Apr 01 2014

Food Dyes and ADHD

There has been a recent increase in attention paid to the old question about food dyes and behavior in children. The idea that food coloring causes hyperactivity in children started with Ben Feingold in the 1970s. He popularized his “Feingold diet” for ADHD, which is still being promoted by some today.

Initial research showed a possible connection between certain food dyes, especially synthetic dyes, and hyperactive behavior in children. However, the next 20 years produced better controlled studies that did not show the alleged effect. It seemed like just another case of preliminary positive evidence that did not hold up to later more rigorous replication. Serious scientific interest in the question waned with this negative data.

However, recent popular interest in such issues has caused another wave of research. Dr. Oz’s website, for example, discusses the issue, giving it credence. Unfortunately, while it has renewed interest in the food dye question, the more recent research has not definitively answered the core question.

This is a complex research area because hyperactivity is often a subjective judgment, and behavior in children is subject to observer effects and placebo effects. Strict blinding and controls are therefore necessary.

Several recent reviews come to similar conclusions, which are more than a bit wishy washy. The Dr. Oz article cited one meta-analysis, but the conclusion of the analysis hedges:

Despite indications of publication bias and other limitations, this study is consistent with accumulating evidence that neurobehavioral toxicity may characterize a variety of widely distributed chemicals. Improvement in the identification of responders is required before strong clinical recommendations can be made.

Like other reviews and meta-analyses, they find a small effect, but also find serious problems in the data such as publication bias. They also find that the effect is most significant in a subset of children (called responders). While it is plausible that a subset of children, due to genetic differences, may have an adverse effect to some food dyes, while others do not, this makes interpreting the research more tricky.

A 2012 meta-analysis showed:

A restriction diet benefits some children with ADHD. Effects of food colors were notable were but susceptible to publication bias or were derived from small, nongeneralizable samples. Renewed investigation of diet and ADHD is warranted.

Again we see there are problems with publication bias (a tendency to publish positive studies more than negative studies), but also point out problems with the sample sizes. They also found an effect in some children but not others.

Conclusion

At present there does not seem to be a definitive answer to the question of whether or not any specific food coloring or combination of food dyes worsens the symptoms of ADHD or contributes to hyperactivity in children with or without ADHD. To clarify, there is no research showing that food dyes cause ADHD, the question is restricted to short term effects on behavior.

There are some common themes in the reviews and meta-analyses. The existing research is currently inadequate to definitively answer the question, and further research is warranted. There appears to be publication bias affecting such reviews. Many studies are small, have problems with selecting subjects, and have small and inconsistent effects.

It is possible there is an adverse effect on behavior in a subset of children.

I agree with one reviewer who concluded:

While these strictures could have positive effects on behavior, the removal of food dyes is not a panacea for ADHD, which is a multifaceted disorder with both biological and environmental underpinnings.

An effect from food dyes is possible, but its overall effect on ADHD is likely minor and only one piece to a larger puzzle. Unfortunately this leaves us without a clear recommendation for consumers.

It may seem obvious to recommend to parents of children with ADHD to try a dye-restricted diet in their children to see if it works. However, such subjective evaluation by parents is likely to be overwhelmed with confirmation and observer bias. It still may not be unreasonable to try it. At least there is no health risk to such a trial. But I would advice caution in interpreting the results, and weigh any perceived benefit against any inconvenience or added cost. I would not recommend draconian measures in the hopes of a dramatic effect.

Mostly I hope to see some further rigorous trials to more definitively put this question to rest.

 

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14 responses so far

14 Responses to “Food Dyes and ADHD”

  1. zorrobanditoon 01 Apr 2014 at 2:22 pm

    I am wondering if or why artificial food dyes are necessary in our food. (Of course the answer is, they aren’t.) I know that the cakes my daughter makes in the Netherlands are somewhat less colorful because some of the dyes available here are banned in Europe (for what reason I do not know), but they taste just fine, and her children do not turn their noses up at them.

    In general it seems a good rule to avoid highly processed foods, ingredients like dyes which make no nutritional contribution, stabilizers which make food inedible for long periods of time, and so forth, at least when possible. If bacteria will not eat it, do they know something we don’t?

    I am remembering one instance when I was camping in the wilderness and left some cookie crumbs near an ant hill (with vaguely god-like aspirations…see! manna!). The ants took all the crumbs into their nest, with great labor. Then, when I looked the next day, they had dragged all of it out again and left it on their trash heap.

    I didn’t eat the rest of my own share. I decided that they were giving out advice about some ingredient or other.

    I’d like to see more rigorous testing of some of these matters too. (Not by ants, by people.) If food dyes, for example, are actually harming a small proportion of the population….well, we can do without them.

  2. YtterbiJumon 01 Apr 2014 at 4:08 pm

    Steve, you are missing the obvious. A careful review of the literature on the topic of food dyes and ADHD will show that the causal link is in the other direction.

