Circulating insulin-like growth factor-1 is positively associated with growth and cognition in 6- to 9-year-old schoolchildren from Ghana

Authors: GRENOV, BENEDIKTE - University Of Copenhagen; LARNKJAER, ANNI - University Of Copenhagen; LEE, REGINALD - Washington University; SERENA, ANJA - Arla Foods Ingredients Group P/s; MOLGAARD, CHRISTIAN - University Of Copenhagen; MICHAELSEN, KIM - University Of Copenhagen; MANARY, MARK - Children'S Nutrition Research Center (CNRC)

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2020
Publication Date: 3/25/2020
Citation: Grenov, B., Larnkjaer, A., Lee, R., Serena, A., Molgaard, C., Michaelsen, K.F., Manary, M.J. 2020. Circulating insulin-like growth factor-1 is positively associated with growth and cognition in 6- to 9-year-old schoolchildren from Ghana. Journal of Nutrition. 150(6):1405-1412. https://doi.org/10.1093/jn/nxaa075.
DOI: https://doi.org/10.1093/jn/nxaa075

Interpretive Summary: Consumption of milk stimulates linear growth and improved brain function in school age children. Blood samples from 6-9 year old Ghanaian children receiving different amounts of milk were tested for small milk proteins. Children with higher levels of a certain small milk protein called insulin-like growth factor had better brain function. This small protein might be the cause for improved brain function and futher indepth research is needed.

Technical Abstract: Milk intake stimulates linear growth and improves cognition in children from low-income countries. These effects may be mediated through insulin-like growth factor-1 (IGF-1). The objective was to assess the effect of milk supplement on circulating IGF-1 and to assess IGF-1 as a correlate of growth and cognition in children. Secondary data on blood spot IGF-1 from a randomized, double-blind, controlled trial in 6-9-y-old children from rural Ghana were analyzed. Intervention groups received porridge with non-energy-balanced supplements: 8.8 g milk protein/d, 100 kcal/d (Milk8); 4.4 g milk and 4.4 g rice protein/d, 100 kcal/d (Milk/rice); 4.4 g milk protein/d, 48 kcal/d (Milk4); or a control (no protein, 10 kcal/d). IGF-1, length, body composition, and Cambridge Neuropsychological Test Automated Battery (CANTAB) were measured at 3.5 or 8.5 mo. Linear regressions were used to assess the effect of milk interventions on IGF-1 and IGF-1 as a correlate of growth and cognition. The increase in IGF-1 was 15.3 (95% CI: 3.3, 27.3) ng/mL higher in children receiving Milk8 compared with the control. The IGF-1 increases in the isonitrogenous, isoenergetic Milk/rice or the Milk4 groups were not different from the control (P>=0.49). The increase in IGF-1 was associated with improvements in 4 out of 5 CANTAB domains. The strongest associations included reductions in "mean correct latency" from Pattern Recognition Memory and "pre-extradimensional (pre-ED) shift errors" from Intra/Extradimensional Set Shift (P<=0.005). In addition, change in IGF-1 was positively associated with changes in height, weight, and fat-free mass (P<=0.001). Intake of skimmed milk powder corresponding to one, but not half a glass of milk on school days stimulates IGF-1 in 6-9-y-old Ghanian children. IGF-1 seems to mediate the effect of milk intake on growth and cognition. The association between IGF-1 and cognition in relation to milk intake is novel and opens possibilities for dietary interventions to improve cognition.