Effects of whey protein plus vitamin D supplementation combined with progressive resistance training on glycaemic control, body composition, muscle function and cardiometabolic risk factors in middle‐aged and older overweight/obese adults with type 2 diabetes: A 24‐week randomized controlled trial

Abstract

Aim To determine the effect of whey protein plus vitamin D supplementation combined with progressive resistance training (PRT) on glycaemic control, body composition, muscle function and cardiometabolic risk factors in middle‐aged and older adults with type 2 diabetes (T2D). Materials and Methods In this 24‐week, randomized controlled trial, 198 overweight/obese adults (aged 50–75 years) with T2D undertook PRT (2‐3 days/week) with random allocation to whey protein (20 g each morning plus 20 g postexercise) plus vitamin D3 (2000 IU/day) (PRT + ProD, n = 98) or no supplementation (PRT, n = 100). Primary outcomes were HbA1c and homeostatic model assessment‐2 of insulin resistance (HOMA2‐IR). Secondary endpoints included fasting plasma glucose (FPG), body composition, muscle strength, physical function, blood pressure, blood lipids and inflammatory markers. Results At 24 weeks, supplementation did not enhance the effects of PRT on HbA1c (mean absolute change: PRT + ProD −0.10% [95% CI, −0.24%, 0.05%] vs. PRT −0.17% [95% CI, −0.32%, −0.03%], p = .322) or HOMA2‐IR (PRT + ProD −0.12 [95% CI, −0.27, 0.03] vs. PRT −0.03 [95% CI, −0.14, 0.09], p = .370). There were also no significant between‐group differences for the mean changes in the secondary outcomes, except that FPG improved in PRT versus PRT + ProD (net difference, 0.6 mmol/L [95% CI, 0.1, 1.0], P = .018), while interleukin IL‐10 (61% [95% CI 31%, 92%], P < .001), tumour necrosis factor‐α (16% [95% CI, 3%, 29%], p = .015) and 30‐s sit‐to‐stand performance (number, 1.0 [95% CI, −0.05, 1.5], p = .047) increased in PRT + ProD versus PRT. Conclusions In older overweight/obese adults with T2D, daily whey protein plus vitamin D supplementation did not augment the effects of PRT on measures of glycaemic control, body composition, muscle strength or cardiometabolic risk factors.

Leucine‐enriched whey protein supplementation, resistance‐based exercise, and cardiometabolic health in older adults: a randomized controlled trial

“…Other RCTs in older adults have revealed conflicting findings. After 24 weeks, Miller et al 27 showed no greater improvements of whey protein supplementation (increasing In our study, the mechanisms by which leucine-enriched whey protein isolate supplementation induced beneficial changes in LDL-cholesterol, fasting insulin, and HOMA-IR likely relates to the composite of the supplement (and particularly the high concentration of leucine ∼3-5 g per drink). Recent commentary 9,10 of pre-clinical and human work suggests whey protein exerts benefits on lipid metabolism and insulin resistance via interconnected pathways.…”

“…After 24 weeks, Miller et al . 27 showed no greater improvements of whey protein supplementation (increasing total protein intake to ∼1.4 g/kg/day (average of training/non‐training days) plus vitamin D and resistance exercise on HbA1c or HOMA2‐IR when compared with resistance exercise alone in overweight/obese older adults with type 2 diabetes. Huang et al .…”

“…First, the secondary outcomes reported here were based on cardiometabolic health, with the initial power calculation based on primary outcomes focusing on musculoskeletal health. Second, the RCT was not placebo-controlled which increases the risk of bias, although as Miller et al 27 highlighted the inclusion of a common isoenergetic carbohydrate placebo, such as maltodextrin, has the potential to influence glycaemic control. Third, we were not able to include changes in energy and macronutrient (fat and carbohydrate) intake as a covariate in the main analyses due to the number of missing food diaries relative to blood biomarkers at post-intervention in some groups (n = 11/ 24, ~46% of the exercise group), although we do not believe this significantly impacted findings given there was no difference in energy or macronutrient intake at baseline (from n = 81 food diaries) and all participants were instructured to maintain their habitual dietary intake throughout the trial.…”

Exercise Interventions Combined With Dietary Supplements in Type 2 Diabetes Mellitus Patients—A Systematic Review of Relevant Health Outcomes

“…The selection process is presented in the flow diagram (Figure 1). Ten studies met the inclusion criteria (28)(29)(30)(31)(32)(33)(34)(35)(36)(37). The studies were published between 2006 and 2021.…”

“…Five of the eligible studies investigated the effect of vitamin D (VD) ( 28 , 31 , 33 , 34 , 36 ). Different dosages of VD supplements were taken over different time spans.…”