Diet & ADHD: Are There Links Between ADHD & Diet?

Wednesday, October 4, 2006 - 2:40pm

By Erica Lesperance, RD, LD

Attention Deficit with Hyperactivity Disorder (ADHD) is a chronic disorder of the central nervous system that affects one's ability to maintain attention. It is currently one of the most commonly diagnosed behavioral disorders in children, with a prevalence of 3-8% worldwide. This is an important problem to address in schools, since children who suffer from ADHD have difficulty maintaining attention and controlling their activity levels. In addition, children with ADHD have difficulty starting and finishing work, memorizing facts and controlling emotions.

Treatment for ADHD

Stimulant medications such as Ritalin and Adderall are the only treatment for ADHD that have scientifically been proven effective. For those who are properly diagnosed with ADHD by a health care professional, this may be the best course of action. However, an increase in ADHD diagnoses in the last 15 years means that currently at least 1.5 million children ages five through eighteen, or almost 3%, of U.S. school-age children are taking stimulant medication. According to a recent article in the Journal of the American Medical Association, the use of Ritalin alone is up 250% since 1990. Many are concerned about the potential long-term effects of these medications and are looking for alternative treatments.

Linking ADHD to diet

Wherever causes of and treatment for ADHD are discussed, diet is part of the conversation. While many parents and teachers feel strongly about the link between ADHD and diet, research shows mixed results. Recent research on the diet-behavior connection has not only looked into what is in our food that might trigger or worsen ADHD, but also what might be deficient in the diets of those with ADHD. Following are some of the existing beliefs about ADHD and diet.

Does removing food dyes, preservatives, and other additives from the diet work?

Research on diet and ADHD first began in the 1970s when pediatrician Ben Feingold claimed that ADHD, among other behavioral and health problems, could be improved by the elimination of certain food additives. Though some studies showed improvements in behavior on the Feingold diet, it was extremely restrictive and difficult to follow. However, the fact that some children did respond indicated that diet can have positive effects on behavior. Two recent studies that have looked at specific additives and preservatives, and their results are noteworthy. Results showed that these additives, when given during the critical development window, affect growth of cells in the brain. A second study, looking at the effect of a food colorings and the preservative sodium benzoate on hyperactivity in three year old children, showed significant reductions in hyperactive behavior when the additives were removed from the diet. Though this is intriguing research, the studies were small and their results do not prove that ADHD is caused or aggravated by diet.

Can removing sugar from the diet help?

Although parents often blame sugar for causing children to become impulsive or hyperactive, a number of studies now strongly suggest that sugar plays no role in hyperactivity. In fact, it is more often shown to make children sluggish.

Can mercury exposure increase the risk of autism and ADHD?

According to a 2004 study, exposure to the mercury-based vaccine additive, thimerosal, may increase the risk of autism and ADHD. More specifically, researchers have found that exposure to thimerosal, along with other substances, interrupts processes that are critical to proper brain development in infants and children. While this does not mean that mercury, thimerosal, or mercury -based vaccines are the cause of ADHD, it raises a red flag that has driven the creation of mercury-free forms of the routinely recommended vaccines for children.

Can a lack of essential fatty acids lead to ADHD?

Essential fatty acid deficiency has been linked to poor brain function and mental health problems. Studies show that children who have deficiencies in omega-3 fatty acids have more behavioral, learning, and health problems than do normal children. The symptoms of essential fatty acid deficiency are all also common in ADHD children, leading many to believe that ADHD is caused by this deficiency. However, no studies have confirmed this hypothesis. It is possible that those with behavior and attention problems are misdiagnosed with ADHD when they actually have a simple nutrient deficiency.

Magnesium and ADHD

Some children with ADHD have low levels of magnesium. At least two studies have shown significant improvement in behavior with magnesium supplementation. It is important to note, however, that it is difficult to measure improvement in behavior, and most studies rely on reports from parents, which can be biased.

Can lack of iron lead to ADHD?

Recent research has linked low iron stores to ADHD. A study published in the Archives of Pediatric and Adolescent Medicine looked at serum ferritin stores in 53 children with ADHD and 27 children without ADHD (ferritin is used as a measure of iron stores, as it allows the body to store iron). The study showed that the serum ferritin levels of 87% of the children with ADHD were abnormally low, compared with only 18% of children without ADHD. It was also noted that the children with the most severe iron deficiencies were the most inattentive, impulsive, and hyperactive. The researchers concluded that “low iron stores may explain as much as 30% of ADHD severity.”1 The question that remains, however, is whether ADHD is caused by iron deficiency or if iron deficiency only makes the symptoms of ADHD more severe. Either way, it makes sense to consume a diet high in iron-rich foods to prevent iron deficiency. Good sources of iron include, but are not limited to, eggs, fish, kidney beans, poultry, whole grain cereals and breads, almonds, peaches, pears, and green leafy vegetables.

Would vitamin B6 supplements help?

Adequate levels of Vitamin B 6 are required for normal brain development. A preliminary study found that Vitamin B 6 was slightly more effective than a stimulant medication in improving behavior among hyperactive children. Although intriguing, the results of this study were not significant and no other studies have been able to confirm these findings. Therefore, supplementation with Vitamin B 6 is not considered standard treatment for ADHD.

Can zinc supplements help?

Zinc deficiency contributes to hyperactivity and impaired concentration. Recent research has found that only 65% of patients with ADHD had normal zinc levels. While this does not mean that low zinc causes ADHD, zinc deficiency may intensify the symptoms. One small study reported that children with ADHD who took zinc supplements along with their ADHD medications had greater improvement than those who took medication alone.

Causes of ADHD are still unknown

Though the cause of ADHD continues to mystify the entire health care community, research does clearly indicate that it is not caused by diet. However, we do know that a properly balanced diet helps to develop healthy brain cells and the chemicals needed to help those cells work efficiently. Therefore, in addition to making sure children are not deficient in important nutrients, it is a good idea to remove as many processed and unnatural foods as possible from the diet. By eliminating the dietary contribution to behavior problems and hyperactivity, it may be easier to properly diagnose and effectively treat ADHD.

1. Konofal, E. Archives of Pediatric and Adolescent Medicine, December 2004; vol 158: pp 1113-1115. Eric Konofal, MD, PhD, Hospital Robert Debre, Paris. William Coleman, MD, professor of pediatrics, Center for Development and Learning, University of North Carolina Medical School, Chapel Hill.