Gaps in the research on diet and ADHD – how dietitians can fill the current research needs

A 2012 State-of-the-Art Review article on diet and behaviour recommends just a healthy diet for treatment of attention deficit hyperactivity disorder (ADHD). However there is sufficient research available to say a diet free of additive colours, flavours and some preservatives has a role in some of children with ADHD. The best summary is to say that diet factors “aggravate the underlying disorder in susceptible people”.

My aim has been to contribute to diet and ADHD thinking. The reactions are not allergy but food chemical intolerance. The new focus is on individuals and the additives and foods they react to. There is no one correct diet for ADHD. Each diet-responder develops their own.

 

For this study quantitative and qualitative research with emphasis on the diet therapy practice from 1974 to 2012 was investigated. What was found? Overall research has shown that diet has a role in some. The diet therapy practice of managing diet investigation is known. Initial diet options are available. Clinical research has provided most information on which diet is most effective, which children are likely to respond and what diet changes. However the gaps in the research still affect acceptance of this useful treatment.

 

First gap – which diet is best to begin investigation?

The first gap is the lack of clarification of which of the various diets is best for screening, depending on age, sensitivity, motivation, and symptom severity. The diets used in research range from a strict few foods diet to the low chemical diets, and the Feingold Diet. Dietitians can fill the gap by individualising the Diet Detective Baseline diet: a diet limiting additives, salicylates, amines, and monosodium glutamate. They can incorporate suspect food the patient suspects as causing reactions, suspect foods and environmental factors that are implicated in the range of symptoms that food sensitive family members often have. They can individualise the exclusions via the Family Sensitivity History, developed from clinical findings, as well as any foods shown as positive in allergy tests. Additional information with regard to sensitivity to smells, especially noticing stale foods, or foods that are regarded as “strong”, “off” or “too rich”, or are strongly disliked or avoided, needs to be attended to. Smells include perfumes, and any other environmental smells, often really liked or hated. This individualisation produces the Family Baseline Diet.

The dietitian can decide on the strictness of the reduction of suspect chemicals and whole foods. There is a place for reduction of suspect foods to avoid complete exclusion such as use of limited well cooked crusty or toasted bread or dry biscuits, rather than wheat exclusion. Useful low chemical foods providing nutrition, including canned tuna, cornflakes, and peanut butter, can be retained in limited amounts. Favoured foods can be replaced with others, such as use of home-made gravy or very mild chutney rather than highly flavoured commercial products. Children over eight years can manage a more liberal diet than younger children.

 

Second gap – the cause of the food reaction is not known

The lack of a single well defined cause [some physiological problem] prevents knowledge of a test for responders. This is important as food sensitivity is in the child not in the diagnosis. The tendency to be food sensitive is probably genetic. Dietitians can collect information about the three generations using the Family Sensitivity History tool. A positive diet response is more likely in families which have more of the symptoms known to respond to diet. These include eczema, migraine, irritable bowel syndrome, asthma, chronic headaches, car sickness, mouth ulcers, whether or not these are connected to known reactions to foods or additives. It is interesting to note that these clusters of symptoms are less often present in those with lifestyle disorders.

 

Third gap – insufficient data on individual variation

Research has shown that the foods which cause most reactions include some additives, natural chemicals and whole foods. It is becoming more evident that individuals differ in what causes reactions, not just in which challenges they react to but to individual foods in each challenge category. Dietitians can fill the gap by collating clinical findings on individual variation, remembering that food sensitivity is in the person and that that person has their own biochemistry. Note what was found in families where ADHD was being investigated. Of 100% who reacted to additive colours and flavours, 80% reacted to chocolate and tomato sauce, 50% reacted to soy sauce, 33% limited dairy, 25% limited wheat, carob and vanilla, and only 2% reacted to cane sugar. It is important to allow challenges and food trials to take around 3 months for each patient to clarify their own best diet. Individual food challenges provide the flexibility needed for each person, remembering that individual tolerance changes over time and people vary in what foods they want to attend to. The sum total of all that affects tolerance is the Total Body Load of all that can contribute to the threshold for a reaction. It includes suspect whole foods, inhalants, additives, smells in the food or in environment, seasons, hormone changes, infections, sensory input, stress, and age.

Fourth gap – which foods cause most reactions

Dietitians can fill that gap by collecting data on what patients report reactions to. This is research into adverse reactions, so we need to shift to applied-research clinical findings,  from narrow double-blind-placebo-controlled trials, or reliance on tables of analyses of suspect substances. Each dietitian can collect more data on tolerance of individual foods to provide information on likely risk of a reaction, to update findings over years. Clinical findings have value where each patient is an individual with their own “metabolic fingerprint”. We accept that some people have side effects to medicines, so documenting side effects to foods and additives is important as well.

Conclusion

Dietitians need to be assertive, as dietetics is the profession that can best provide answers about diet and behaviour. Clinical findings can be collated to provide a basis for a sophisticated understanding of the best initial diet, which children are diet responders, and what foods and additives are not commonly tolerated. This information will inform those who are researching the possible mechanism so that food sensitivity is better accepted, and those who wish to provide best dietetic practice are as well informed as possible.

Presentation at the International Congress of Dietetics  Scientific meeting by Joan Breakey Sept 2012