    Of course, children with ADHD are more likely to eat foods with large amounts of dye, due to the children’s natural attraction to bright colors and fussy behavior. In fact, a study where the children are “blind” should not show much if any connection at all between ADHD and food dye simply because the children can’t see the food.

    Therefore, we can clearly see that it is not the food dye that causes ADHD, but rather the ADHD that causes excessive consumption of dyed food.

    (April Fools! :D )

  3. BBBlueon 01 Apr 2014 at 4:37 pm

    There is truth in the observation that we “first eat with our eyes”. Visual cues are an important part of our perception of flavor and obviously, dyes are used to make food more appealing. Of course this is just cosmetic, but food color has a real effect on consumer preferences, so there is an obvious motive for the addition of food dyes. And then there are the clear negative consequences of removing certain food dyes: I, for one, was deeply traumatized when red M&Ms were discontinued.

  4. BillyJoe7on 01 Apr 2014 at 5:01 pm

    zorrobandito,

    If you went to a restaurant and they served you up a meal in which every item on your plate was white, would you object? Or would you just be happy that it tastes just fine.
    In the last thread, placebo meant everything to you but, in this thread, it is apparently useless.

    And I suppose we should eat only bread with mould on it, because if mould won’t eat our bread…

    And perhaps we should all be eating carrion like those birds who obviously know something we don’t.

  5. Teaseron 01 Apr 2014 at 6:19 pm

    “However, such subjective evaluation by parents is likely to be overwhelmed with confirmation and observer bias. It still may not be unreasonable to try it. At least there is no health risk to such a trial. But I would advice caution in interpreting the results, and weigh any perceived benefit against any inconvenience or added cost. I would not recommend draconian measures in the hopes of a dramatic effect.”

    You would not advise parents of children with ADHD to cut out all foods that contain dyes because they may be “overwhelmed with confirmation and observer bias”?

    The conclusion = “The science is in! No problem here folks, move along, just a little food dye….keep moving. Better luck next time!”

    The inference: “A personal note to parents. Rest assured your kids will grow big and strong on junk food! There is no evidence that dye’s contribute to ADHD. Plus its too scary to control what your kids eat so just keep feeding them any old crap that’s convenient. Don’t bother yourself with reading labels. Leave that to the experts.”

  6. Erinon 01 Apr 2014 at 7:12 pm

    My mom was a pre-school teacher for many years, and children’s pastor for a long time after that (not to mention a mother of several kids). She is absolutely convinced beyond a shadow of a doubt that food coloring–especially red dye #3, for some reason–causes kids to be hyperactive. It doesn’t matter what the research has shown. “I’ve seen it for myself! I don’t care what your studies say–that just proves your studies are wrong and science doesn’t know everything.” (My studies. Funny, I don’t remember becoming a researcher.)

    It’s impossible to discuss science-based medicine with her. She is utterly unmoved by any arguments about things like regression to the mean or placebo effect. If she believes that she’s personally experienced something and seen it work–from nutrition woo, to homeopathy, chiropractic, folk remedies, prayer, etc.–than there is nothing that will convince her it doesn’t work. Likewise, if she (or someone she knows) has had a bad experience, then there is nothing that will convince her to try it, which unfortunately has kept her from a few interventions over the years that might have really helped her (like an epidural when giving birth, or medicine when she has a UTI–”I just need to drink more cranberry juice!”). Hell, I wasn’t allowed to get my ears pierced until I was 18 because there was a little girl in the pre-school she directed that got a terrible infection from a piercing. It didn’t matter that it was no longer 1981, or that I was 13, not 3.

    It’s frustrating, because I’m disabled and so I’m living with my folks right now, and I’m pretty dependent on them. Mom is always hearing about new treatments or alternative practitioners who she’s convinced will be able to “fix” me (even though it’s an incurable, chronic condition). It doesn’t help that we live in Marin County, CA: woo central. And when I turn down her advice, because I know that the evidence doesn’t show that the particular treatment works, than she accuses me of not wanting to get better. I’m just glad I don’t have kids…as annoying as it is right now, I’m pretty sure she’ll be nearly unbearable once she’s a grandma.

  7. grabulaon 02 Apr 2014 at 1:51 am

    @Bandito

    ” If bacteria will not eat it, do they know something we don’t? ”

    No. In fact some of those additives are designed to keep kinds of bacteria away, for what should be pretty obvious reasons so this line of logic is pretty bad.

    I often see people point to countries who ban things we still use as if that’s an indicator of something they know (or a government/corporate conspiracy) that we don’t. However a little research shows we too ban things others around the world find acceptable. I generally find that a weak argument.

