Diet and the ADHD child: part 2, by Dr Nina Bailey

Part two –identifying dietary triggers

In August this year I drew attention to issues centred on feeding and nutritional deficiencies often associated with ADHD.   Whilst the benefits of several nutrients, including omega fatty acids, amino acids and numerous vitamins, are well documented for their favourable outcomes on the symptoms of ADHD, the negative effects of certain dietary components on ADHD symptoms are also of long-standing interest.    In this article I aim to outline some of the difficulties that sufferers can experience when it comes to establishing (and therefore avoiding) those foods or food components that may trigger or exacerbate symptoms.

Is food the real medicine? Many parents report dramatic improvements in their children with simple dietary adjustments

One of the most acknowledged of the dietary theories for ADHD is the hypothesis that allergies or hypersensitivity to certain foods or ingredients cause learning and behavioural problems and has been of great debate for several decades.  A specific hypothesis that food additives, which include synthetic food colourings and flavouring, influence ADHD was first suggested in the 1970s by Dr Benjamin Feingold.  Working as a paediatrician and allergist, he wrote a book entitled ‘Why Your Child is Hyperactive’[1]; his theories that a sensitivity to food additives and naturally occurring aspirin-like substances called  ‘salicylates’ found in fruits and vegetables, are responsible for ADD or ADHD now form the basis of the Feingold elimination diet.      His observations have led to many scientific studies and, while not all clinical studies have supported his findings, a recent review has suggested that, of those children with suspected sensitivities, 65% to 89% have reacted when challenged with at least 100 mg of artificial food colouring [2] and that around one third of children with ADHD can respond to a dietary intervention that excludes artificial food additives [3].

The Oligoantigenic diet

In addition to sensitivity to artificial food colourings and salicylates, some children are also sensitive to common non-salicylate foods (such as dairy, chocolate, soy, eggs, wheat, corn, legumes).  In contrast to Feingold’s theory, it is hypothesised that some symptoms of ADHD may be the result of opioid peptides formed from the incomplete breakdown of foods containing gluten and casein.  Opioid peptides are short sequences of amino acids (the building blocks that make up protein) that bind to specific receptors in the brain.   Increased intestinal permeability, also referred to as ’leaky gut syndrome’, allows these peptides to cross the intestinal membrane, enter the bloodstream, and cross the blood-brain barrier.  Given that the opioid peptide system is known to play an important role in motivation, emotion, attachment behaviour, the response to stress and pain, and the control of food intake, their production could produce opioid-like activity on the brain, causing significant changes in behaviour, thus explaining some of the symptoms associated with ADHD [4]. Fortunately, there is plenty of evidence that probiotic supplementation can beneficially influence intestinal barrier integrity, helping to combat leaky gut by improving the naturally health gut flora [5].

The sugar link

Sugar has long been suspected to be a culprit,  not only in the symptoms of ADHD, but also in aggravating hyperactivity in children generally.  White sugar and other refined (simple) carbohydrates, such as those found in processed white bread and white pasta, white rice and most convenience foods, require little digestion whilst supplying few nutrients, but leech the body of important nutrients essential for the nervous and immune systems, as well as for healthy digestion.

Diets rich in simple sugars but low in complex carbohydrate can cause blood sugar levels to rise quickly. The body responds by producing insulin and other hormones that drive sugar down to too-low levels, causing the release of stress hormones, when it can make children irritable and moody.

The overall effect of this is the ‘sugar rush’ that ultimately leads to lack of focus, concentration and, overall, feeling fatigued and groggy. Sugar can also attach to protein and fat molecules, creating ‘glycation’ products that damage blood vessels and nerves, leading to tissue and organ damage.

A diet high in refined sugar provides ‘empty’ calories, can suppress the immune system, increase inflammation and can ultimately induce insulin resistance, leading to diabetes and numerous health issues [6].

The glycaemic index

The glycaemic index (GI) ranks carbohydrates according to their effect on blood glucose levels, and is a good guide as to which foods we should eat more of, and which we should reduce. Low GI foods release their complex carbohydrates slowly, thus avoiding the sudden spike in blood sugar – these we should eat more of!  Avoiding refined foods and sugar (rated high on the GI scale), as well as consuming foods with a low GI value, will help to keep blood sugar levels even and avoid unpleasant and unhealthy ‘sugar rushes’.

Is there a role for a ketogenic diet?

Much attention has been given to the concept that ADHD symptoms are associated with a ’Western-style’ diet, i.e. one that predominantly features energy-dense but nutrient-poor foods, high in refined grains, added sugars, and added omega-6 fats, but low in fish, fresh vegetables and fruit, vitamins, minerals, fibre and omega-3 fatty acids.    Observing our ancestors’ ‘hunter-gather’ style of diet (also known the Palaeolithic diet) that consisted of unprocessed animal and plant foods, with no grains, flour, sugar or refined fats has been suggested by many to have health-promoting properties beneficial in the management of ‘western-associated’ diseases [5] .

The very similar  ‘ketogenic diet’, which is low in carbohydrate but high in protein and fat, has been used very successfully in the treatment of intractable epilepsy, also appears to improve symptoms of ADHD in individuals with both disorders [6].  Two hallmark features of ketogenic treatment are the rise in ketone body production by the liver (as the body derives its energy from fat stores rather than carbohydrate) and a reduction in blood glucose levels [6].

