1.
Muscle Mass Changes After Daily Consumption of Protein Mix Supplemented With Vitamin D in Adults Over 50 Years of Age: Subgroup Analysis According to the Serum 25(OH)D Levels of a Randomized Controlled Trial.
Kang, Y, Kim, N, Lee, Y, An, X, Chung, YS, Park, YK
Clinical nutrition research. 2023;12(3):184-198
-
-
-
-
Free full text
Plain language summary
Sarcopenia is an age-related decrease in muscle mass and strength and increases the risk of falls and death. Protein intake and vitamin D are important for the maintenance of muscle mass, and the amino acid leucine plays a role in the regulation of muscle protein turnover. The aim of this 12-week double-blind, randomised, placebo-controlled trial was to evaluate the efficacy of a supplement containing protein, vitamin D, leucine and calcium for maintaining muscle mass, strength and physical functioning in healthy Koreans aged 50-80 years. Increases in muscle mass were seen in those with low vitamin D levels (< 30 ng/ml) but not in those with higher vitamin D levels. No differences were observed in muscle strength and physical functioning. The authors concluded that a supplement containing protein, including high levels of leucine, vitamin D and calcium may be of benefit for muscle mass to middle-aged and older adults with low vitamin D levels.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Consider supplementing protein in combination with leucine, vitamin D and calcium in middle-aged or older adults with insufficient vitamin D levels for prevention of sarcopenia.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Introduction
- Sarcopenia increases the risk of falls and death
- Protein and vitamin D are important for maintaining muscle mass whilst leucine is involved in regulating muscle protein turnover
- The aim of this study was to evaluate the effects of a supplement containing protein, vitamin D, leucine and calcium on muscle mass, physical functioning, muscle strength, and physical ability in middle-aged and older adults.
Methods
- Double-blind, randomised, placebo-controlled trial, with a duration of 12 weeks. Included 120 healthy Koreans aged 50-80 years
- Participants were assigned to “insufficient” subgroup if vitamin D levels were <30ng/ml and to the “sufficient” subgroup if vitamin D was 30ng/ml or higher
- Intervention: 2.5g powder (containing 20g protein (90% milk/10% soya, incl. 3g leucine), 800 IU vitamin D, 300 mg calcium) mixed into beverage of choice twice a day. Control: isocaloric placebo powder
- Primary outcome: Muscle mass determined by dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA)
- Secondary outcomes: Muscle strength (femoral muscle and grip strength); physical functioning (short physical performance battery (SPPB), International Physical Activity Questionnaire (IPAQ)).
Results
- At baseline, age of participants in the “sufficient” intervention subgroup was higher than that of the “sufficient” control subgroup (p=0.02)
- Increase in vitamin D levels in intervention group relative to control group, in both sufficient and insufficient subgroups (difference in changes between groups 11.5 ng/ml and 13.9 ng/ml, respectively, both p=0.00)
- No difference in change in muscle index as measured by DXA between groups
- In the “insufficient” subgroup, BIA increases in muscle mass were seen when normalised by height (p=0.037) and weight (p=0.05)
- No differences in changes in physical functioning or muscle strength between groups.
Conclusion
- The authors conclude that a supplement containing protein, with high levels of leucine, vitamin D and calcium may be of benefit for muscle mass to middle-aged and older adults with insufficient vitamin D levels.
Clinical practice applications:
- Middle-aged and older adults with insufficient vitamin D levels may gain muscle mass through supplementation of protein, leucine, vitamin D and calcium
- Middle-age and older adults with sufficient vitamin D levels do not appear to benefit from the same intervention.
Considerations for future research:
- Longer-term studies may help identify whether increases in muscle mass lead to improved physical functioning over time
- A study combining supplementation and exercise may help identify additive or synergistic effects.
Abstract
UNLABELLED Early prevention of sarcopenia can be an important strategy for muscle maintenance, but most studies target subjects at slightly pre-sarcopenic state. Our previous paper describes the effect of protein supplements rich in leucine and vitamin D on muscle condition, and in this paper, we performed a sub-analysis to evaluate who benefitted the most in terms of improvement in muscle health. A 12-week randomized clinical trial of 120 healthy adults (aged 50 to 80) assigned to an intervention group (n = 60) or control group (n = 60) were analyzed. Subjects in the intervention group received, twice per day, a protein supplement containing (per serving) 800 IU of vitamin D, 20 g of protein (3 g of total leucine), 300 mg of calcium, 1.1 g of fat, and 2.5 g of carbohydrate. The subjects were classified into 'insufficient' and 'sufficient' groups at 25-hydroxyvitamin D (25[OH]D) value of 30 ng/mL. The skeletal muscle mass index normalized to the square of the skeletal muscle mass (SMM) height (kg/m2) increased significantly in the 'insufficient group' difference value of change between weeks 0 and 12 (Δ1.07 ± 2.20; p = 0.037). The SMM normalized by body weight (kg/kg, %) was higher, but not significantly, in the insufficient group (Δ0.38 ± 0.69; p = 0.050). For people with insufficient (serum 25[OH]D), supplemental intake of protein and vitamin D, calcium, and leucine and adequate energy intake increases muscle mass in middle-aged and older adults and would be likely to exert a beneficial effect on muscle health. TRIAL REGISTRATION Clinical Research Information Service Identifier: KCT0005111.
