Sunday, January 15, 2012

Diet and ADHD - A Literature Review

Last Thursday I had to report for jury duty.  Fortunately my number was on the higher side, so it involved me sitting in a room for a while reading some papers while the slots for the criminal case were filled.  I'm glad I wasn't selected -- the case involved the deaths of small children in a fire.  Ever since I had a couple of my own small children, I find it much harder to be "clinical" about violence and death when it comes to kids.  I put down Blood Meridian five years ago and haven't picked it up since.

Grieg - Holberg Suite (Prelude)

One of the terrific articles released this month is The Diet Factor in Attention-Deficit/Hyperactivity Disorder, in Pediatrics.  A couple of neurologists culled the literature, including not only the modern work done in Australia, England, and Belgium, but also the old Feingold stuff from the 70s.  They offer both an historical and evidence-based perspective, which enables one to see not only the science, but the human story of dietary treatments for ADHD.  Let's dive in, as there is a lot to cover.

The paper begins with a brief overview.  Basically, when it comes to dietary treatments for ADHD, there isn't that much to choose from that has been studied.   We start with the old anti-salycilate Feingold approach (which also avoids other major allergens, such as food dyes and other additives.) The diet involves avoiding apples, grapes, lunch meats, and any foods containing artificial preservatives or dyes.   One could eat certain cereals, beef, lamb, pineapples, bananas, pears, grapefruit, milk, eggs, and color-free vitamins.  Enthusiasm for Feingold was huge in the 1970s, however, clinical trial results weren't as impressive as the case reports.  Occasionally, certain children would have an amazing response, but overall the treatment was not helpful to most.

After Feingold waxed and waned (20 articles in pubmed between 1979-1988, 2 between 1990-2010), a newer elimination diet approach has come to the fore (based on the Southhampton Study I've written about several times, with the follow-up INCA study that was quite impressive).  The theory behind these diets and Feingold is that ADHD behaviors are, for some, a display of intolerance to certain foods.  The Southamption study backed this theory up with some superfly demonstration that the kids who were sensitive to food dyes had histamine systems that seemed to be more brittle and less able to clear out junk than other kids.

Hypoallergenic diets are a version of your basic "paleo autoimmune" diet - no wheat, cow's milk, cheese, eggs, nuts, chocolate, or citrus fruits.  Hypoallergenic foods include lamb, beef, potato, tapioca, carrots, peas, and pears.  (Another example is a "few foods elimination diet" consisting of turkey, rice, pear, and lettuce, in which 62% of children had a >50% improvement in behavior on the diet).  In pilot studies and the larger INCA trial, these diets typically resulted in significant improvement in 60% of the children who tried them.

The problem with elimination diets is that they are tough.  You have to be very strict, and the whole family has to be on the same page.  With every Disney character advertising a new processed food these days, it is harder than you think to keep the kids' diet clean even for a short duration of an elimination diet trial.  I know when I show up at snack time at the preschool, most of the kids have spritely-colored gogurt and goldfish and juice boxes.   My poor children (who don't seem to have behavioral or attentional problems) are stuck with water, prissy whole milk straight from the dairy delivered in glass bottles, fruits, meats, home fries, mashed potatoes, stew, veggies, and if they are lucky, the occasional organic pudding, yobaby full fat yogurt, or gluten-free pretzels.  Frankly, the only way I get them to eat mostly healthy is by stuffing them full of good stuff first and bribing them with a small amount of bad.

BUT, considering that such diets, when done with care, are a relatively harmless maneuver, it seems worth trying. And considering that most of the moms I know seem to have at least one son with some real attention-related issues, I wish there were more public support for these diets.  One mustn't have the expectation that the diets are a cure all, however.  Typically, 40% of kids will not respond.

Grieg - Holberg Suite (Air) - Right click to open in new tab.  I do like this piece.  One of my all time favorites.

Besides elimination diets, supplements with iron, zinc, and omega 3 fatty acids have also been attempted in the treatment of ADHD.  Long chain omega 3 PUFAs are lower in the RBC membranes of kids with ADHD compared to controls.  Kids with ADHD may have low O3 intake as well as reduced conversion of other long chain PUFAs to the essential O3s.  In the Oxford-Durham study, kids with coordination problems were given supplements made of 80/20 O3/O6.  ADHD symptoms improved in most of the kids, whereas no change was found in the placebo group.  Spelling and reading gains were also substantial in the experimental group over the 3-6 month follow up.  There were no adverse effects.  These authors, reviewing the 16 studies over the years, recommend doses of 300-600mg daily of Omega 3 with no more than 30-60mg O6 in the supplements (nordic fishes chews, nordic gummy bears, megared krill oil, and nature made were some examples of supplements used.) The authors note that in their clinic, most parents are enthusiastic about using omega 3 supplementation, but in almost all cases, additional medication treatment is required for meaningful symptom improvement.

