Supplementation with Nutrients Modulating Insulin-like Growth Factor-1 Negatively Correlated with Changes in the Levels of Pro-inflammatory Cytokines in Community-dwelling Elderly People at Risk of Undernutrition

Background: Suboptimal nutrition accompanied by chronic low-grade increases in circulating cytokine levels is more common in elderly people. We explored the improvement in nutritional status, especially in the level of insulin-like growth factor-1 (IGF-1) and its relationship with changes in circulating cytokine levels, after providing extra protein and energy content to community-dwelling older adults at risk of undernutrition.

Methods: Sixty nondiabetic subjects, aged ≥65 years and living independently in a community for elderly people, with a serum pre-albumin level ≤30 mg dL and a body mass index <25 kg m , were recruited. The subjects were followed for a 2-week pre-intervention period, during which they maintained routine dietary habits. This was followed by an intervention period, during which they received oral nutritional supplementation for 2 weeks.

Results: Following 2 weeks of intervention, there were significant increases in total lymphocyte count (TLC) and insulin-like growth factor (IGF)-1, pre-albumin and transferrin compared to baseline. Body weight and mid-arm circumference significantly increased without alteration of tricep skinfold thickness at the end of the intervention. There was a significant reduction in interleukin (IL)-6 levels and a trend toward a decrease in the tumor necrosis factor (TNF)-α levels. At baseline, age was negatively correlated with IGF-1 levels and positively correlated with IL-6 and TNF-α levels. The change (▵, from baseline) in IGF-1 level was positively correlated with age and negatively correlated with ▵IL-6 and ▵TNF-α.

Conclusions: A 2-week intervention with oral nutritional supplementation improved nutritional status and decreased circulating cytokine levels. Specifically, ▵IGF-1 was negatively correlated with changes in pro-inflammatory cytokine levels in community-dwelling elderly people at risk of undernutrition. (Clinicaltrials.gov: NCT02656186).