PROTEIN SUPPLEMENTATION NEGATIVELY IMPACTS GLUCOSE HOMEOSTASIS IN A WEIGHT LOSS INTERVENTION IN OLDER ADULTS

Abstract

Abstract Background Higher dietary intake of protein has also been associated with increased risk of type 2 diabetes, yet losing weight improves glucose metabolism and homeostasis. We evaluated whether a multicomponent weight loss intervention in older persons with obesity aged 65+ years augmented with protein supplementation impacts glucose homeostasis. Methods A 12-week, non-randomized, parallel group intervention in 28 older rural adults with obesity (body mass index (BMI)≥30kg/m2) was conducted at a community aging center of a protein and non-protein arms. Both received individualized, weekly dietitian visits with twice weekly physical therapist-led group strength training classes; aerobic exercise was prescribed outside the classes. The protein group was provided with whey protein supplementation three times weekly post-strength training. Pre/post fasting glucose, insulin, and c-peptide levels were assessed with HOMA-IR and HOMA beta-cell function calculated. Results Mean age was 72.9±4.4 (86% female) and 73.0±6.3 (79% female), p=0.94, with baseline BMI of 37.6±6.9 and 36.6±5.5, in the protein and non-protein groups, respectively. Mean weight-loss was -3.45±2.86kg and -5.79±3.08kg (both p< 0.001; Δ p=0.047). Visceral fat decreased less in the protein group (-0.02mL vs. -1.02ml;p=0.007), while appendicular lean mass did not (p=0.44). There was lower fasting glucose (protein:-4mg±13.9mg/dL vs. non-protein: 12.2±25.8, effect size:-0.40;p=.10), insulin (-1.32±4.68 vs. -7.79±10.14, ES:0.82;p=0.01), and higher c-peptide (-0.02±0.67 vs. -0.69±1.25,ES:0.66;p=0.06) at follow-up. HOMA-IR also decreased less (-0.18±0.64 vs. -1.08±1.50, ES:0.78; p=0.02) and b-cell function (-3.94±22.61 vs. -16.81±33.85; ES:0.45; p=0.09]). Conclusions A multicomponent obesity intervention incorporating protein supplementation led to lower degree of weight loss and mitigated the benefit on glucose homeostasis.