Question: Leslie, what exactly is ADHD?

Attention Deficit Hyperactivity Disorder, or ADHD, affects up to 5% of Canadian kids and it usually surfaces before the age of seven. A child is considered to have ADHD if he or she demonstrates symptoms of inattention, hyperactivity, and impulsivity for at least six months in two settings such as home and school. It's estimated that 30 to 70 percent of children with ADHD will continue to have symptoms as adults.

Researchers believe both genetics and environmental factors play a role. ADHD tends to run in families. Smoking, drinking alcohol and exposure to toxins such as PCBs (polychlorinated biphenyls) during pregnancy has been linked to later ADHD in a child.

Question: Can diet help treat ADHD?

Currently, the only therapies proven effective in scientific studies are medications and/or behavioural therapy. Studies haven't found a consistent link between dietary interventions and ADHD symptom improvement, but a few approaches may benefit some children. (Dietary modification and nutritional supplements should not be used instead of the usual medication without a doctor being involved.)

In 1975, Benjamin Feingold, an allergist from California, suggested that avoidance of artificial colours, flavours, and preservatives as well as naturally occurring salicylates (compounds found in fruits and vegetables such as apricots, berries, cherries, raisins and tomatoes) could dramatically improve ADHD symptoms in kids.

A 1986 review of the Feingold diet determined that only 1 percent of children consistently improved on the diet and 10 percent developed symptoms when dyes were consumed.

Since then, numerous well designed studies have found that the behaviour of some children improved when food colouring and common food allergens (corn, milk, fish, eggs, peanuts, soy, wheat, oranges) were removed and significantly worsened when reintroduced.

Last year, a British study of 300 children between the ages of 3 and 9 years old who did not have ADHD found that consuming food dyes added to fruit drinks - equivalent to two or four 56-gram bags of candy - significantly exacerbated hyperactive behaviours.

Elimination diets are thought to benefit only 5 percent of kids with ADHD. Children most likely to respond are those with a history of allergic conditions such as asthma or eczema, a family history of migraine, and/or a family history of food sensitivities.

If you think certain foods affect your child's behaviour, eliminate them one at a time to see if symptoms improve. Elimination diets that remove many suspect foods should be used under the guidance of a registered dietitian to ensure nutritional needs are met.

Q: What about sugar? Does it make ADHD worse?

No studies support the widespread belief that sugar and aspartame cause or worsen ADHD symptoms. Even so, it's wise to limit your child's intake of sugar from candy, soft drinks, fruit drinks and frozen desserts since these foods may contain preservatives and dyes linked with hyperactive behaviour.

Q: What about specific vitamins and minerals?

Magnesium. Research suggests that many children with ADHD are deficient in magnesium, a mineral that helps brain chemicals work properly. In a study of 116 magnesium-deficient children with ADHD, magnesium supplements improved behaviour.

One study isn't enough to justify routine magnesium supplementation in ADHD. However, it's wise to add magnesium-rich foods to your child's diet since most diets don't supply enough of the mineral. The best food sources include wheat germ, sunflower seeds, almonds, legumes, figs, spinach and Swiss chard.

Zinc. Two studies revealed that children with ADHD have lower blood levels of zinc compared to kids without ADHD. One small study also found that school-aged kids taking the stimulant medication Ritalin, along with a 15 milligram zinc supplement, had greater improvement than those who took their medication alone.

The body relies on zinc for the activity of brain chemicals, fatty acids and melatonin (a naturally occurring hormone related to sleep), all of which are related to behaviour.

Kids with ADHD should take a children's multivitamin with zinc. Zinc-rich foods include beef, pork, yogurt, wheat germ, bran cereals, baked beans, chickpeas, lentils, and pumpkin seeds.

Children with erratic eating habits and reduced appetite from stimulant medication will also benefit from a daily multivitamin and mineral.

Q: We hear that fish is good for the brain...should parents give kids a fish oil supplement?

Omega-3 fatty acids (called DHA and EPA) found in salmon, trout, sardines, mackerel, herring and fish oil capsules are concentrated in the brain and play an essential role in cognition and behaviour.

Kids with ADHD are more likely to have lower levels of omega-3's in their blood than children without ADHD. Some, but not all, clinical studies using omega-3 supplements have demonstrated improvement in symptoms of inattention and hyperactivity.

Look for a fish oil supplement that contains DHA and EPA. Most experts agree than a daily intake of 250 to 500 milligrams of DHA plus EPA combined is a reasonable target for children and adults.

Children who have an allergy to fish, a bleeding disorder, or who are taking anti-coagulant medications should not take fish oil.