    This is similar to the yoga mat bread argument a few weeks ago. We understand how the body processes foods and additives pretty well. Admittedly sometimes mistakes are made but overall those are few and far between and are often way more exaggerated than the reality. The reason things are added like dyes and ‘fluffers’ is because things that look prettier and fluffier are chosen over things that are flat and colorless.

    Anecdotally, my mother in law has bought into the idea that she is gluten sensitive (as usual no science behind the choice, just cruising the interwebs – but I pick my fights appropriately). Gluten free foods in general definitely taste different, and when made from scratch don’t look a lot like they should, or I think they should. But you can bet they’re putting stuff in the mass produced stuff to make it look more palatable. They don’t need too, but it certainly sells gluten free product.

  8. Bill Openthalton 02 Apr 2014 at 4:08 am

    grabula –

    Anecdotally, my mother in law has bought into the idea that she is gluten sensitive

    Another one bites the dust.

  9. grabulaon 02 Apr 2014 at 5:49 am

    yeah, don’t even get me started. My fear is it’s going to lead her down a darker path, or convince my wife it’s all ok. That’s primarily why I’ve chosen to stay out of it, if I have to fight to raise my daughter in a rational house then I’ll step up at that time.

  10. Bill Openthalton 02 Apr 2014 at 6:35 am

    grabula –

    My daughter went down that rabbit hole. My wife is a staunch believer in vitamin supplements. No amount of evidence will shake a believing mind. On the contrary, in many (if not most) cases, incontrovertible evidence seems to strengthen the convictions, leading to a post-modernist rejection of science.

  11. SteveAon 02 Apr 2014 at 7:45 am

    zorrobandito: “I know that the cakes my daughter makes in the Netherlands are somewhat less colorful because some of the dyes available here are banned in Europe (for what reason I do not know).”

    The European Union operates a ‘white list’ with regards to food additives. If it’s tested and approved it gets an ‘E-number’ to signify it can be used within the EU. Just because an additive is not used in the EU does not mean it’s been banned (a ‘black list’); it could mean it’s not been put forward for testing. There might be many reasons for this, for example, there’s an approved ‘E’ additive that already produces the effect you’re after.

    To get an E-number, an additive has to meet the regulations of every EU Member State, yet some ‘whole-food’ nut-jobs still treat them as the mark of Satan. I guess ‘E’ sounds too ‘chemically’ for them. They forget that even vitamins have E-numbers.

  12. Kawarthajonon 02 Apr 2014 at 9:33 am

    I see many parents who have eschewed their family doctor in favour of a “Naturopath”, whom they are now using as their primary health care provider. When their children have behavioural or attentional problems, they take them to the “Dr.”, who prescribes them gluten-free, dairy free, sugar free and dye free diets, as well as prescribing all kinds of nonsensical “natural medicines”. At first the parents report an “improvement”, but invariably the “improvement” doesn’t last and the parents end up in my office asking for advice on how to manage their out of control child.

    In Canada, where I live, access to a real physician is free. Access to a Naturopathic “doctor” is not, but extended healthcare benefits often cover these services. It is unfortunate that employee benefit packages are helping to support people in “switching” to a Naturopathic “doctor”, instead of getting real healthcare. The idea that dyes (and other nonsense) cause behavioural problems in children is a powerful one in my area and often blinds parents to the real causes of their child’s problems – inappropriate marital conflict, inadequate parenting, and a child’s natural temperament. It causes parents to delay getting appropriate support and care, while they try various nonsensical diets and supplements – a seemingly easy fix to a very complex problem.

    Hope you liked my “liberal” use of quotations! ;)

  13. ccbowerson 02 Apr 2014 at 11:03 pm

    “However, such subjective evaluation by parents is likely to be overwhelmed with confirmation and observer bias. It still may not be unreasonable to try it.”

    That is a tough situation, for the reasons you mentioned. It seems that some people are particularly prone to confirmation bias, and when you combine that with a person who is prone to the naturalistic fallacy and health fads, it can be problematic. It’s one thing if an adult has convinced themselves that they are gluten sensitive, require raw foods, and is in need of weekly coffee enemas, but I do get concerned when those same people are then making decisions for their kids with that same mind set.

    Is diet an area in which a person is likely to see improvements with ADHD? I don’t know, maybe it is reasonable to try, but it also seems like a problem if there are treatments that clearly help, and a perons becomes focused on the ones that ‘might’ help (‘might’ being primarily supported by arguing for subgroup benefit and appealing to future evidence).

    A person could easily send themselves on a wild goose chases, trying to identify foods that correlate with something as erratic as a child’s behavior.

  14. grabulaon 03 Apr 2014 at 5:29 am

    Bill, I sympathize. I can’t stop my daughter when she becomes an adult from making the wrong decisions. I can only hope to teach her to look at the world rationally and hope she follows that path. As for while she’s a child my wife and I have talked and so far she’s promised not to buy anything approaching fakemed without talking to me first. I can only hope.

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