough to make any biological scientist's heart go pitter patter. So what did the researchers do? They took 153 3 year-olds and 144 8/9 year-olds recruited from the community, and did a baseline measure of hyperactivity on the kids via a questionnaire filled out by teachers. All the kids were put on an additive and preservative free diet. At weeks 2, 4, and 6, half the kids were randomly/but in crossover fashion given a study juice drink containing either Mix A (with tartrazine (yellow #5), sodium benzoate, sunset yellow, carmoisine, ponceau 4R) or Mix B (sodium benzoate, sunset yellow, carmoisine, quinoline yellow, and allura red AC). Mix A was supposed to be equal to the additives and preservatives found in 2 bags of candy and was similar to a mix in previous studies, and Mix B to 4 bags of candy - meant to be a representation of the average amount of additives a kid on a normal diet might receive. The other half of the kids got a placebo drink that was the same color and flavor as the test drinks, but had no artificial colors or preservatives (I'm sure they managed it somehow). On weeks 3 and 5, everyone got a placebo (these were "washout weeks."

Then the researchers asked parents and teachers to assess the children's behavior using standard clinical instruments, and also asked independent reviewers to observe the kids at school. The investigators found a significant increase in hyperactivity during the weeks the kids (both 3 year olds and 8/9 year olds) consumed the drinks containing the artificial colors. Some kids appeared to be more vulnerable to the effect than others, but the overall effect was a 10% increase in hyperactivity. It was similar to the results found by an earlier meta analysis, and, in summary, the effect of removing additives from the kids' diet is about 1/3 the effect of giving kids Ritalin to calm them down.

The analysis of the study came down to this - some kids are very sensitive to additives, and their behavior will be significantly impacted. With other kids, it won't matter much. The results of the study, however, were impressive enough that the UK and several other European countries banned the use of the studied food additives, so Skittles sold in the UK have no sunset yellow or tartrazine, though as far as I know, Skittles in the US have the same old recipe of hyperactive family fun. Sodium benzoate was not banned.

So why is the Harvard Mental Health Letter so noncommittal? Well, they cite a well known study of 35 mother-son pairs where the mothers believed the boys, ages 5 to 7, were sugar sensitive. The researchers told the Moms that the boys would be randomly assigned to a dose of high sugar or a dose of aspartame. In reality, all the boys received aspartame. The mothers who thought their sons got sugar reported their child's behavior to be significantly more hyperactive afterward. "The researchers concluded that parental expectation may color perception when it comes to food related behaviors." Really? Well, doesn't a double-blind prospective cross-over design with independent examiners CONTROL for that sort of thing in the Southampton Study? I would think so.

The medical letter goes on to talk about Omega 6 to Omega 3 fatty acids (they recommended kids consume 12 ounces of low mercury shellfish or fish a week) and micronutrients (deficiencies in zinc, iron, magnesium, and vitamin B6 have been documented in children with ADHD, but there is no evidence that supplementation is helpful, and megadoses, which can be toxic, should be avoided). Eventually, they recommend "a healthful diet" for kids and minimizing processed and fast food. Well, I can get behind that. And, frankly, I don't recommend a steady diet of skittles to anyone, though it would be nice to have the option (as the European moms do) of having candy without the crappy additives. Since hyperactivity affects 10% of children (1), what they eat can have a large effect, overall, on kids and parents alike.


  1. The Southampton study is a gem of a find! I wonder what makes some kids more sensitive to additives and preservatives than others. I'm guessing epigenetics plays a big role here.

  2. It was a bombshell in Europe, but I don't remember hearing a peep about it in the US. I first heard about it in a book called "The Unhealthy Truth," which isn't the greatest book in the world, but it has some interesting speculation in it as to some reasons our kids are getting so unhealthy so quickly (rise in asthma, allergies, obesity, autism, etc.). She mostly suspected food allergies and genetically modified soy and wheat.

    Anyway, Europe with socialized medicine saw that study and decided that they would ban the food additives - cuts the bottom line to have kids less hyperactive and needing less medical attention for hyperactivity. In the US we don't really have the same bottom line motivation. Though a lot of kids are on Medicaid, Medicaid is organized by state and, in my experience, not particularly thoughtfully or efficiently run.

    I read a couple of other articles diminishing the results of previous trials (which weren't as well done as Southampton, being too short, or without clear results from independent examiners). They focused on the "hardship" of adopting a "different" diet when the benefit is unclear. Since the benefit and hardships are really individualized, I feel that the results of Southampton should be made known, so that parents can make an informed decision if they want to avoid food additives or not. Though I don't see food additives as that difficult to avoid - unlike dairy or gluten. There is even quite a bit of processed food without the sketchy additives - usually they are in the organic section, but often they are no more expensive than the regular brand name yellow number five food. But of course there are kids who will only eat the orange Mac and cheese and any other food brings on WWIII. Which, once again brings the decision back to the parents, where it belongs.

  3. Emily,

    Great post! I love your blog and all the neuro aspects of your insights!

    Dr. Dan at Darwin's Table just on Russell Blaylock MD, neurosurgeon who advises gluten and soy-free lifestyles (sounds evolutionary!). He talks about food dyes and other neurotoxins (sugar, insulin , aspartame, etc). The lecture is good.


  4. Thanks Dr. BG! To be perfectly honest, I had avoided reading Blaylock up until now, as I've consumed more than my fair share of diet soda over the years. Some things you just don't want to know... however, that PDF is very interesting. As I was reading it, it struck me how he described excess nitric oxide as part of oxidative stress. I never understood why the endothelium becomes resistant to nitric oxide in metabolic syndrome. Do you think it could be a protective mechanism? (This is the best part of these blogs - tossing ideas about.) I'll get around to linking Animal Pharm very soon!

  5. EMILY!

    One of my best gal pals, her mom recovered from breast CA and LOVES LOVES LOVES Blaylock. He appears PALEO (though my girlfriend is a pastry chef -- so she tried some gluten-free amaranth baking etc which tastes like DIRT and subsequently reverted). I added oregano oil to our grassfed ground pork/beef chili and rice pasta/veggie/meat Italian dishes and WOW the flavor is great and the kids don't even pick up on it.

    If Blaylock weren't so science oriented, his charm, southern accent and quirky grin would turn me off. NOT. *haa*

    I never thought of NO resistance...! I believe you are entirely on to something. Personally I have never heard of thyroid hormone resistance either, but why not? And apparently it exists. Must be adaptive too? The more I know, the less I know...



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