Researchers from University College London and the Federal University of San Carlos in Brazil conducted a study on vitamin D supplementation and its impact on age-related muscle strength decline. The findings indicate that older adults who took vitamin D had a significantly lower risk of experiencing loss of muscle strength, with a relative reduction of about 78 percent reported in the study results. The work was published in Calcified Tissue International and Musculoskeletal Research, contributing to a growing body of evidence about how vitamin D supports musculoskeletal health in later life.
The issue under investigation is commonly described as dynapenia, the gradual decrease in muscle strength that accompanies aging. This decline is partly driven by changes in muscle mass and quality, but it is also influenced by nutritional status, physical activity, and other health conditions. The investigation notes that individuals who experience dynapenia tend to have higher risks of falls, hospitalizations, and adverse health outcomes later on, underscoring the practical importance of maintaining muscle strength as part of healthy aging.
The study analyzed data from 3,205 adults aged 50 and older who did not have dynapenia at the start of the observation period. Grip strength, widely used as a proxy for overall muscle strength, was assessed on the basis of standardized thresholds: 26 kilograms or more for men and 16 kilograms or more for women. Those numbers served as reference points to track changes over time and to help identify individuals at greater risk for future weakness and related complications.
A key finding emerged regarding vitamin D status. Participants classified as vitamin D deficient, defined as circulating levels below 30 nanomoles per liter, showed a notably higher risk of developing lower muscle strength by the end of the four-year follow-up. Specifically, compared with those who maintained normal vitamin D levels, the deficiency group exhibited about a 70 percent increased risk of falling into lower strength categories, even when other factors were considered. When individuals with osteoporosis or those actively taking vitamin D were excluded from the analysis, the observed risk in the deficient group remained elevated, with about a 78 percent higher likelihood of developing weaker muscles over the study period.
Vitamin D plays several important roles that relate to musculoskeletal health. It helps regulate the body’s absorption of calcium and phosphorus, which are essential for bone mineralization and muscle function. Beyond skeletal health, vitamin D supports immune system performance and brain health, and it can influence the rate at which muscles recover after exertion. The study’s implications suggest that maintaining adequate vitamin D levels could be a practical component of strategies aimed at preserving muscle strength and reducing fall risk in older adults, though it also highlights that supplementation should be considered in the context of a broader health plan and individual medical guidance.