Jaekyung No

Yang Du, Shuting Tao, Chorong Oh, Jaekyung No. J Obes Metab Syndr 2023;32:77-86. https://doi.org/10.7570/jomes22057

Background: The effect of nutrients such as vitamin D, protein and calcium, to increase muscle mass and stimulate muscle synthesis has been verified. While the latent association between these nutrients and sarcopenia was poorly investigated. Therefore, this study summarized current studies reporting vitamin D, protein and calcium among patients with sarcopenia vs. people without sarcopenia (controls) with meta-analysis to explore their possible relationship. Methods: An electronic search of PubMed and Science Direct from January 1, 1989 to May 30, 2018 was conducted for data collection and meta-analysis of cross-sectional studies was performed. Out of 105,700 initial hits, 6 studies with a total of 6,221 participants (1,156 with sarcopenia vs. 5,065 without) were meta-analyzed. Results: Sarcopenic participants had significantly lower levels of 25(OH)D (SMD = 0.791; 95%CI 0.073, 1.510; p < 0.05; I² = 98.790%), protein (SMD = 0.574; 95%CI 0.088, 1.060; p < 0.05; I² = 97.276%) and calcium (SMD =1.258; 95%CI 0.429, 2.087; p < 0.01; I² = 99.067%) than controls. Conclusions: In conclusion, sarcopenia is associated with intake level of vitamin D, protein and calcium. Among these nutrients, calcium has the greatest impact. Therefore, the significance of calcium to the prevention of sarcopenia should be well-focused.

Sijia Tang, Yang Du, Chorong Oh, Jaekyung No. J Obes Metab Syndr 2020;29:180-7. https://doi.org/10.7570/jomes20006

There are many studies investigating nutritional factors that affect both sarcopenia and muscle formation. According to extensive research, protein has an essential role in muscle formation. More recently, vitamin D has emerged as an important factor that regulates muscle metabolism. However, studies and research of association between 25-Hydroxyvitamin D (25(OH)D) status and components of homeostasis model assessment of insulin resistance ( HOMA-IR) in older are limited. Nineteen studies were found through a search of electronic databases and were subjected to a meta-analysis to investigate the differences in serum levels of 25(OH)D and HOMA-IR between patients with controls and sarcopenia. The random-effects standardized mean difference (SD) and 95% confidence interval (CI) were calculated as the effect size. Nineteen studies with 19,528 participants (5,081 with sarcopenia and 14,447 without) were analyzed. Sarcopenic participants had significantly lower serum levels of 25(OH) D (SD =1.163; 95% CI 0.514, 1.812; p<0.001; I-2=99.652%) and HOMA-IR (SD=-2.040; 95% CI -3.376, -0.705; p<0.005; I-2=99.837%) than controls. It has been reiterated that sarcopenia may be related serum levels of 25(OH) D and HOMA-IR. This relationship needs to be clarified by future longitudinal studies.