Nutrition for children with ADHD: what helps and what does not

Is there a diet for ADHD?

No. ADHD is a neurodevelopmental disorder, which means it affects how the brain matures. No consensus guideline recognises a dietary treatment for it. The British NICE guideline recommends the same for these children as for any other child: a balanced diet, good nutrition and regular exercise [1].

Paediatric guidelines take the same approach. They place dietary changes among interventions with very little evidence or little to no benefit [4]. The approaches with strong support are approved medication and parent training in behaviour management, with the school included in the plan [4].

So diet is not part of the treatment. It does matter for supporting appetite and growth, because ADHD and its medication affect how a child eats.

Do colourings and sugar make ADHD worse?

There is some truth to this. Since July 2010, European regulations have required a warning on the label for six colourings [2]. These are tartrazine, quinoline yellow, sunset yellow, carmoisine, cochineal red A and Allura Red AC. The warning states that they “may have an adverse effect on activity and attention in children” [2]. It is a precaution that applies to the child population as a whole.

The exaggeration is to turn that warning into a diet. Guidelines say not to recommend removing colourings and additives as a general treatment for ADHD [1]. As for broad elimination diets, in which many foods are removed and then reintroduced, there is no evidence of long-term effectiveness or of their possible harms [1]. The benefit seen in the short term is limited [1].

If you think a particular food changes your child’s behaviour, record it in a food and behaviour diary [1]. If the diary confirms it, the next step is a referral to a dietitian-nutritionist to work on it together with the paediatrician [1]. Removing foods on your own leaves your child with fewer choices.

Sugar is similar. An analysis of seven observational studies found an association between sugar, sugary drinks and ADHD symptoms [5]. The authors themselves urge caution because the studies differed greatly from one another [5]. Association is not causation. Even so, it is a good idea to reduce sweets and soft drinks for a simple reason: they take away appetite just when it is needed.

Do omega-3, vitamins or amino acids help?

Not as a treatment for symptoms. The 2023 Cochrane review brought together 37 trials in children and adolescents with ADHD [6]. It concluded, with high certainty, that polyunsaturated fatty acids such as omega-3 do not improve overall symptoms, as assessed by parents, compared with placebo [6]. They did not improve inattention or hyperactivity either [6]. Guidelines advise against offering these supplements to treat ADHD [1]. If there is an indication for another reason, your doctor or dietitian-nutritionist should prescribe them.

The idea that amino acids “feed” neurotransmitters, such as tryptophan or tyrosine, is not supported by trials. A 2022 review found 14 trials on tryptophan in ADHD, and none gave it as a supplement [7]. They withdrew it for a few hours to study its role, and most did not measure the main symptoms [7].

Gluten-free or casein-free diets—casein is the protein in milk—are listed among therapies without demonstrated scientific basis [3]. Some of these therapies can also cause harm, such as megadoses of vitamins [3]. If a blood test shows low iron or vitamin D, it is corrected because it is low, as advised by the paediatrician.

What should I do if the medication takes away their appetite?

This is the part we deal with most often. Loss of appetite is the most common adverse effect of stimulants, alongside stomach ache, headache and sleep problems [4]. It occurs with methylphenidate, lisdexamfetamine and atomoxetine too [3]. Stomach aches and headaches during the first few days usually pass quickly [3]. If they also have difficulty going to the toilet, our constipation guide includes dietary advice for this.

Regarding growth, a long-term follow-up study found an adult height 1 to 2 cm below the predicted height [4]. This occurred mainly with high, sustained doses. The effect slowed around the third year of treatment, and there was no subsequent catch-up growth [4]. That is why growth is monitored closely.

When weight loss is a concern, the NICE guideline suggests six strategies [1]:

• Ask the prescriber whether it would be better to take the medication with or after food instead of before.
• Add meals or snacks early in the morning or later in the day, when the effect has worn off.
• Ask for dietary advice.
• Offer foods that are energy-dense and nutritionally good quality.
• Ask the prescriber whether a planned break from treatment would be appropriate.
• Ask the prescriber whether switching medication would be appropriate.

The first and last two decisions are made by the prescriber. Before changing the timing of doses, talk to them. The other three are within our remit. The idea is to make the most of the times when appetite returns and ensure there is good food available then.

For children taking medication, height is measured every 6 months, and weight every 3 months until age 10, using the growth chart [1]. In Spain, the paediatric protocol suggests a check-up one or two months after starting, and then every 6 months, including weight, height and blood pressure [3].

What mistakes do we see in consultations?

Three mistakes come up repeatedly in consultations, and none is due to a lack of trying.

• Insisting on lunch. This is when appetite is lowest. Fighting over that meal tires everyone, while a well-planned afternoon snack and dinner can make more of a difference.
• Removing several foods at once. Cutting out colourings, gluten and dairy in the same week leaves a child who already eats little with a short menu. It also tells you nothing about what was working.
• Filling hunger with grazing. Biscuits or juice late in the afternoon may seem helpful. They arrive just before dinner, when the child might otherwise be hungry.

If they only eat four or five things

This is common. Variety comes from putting a new food next to a familiar one, in a small amount, without commenting on it or requiring them to try it. It matters more that the food is offered many times than what happens on the first day.

It helps to offer the same food in different forms, because raw carrot sticks are not the same as carrot in a stew. It also helps to involve them in shopping and cooking, and to keep mealtimes separate from conversations about school.

If they eat fewer than ten or fifteen different foods and reject entire food groups, tell the paediatrician. This is one of the warning signs. Our guide to nutrition during school age provides general guidance for this age.

What a day can look like, meal by meal

There is no fixed weekly menu, because the schedule depends on which medication is taken and at what time. This outline places the main meals when appetite is present.

Time	What to offer
Breakfast	The most substantial meal of the day if the medication is taken afterwards. Milk or yoghurt, bread with oil and tomato or with egg, and fruit
School break	Something that can be eaten with one hand and without cutlery. A small sandwich, including one with nut butter, and a piece of fruit
Lunch	Usually the meal that goes down least well. One small dish combining vegetables, protein and grains or potatoes, rather than three large courses
Afternoon snack	An important meal, because the effect starts to wear off after school. Yoghurt, fruit, bread with cheese or tuna
Dinner	The second opportunity of the day. Egg, fish, pulses or chicken with vegetables and bread. If they are hungry at bedtime, a glass of milk or a piece of fruit

For the school break and afternoon snack, how to prepare healthy school snacks for your children includes combinations we use in consultations. If they continue to eat little or lose weight with this outline, a paediatric dietitian working in coordination with the paediatrician may be able to help.