Which diet would suit my child?

Each child with ADHD is an individual, responding differently to nutrients and foods; as such, there is no ‘one diet fits all’ approach.  Any diet that focuses on eliminating food groups or specific nutrients or anti-nutrients is time-consuming and can be disruptive to the household.  It’s worth persevering in identifying your child’s trigger foods and this will certainly help to narrow which food groups or specific nutrients or anti-nutrients to avoid.  Keeping a behaviour record linking meals/foods to behaviour can be a useful way to track dietary culprits. Some children will respond with only a few adjustments to their diet whilst others may need a more rigorous diet plan.


Start with the most obvious. Simply by cooking ‘from scratch’ with fresh organic products you can make some positive steps to eliminating:

•           Processed and refined foods

•             Artificial colouring, flavourings and preservatives

Not only is it easier to determine what your child is eating if you cook from raw ingredients, but the overall health benefits will also be superior.


Such a wide variety of nutritious foods contain salicylates that attempting to restrict them because of their salicylate content can cause deficiencies in a variety of vitamins and minerals that are required for the normal growth and development of the child.   For concise lists of foods high and low in salicylate see  Whilst avoiding them can be challenging, many children do respond well when they are eliminated or reduced.   Be aware, however, that deficiencies of certain minerals (such as zinc, iron, magnesium and iodine) may have a significant impact on the development and deepening of the symptoms of ADHD in some children and supplementing is certainly advisable to ensure your child’s requirements are met. The advice and guidance of a professional nutritionist may be of great help in such cases.

Wheat and dairy

The Gluten/Casein Peptides Test can determine if your child is unable to digest wheat, rye, barley and milk.  It may be worth speaking to your GP or a nutritionist/dietician and ask for your child to be referred for testing.   If you know your child is intolerant or has leaky gut, eliminating gluten and casein and sourcing a good quality prebiotic/probiotic supplement may help.   Increasing numbers of people are choosing to avoid grains in their diet, concentrating more on protein in the form of lean meats, poultry and seafood which reduces the appetite and promotes a longer satiety.  The Palaeolithic diet also emphasises fruits and vegetables, which are full of fibre, vitamins, minerals, antioxidants and other beneficial phytochemicals.

Making additions

When it comes to ensuring your child gets the right balance of nutrients (certainly where certain foods are eliminated) I would suggest supplementing with:

•           Vitamin and mineral supplement

•             Omega-3 EPA fish oil

•             Probiotics


Establishing the most effective diet regime can be exhausting in some cases; for example, balancing a grain-free diet with a low salicylate diet may be a challenging process.   The more foods you try to eliminate, the more complicated it will be to provide healthy meals and, with many children being picky eaters anyway, it can be challenging to win your child’s cooperation. Many of the restrictions put in place could be temporary, as you will discover ‘safe’ foods that do not cause problems, as well as those that do. Whilst it is important not to expect dietary changes to bring about either immediate or miraculous improvements in behaviour, many parents do find that, once a child settles into an appropriate routine, the outcomes are generally favourable.


1.            Feingold BF. Why Your Child is Hyperactive.  New York, NY: Random House; 1975

2.            Stevens LJ, Kuczek T, Burgess JR, Hurt E, Arnold LE: Dietary sensitivities and ADHD symptoms: thirty-five years of research. Clinical pediatrics 2011, 50:279-293.

3.            Nigg JT, Lewis K, Edinger T, Falk M: Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives. Journal of the American Academy of Child and Adolescent Psychiatry 2012, 51:86-97 e88.

5.            Souza NC, Mendonca JN, Portari GV, Jordao Junior AA, Marchini JS, Chiarello PG: Intestinal permeability and nutritional status in developmental disorders. Alternative therapies in health and medicine 2012, 18:19-24.

6.            Kondaki K, Grammatikaki E, Jimenez-Pavon D, De Henauw S, Gonzalez-Gross M, Sjostrom M, Gottrand F, Molnar D, Moreno LA, Kafatos A, et al: Daily sugar-sweetened beverage consumption and insulin resistance in European adolescents: the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study. Public health nutrition 2012:1-8.

7.            Spreadbury I: Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity. Diabetes, metabolic syndrome and obesity : targets and therapy 2012, 5:175-189.

8.            Stafstrom CE, Rho JM: The ketogenic diet as a treatment paradigm for diverse neurological disorders. Frontiers in pharmacology 2012, 3:59.

Print Friendly, PDF & Email
Seeking the antiageing elixir by Dr Nina Bailey
Feature story: Teresa Wilmott

Dr Nina Bailey

About Dr Nina Bailey

Nina is a leading expert in marine fatty acids and their role in health and disease. Nina holds a master’s degree in Clinical Nutrition and received her doctorate from Cambridge University. Nina’s main area of interest is the role of essential fatty acids in inflammatory disorders. She is a published scientist and regularly features in national health publications and has featured as a nutrition expert on several leading and regional radio stations including SKY.FM, various BBC stations and London’s Biggest Conversation. Nina regularly holds training workshops and webinars both with the public and health practitioners.