Does Sugar Cause ADHD?

00:00 Introduction to the Topic
01:54 A meta-analysis of the relationship of sugar consumption to ADHD symptoms
03:45 Review of a large longitudinal study on the association of sugar consumption to ADHD across childhood
5:20 Discussion of a large scale study of twins on the shared genetics between ADHD and sugar consumption
09:45 Discussion of a review of the evidence from direct intervention studies manipulating sugar exposure against a placebo with blinded evaluations of ADHD symptoms
10:58 Discussion of a specific study that manipulated exposure to sugar in children with ADHD using a placebo and double blind conditions – no evidence sugar caused ADHD
11:53 Study of parental expectations about sugar and degree of behavior problems when children were exposed to aspartame while parents were told it was sugar
14:10 Comments on a website, FinallyFocused.org, that claims that the ADHD brain processes sugar differently than a typical brain. That is not what the evidence says.
13:44 Conclusion

This lecture explores the nearly age-old question of whether sugar causes ADHD. I discuss the numerous studies that show a correlation between sugar consumption and degree of ADHD symptoms. Yet these cannot be used to infer any sort of causation between sugar and ADHD. An equally if not more plausible explanation is that the degree of ADHD increases the likelihood that one will be more prone to consuming sugar containing foods and beverages. How can we untangle this association to get some idea about causation? One is to follow children over time in a longitudinal study measuring both sugar consumption and levels of ADHD and see what they predict from baseline to the follow-up years while controlling for each variable at the baseline period. I discuss the results of such a study. Sugar consumption at baseline does not predict increased ADHD over time after controlling for baseline ADHD. But baseline ADHD does predict increasing sugar consumption over time even controlling for sugar consumption at baseline. A second means is to examine the possible genetic contributions to each (ADHD, sugar consumption) using a large study of twins. Do these two things share common genetics? I discuss the results of such a study, which found shared genetic contributions to both. The third and most convincing method is to actually introduce sugar into the diet as well as a placebo (such as aspartame) while the parents and children are blinded to what the child is actually receiving. There are 6 such intervention studies, all negative. I discuss two of them. My conclusion is that sugar consumption does not contribute to ADHD symptom severity, but having ADHD increases the likelihood that one will consume more sugar over time.

References cited in video:

Alireza Farsad-Naeimi et al. (2020). Sugar consumption, sugar sweetened beverages and Attention Deficit Hyperactivity Disorder: A systematic review and meta-analysis. Complementary Therapies in Medicine, Volume 53, September 2020, https://doi.org/10.1016/j.ctim.2020.1...

Bianca Del-Ponte et al. (2019). Sugar consumption and attention-deficit/hyperactivity disorder (ADHD): A birth cohort study. Journal of Affective Disorders. Volume 243, 15 January 2019, Pages 290-296. https://doi.org/10.1016/j.jad.2018.09...

Lin Li et al. (2020). Attention-deficit/hyperactivity disorder symptoms and dietary habits in adulthood: A large population-based twin study in Sweden. American Journal of Medical Genetics. Volume183, Issue8, December 2020, Pages 475-485.
https://doi.org/10.1002/ajmg.b.32825

Nanna Maria Uldall Torp & Per Hove Thomsen. (2020). The use of diet interventions to treat symptoms of ADHD in children and adolescents – a systematic review of randomized controlled trials. Nordic Journal of Psychiatry Volume 74, 2020 - Issue 8, pp. 558-568. https://doi.org/10.1080/08039488.2020...

Mark Wolraich et al. (1985). Effects of sucrose ingestion on the behavior of hyperactive boys. The Journal of Pediatrics
Volume 106, Issue 4, April 1985, Pages 675-682. https://doi.org/10.1016/S0022-3476(85...

D. W. Hoover & R. Milich. (1994). Effects of sugar ingestion expectancies on mother-child interactions. Journal of Abnormal Child Psychology, 22, 501-515. https://link.springer.com/article/10....

J. M. Greenblatt, Finally Focused website, finallyfocused.org. How the ADHD Brain Processes Sugar Differently.