ADHD symptoms and diagnosis

adhd-nutritionScientific proof that the behavioral disorder known as ADHD is caused by diet doesn’t exist, but research indicates a nutritional approach to improving symptoms can be very effective in some cases.

Attention deficit hyperactivity disorder (ADHD) has been the focus of many studies, and the role of dietary adjustments, as well as supplements, is still being explored.

Both children and adults can be affected by ADHD, and it is believed that genetics influence the risk for developing the disorder. (1, 2)

Malnutrition in early life has also been implicated, and exposure to toxic substances in the environment is under investigation as a contributing factor. (3, 4)


Reduced levels of noradrenaline and dopamine in parts of the brain responsible for self-regulation may be the origin point of problems associated with ADHD, leading to behavioral issues like these: (5, 6, 7, 8)

  • Difficulty in completing tasks
  • Impaired ability to perceive time
  • Inappropriate behavior
  • Trouble staying focused

These challenges often lead to problems in classrooms, as well as the ability to perform work or participate in satisfying relationships.

Considered incurable, ADHD treatments are usually focused on a reduction of symptoms through behavioral therapy and medication. (9, 10)

While the science behind how food impacts behavior is in developmental stages, the association clearly exists. Caffeine increases alertness, chocolate affects brain function, and alcohol consumption alters conduct. (11)

A lack of certain nutrients can also have significant effects; a recent study showed that test subjects displayed a significant reduction in anti-social behavior when given supplements containing minerals, vitamins and essential fatty acids. (12)

Violent behavior among high-risk school children decreased when they took supplements that bumped up intake of vitamins, minerals and poly-unsaturated fatty acids. (13)

Studies show children with ADHD often suffer from nutritional deficiencies and/or have eating habits that don’t promote good health. (14, 15)

Researchers have focused on two main areas of study in nutrition and its effects on ADHD:

  • Supplementation with one or more nutrients
  • Elimination of one or more dietary components

We’ll take a look at each approach with details about scientific conclusions.

  1. Amino Acid Supplements

Amino acids are necessary for functions carried out in every cell of the body, including the process of making neurotransmitters that send signals in the brain.

Neurotransmitters such as serotonin, norepinephrine, and dopamine require the presence of amino acids known as tyrosine, tryptophan and phenylalanine.

ADHD patients often have low levels of these amino acids in blood and urine. (16, 17)

Trials using supplementation of s-adenosylmethionine and L-tyrosine show mixed results, with some studies showing improvement in symptoms and others resulting in no change. (18, 19)

  1. Mineral and Vitamin Supplements

Children’s cognitive development can be negatively impacted by zinc and iron deficiencies whether or not ADHD is a consideration. (20, 21)

Reduced levels of magnesium, iron, phosphorus and calcium have been noted in children diagnosed with ADHD. (22, 23)

Zinc and iron supplementation have been shown to lead to improvements for children suffering from ADHD. (24, 25)

Mega-dosing with vitamins C and B3, B5 and B6 did not lead to notable improvements in children, but a multivitamin and mineral supplement used in an adult trail caused significant positive differences on an ADHD rating scale over an 8-week period. (26, 27)

  1. Supplementing with Omega-3 Fatty Acids

Children who don’t have ADHD generally have much higher levels of omega-3 fatty acids in their systems, and studies show children diagnosed with ADHD have much more trouble with behavior and learning disabilities when they are deficient in these essential nutrients. (28, 29)

Omega-3 supplements lead to significant improvements in children with ADHD, making positive differences in the following behavioral categories: hyperactivity, restlessness, aggression and impulsiveness. (30, 31, 32)

  1. Elimination of Food Additives and Salicylates

The fact that those diagnosed with ADHD are more likely to suffer adverse reactions to foods led to the idea that eliminating specific foods might be helpful. (33)

An allergist named Dr. Feingold conducting research in the 1970s in an attempt to relieve patients’ symptoms accidentally discovered that the elimination of foods containing salicylates affected behavior.

Salicylates are compounds found in many foods, medications and additives. Dr. Feingold believed children with hyperactivity disorders could be helped by this approach and claimed between 30% of 50% of the children placed on this diet improved. (34)

His work inspired further research into the connection between food and attention disorders; while mixed evidence was found in a meta-analysis of studies on how salicylates influence behavior, further explorations of the effects of diet on ADHD may result in new information. (35)

  1. Preservatives and Artificial Food Colors

Studies have shown both these substances affect behavior, regardless of whether or not ADHD is an issue. (36, 37)

One study following 800 children believed to suffer from hyperactivity found that 75% improved on a diet free of artificial food coloring, but relapsed when foods containing the compounds were re-introduced. (38)

Another trial showed that hyperactivity issues increased when more than 1,800 children added artificial colorings and sodium benzoate, a preservative, to their diets. (39)

Although some believe the evidence found wasn’t conclusive, the FDA requires manufacturers to list these substances on food labels. (40)

  1. Sugar and Artificial Sweeteners

Soft drinks have long been associated with behavioral problems in children, and those diagnosed with ADHD often have low blood sugar as well. (41)

Observational studies indicate high sugar intake has a detrimental effect on ADHD symptoms in both children and adolescents. (42)

While a review of studies suggested no clear link between sugar consumption and behavior exists, some experts believe that sugar may be more influential on attention spans than it is on hyperactivity. (43)

Two trials testing the effects of aspartame, an artificial sweetener, found no strong association between the use of this substance and symptoms of ADHD. (44)

  1. Few Foods Elimination Diet

This approach has been developed to measure the response of ADHD patients to various foods. It works like this:

  • Patients follow a diet from which foods likely to cause reactions have been removed; if improvements are noted, they go on to the next phase.
  • Foods that may cause problems are re-introduced one at a time, at intervals between 3 and 7 days; if symptoms return, the food is labeled as “sensitizing.”
  • A diet is prescribed that eliminates foods identified as problematic.

Eleven of the twelve studies done with the Few Foods Elimination Diet showed significant improvement of symptoms for 50% to 80% of children diagnosed with ADHD, while the final study clocked in at a reduced 25% level of improvement. (45, 46, 47)

Most children who responded favorably to the diet reacted to multiple foods, with wheat and cow’s milk the most common sensitizing dietary components. (48, 49)


Research continues to broaden knowledge about how nutrition affects children and adults suffering from ADHD.

Data collected thus far indicates diet, along with nutritional components that are present or missing, can both have significant effects on ADHD symptoms.

If you or someone you love suffers from ADHD, dietary modifications and nutritional supplementation may help relieve symptoms; up to half of children affected by ADHD experienced improvements through dietary adjustments alone.

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