The association of diet quality and lifestyle factors in children and adults with ADHD: a systematic review and meta-analysis

Eating habits of individuals with learning and behavioral difficulties is an important and emerging area of ​​nutrition expertise. An unhealthy diet, combined with limited physical activity, is linked with an increased risk of chronic diseases and a lower quality of life. The study aims to review in a systematic way evidence on: (a) the relationship between diet quality and ADHD; and (b) the effect of three lifestyle factors, physical activity, quality of sleep, and stress on children and adults with ADHD. In December 2020, we searched for relevant articles in PubMed and Scopus. The studies included were those that assessed diet, physical activity, sleep, and stress, of children and adults with ADHD. We identified a total of eighteen studies with an invasive and observational approach that matched our research criteria. Fourteen of these studies were included in the meta-analysis. The pooled analysis showed that a high-diet quality decreases the prevalence of ADHD in children (OR: 0.43, 95% CI: 0.28-0.70), while a poor diet quality is associated with an increased risk of ADHD in both children and adults (OR: 2.24, 95% CI: 1.49-3.65). Also, a poor lifestyle indicates a higher prevalence of ADHD in both children and adults (OR: 1.90, 95% CI: 1.43-2.61). This study is limited to its ability to extract data from some of the included studies while sampling was limited due to the absence of studies in adults with ADHD. The present study suggests that a high-quality diet with increased consumption of fruits, vegetables, and fish, may be protective against ADHD in children. On top of that, a poor-quality diet with higher consumption of sugar, sweetened drinks, and junk food, as well as a lifestyle that is characterized by reduced sleep and physical activity can be associated with increased risk of ADHD, for both children and adults. The current domain needs more experimental data