Vitamin D supplementation improves a biomarker of aging, but will it make you live longer?
The United Nations projects that one in five people will be over the age of 60 by 2025. As our population ages, scientists are looking for ways to improve our health. They have identified several hallmarks of aging, including telomere attrition, as drivers of the aging process. Telomeres are the safety caps on the end of chromosomes – the packaged DNA in our cells – that help keep our genome stable. Telomere attrition is the shortening of those safety caps. When telomeres reach a critically short size, the chromosomes become unstable. This is the primary mechanism by which telomere attrition can cause aging.
Zhu and colleagues investigated how supplementing with 2000 IU/day (50 micrograms) of vitamin D over four years affected the telomere length of leukocytes, immune cells, in a group of mixed-sex, primarily white individuals over the age of 50. The placebo group showed a 1.8% reduction in telomere length, while the vitamin D group showed only a 0.2% reduction. When compared to data tracking telomere attrition over 10 years, this reduction translates to a three-year difference in age-related telomere reduction. Interestingly, these benefits were not seen in individuals taking any kind of cholesterol medication.
While these findings are exciting, this study did not link telomere reduction to any functional outcomes. There is some evidence linking leukocyte telomere attrition to the immune function decline with age; however, this link is still being established. Some scientists argue against supplementing with vitamin D above 1000IU/day, and a study looking at supplementation of both calcium and vitamin D over seven years showed increased mortality from cardiovascular disease and decreased mortality from cancer with no change in average life expectancy in postmenopausal women. While the findings from Zhu and colleagues are encouraging, more research is needed to know if lengthening leukocyte telomeres with vitamin D is worth the risks.
Managing Correspondent: Samuel Lapp
Press Article: Vitamin D may slow a process related to aging, new study suggests (Washington Post)
Original Journal Article: Vitamin D3 and marine ω-3 fatty acids supplementation and leukocyte telomere length: 4-year findings from the VITamin D and OmegA-3 TriaL (VITAL) randomized controlled trial (American Journal of Clinical Nutrition)
Image Credit: Pixabay