The effect of vitamin D2 supplementation on muscle strength in early postmenopausal women: a randomized, double-blind, placebo-controlled trial

The effect of vitamin D2 supplementation on vitamin D levels in humans: A time and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Inconsistencies exist regarding the influence of vitamin D2 (ergocalciferol) supplementation on serum vitamin D levels. These inconsistencies could be attributed to numerous factors, such as dosage, baseline vitamin D levels, and duration of intervention. Hence, this dose-response meta-analysis of randomized controlled trials was conducted to assess the efficacy of vitamin D2 supplementation on vitamin D levels.

METHODS

Relevant studies were searched in PubMed/Medline, Web of Science, Embase, and Scopus, from their inception to 3 January 2023. Variable alterations were considered to calculate the pooled weighted mean difference (WMD) with 95% confidence interval (CI) using the random effects model.

RESULTS

Pooled results from 33 study arms demonstrated that Vitamin D2 treatment significantly increases total vitamin D concentrations (WMD: 11.47 ng/mL, 95 %CI: 9.29 to 13.64, p < 0.001), 25(OH)D2 concentrations (WMD: 11.40 ng/mL, 95 %CI: 4.72 to 18.09, p = 0.001), and 1,25(OH)D concentrations (WMD: 5.61 ng/mL, 95 %CI: 0.74 to 10.48, p = 0.024), but decreases 25(OH)D3 concentrations (WMD: -4.63 ng/mL, 95 %CI: -6.46 to -2.81, p < 0.001). In subgroup analyses, increase in total vitamin D concentrations was more significant in vitamin D2 doses >2000 IU/day (WMD: 13.82 ng/mL), studies with duration ≤12 weeks (WMD: 12.53 ng/mL), participants aged ≥60 years (WMD: 14.40 ng/mL), and trials with basal 25(OH)D concentrations <20 ng/mL (WMD: 11.47 ng/mL).

CONCLUSIONS

This meta-analysis indicates that the supplementation of vitamin D2 significantly increases the serum concentrations of total vitamin D, 25(OH)D2, and 1,25(OH)D, but decreases 25(OH)D3 concentrations. Careful consideration of patient characteristics, dosage, and treatment duration is recommended for vitamin D2 supplementation.

Nutrition Interventions on Muscle-Related Components of Sarcopenia in Females: A Systematic Review of Randomized Controlled Trials

Sarcopenia is a skeletal muscle disease categorized by low muscle strength, muscle quantity or quality, and physical performance. Sarcopenia etiology is multifaceted, and while resistance training is widely agreed upon for prevention and treatment, disease progression is also highly related to poor diet. The incidence of sarcopenia appears sex-specific and may be increased in females, which is problematic because dietary quality is often altered later in life, particularly after menopause. Identifying effective nutrition or supplementation interventions could be an important strategy to delay sarcopenia and related comorbidities in this vulnerable population. This systematic review examined randomized controlled trials (RCTs) of nutrition strategies on muscle-related components of sarcopenia in middle-aged and older females. A protocol was registered (PROSPERO CRD42022382943) and a systematic search of MEDLINE and CINAHL was undertaken. RCTs from 2013 to 2023 that assessed nutrition-only interventions on muscle mass, muscle strength, and physical function in female participants were included. Fourteen RCTs were included based on selection criteria. Study designs and interventions were heterogeneous in supplementation type and amount, age, and duration. Six RCTs reported beneficial effects of protein, Vitamin D, Vitamin D and Magnesium (Mg), and fish oil on muscle protein synthesis, muscle strength, and/or muscle function. Eight studies that examined various protein interventions, VitD alone, Mg alone, and dairy derivatives did not demonstrate any effect. Exercise appeared to modulate results in several studies. Nutrition interventions alone are likely to have a limited but positive effect on muscle-related components of sarcopenia in females. Current evidence suggests that a combination of dietary intervention and exercise is likely to be key to preventing and treating sarcopenia in middle aged and older females and there is a need for well-designed nutrition based studies in this population.

Effect of non-pharmacological interventions on the prevention of sarcopenia in menopausal women: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Sarcopenia is a chronic disease marked by gradual muscle system and functional decline. Prior research indicates its prevalence in those under 60 varies from 8 to 36%. There is limited evidence on the effectiveness of non-pharmacological interventions for sarcopenia prevention in menopausal women aged 40-60. This study examines the influence of such interventions for sarcopenia prevention on these women.

