Most notable among ADHD studies are the ones specifically examining the relationship between dietary zinc and ADHD. Increased zinc in the diet may be a remedy for ADHD in children. Indeed, zinc is basic for the production and modulation of melatonin, which helps regulate dopamine function, an important factor in ADHD and its treatment. Therefore, ADHD children with zinc deficiency might benefit from a change in diet or from a therapeutic trial with zinc supplementation.
The present study shows the Parent and Teacher Rating Scale scores improved with zinc sulfate over this 6-week, double blind and placebo controlled trial. The efficacy of zinc sulfate to obtain a better improvement in children with ADHD seems to support the role of zinc deficiency in the etiopathogenesis [the cause and development] of ADHD. This study is in line with the recent trial that suggests a beneficial effect of zinc sulfate in the treatment of ADHD. ( BMC Psychiatry 2004, 4: 9 ).
… this group, least expected to have marginal zinc deficiency and with a nutritionally adequate diet by the Food Frequency Questionnaire, shown an involvement of zinc levels in ADHD symptoms. The data reported here suggest that zinc nutrition is involved in symptoms of inattention and, therefore, improving zinc nutritional status may improve inattentive symptoms. ( J Child Adolesc Psychopharmacol 2005 Aug; 15 (4): 628-36 ).
Zinc supplements may exert their positive effects by helping to regulate the function of the neurotransmitter dopamine.
… a dopamine deficiency may underlie ADHD. Nora Volkow, MD, a psychiatrist with Brookhaven National Laboratory in Upton, NY, and her colleagues found that intravenous injections of the drug most often prescribed to treat ADHD – methylphenidate (Ritalin) – increased dopamine levels in the brain. This result suggests that methylphenidate counters ADHD by increasing brain levels of dopamine. ( Psychiatric News 16/3/2001 Volume 36 Number 6 ).
In a study led by scientists with USDA's Agricultural Research Service, daily zinc supplements helped Chinese schools with very low body zinc levels to score better in perception, memory, reasoning and psychomotor skills such as eye-hand coordination.
Findings of the study with 372 Chinese schools – conducted in three poor, urban areas of China – support previous adult studies and have important implications for countries where low zinc intakes are common. They could also apply to the 10 percent of US grade-school-age girls and 6 percent of boys who get less than half the Recommended Dietary Allowance of zinc through their diets. The RDA for this age group is 10 milligrams daily.
The Chinese children, age 6 to 9 years, were divided into three groups. One group took a 20-milligram zinc supplement daily for 10 weeks. A second group took the zinc supplement plus a micronutrient supplement containing all essential vitamins and minerals, except for zinc and four other minerals known to interfere with its absorption. A control group got only the micronutrients to alleviate any other deficiency that could affect performance on the psychological tests.
Before and after the supplement period, each child took a series of computer-administered tasks developed by the ARS psychologist. The tasks measured attention, perception, memory, reasoning and motor and spatial skills necessary for successful school performance.
The children who got the zinc supplement or zinc plus the micronutrients had the most improved performance, especially in perception, memory and reasoning skills.
In addition to peanuts, popcorn and whole wheat products, the most common source of zinc is red meat. Oysters are the richest source.
USDA's Agricultural Research Service.
Shahin Akhondzadeh, Mohammad-Reza Mohammadi and Mojgan Khademi. Zinc sulfate as an adjunct to methylphenidate for the treatment of attention deficit hyperactivity disorder in children: A double blind and randomized trial [ISRCTN]. BMC Psychiatry 2004, 4: 9doi: 10.1186 / 1471-244X-4-9. © 2004 Akhondzadeh et al; licensee BioMed Central Ltd.
This is an Open Access article.