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Background: Iron deficiency (ID) is the most prevalent nutritional deficiency in the world. In children, both inadequate iron and fatty acid (FA) status have been found to have an effect on cognitive and behavioural function, including physical activity behaviour and attention deficit hyperactivity disorder (ADHD)–related behaviour. Aim: To investigate the effects of supplementation with iron and omega–3 fatty acids (n–3 FAs), alone and in combination, on spontaneous motor activity and ADHD–related behaviour in iron deficient primary school children in KwaZulu–Natal. An additional aim was to evaluate the use of the Actical accelerometer as a tool to assess physical activity behaviour. Methods: The study design was a 2x2 factorial, randomized, double–blind and placebo–controlled trial. Iron deficient school children aged six to ten years with or without mild anaemia were included in the study (n = 321). Subjects were randomly assigned to receive one of the following supplement combinations: (1) 420mg docosahexaenoic acid (DHA)/80 mg eicosapentaenoic acid (EPA) + 50mg of iron as ferrous sulphate (Fe); (2) 420mg DHA/80mg EPA + placebo; (3) 50mg of Fe + placebo; (4) placebo + placebo. Supplements were provided four times a week for a duration of 8.5 months (excluding school holidays). Physical activity of a subgroup of subjects (n=98) was recorded on four random school days at baseline, midpoint and endpoint (12 days in total) during three different time periods namely class time 1 (08h00-10h30), break time (10h30–11h00) and class time 2 (11h00–12h00). Classroom behaviour of study subjects was assessed by teachers at baseline and endpoint using the Conners’ Teacher Rating Scale–Revised: Short Forms (CTRS). Iron status indicators and red blood cell (RBC) FA composition were measured at baseline and endpoint. Treatment effects were assessed for activity and CTRS scores. Furthermore, the relationship between activity, CTRS scores and iron/FA status indicators was determined using bivariate correlation and multivariate linear regression analysis. Results: Overall activity of all subjects varied over time from baseline and midpoint to endpoint. A significant cycle x age interaction (P = 0.005) as well as a significant cycle x time period x gender interaction (P = 0.036) was observed on overall activity. There were no significant interactions of cycle or time period with treatment. However, there was a significant main effect of DHA/EPA supplementation for lower class time 1 activity at endpoint (P = 0.014). Biological markers indicating better or poorer iron status were positively and negatively associated with activity at break time, respectively. Subjects in the group receiving both iron and DHA/EPA supplements showed a significant improvement from baseline to endpoint on the cognitive problems/inattention subscale (P = 0.005) of the CTRS. Hyperactivity scores increased iv significantly from baseline to endpoint in all groups (P = 0.006). DHA (r = –.203; P = 0.040) and EPA (r = –.199; P = 0.044) content of RBC were negatively associated with activity at class time 1. No significant associations were observed between activity and CTRS scores at baseline. At endpoint, class time 1 activity was positively associated with all CTRS subscale scores except for the cognitive problems subscale, which only bordered significance (correlation, P = 0.051; regression, P = 0.073). Conclusions: These findings suggest that n–3 FA supplementation may have an influence on ADHD–related behaviour during class time. During school break time when subjects were allowed to move around freely, iron status was positively associated with spontaneous motor activity. Furthermore, the accelerometer might be a useful complimentary tool for assessing both classroom and break time activity behaviour in school children. Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2012.

Both Fe deficiency and poorn-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 (n98, 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.