METHODS

PubMed, EMBASE, Medline, Cochrane Library, CINAHL, PEDro, and Airiti Library were searched from inception until May 5, 2023. Randomized controlled trials that examined exercise, vitamin D and protein supplementation effects on muscle mass, strength, and physical function. Quality assessment used the Cochrane risk of bias tool, and analysis employed Comprehensive Meta-Analysis version 2.0.

RESULTS

A total of 27 randomized controlled trials, involving 1,989 participants were identified. Meta-analysis results showed exercise improved lean body mass (SMD = 0.232, 95% CI: 0.097, 0.366), handgrip strength (SMD = 0.901, 95% CI: 0.362, 1.441), knee extension strength (SMD = 0.698, 95% CI: 0.384, 1.013). Resistance training had a small effect on lean body mass, longer exercise duration (> 12 weeks) and higher frequency (60-90 min, 3 sessions/week) showed small to moderate effects on lean body mass. Vitamin D supplementation improved handgrip strength (SMD = 0.303, 95% CI: 0.130, 0.476), but not knee extension strength. There was insufficient data to assess the impact of protein supplementation on muscle strength.

CONCLUSIONS

Exercise effectively improves muscle mass, and strength in menopausal women. Resistance training with 3 sessions per week, lasting 20-90 min for at least 6 weeks, is most effective. Vitamin D supplementation enhances small muscle group strength. Further trials are needed to assess the effects of vitamin D and protein supplementation on sarcopenia prevention.

REGISTRATION NUMBER

This review was registered on PROSPERO CRD42022329273.

The Effects of Protein and Supplements on Sarcopenia in Human Clinical Studies: How Older Adults Should Consume Protein and Supplements

Sarcopenia is a condition in which muscle mass, strength, and performance decrease with age. It is associated with chronic diseases such as diabetes, cardiovascular disease, and hypertension, and contributes to an increase in mortality. Because managing sarcopenia is critical for maintaining good health and quality of life for the elderly, the condition has sparked concern among many researchers. To counteract sarcopenia, intake of protein is an important factor, while a lack of either protein or vitamin D is a major cause of sarcopenia. In addition, essential amino acids, leucine, β-hydroxy β-methylbutyrate (HMB), creatine, and citrulline are used as supplements for muscle health and are suggested as alternatives for controlling sarcopenia. There are many studies on such proteins and supplements, but it is necessary to actually organize the types, amounts, and methods by which proteins and supplements should be consumed to inhibit sarcopenia. In this study, the efficacy of proteins and supplements for controlling sarcopenia according to human clinical studies is summarized to provide suggestions about how the elderly may consume proteins, amino acids, and other supplements.

Nutrients against Glucocorticoid-Induced Muscle Atrophy

Glucocorticoid excess is a critical factor contributing to muscle atrophy. Both endogenous and exogenous glucocorticoids negatively affect the preservation of muscle mass and function. To date, the most effective intervention to prevent muscle atrophy is to apply a mechanical load in the form of resistance exercise. However, glucocorticoid-induced skeletal muscle atrophy easily causes fatigue in daily physical activities, such as climbing stairs and walking at a brisk pace, and reduces body movements to cause a decreased ability to perform physical activity. Therefore, providing adequate nutrients in these circumstances is a key factor in limiting muscle wasting and improving muscle mass recovery. The present review will provide an up-to-date review of the effects of various nutrients, including amino acids such as branched-chain amino acids (BCAAs) and β–hydroxy β–methylbutyrate (HMB), fatty acids such as omega-3, and vitamins and their derivates on the prevention and improvement of glucocorticoid-induced muscle atrophy.

Vitamin D Supplementation Improves Handgrip Strength in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

In postmenopausal women, vitamin D deficiency (as defined by the circulating level of 25(OH)D being below 20 ng/ml (50 nmol/L)) is a regular occurrence. The effect of vitamin D supplementation on the muscle function of postmenopausal women has been controversial. This systematic review and meta-analysis of randomized controlled trials (RCTs) examines and summarizes the effects of vitamin D supplementation on the muscular strength and mobility of postmenopausal women.

