BACKGROUND: Sleep is important for children as it directly impacts their mental and physical development. Sleep is not only influenced by the timing but also the macronutrient (carbohydrate and protein) content of meals. Glycaemic index (GI) and glycaemic load (GL) describe the quality of carbohydrates in a food and the burden of these foods on the body's blood glucose response. Diets with a high GI/GL may increase the risk of developing obesity and type 2 diabetes mellitus in adulthood. The present study is piloted to evaluate the short-term impact of milk products with differing glycaemic properties on the sleep patterns of toddlers.
METHODS: Toddlers were recruited from various day care centres. Informed consent was obtained from both the mothers and the centres. A double-blind randomised controlled trial with a between-subjects design was adopted. The toddlers were randomised to either one of two types of milk with a differing GI ("Low" = 23 and "High = 65") for a period of 3.5 days. There were no other dietary restrictions imposed except that the enrolled child did not consume any other milk during the study period. The sleep patterns were recorded using a Phillips Actiwatch-2, which was worn on the wrist for 24 h over 4 days. The parameters used to measure the sleep pattern were sleep-onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO) and sleep efficiency (SE).
RESULTS: A total of 56 toddlers completed the study. The toddlers had a mean age of 19.9 +/- 4.3 months. There were no significant differences (p > 0.05) between the two GI groups for SOL, TST, WASO and SE at the end of the feeding period.
CONCLUSIONS: Sleep patterns of toddlers on low-GI milk did not differ from those with high-GI milk consumed over a short period. Future studies should consider the glycaemic effects of other foods, along with milk with differing GI, consumed for a longer feeding duration.
TRIAL REGISTRATION: ClinicalTrial.gov NCT01589003.
A SYMPOSIUM ON NUTRITION AND COGNITION: Towards research and application for different life stages was held on October 2010 in Malaysia. The influence of diet and nutrition on the cognitive development of the child and on cognitive decline in later life was reviewed. Central to the study of such topics is the assessment of cognitive functioning. Cognitive functioning falls into six main areas: executive functioning, memory, attention, perception, psychomotor and language skills, although each domain can be further subdivided. As it is in the nature of human functioning that the performance on any cognitive test can reflect aspects of many of these domains, ideally a battery of tests should be used to establish the basis of any difference in performance. In intervention studies, frequently there has been a failure to demonstrate a beneficial influence of changes in diet. A possible reason is that studies have failed to acknowledge the time scale and critical ages over which diet has an impact. Diet may have a slow and progressive influence making it difficult for short-term studies to show an improvement. In addition, as many factors influence human behaviour, dietary interventions should only be one part of a coordinated approach; the effect of diet will depend on the social and psychological context in which an individual lives. Placing diet into a broader social and psychological context greatly increases the chance of generating significant findings. This report highlights and reviews presentations and discussions at the symposium.