A Prospective Study of the Physiological and Neurobehavioral Effects of Ramadan Fasting in Preteen and Teenage Boys

Abstract

Background: Intermittent fasting during the month of Ramadan, although not obligatory, is commonly practiced by Muslim children.

Objective: Our aim was to describe the effects of Ramadan fasting on various physiological and neurobehavioral measures in preteen and teenaged boys.

Design: We conduced a prospective cohort study during Ramadan, observed from August 9 to September 11, 2010.

Participants: Eighteen healthy Muslim boys (mean age±standard deviation 12.6±1.5 years) were recruited and assessed before, during (1st and 4th weeks), and after Ramadan. Subjects were classified as preteens (aged 9 to 12 years) or teens (aged 13 to 15 years).

Intervention: On each clinic visit, participants completed a match-to-sample test, a spatial planning and working memory task, and a working memory capacity test using the Cambridge Neuropsychological Test Automated Battery. Participants were also assessed for their sleep patterns, daily energy expenditure, and dietary intake. Body composition was determined using a dual-energy x-ray scan. Complete blood count, lipid profile analysis, and iron indices were conducted.

Main outcome measures: We measured morphologic, metabolic, and neurobehavioral parameters.

Statistical analyses: A linear mixed model was used to assess changes in outcome measures. Post hoc pairwise comparisons were performed as necessary with Bonferroni adjustment.

Results: Within 1 week of fasting, there was a drop in body fat only in preteens (P=0.001). Reported fat (P=0.004) and protein intake (P=0.037) was higher during Ramadan, but energy expenditure did not change. By the end of Ramadan, there was a significant reduction in hemoglobin (mean±standard error -0.48±0.4 mmol/L) and serum iron (-25.7±31.8 μg/dL [-4.6±5.7 μmol/L]) levels. During week 4, total sleep duration decreased by 1.8 hours. At week 4, performance on the spatial planning and working memory task and working memory capacity test increased significantly (P=0.002), while match-to-sample test performance declined in preteens only (P=0.045).

Conclusions: Ramadan fasting was associated with significant changes in body composition, dietary intake, and sleep patterns. Reductions in attention and iron indices were observed in preteens only.

Keywords: Body composition; Cognitive ability; Pediatrics; Ramadan fasting; School health.