Zinc!  I like zinc.  And in studies in Turkey and the Middle East, kids with zinc deficiency tend to be more hyperactive.  These regions have endemic zinc deficiency, unlike the West in general.  In a few US studies, zinc supplementation enhanced the benefit from d-amphetamine medicine.  The optimal dose of stimulant was decreased by 30% when compared to placebo. Since zinc is a cofactor for the metabolism of many neurotransmitters and fatty acids, it would make sense that having zinc stores tip top would help in ADHD.

Iron - kids with documented iron deficiency or low ferritin do seem to have more problems with learning disorders and cognitive function (yes, your brain needs oxygen!), however, in a random sampling of kids with ADHD, ferritin and iron was no different than those of controls.  It makes sense to check for iron deficiency in kids with ADHD, nevertheless.

Ketogenic diets have not been studied in ADHD, though in kids with epilepsy, attentional and behavioral problems often improve on the ketogenic diet.

Finally - sugar.  Despite the sworn testimony of every parent and pre-school teacher everywhere, sugar has never been consistently shown to increase aggression or activity in children compared to placebo, aspartame, or saccharine.  However, there is some data to suggest a cranky downward hypoglycemic response in some sensitive children.  And while adults don't tend to show behavior symptoms at a blood sugar greater than 54, children consistently show changes on EEG and in behavior at blood sugar levels less than 75 mg/dl.  Such a level is easily obtained by giving kids sugar only, while protein and fat can smooth the sugar spike and hypoglycemic aftermath.

Grieg - Solveig's Song (also very pretty).

And finally, the authors of the paper give a shout-out to the Australian study showing a link between Western Diet and ADHD symptoms.  The diet pattern had a higher intake of "total fat, saturated fat, refined sugars, and sodium, and is deficient in omega 3 fatty acids, fiber, and folate."  The "Healthy diet pattern... is rich in fish, vegetables, fruit, legumes, and whole-grain foods."  Of course, a family eating ho-hos, icing, and cotton candy is going to be a different sort of family than the one who eats whole grains and fish.  However, I'm all in favor of reducing processed foods.  Duh.

And that wraps up the summary of the study of dietary factors and ADHD.  GAPS was not mentioned.  In general, I would say, avoid additives and processed food, make sure your kids are stocked up with minerals, and don't go nuts with the sugar.  Elimination diets to determine special food sensitivities or gut bacterial overgrowth problems would probably be more helpful than harmful.  Pick your battles, but good food is a worthy fight, I would say.

(A sublime soprano version of Solveig's song by Marita Solberg can be found here.  Chills.  And I'm a much bigger fan of orchestral music than opera.)


  1. I enjoyed the music :)
    It would be interesting to create an optimal brain-diet, based on an individual's deficiencies, concerns. Like natural neurofeedback, except based on how each mineral/supplement/protein does what to brain's EEG.

    Hm, what minerals do you think are the most important for the brain? I wonder what the uniformity is of EEGs in children with ADD or ADHD

  2. It seems clear that medicine -- even evolutionary medicine -- has already harvested the low-hanging fruit. Our current challenges appear to be resolutely multifactorial both in cause and in treatment.

    It's certainly instructive, though, that there are so many dietary/nutritional interventions that make a measurable difference. And I'm still waiting for a study that demonstrates any meaningful disadvantages of any version of the paleo diet, whether traditional or functional...leaving us with the wisdom of Dr. Doug McGuff:

    "If the number is bad, eat healthy.
    If the number is good, eat healthy."

    Translated to the situation at hand: if your children are healthy, feed them real food. If they have issues, feed them real food.


  3. I'm convinced that diet is a factor. I'm also wondering what you think of the genetic hypothesis of ADHD, that it's associated with creativity as per this paper and as talked about in the 10,000 year explosion and discussed in this Atlantic article I've not read the book myself just the Atlantic article and did a little google research.

  4. Genetic? I think the answer is becoming much more obvious to us who actually read this stuff........its epigenetic!!! And that is all diet.
    Great Blog Emily.

  5. Sorry Valtsu, I deleted your comment by accident.

    Here it is:

    Valtsu has left a new comment on your post "Diet and ADHD - A Literature Review":

    Seen these papers? (table 1 is quite impressive)

  6. John, whenever someone states that something in its early stages of understanding is so "obvious" I immediately discount their opinion as dogmatic foolishness. Consider yourself discounted. Is the lipid hypothesis so obviously correct, also? You can double that down for the "those of us in the know" appeal to authority. I was merely curious if Emily thought there was any merit to the genetic factor hypothesis such as this association with the DRD4 gene.

  7. Hi Emily,
    I'm so glad to have found your blog. I have recently gotten great results after switching to a mostly "paleo" diet. However, I am a PhD (genetics/biochemistry) and have serious issues with the way that the paleosphere explains these results using drastic reductionism of amazing complex metabolic systems.

