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

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.