Blog Post

Nutrition for ADHD: A Dietitian’s Guide

Nutrition for ADHD Featured Image Ideal Nutrition

When it comes to ADHD, the connection between diet and symptom management is both fascinating and significant.

ADHD is a broad topic though.

The goal of this post is to cover most of the key things that matter.

I want to acknowledge that:

  • It would be silly to say that nutrition can “solve” or “cure” ADHD.
  • It would be equally silly to say that nutrition plays no role in ADHD.

The first section of this article will cover nutrients of interest. The reason we will start there is because there is a lot of research highlighting situations where nutrition can play a clear role in helping symptoms.

The other sections of this article will focus on:

  • Logistical challenges
  • Elimination diets
  • Thoughts on food colours
  • Thoughts on sugar intake.

Feel free to jump straight to whichever section interests you.

Quick Caveats

The consensus is there is no clear evidence that ADHD is caused by nutrition. That is true. While that is true, we also have evidence that ADHD is more common in those following a Western dietary pattern.

Since diet can play a role in symptoms, it could also play a role in pushing somebody over the edge to getting a diagnosis as well.

The other thing I wanted to touch on is that some of the theoretical stuff I touch on might be more practical for some cases than others.

For example, parents trying to help their child with ADHD will face different challenges than an adult with ADHD looking after their own nutrition.

This article is meant to be broad and relevant for most cases. But that also means some components will be less practical for certain people.

Nutrients of Interest

There are a lot of nutrients that have been identified as playing a role in ADHD.

Many nutrients have been identified as having different intakes and levels within the bodies of those with ADHD.

The issue with that is that it leads to a “chicken or the egg” problem.

Are people with ADHD more likely to be deficient in certain nutrients because of how they eat? Or are they more likely to have more severe ADHD symptoms because of these deficiencies?

This problem will be factored in, by largely focusing on how addressing certain nutrients has been shown to improve symptoms in research.

Iron

Foods that are high in iron

Low levels of iron have been correlated with inattention, cognitive deficits, and other symptoms of ADHD.

One study found that ferritin levels (a marker of iron stores) were low in 84% of children with ADHD. In the control group, 18% of children had low ferritin. That is a huge difference.

Research has consistently found that addressing this with iron supplements has led to improvements in symptoms on average.

More research would be helpful to potentially make this link clearer.

Omega-3 and Omega-6

Omega 3 Supplements

A 2017 review identified that 13 out of 16 studies on omega-3 and omega-6 supplementation found favourable improvements in hyperactivity, impulsivity, attention, visual learning, word reading, and working/short-term memory.

A proposed mechanism of action is that they play a role in the optimal transmission of messages in the brain and have an antioxidant effect which is relevant for ADHD.

Blood levels of EPA and DHA have also been found to be lower in those with ADHD. Lower blood levels have also been linked with more learning and behavioural difficulties in children.

Supplementation of omega-3 has been found to produce a small favourable improvement on average.

Zinc

Sources of zinc

Addressing a zinc deficiency has been shown to help improve ADHD symptoms.

Every study that has involved zinc supplementation has led to an improvement in symptoms. Examples are included below:

There is a common trend though. The benefits are likely more relevant in cases where intake was low at the baseline.

There are downsides to excessive supplementation of zinc supplementation. It is worth seeing your doctor to check your zinc levels and exploring an appropriate supplement dose if going down this route.

Magnesium

Magnesium

Those with ADHD have lower levels of magnesium in their bodies on average.

It is thought that magnesium supplementation could help improve symptoms of inattention, hyperactivity and impulsivity, particularly if addressing a deficiency. Small studies have backed up this assumption.

There is less research looking at this topic than other areas of ADHD though.

Vitamin D

Vitamin D3

Low vitamin D status has been associated with ADHD. And there is research indicating that addressing this leads to an improvement in symptoms on average.

The effect is likely relatively small, and more research is needed to confirm if this impact is consistent.

B Vitamins

B Vitamins - Blackmores

Adults with ADHD have been found to have lower levels of vitamins B2, B6 and B9.

From another perspective, supplementing B vitamins has not led to an improvement in symptoms on average.

Summary of Nutrients of Interest

An additional thing that makes this topic interesting is that multivitamin supplementation has been shown to improve ADHD symptoms on average as well.

Multivitamin Supplement

Although this section has largely focused on supplementation to address deficiency, it makes sense to prioritise a food-first approach where possible.