METHODS

RCTs that met the inclusion criteria for this study were identified by searching PubMed, EMBASE, and the Cochrane Library. Postmenopausal women who were included in the study were exposed to RCTs assessing the effectiveness of vitamin D supplements. Meta-analysis data were extracted by two independent reviewers and screened for methodological quality. RCTs that did not meet the minimum requirement for assessment were excluded. In the meta-analysis, the effect size (weighted mean differences, WMD) of handgrip strength (HGS) and timed-up and go test (TUG) with a 95% confidence interval (CI) was obtained to compare reported results across the included RCTs.

RESULTS

A total of 19 trials were included in this systematic review, among which 13 trials were eligible for the meta-analysis. In the 13 included studies, supplementing with vitamin D produced a weighted mean difference of 0.876 kg (95% CI = 0.180 to 1.571, P = 0.014, I² = 68.5%) for HGS, a measurement of muscle strength. However, an insignificant decrease of 0.044 s was observed after analyzing the TUG (95% CI = -0.979 to 0.892, P = 0.927, I² = 95%). According to subgroup analysis, vitamin D supplementation increased HGS in patients over the age of 60 (P = 0.001), in those without calcium supplementation (P = 0.032), and in those whose baseline vitamin D level was greater than 75 nmol/L (30 ng/ml) (P = 0.003).

CONCLUSIONS

Taking into account the studies in this systematic review, vitamin D supplementation improved muscle strength in postmenopausal women. However, an insignificant result was demonstrated in terms of mobility after vitamin D supplementation.

Effect Size of Dietary Supplementation and Physical Exercise Interventions for Sarcopenia in Middle-Aged Women

The purpose of this meta-analysis was to comprehensively analyze the relationship between intervention (di-etary supplementation and physical exercise), body composition, and physical activity capacity in middle-aged women with sarcopenia. A total of 19 studies published in the last ten years were selected. The overall effect size was small (0.29; 95% confidence interval: 0.195∼0.385). The Q value was 100.214 and the Higgin’s I² value was 82.038. Each study was found to be heterogeneous and there was no publication bias. The effect size was increased when the number of study partici-pants increased from 50 to 100 and when dietary vitamin D supplementation was combined with resistance exercise. Fur-thermore, the effect on physical activity capacity was higher than that on body composition. In conclusion, dietary vitamin D supplementation combined with resistance training had a positive impact on middle-aged women with sarcopenia.

Vitamin D and Muscle Health: A Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials

The objective of this study was to investigate the effects of vitamin D supplementation versus placebo on muscle health. For this systematic review and trial-level meta-analysis of placebo-controlled trials, a systematic search of randomized controlled trials published until October 2020 was performed in Medline, Embase, and Google Scholar. We included studies in humans (except athletes) on supplementation with vitamin D2 or D3 versus placebo, regardless of administration form (daily, bolus, and duration) with or without calcium co-supplementation. The predefined endpoints were physical performance reported as timed up and go test (TUG; seconds), chair rising test (seconds), 6-minute walking distance (m), and Short Physical Performance Battery (SPPB; points). Furthermore, endpoints were maximum muscle strength (Newton) measured at handgrip, elbow flexion, elbow extension, knee flexion, and knee extension, as well as muscle (lean tissue) mass (kg). Falls were not included in the analysis. Cochrane Review Manager (version 5.4.1.) calculating mean difference (MD) using a random effect model was used. In total, 54 randomized controlled trials involving 8747 individuals were included. Vitamin D versus placebo was associated with a significantly longer time spent performing the TUG (MD 0.15 [95% confidence interval (CI) 0.03 to 0.26] seconds, N = 19 studies, I²  = 0%, n = 5223 participants) and a significant lower maximum knee flexion strength (MD -3.3 [-6.63 to -0.03] Newton, N = 12 studies, I²  = 0%, n = 765 participants). Total score in the SPPB showed a tendency toward worsening in response to vitamin D compared with placebo (MD -0.18 [-0.37 to 0.01] points, N = 8 studies, I²  = 0%, n = 856 participants). Other measures of muscle health did not show between-group differences. In subgroup analyses, including studies with low vitamin D levels, effects of vitamin D supplementation did not differ from placebo. Available evidence does not support a beneficial effect of vitamin D supplementation on muscle health. Vitamin D may have adverse effects on muscle health, which needs to be considered when recommending vitamin D supplementation. © 2021 American Society for Bone and Mineral Research (ASBMR).

