title: Long-chain n-3 PUFA supplementation decreases physical activity during class time in iron-deficient South African school children.
abstract: Both Fe deficiency and poor n-3 fatty acid status have been associated with behavioural changes in children. In the present study, we investigated the effects of Fe and DHA+EPA supplementation, alone or in combination, on physical activity during school days and on teacher-rated behaviour in healthy Fe-deficient school children. In a 2 × 2 factorial design, children (n 98, 6-11 years) were randomly assigned to receive (1) Fe (50 mg) plus DHA (420 mg)+EPA (80 mg), (2) Fe plus placebo, (3) placebo plus DHA+EPA or (4) placebo plus placebo as oral supplements (4 d/week) for 8.5 months. Physical activity was measured during four school days at baseline and endpoint using accelerometers, and data were stratified into morning class time (08.00-10.29 hours), break time (10.30-11.00 hours) and after-break class time (11.01-12.00 hours) for analysis. Classroom behaviour was assessed at endpoint using Conners' Teacher Rating Scales. DHA+EPA supplementation decreased physical activity counts during morning class time, increased sedentary physical activity, and decreased light- and moderate-intensity physical activities. Consistently, DHA+EPA supplementation increased sedentary physical activity and decreased light-intensity physical activity during after-break class time. Even though there were no treatment effects found on teacher-rated behaviour, lower physical activity during morning class time was associated with lower levels of teacher-rated hyperactivity and oppositional behaviour at endpoint. Despite a positive association between Fe status and physical activity during break time at baseline, Fe supplementation did not affect physical activity during break time and class time. Our findings suggest that DHA+EPA supplementation may decrease physical activity levels during class time, and further indicate that accelerometry might be a useful tool to assess classroom behaviour in healthy children.
authors.affiliation: Centre of Excellence for Nutrition, North-West University,Potchefstroom Campus, Private Bag X6001,Potchefstroom2520,South Africa.
authors.forename: Cornelius M
authors.initials: CM
authors.lastname: Smuts
authors.affiliation: Centre of Excellence for Nutrition, North-West University,Potchefstroom Campus, Private Bag X6001,Potchefstroom2520,South Africa.
authors.forename: Jani
authors.initials: J
authors.lastname: Greeff
authors.affiliation: Department of Psychology,University of KwaZulu-Natal,Durban,South Africa.
authors.forename: Jane
authors.initials: J
authors.lastname: Kvalsvig
authors.affiliation: Laboratory of Human Nutrition, Institute of Food, Nutrition and Health,ETH Zürich,Switzerland.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Zimmermann
authors.affiliation: Centre of Excellence for Nutrition, North-West University,Potchefstroom Campus, Private Bag X6001,Potchefstroom2520,South Africa.
authors.forename: Jeannine
authors.initials: J
authors.lastname: Baumgartner
mesh_terms: D056044:Actigraphy; D018798:Anemia, Iron-Deficiency / Q000150:complications / Q000178:diet therapy* / Q000503:physiopathology; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology / Q000517:prevention & control*; D002214:Capsules; D002648:Child; D002652:Child Behavior; D002664:Child Nutritional Physiological Phenomena; D003677:Deficiency Diseases / Q000150:complications / Q000178:diet therapy* / Q000503:physiopathology; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005228:Fatty Acids, Essential / Q000172:deficiency*; D015525:Fatty Acids, Omega-3 / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D019266:Iron, Dietary / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009043:Motor Activity; D012574:Schools; D013019:South Africa; D013607:Tablets
chemical_list: D002214:Capsules; D005228:Fatty Acids, Essential; D015525:Fatty Acids, Omega-3; D019266:Iron, Dietary; D013607:Tablets
keywords: Behaviour; Iron; Physical activity; School children; n-3 Fatty acids