Does fish oil help with ADHD?

Q. As a primary care pediatrician, I work closely with mental health professionals in the care of my patients with attention deficit hyperactivity disorder and other behavioral conditions. I have increasingly seen psychologists recommend to parents the use of omega-3 fish oils to help with attention and behavioral problems. What is the evidence for this recommendation?

Jeffrey Zaref, MD, MPHFramingham, Mass.

A. Some background will help place the recommendations in context: Stimulant medications are the most frequently prescribed drug therapy for ADHD, but they are effective for only about 70% of children and carry a substantial burden of side effects. Also, the stigma of taking a psychoactive medication is troubling for some families. Even nonstimulant medications, such as atomoxetine, have side effects, including the risk of hepatotoxicity. Side effects and stigma lead many children and families to stop using the medications and to seek complementary or alternative therapies because "at least they're natural."

In recent years, fish oil has become a popular dietary supplement. It contains long-chain polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) that appear to improve a variety of health conditions. DHA is the predominant structural fatty acid in the central nervous system and retina, and its availability is crucial for brain development. Many infant formulas now contain DHA because clinical trial evidence suggests that DHA enhances brain development in infants. EPA and DHA also appear to be helpful for mental health problems such as depression, which often coexist with ADHD.

Epidemiologically, DHA levels found in the phospholipid isolated from red blood cell membranes of children with ADHD have been lower than those found in unaffected children.² In the serum phospholipids of adults with ADHD symptoms, levels of total saturated, total polyunsaturated, and total omega-6 (n-6) fatty acids, as well as omega-3 (n-3) LCPUFA DHA (22:6n-3), are significantly lower than in unaffected adults, and levels of total monounsaturated fatty acid and the n-3 LCPUFA docosapentaenoic acid (22:5n-3) are significantly higher. Similarly, adults with ADHD symptoms have significantly lower levels of total PUFA, total omega-3 fatty acid, and DHA, and significantly higher levels of total saturated fatty acid than unaffected adults.³

Two randomized controlled trials of children with mild ADHD failed to show any improvement in ADHD behaviors among those who received supplementation with a low or moderate dosage of DHA.^4,5 However, a recent randomized, controlled trial yielded different results: Three months of dietary supplementation with omega-3 fatty acid was compared with placebo in 117 children (5 to 12 years of age) who had developmental coordination disorder.⁶ The study found significant improvements for the active treatment group in reading, spelling, and behavior.

Supplementation with fish oil is generally safe. Large doses of unrefined cod liver oil may lead to excessive vitamin A intake, however. The more refined preparations generally contain less vitamin A and have a less fishy taste. Many of the liquid pediatric preparations are citrus or peach flavored, enhancing patient compliance. Doses greater than 3 grams daily of EPA+DHA may increase the risk of bleeding; children who routinely take anticoagulant medications or suffer from a bleeding diathesis should be monitored regularly when taking a high-dose fish oil supplement.

To sum up: Fish oil supplements are popular, and there is some rationale for supplementation in adults with a variety of mental health conditions that frequently occur with ADHD. As for the pediatric ADHD population, randomized trials of moderate- to high-dose supplementation with refined fish oil (DHA+EPA) are urgently needed.

Kathi J. Kemper, MD, MPH

Dr. Kemper is Caryl J Guth Chair for Holistic and Integrative Medicine, and Professor, Pediatrics, Public Health Sciences and Family Medicine, Wake Forest University School of Medicine, Winston-Salem, N.C.