A lot of these situations where supplements have been beneficial have been when they are addressing a low dietary intake and/or low stores of that nutrient in the body.

It is arguably worth screening people with ADHD for nutrient deficiencies.

These things are worth addressing regardless of ADHD. The fact that they could help improve symptoms is a bonus.

Challenges People with ADHD Face

ADHD and Nutrition Challenges
Credit to The Nutrition Junky (https://thenutritionjunky.com/adhd-diet-nutrition-tips-from-a-dietitian/)

Many challenges are faced by people with ADHD.

Some of these include:

  • Inconsistent meal timing leading to overconsumption at night.
  • Struggles with binge eating disorder.
  • Impulsiveness impacting food choices.
  • Limited food selection due to preferences or sensitivities.
  • Digestive issues.
  • Hyperfocus leading to neglecting to eat for long periods.
  • Lack of appetite due to stimulant medications.
  • Frequently resorting to takeaway or other convenience options.
  • Eating to alleviate boredom or for stimulation.
  • Issues with meal prep and planning.

Addressing each of these is a case-by-case basis. And this section could get massive. So instead, some quick tips will be listed below.

Note: These tips are not going to be relevant or helpful for everybody. Take from this list what is helpful for you and leave what is not.

Tips for Overcoming These Challenges

  • Planning everything where relevant/possible.
  • Consider meal-prepping things in advance.
  • Use options that save time such as microwavable rice, pre-cut/cooked meat, frozen fruit and vegetables.
  • If appetite is limited by medication, consider eating breakfast prior to taking the medication. Other regular tips for getting more nutrition in can also apply here too.  
  • Use visual reminders such as placing food in places you regularly see.
  • If you are likely to miss key nutrients in your diet, it can be worth supplementing to cover those gaps.
  • Prioritise sleep, hydration and stress management. These all can play a large role in ADHD symptoms too.
  • Use tools where relevant such as checklists, reminders, alarms and calendars.
  • If you are having issues with binge eating, prioritising eating relatively frequently and eating enough total food throughout the day is super important. This is where the tools above can be especially useful.

Elimination Diets

It does not take much searching to find that a lot of people with ADHD have reported improvements in symptoms after cutting out specific foods.

There are many explanations for why this occurs. Directly looking at outcomes, the research has been consistently positive.

A 2020 systematic review found that only 2 out of 6 studies concluded that removing artificial colours was beneficial, but 10 out of 12 studies concluded that an elimination diet could improve symptoms.

In 10 of those studies, 50-80% of participants found improvements in symptoms. An 11th found improvements in 24% of children.

The most effective elimination dietary approach has focused on “oligoantigenic” foods. Basically, they have involved eliminating suspected high-allergenic foods.

List of High Allergy Foods

The Few Foods Diet

The most common method that has been utilised is “The Few Foods Diet.”

In order of steps, it is laid out like:

  • Elimination: This step involves following a strict diet of low-allergen foods that are unlikely to cause symptoms. If things improve, enter the next phase.
  • Reintroduction: Foods suspected of causing symptoms are reintroduced every 3–7 days. If symptoms return, the food is identified as “sensitizing.”
  • Treatment: A personalised protocol that is designed to balance food flexibility with minimising symptoms.

There is not as much easily accessible info on how to implement this diet as I would like. But if you are interested, this is an article worth checking out.

Caveat on the Effectiveness

From an effectiveness perspective, elimination diets look like they have the potential to be a useful tool to trial for ADHD.

One meta-analysis highlighted that a lot of the studies identifying the most benefit from elimination diets used non-blinded participants though. When accounting for blinding (which makes the research a lot more relevant) the benefits decreased to about 1/3 of their original size.

This point about research using blinding and placebo control is important. Particularly when analysing anecdotal evidence.

Example:

Scenario 1: Somebody makes a dietary change intentionally and notices an improvement in symptoms.

Scenario 2: Somebody has a dietary change made without their knowledge and symptoms improve. They then have the change reversed without their knowledge and symptoms get worse.

Which is more relevant?

I’d say the latter is more relevant.

But scenario one is still worth being aware of too.

Specifically with elimination diets, the research is still in their favour. It is just that they are likely slightly less effective than the average that has been found in the research.

In addition to the issue of blinding, another issue exists. Most of the research has just looked at the elimination phase. Theoretically, the treatment/individualisation phase should have similar results. But we don’t have research directly looking at that.