Pinpointing a Role for Vitamin D in Frailty: A Time for Animal Models?

Frailty is a condition marked by greater susceptibility to adverse outcomes, including disability and mortality, which affects up to 50% of those 80 years of age and older. Concurrently, serum vitamin D insufficiency and deficiency, for which as many as 70% of older adults may be at risk, potentially play an important role in frailty onset and progression. Large population driven studies have uncovered associations between low serum vitamin D levels and higher incidence of frailty. However, attempts to apply vitamin D therapeutically to treat and/or prevent frailty have not yielded consistent support for benefits. Given the complexity and inconsistency arising from human studies involving vitamin D, our research group has recently published on animal models of vitamin D insufficiency. Combining our model with the emerging development of animal frailty assessment, we identified that higher than standard levels of vitamin D supplementation may delay frailty in mice. In this viewpoint article, we will discuss current knowledge regarding the importance of vitamin D in frailty progression, the emerging significance of animal models in addressing these relationships, and the future for pre-clinical and clinical research.

Vitamin D supplementation: upper limit for safety revisited?

Vitamin D overdosing includes hypercalcemia, hypercalciuria, and mineral deposits in soft tissues. A safety upper limit of 4000 IU/day, which is consistently accepted, has been challenged, since the risk of adverse events in other systems than calcium-phosphate homeostasis may depend not only on the dose, but on the outcome, the treatment regimen, and possibly the age, sex and vitamin D status. The therapeutic window of vitamin D supplementation may be narrower than hitherto recognized. The prevention and/or correction of vitamin D deficiency/insufficiency with 800–1000 IU/daily of vitamin D or 10 µg/day of calcifediol are safe. Because of their potential harm, larger doses given on the long term or in intermittent regimens should not be selected.

Vitamin D status and supplementation impacts on skeletal muscle function: comparisons between young athletes and older adults

PURPOSE OF REVIEW

The present narrative review analyzes emerging research implicating vitamin D status and supplementation with skeletal muscle homeostasis and functions in two distinct segments of the adult population: young athletes and older adults.

RECENT FINDINGS

Vitamin D deficiency compromises multiple indices of muscle function in young athletes and older adults. A variety of vitamin D3 (cholecalciferol) supplementation regimens may transition young athletes and older adults from deficient or inadequate to adequate vitamin D status. Vitamin D supplementation, used to treat a vitamin D deficiency, but not necessarily an inadequacy, promotes muscle anabolism in older adults. For both young athletes and older adults, vitamin D supplementation, which transitions them from inadequate to adequate vitamin D status, may not beneficially affect measures of muscle strength and power, or physical performance. Also, when vitamin D status is adequate, vitamin D supplementation to further increase serum 25(OH)D concentrations does not seem to confer additional benefits to muscle strength and power and physical performance.

SUMMARY

The impacts of vitamin D status and supplementation on skeletal muscle homeostasis and functions seem comparable in young athletes who strive to maximize physical performance and older adults who seek to attenuate muscle mass and physical performance declines.

No independent or combined effects of vitamin D and conjugated linoleic acids on muscle protein synthesis in older adults: a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Aging is associated with skeletal muscle anabolic resistance (i.e., reduced muscle protein synthesis during anabolic conditions such as hyperaminoacidemia). The results from studies conducted in cell culture systems and animals suggest that both vitamin D and conjugated linoleic acids (CLAs) stimulate muscle protein synthesis.

OBJECTIVES

To conduct a randomized, double-blind, placebo-controlled clinical trial to determine the independent and combined effects of dietary vitamin D and CLA supplementation on myofibrillar protein synthesis rates in sedentary older adults.

METHODS

Thirty-two sedentary, older adults were randomized to receive either: 1) 2000 IU vitamin D-3 (Vit D) per day; 2) 4000 mg CLA per day; 3) both Vit D (2000 IU/d) and CLA (4000 mg/d); or 4) placebo for 8 wk. Myofibrillar protein synthesis rates were evaluated by using intravenous [ring-2H5]phenylalanine infusion in conjunction with muscle biopsies during basal, postabsorptive conditions and during combined amino acid and insulin infusion before and after the supplementation period.

