Does a Diet Work for ADHD? Elimination Diets, Dyes and Sugar

In the first months after the diagnosis the subject on which I received the most advice was nutrition. Cut this, add that, never touch that group.

All the advice was well-meant and none of it told me its source. So I sat down and looked, because part of my job is already looking behind claims.

The picture that came out was clearer and more boring than I expected. In this area there are many claims and little evidence. But "little" does not mean "none," so they have to be separated one by one.

Sugar: no evidence

The most widespread belief and the best refuted one.

The meta-analysis by Wolraich and colleagues (1995) combined 23 double-blind controlled studies and concluded that sugar does not affect children's behavior or cognitive performance.

The interesting side of this finding is this: in the same research area it has also been shown that parents who believed their child had eaten sugar rated the child as more active. So the effect happens in the observer. I covered the details in the article on whether sugar causes ADHD.

Food dyes: small and limited evidence

Here the picture is more mixed, and nobody likes to say it in a single sentence.

The meta-analysis by Nigg and colleagues (2012) reports that artificial food dyes may have a small effect on behavior in some children.

Three notes have to be held together:

• The effect is small and is not seen in all children.
• A sensitive subgroup is mentioned, but who makes up this group is not clear.
• This finding does not mean that dyes cause ADHD.

While writing this I ask myself: what does this information give a family? In my opinion, one thing. Cutting down on a product with artificial dyes is a cheap and harmless trial. But thinking that this is a treatment will cost you dearly.

Elimination diets: hard to follow, evidence disputed

An elimination diet is based on taking out possible trigger foods and then adding them back one by one.

Positive results have been reported in some studies. But the meta-analysis by Sonuga-Barke and colleagues (2013) gives a critical warning: the effects in this area shrink markedly when the assessment is blinded.

The reason is understandable. A family that follows a laborious diet for weeks tends to see the change. This is not bad faith, it is a feature of being human. I noticed that I do the same in my own trials: when I put effort into something, I want it to have worked, and I see what I want.

We cannot measure whether a method works through the observation of the person applying it. This is why blinded assessment is the whole point.

The risk of restrictive diets

This is the most skipped side and, in my opinion, the most important.

Taking an entire food group out of a child's nutrition, when done without a doctor's supervision:

• It can lead to nutritional deficiency.
• It can affect growth.
• It can produce tension and anxiety around food.
• It can set the child apart socially: birthdays, school, visiting.

There is also an invisible cost. While the family spends all its energy on the diet, treatments with strong evidence are postponed. Time is a resource too, and childhood does not come back.

If elimination is to be done, it should be done with supervision. If removing a food is to be tried, it has to be planned with a doctor and, if possible, a dietitian. The period should be limited, the adding back should be planned, and whether there really is an effect should be assessed with a criterion set in advance. The decision on diagnosis and treatment is the doctor's job.

So is nutrition not important at all

I am not saying that. But the role has to be named correctly: it is not a treatment, it is a groundwork.

The real and practical matters about nutrition in ADHD are, in my opinion, these:

Skipping meals. Not eating for a long time directly spoils focus. This is the most obvious one for me: when I get absorbed in a job I do not notice lunch, and in the late afternoon I wonder why I cannot think of anything. The name for noticing hunger late is body signal blindness.

Stimulant medication and appetite. Suppression of appetite is a known side effect. Not eating through the day can lead to making up for it in the evening. This is something to tell the doctor.

Irregular eating patterns. Impulsive food choice and emotional eating are commonly reported. I covered the relationship between binge eating and ADHD in a separate article.

Iron and B12 deficiency. These are not a diet matter, they are a treatment matter. A deficiency can produce tiredness and attention problems and is checked with a blood test.

The omega-3 debate is a separate heading and has its own table of evidence; I covered it in the article on whether omega-3 is good for ADHD. The practice of the kitchen side is in the article on nutrition.

Why are there so many claims in this area

A question stuck with me: when the evidence is this weak, why is this subject talked about so much?

I found a few reasons. The first is that nutrition is something you can control. The diagnostic process is long, there are waiting lists, the decision on treatment is in someone else's hands. The fridge is in your hands. Clinging to what is in your hands is very human.

The second is guilt. Especially families whose child has been given a diagnosis are left alone with the question "what did I do for it to turn out like this." Diet promises an answer to that question and a way of making up for it. Because the promise is strong, the demand for evidence weakens.

The third is that ADHD is a fluctuating picture. There are good days and bad days. If the week you make a change happens to be a good week, it is very easy to count that change as the cause. I lived this with my own coffee hour: I saw two good days and believed that I had a rule.

Understanding these reduced my anger at the people who give advice. But it made me take the advice itself less into account.

If you want to try something

Setting up the trial like an experiment is the only approach that has worked for me.

1. First write what will change. "It will be better" cannot be measured. "How many times the teacher warned in a week" can be measured.
2. Set a period. Something like four weeks. Open-ended trials do not end, they are just forgotten.
3. Change one thing. If three things are changed at the same time, it cannot be known which one worked. I broke this one most on myself: in the same week I would change my sleep hour, the coffee and the breakfast, and then look at the result.
4. If possible, get the observation of someone who does not know. If the teacher does not know what is being tried, her observation is more valuable.
5. Plan the stopping too. Decide at the start when you will stop if it did not work. Otherwise a method turns into a burden that produces guilt when you drop it.

Where I arrived on this

There is no general ADHD diet. For sugar there is no evidence, for food dyes there is small and limited evidence, for elimination diets the effects shrink with blinded assessment.

What really relieved me was this information. Because knowing that there is no evidence behind the sentence "if you had eaten right you would not be like this" lightened a guilt I had carried for a long time.

The reason I pay attention to nutrition today is not to cure ADHD. It is knowing that I cannot do anything when I go hungry. Even that much makes the difference of some days.