Energy and protein intakes and their association with a decline in functional capacity among diabetic older adults from the NuAge cohort

Purpose Diabetic older adults (OA) are at greater risk of muscle strength (MS) loss and functional capacity (FC) decline than non-diabetics. Protein and energy intakes are important determinants of muscle mass and MS maintenance and indirectly affect FC. The study sought to determine whether low protein and energy intakes were associated with FC decline and whether this association was mediated by MS in diabetic OA over a 3-year follow-up, in secondary analyses of the Quebec Longitudinal Study on Nutrition and Successful Aging. Methods In 172 diabetic OA (62 % men, mean age = 75 years), FC decline was defined as the change between SMAF (Systeme de Mesure de l'Autonomie Fonctionnelle) scores at baseline (T1) and 3 years later (T4). Baseline adequate protein and energy intakes were set at >= 1 g/kg BW and >= 30 kcal/kg BW, respectively. Sex-stratified linear regressions were controlled for confounding variables. Results Mean body weight (BW) was 85.42 +/- 13.8 in men and 79.7 +/- 11.5 in women (p <= .001). Adequate protein intake in women was associated with lesser FC decline (mean +/- SE) (2.11 +/- 0.81 vs. 4.91 +/- 0.72; p = .029), while adequate energy intake was not associated with FC decline either in men or in women. In women, 1 g protein/kg BW helped maintain MS, hence minimizing FC decline. Conclusions These results demonstrate that protein intake is important in maintaining FC in diabetic OA, albeit with sex differences. This study provides further evidence that protein requirements may be greater than the 0.8 g/kg BW currently recommended for OA. Future research in larger samples over longer follow-up is needed to confirm these results.