2.
Low free 25-hydroxyvitamin D and high vitamin D binding protein and parathyroid hormone in obese Caucasians. A complex association with bone?
Saarnio, E, Pekkinen, M, Itkonen, ST, Kemi, V, Karp, H, Ivaska, KK, Risteli, J, Koivula, MK, Kärkkäinen, M, Mäkitie, O, et al
PloS one. 2018;13(2):e0192596
-
-
-
Free full text
Plain language summary
Obese people are at a higher risk of vitamin D deficiency, and this could have an impact on bone mineral density. This study examined whether there were any differences between obese, overweight and normal-weight adults in levels of vitamin D, vitamin D binding protein (DBP), parathyroid hormone (PTH) and bone density. More than 500 healthy Finnish men and women aged 37-47 years took part in the study. Vitamin D levels were found to be lower in obese than in normal weight people. Levels of DBP and PTH were higher in obese than normal weight women. Some measures of bone density were higher in obese women. Markers of bone turnover were lower in obese people than those of normal weight. The findings of this study suggest that obese people may differ from normal weight subjects in vitamin D metabolism. It is not yet clear what impact this has on bone health.
Abstract
BACKGROUND Studies have shown altered vitamin D metabolism in obesity. We assessed differences between obese and normal-weight subjects in total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D, 25(OH)DFree, and 25(OH)DBio, respectively), vitamin D binding protein (DBP), parathyroid hormone (PTH) and bone traits. METHODS 595 37-47-year-old healthy Finnish men and women stratified by BMI were examined in this cross-sectional study. Background characteristic and intakes of vitamin D and calcium were collected. The concentrations of 25(OH)D, PTH, DBP, albumin and bone turnover markers were determined from blood. 25(OH)DFree and 25(OH)DBio were calculated. pQCT was performed at radius and tibia. RESULTS Mean±SE (ANCOVA) 25(OH)DFree (10.8±0.6 vs 12.9±0.4 nmol/L; P = 0.008) and 25(OH)DBio (4.1±0.3 vs 5.1±0.1 nmol/L; P = 0.003) were lower in obese than in normal-weight women. In men, 25(OH)D (48.0±2.4 vs 56.4±2.0 nmol/L, P = 0.003), 25(OH)DFree (10.3±0.7 vs 12.5±0.6 pmol/L; P = 0.044) and 25(OH)DBio (4.2±0.3 vs 5.1±0.2 nmol/L; P = 0.032) were lower in obese. Similarly in all subjects, 25(OH)D, 25(OH)DFree and 25(OH)DBio were lower in obese (P<0.001). DBP (399±12 vs 356±7mg/L, P = 0.008) and PTH (62.2±3.0 vs 53.3±1.9 ng/L; P = 0.045) were higher in obese than in normal-weight women. In all subjects, PTH and DBP were higher in obese (P = 0.047and P = 0.004, respectively). In obese women, 25(OH)D was negatively associated with distal radius trabecular density (R2 = 0.089, P = 0.009) and tibial shaft cortical strength index (CSI) (R2 = 0.146, P = 0.004). 25(OH)DFree was negatively associated with distal radius CSI (R2 = 0.070, P = 0.049), radial shaft cortical density (CorD) (R2 = 0.050, P = 0.045), and tibial shaft CSI (R2 = 0.113, P = 0.012). 25(OH)DBio was negatively associated with distal radius CSI (R2 = 0.072, P = 0.045), radial shaft CorD (R2 = 0.059, P = 0.032), and tibial shaft CSI (R2 = 0.093, P = 0.024). CONCLUSIONS The associations between BMI and 25(OH)D, 25(OH)DFree, and 25(OH)DBio, DBP, and PTH suggest that obese subjects may differ from normal-weight subjects in vitamin D metabolism. BMI associated positively with trabecular bone traits and CSI in our study, and slightly negatively with cortical bone traits. Surprisingly, there was a negative association of free and bioavailable 25(OH)D and some of the bone traits in obese women.