Downsides of Elimination Diets for ADHD

One of the trickiest parts about writing about this topic and working in this space is identifying WHEN an elimination diet could be a good idea.

The first step in that process is to identify downsides.

A lot of people with ADHD have difficulty achieving good diets in the first place. Elimination diets make this harder.

If nutrient deficiencies are already so prevalent, cutting out a bunch of nutrient-rich foods could make that issue worse. That could be resolved with supplementation, but this is still a downside worth identifying.

For those who struggle with binge eating, this could be counterproductive. Adding restriction is well-known for being problematic for somebody with a binge-eating disorder.

It is logistically hard to stick to as well. Things such as eating out and social eating, in general, can be quite difficult on an elimination diet like this.

Statistically speaking, not everybody benefits from it either. The highest success rates recorded involved ~80% of participants noticing benefits. But that still means the best-case scenario is that 20% did not get benefits. And logically thinking, the odds of success are significantly lower than that once you factor everything else in that has been spoken about.

And even in those who do experience benefit, it ranges from mild through to significant benefit.

The decision as to whether you should explore an elimination diet is very case-dependent. For some people, it will be worth it, and for many others, it will not be.

If going down this route, I urge caution and highly encourage working with a dietitian with experience in this space.

Thoughts on Food Colours

Lollies that contain Food Colours

Food colours have been consistently linked with ADHD symptoms, but the research and current consensus is nuanced.

One relatively well-designed study from 1994 explored this topic. They used a double-blinded placebo-controlled model. Then they gave children (200 total) either a placebo or tartrazine.

At the end of the study, a lot (but not all) were identified as clear reactors. There was also a dose-response effect. Higher dosages led to more symptoms.

It is not as clear-cut as that though, unfortunately.

Outside of that study, quite a lot of research has linked artificial colours with ADHD. However, a review of that research identified a lot of flaws that make it a bit less compelling than the research has indicated.

Another issue is that the same review highlighted that BOTH children with and without diagnosable ADHD appear to be affected by artificial colours. They concluded that artificial colours are less of an ADHD issue and more of a public health issue.

Some artificial colours are more closely linked with ADHD symptoms than others too.

My thoughts are:

  • Limiting intake of artificial colours to a certain degree is probably a good idea for most people, with or without ADHD.
  • It’s also worth acknowledging that not everybody experiences improvements in symptoms when excluding artificial colours completely. And some of the people who did experience improvements may not have experienced large improvements.
  • If avoiding them was unrealistic for whatever reason, at least trying to minimise intake of them could be worth trying.

Thoughts on Sugar

Sugar

Sugar can be a controversial topic.

Anecdotally a lot of people report sugar being a factor. However, research has not identified that link to a similar degree.

For example, a large meta-analysis found that sugar did not influence cognition and behaviour in children.

Why then would people identify stuff anecdotally?

There are a lot of explanations. Some include:

  1. Sugar gives us energy. If somebody was already hyperactive, this could make that be more of a factor.
  2. Sugar often comes alongside artificial colours. Example: Red frogs.
  3. Higher added sugar intake typically means lower micronutrient intake. We already see deficiencies in those with ADHD, so high sugar intake could contribute to that further.
  4. Expectations of sugar leading to ADHD symptoms potentially change behaviours and how we perceive the outcomes.

There are a lot more explanations.

Limiting added sugar is a good idea in a lot of cases regardless.

From an ADHD-specific perspective, the consensus among researchers (although there are exceptions) is that it likely does not play a direct role in ADHD. But there can be a lot of indirect reasons it could be relevant.

Summary

There is no ADHD-specific diet, unfortunately. And even if there were, the logistical challenges could make it difficult to adhere to a tougher dietary approach.

It is also worth mentioning that I could not cover everything in this post. So, if I have missed something of relevance to you, I apologise. I just wanted to avoid this post becoming massive.

One thing I wanted to add though is that there are pros and cons to research vs personal experience.

Research allows us to explore topics at a larger scale in a more controlled environment. However, due to sample size limitations and insufficient studies, it leaves a lot of gaps. This means that if you have personally found something that works well for you, even if it is not research-based, it might still be worth doing.

At a minimum, a lot of components of an “ADHD diet” line up with good healthy eating. The only exception to that might be if you did an elimination diet. But outside of that, prioritising a healthy, nutrient-rich diet is a great starting point.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.