November 13, 2023
There's a widespread, but so far unsupported, popular belief that sugar consumption, and sugar-sweetened beverages, in particular, trigger symptoms, especially hyperactivity, in youth.
Given the steep rise of sugar consumption by youth, what evidence is there of a link to ADHD?
An Iranian team of researchers carried out a comprehensive search of the peer-reviewed literature on this subject. It identified seven studies - two cross-sectional, two case-control, and three prospective " with a combined total of over 25,000 participants that were amenable to meta-analysis. The studies spanned the globe, including the United States, Brazil, Taiwan, the U. K., Spain, and Norway.
Using a fixed-effects model, they found a tiny 7.5% increase in ADHD associated with sugar consumption. With a random-effects model, that rose to a 22% increase. But correcting for publication bias with a trim-and-fill adjustment removed any evidence of an association (p = 0.8).
Even without adjusting for publication bias, subgroup analysis found no evidence of an association with sugar consumption per se.
On the other hand, two studies that looked exclusively at sugar-sweetened beverages reported an 80% increase in the odds of ADHD. There was no way to evaluate publication bias for just two studies. Furthermore, two studies are insufficient for a proper meta-analysis.
There are two conclusions to be drawn from this meta-analysis: 1) It reinforces previous findings of no significant association between sugar consumption and ADHD; 2) It suggests it would be worth conducting more studies, specifically focusing on sugar-sweetened beverages.
Alireza Farsad-Naeimi, Foad Asjodi, Mahsa Omidian, Mohammadreza Askari, Mehran Nouri, Ana Beatriz Pizarro, Elnaz Daneshzad, "Sugarconsumption, sugar-sweetened beverages, and Attention Deficit hyperactivity disorder: A systematic review and meta-analysis," Complementary Therapies medicine 53 (2020) 102512, https://doi.org/10.1016/j.ctim.2020.102512.