    "The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts." Bertrand Russell

  8. Sarah,
    Our complex metabolic system is just an example of complex systems, which can't be micromanaged , unlike a mechanical clock, or another mechanical system. While people live their lives fixing what they could, their experience tells them they can fix or micromanage anything if they understand how it works while it is not true for things like climate, body, economy. I try to learn how metabolism works because I am curious about is, but the more I learn, the more I realize how little I know about the subject. At the beginning of that learning it was not so clear as it is now. We live in the USA now, most medicine here consists of a very aggressive symptom-management and treating numbers (markers of deceases), which is a good example of an attempt to micromanage something what should be self-regulated. So we are trying to take care about our health by practicing prevention. I am an engineer, never got trained in medicine, very result-oriented. I resolved to some degree every health issue that I had by 45 yo by practicing very LC diet that could be described as a LC paleo. Probably I would never understand every detail why it worked, but it is enough for me to realize what I have to change in the input in my system in order to get the right output . For some ambitious people it may sound like a cheep mentality.

  9. Sean - I think It very plausible that ADHD has an evolutionary advantage. Let me look more closely at that article. (and write about it on something other than my phone)

    1. As an ADHD sufferer from a family rife with it, I cannot find any advantages whatsoever, evolutionary or otherwise. If the world were run by people like me, there would be galvanized nails and darning eggs at the grocery store, which would open at some other time than when you showed up to buy. And that is just the beginning.

      I have always thought the folks who assert evolutionary advantage -- or superior creativity -- are trying to feel better by deluding themselves they are somehow superior to the rest of the people who are in fact able to succeed at the basic stuff the rest of us struggle with.

  10. If there is a "twitchiness" gene that does better in the proper environment but worse in a difficult environment (this orchid effect as Dobbs calls it), then a crappy diet could explain ADHD by putting a huge strain on the system. So, by this reasoning, people with these genes are more prone to flourish in a healthy environment but more prone to be susceptible to NADs (and lousy parenting, etc). It sounds plausible, at least, but plausible ain't necessarily reality.

  11. Emily,
    So much fun reading you over here, and so pleased to find a psych on the same path. Connected from Google+ and do hope that you find CorePsych Blog of interest as I do more into the IgG matters and have considerable experience with productive alternatives and supportive elements [neurotransmitter precursors, immunity and hormone connections] for what doesn't work at times with traditional psych meds.

    Soon I'll be writing considerably on some of these comments regarding D2 receptors and testing for genetic aberrations that significantly add to food, alcohol, opiate, and sex addictions. 9 of these polymorphisms can be tested in the office, and very likely will change the way we practice addiction medicine in the future, and could play an important role in better understanding of ADHD and executive function.

  12. Hi. I have found your article's on omega /6 very interesting. I have read that omega 3 & 6 compete for the same enzyme. Does this mean that too much omega 6 stops the benefits of EPA and DHA. What is a good ratio of omega 6:3 to aim for? What is the optimal ratio?

    Kind Regards

  13. Seeing as how saturated animal fat has historically been a large part of the Human diet, is it possible that the 'low-fat craze' which has been firmly in place since the 1970's may have something to do with the high rates of ADHD (and perhaps other neurodevelopmental and behavioral disorders) in American children? Really, every study I've found investigating a link between fat intake and cognition has been flawed, either by not controlling for carbohydrate intake, or by increasing rates of polyunsaturated vegetable fats (which are not as healthy). Moreover, seeing as how saturated fat is important in many aspects of the development of the brain and body, perhaps eating higher amounts of sugar has starved developing brains of their most basic constituting principles.
    How are rates of ADHD, autism, OCD, ADD, etc. in cultures which eat high amounts of animal fat, some protein, and very few carbohydrates? Have there ever been any studies investigating such a subject?

    1. I actually just read a book called "Why We Get Fat and What to do about it" and "Wheat Belly" which both tough on how we have been misinformed as to what is making us fat and what is healthy food. The "whole grain" craze is debunked in both books (by author Gary Taubes)
      It talked about a study in which wheat affected people with ADHD (as well as those with schizophrenia). I have since taken my daughter off refined sugars and wheat and have seen a remarkable difference in her behavior. She is 4 and has a lot of "signs" of ADHD and while she is only 4 and could outgrow a lot of this behavior it has been trying so I have been doing all I can to help her through this time. These books are extremely interesting to say the least. I highly recommend them.

    2. The books also discussed the importance of good fats (such as nuts and animal fat and coconut oils...including the saturated fats everyone is so afraid of). I myself eat tons of good fats and am not fat. ;)

  14. Hello, thanks a lot you for the nutritional inspiration. Some days ago I came across an article by Johnson RJ et al, dealing with a hypothetical mechanism of sugar causing adhd symptoms. Do you happen to know about any further studies done in this area ?


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