Review articleDietary patterns and attention deficit/hyperactivity disorder (ADHD): A systematic review and meta-analysis
Introduction
The Attention Deficit Hyperactivity Disorder (ADHD) is a neurobiological disorder characterized by persistent symptoms of inattention, impulsivity and hyperactivity (Association AP. 2013). The ADHD begins at childhood and frequently persists until adulthood, causing low educational achievement, as well as cumulative losses throughout life (Barkley and Roizman, 2002), such as family and interpersonal difficulties. The etiology of the disorder is multifactorial, resulting from the interaction between the sex of the child (Arnold, 1996) and genetic and environmental factors, such as intrauterine exposures (Bekkhus et al., 2010) and parent's mental health (Anselmi et al., 2010).
The role of diet in the prevention and/or treatment of ADHD was firstly investigated in the 1980s and 1990s, resulting in a series of studies, mostly experimental, focusing on the effect of additives and sugars on the attention deficit and/or hyperactivity (Wolraich et al., 1995). As a result, dietary therapies were proposed at that time, which mainly included restriction of sugar, additives, food coloring agents and antigens. Later studies showed the protective effect of increased iron intake (Konofal et al., 2008, Konofal et al., 2004), zinc (Akhondzadeh et al., 2004a, Arnold et al., 2005), iodine (Yüksek et al., 2016) and polyunsaturated fatty acids (Johnson et al., 2009, Sinn and Bryan, 2007, Richardson and Montgomery, 2005), and in contrast, adverse effect of excessive ingestion of food coloring agents (Bateman et al., 2004, Rowe and Rowe, 1994), preservatives (McCann et al., 2007) and sugar (Park et al., 2015, Wiles et al., 2009).
Recent studies assessing diet effect on the development of diseases have focused their analysis on dietary patterns, instead of specific nutrients consumption. The analysis of dietary patterns emerged as a complementary approach in the study of the relationship between diet and chronic diseases (Hu, 2002). Thus, the effects of overall diet combinations are evaluated, incorporating complex interactions that occur between nutrients (Hu, 2002). Dietary patterns represent a wider vision of nutrient and food intake and may be more appropriate for the study of the relationship between dietary factors and diseases, (Hu, 2002) as ADHD. Therefore, the purpose of this study was to review systematically the evidence about the relationship between dietary patterns and ADHD. Our hypothesis was that healthy dietary patterns would be protective whereas unhealthy dietary patterns would increase the risk of ADHD.
Section snippets
Methods
In March 2019, we searched indexed articles in PubMed, LILACS and PsycINFO databases using the following combination of descriptors: (“diet” OR “eating pattern” OR “eating patterns” OR “food pattern” OR “food patterns” OR “dietary pattern” OR “dietary patterns” OR “dietary behaviors” OR “dietary behaviours” OR “dietary habits”) AND (“attention deficit hyperactivity disorder” OR “adhd” OR “adh” OR “hyperactive” OR “hyperactivity” OR “inattentive” OR “inattention” OR “hyperactive behaviors” OR
Results
Initially, the 1260 references found in the Pubmed and the 562 found in the other databases (LILACS and PsycINFO) were exported to an EndNote library. A total of 271 duplicates were identified. Next, we selected the titles, resulting in 31 abstracts to be assessed by the reviewer 1 and 44 by the reviewer 2.
After this, reviewer 1 excluded 16 manuscripts based in the following reasons: no assessment of the exposure of interest (like food coloring agents, additives and vitamin supplements) (n
Discussion
In the reviewed papers we found two most frequently consumed dietary patterns, and both indicated dietary effects on ADHD. The healthy patterns characterized predominantly by the consumption of fruits, vegetables and whole grains showed a protective effect against hyperactivity or ADHD, while unhealthy dietary patterns, characterized predominantly by the consumption of saturated fat and refined sugar was associated with increased risk of hyperactivity or ADHD occurrence. However, the
Funding
There was no financing.
Conflict of interest
The authors have no potential conflicts of interest to disclose.
References (51)
- et al.
Dietary patterns and attention deficit hyperactivity disorder among Iranian children
Nutrition
(2012) - et al.
Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder
Prog. Neuro-Psychopharmacol. Biol. Psychiatry
(2004) - et al.
Sugar consumption and attention-deficit/hyperactivity disorder (ADHD): a birth cohort study
J. Affect. Disord.
(2019) - et al.
Associations between attention-deficit/hyperactivity disorder symptoms and dietary habits in elementary school children
Appetite
(2018) - et al.
Effects of iron supplementation on attention deficit hyperactivity disorder in children
Pediatr. Neurol.
(2008) - et al.
Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial
The Lancet
(2007) - et al.
Association between dietary behaviors and attention-deficit/hyperactivity disorder and learning disabilities in school-aged children
Psychiatry Res.
(2012) - et al.
Genetics of childhood disorders: XXIII. ADHD, Part 7: the Serotonin System
J. Am. Acad. Child Adolesc. Psychiatry
(2001) - et al.
Synthetic food coloring and behavior: a dose response effect in a double-blind, placebo-controlled, repeated-measures study
J. Pediatr.
(1994) - et al.
Zinc deficiency in attention-deficit hyperactivity disorder
Biol. Psychiatry
(1996)