Kids who eat Western diet have higher rates of ADHD

Children who eat a Western-style diet high in fast foods are far more likely to develop attention deficit hyperactivity disorder (ADHD) than children who eat a non-Western diet, according to a new Australian study.

Amber Howard and colleagues examined data collected on 1,799 14-year-old children participating in the Raine Study, a prospective study following several thousand children from birth. Of this group, 115 children were diagnosed with ADHD.

The researchers divided the children into two groups: those eating a Western-style diet high in sugary, processed, fried, salty, and refined foods, and those eating a non-Western diet high in fresh fruits and vegetables, whole grains, and fish.

Study coauthor Wendy Oddy reports, “We found a diet high in the Western pattern of foods was associated with more than double the risk of having an ADHD diagnosis compared with a diet low in the Western pattern, after adjusting for numerous other social and family influences.” Specific foods linked to a higher rate of ADHD included fast foods, processed meats, red meat, high-fat dairy products, and candy.

The researchers say the higher rate of ADHD in children eating a Western diet may be due to suboptimal levels of omega-3 fatty acids. A Western diet is high in omega-6 fatty acids but low in omega-3 fatty acids, which are crucial for brain health. The researchers note, “Lower circulating levels of omega-3, higher levels of omega-6, and a lower omega-3 versus omega-6 ratio [have] been reported in adolescents with ADHD.” Another possibility they raise is that a Western diet low in micronutrients or high in food additives, flavorings, and artificial colors may lead to hyperactivity or changes in neurotransmitter function. A third explanation, they say, may be that impulsive children simply make poor food choices. “This is a cross-sectional study so we cannot be sure whether a poor diet leads to ADHD or whether ADHD leads to poor dietary choices and cravings,” Oddy says.

The researchers note that their findings are consistent with several recent studies implicating a nutrient-poor diet in mood or behavior disorders. Two studies by Bonnie Kaplan and colleagues reported that micronutrient supplementation resulted in improvements in mood and reductions in anxiety. A third study, by Julia Rucklidge and colleagues, found that micronutrient supplementation led to a reduction in the severity of ADHD symptoms in adults.

In addition, the new findings are consistent with a 2009 study by Oddy and colleagues, also involving participants in the Raine project. That study showed that externalizing behavior (delinquency and aggression) and internalizing behavior (withdrawal and depression) were significantly associated with a Western diet.