RESULTS

Before the intervention, basal myofibrillar protein synthesis rates were not different among groups (Placebo: 0.033 ± 0.003; Vit D: 0.034 ± 0.002; CLA: 0.029 ± 0.005; Vit D + CLA: 0.038 ± 0.005 %·h-1), and hyperinsulinemia-hyperaminoacidemia increased myofibrillar protein synthesis rates by ∼35%. Compared with placebo, neither Vit D nor CLA nor combined Vit D + CLA supplementation affected the basal myofibrillar protein synthesis rates (placebo: 0.040 ± 0.004%/h; Vit D: 0.044 ± 0.006%/h; CLA: 0.039 ± 0.006%/h; Vit D + CLA: 0.040 ± 0.007%/h) or the hyperinsulinemia-hyperaminoacidemia-induced increase in myofibrillar protein synthesis (percentage increase from basal before and after the interventions: placebo, 30 ± 11 and 36 ± 11; Vit D, 38 ± 8 and 34 ± 10; CLA, 50 ± 14 and 51 ± 16; Vit D + CLA, 29 ± 15 and 35 ± 8).

CONCLUSIONS

Vitamin D and/or CLA supplementation, at the doses provided in our study, does not have muscle anabolic effects in sedentary older adults.The study was registered at clinicaltrials.gov (NCT03115775).

Effect of Whole-Body Vibration Exercise on Power Profile and Bone Mineral Density in Postmenopausal Women With Osteoporosis: A Randomized Controlled Trial

OBJECTIVE

The purpose of this study was to investigate the effect of whole-body vibration (WBV) on muscle work and bone mineral density (BMD) of the lumbar vertebrae and femur in postmenopausal women.

METHODS

Forty-three postmenopausal women with low BMD were randomly assigned to WBV and control groups. Both groups received calcium and vitamin D supplementations once daily, while the WBV group additionally received WBV exercise (twice/wk) for 24 successive weeks. Qualisys gait analysis system was used to measure hip power generation by hip extensors (H1S) and flexors (H3S), hip power absorption by hip flexors (H2S), knee power absorption by quadriceps during loading response (K1S) and preswing (K3S), knee power absorption by hamstring (K4S), knee power generation by quadriceps (K2S), ankle power absorption by dorsiflexors (A1S) and plantar flexors (A2S), and ankle power generation by plantar flexors (A3S). Also, dual-energy X-ray absorptiometry was used to measure BMD of the lumbar vertebrae and femur before and after the intervention.

RESULTS

There were significant increases (P < .05) in the hip muscle work (H1S, H2S, and H3S), knee muscle work (K1S, K2S, K3S, and K4S), ankle muscle work (A1S, A2S, and A3S) during gait, and BMD of the lumbar vertebrae and femur of the WBV group. However, there were no significant changes (P > .05) in the control group. The posttreatment values of the hip, knee, and ankle muscle work and BMD of the WBV group were significantly (P < .05) higher than the posttreatment values of the control group.

CONCLUSION

Whole-body vibration training improved the leg muscle work and lumbar and femoral BMD in postmenopausal women with low BMD.

Nutrition and Sarcopenia-What Do We Know?

Muscle health is important for the functionality and independence of older adults, and certain nutrients as well as dietary patterns have been shown to offer protective effects against declines in strength and function associated with aging. In this paper, micronutrients, macronutrients, and food groups have been reviewed, along with their studied effects on the prevalence and incidence of sarcopenia, as well as their ability to preserve muscle mass and optimize physical performance. Randomized controlled trials appear to suggest a critical role for dietary intake of protein in preventing sarcopenia and muscle loss, although the optimal dose and type of protein is unknown. There are some promising data regarding the role of vitamin D and sarcopenia, but it is unclear whether the dose, frequency of dose, or length of treatment impacts the efficacy of vitamin D on improving muscle mass or function. Selenium, magnesium, and omega 3 fatty acids have been studied as supplements in clinical trials and in the diet, and they appear to demonstrate a potential association with physical activity and muscle performance in older individuals. Following the Mediterranean diet and higher consumption of fruits and vegetables have been associated with improved physical performance and protection against muscle wasting, sarcopenia, and frailty.