- Telomeres, the protective caps at the ends of chromosomes, are an important component of healthy aging.
- One study found that vitamin D supplementation helps to minimize the shortening of telomeres, which happens as people get older, and thus may protect against diseases tied to age and biological aging.
- This data adds to the potential protective components of vitamin D, which experts should consider alongside potential risks and additional research.
A study published in The American Journal of Clinical Nutrition examined how omega-3 fatty acid and vitamin D supplementation affected telomere shortening, a natural process that happens with age.
As the authors of this study explained,
David Cutler, MD, a board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, told Medical News Today that “When telomeres become too short, cells enter senescence (a non-dividing state) or apoptosis (programmed cell death). Either condition of cell inactivity or death is thought to contribute to aging and age-related diseases.”
The researchers found that vitamin D supplementation helped minimize telomere shortening in white blood cells, which could help slow down biological aging.
For this study, researchers used data from the VITAL trial. This trial included a representative sample of adults in the United States who received vitamin D3 supplements, omega-3 fatty acid supplements, or both for around five years. It was a double-blind, placebo-controlled study, so some participants received the supplements while others received the placebo. All female participants were at least fifty-five years old, and all male participants were at least fifty.
This data specifically examined a cohort that visited the Harvard Clinical and Translational Science Centre. At baseline and follow-up visits, participants participated in in-person assessments and provided fasting blood samples.
Researchers examined telomere length in
Researchers were able to analyze over 2,500 samples from over 1,000 participants. They examined telomere length at baseline and at two- and four-year follow-up, though some data was missing.
They conducted a statistical analysis using models to adjust for various covariates. They also did an exploratory subgroup analysis to see how different factors, such as high blood pressure and diabetes, impacted results.
Vitamin D vs. omega-3 fatty acids
Aside from a higher body mass index in the omega-3 fatty acid supplement group, the placebo and intervention groups had similar baseline characteristics. Missing data was also similar between the two groups.
Vitamin D appeared to have a positive impact on telomere length. Among participants who received vitamin D, there was only minimal shortening of telomere length at two and four years. In contrast, there was substantial telomere shortening in the placebo group at both time points.
Omega-3 fatty acids supplementation appeared to have no significant impact on telomere length.
The subgroup analysis further suggested that the effects of vitamin D on telomere length were significant for participants not taking medication for cholesterol, but not for participants who were taking cholesterol medication. Vitamin D also minimized telomere shortening at a statistically significant level for non-white participants.
There was no significant interaction with body mass index, but researchers did observe that participants who were not obese had significantly minimized telomere shortening. Also, taking omega-3 fatty acid supplements did not appear to impact the role of vitamin D on telomere length.
This analysis of telomere length in this study population does have some limitations. First, most participants were white, and all participants were at least fifty, so it may not be possible to generalize the findings to other groups.
Researchers acknowledge that this was a post-hoc analysis of an already completed study and that the study was not originally designed to look at the effects of supplements on leukocyte telomere length. The analysis also excluded participants who did not have data on leukocyte telomere length.
It’s possible that unaccounted-for factors influenced the results, and the study also has any other limitations found in the original study.
Regarding exploratory subgroup analysis results, researchers encourage caution, note limited power, and say people should look at the data as “hypothesis-generating.”
After four years, there were about 37% missing cases. Researchers acknowledge that this reduced power and could be why they did not find omega-3 fatty acid supplementation affected leukocyte telomere length.
Future research can explore why vitamin D may have these effects on telomere length. For example, it could be related to an enzyme called telomerase that helps to lengthen telomeres and how vitamin D may protect against DNA damage.
Cutler also noted the following limitations of the study:
“The present study involved only a relatively small number of people, looked only at telomeres in white blood cells, and did not look extensively at the health impact of these telomere changes. So, the clinical implications one can derive from this study are quite limited.”
This study suggests the potential benefits of vitamin D in relation to aging. The authors suggest that the preservation of telomere length in this study “could mean a 3-year decrease in aging.”
Yoshua Quinones, MD, a board-certified Internist with Medical Offices of Manhattan and contributor to https://www.labfinder.com/, who was also not involved in the study, noted the following to MNT:
“As we know already, vitamin D supports bone, immune system and reduces inflammation, but this study is linked directly with telomere preservation which ties into aging and disease prevention. This [study] gives more of a general idea that vitamin D3 could do more than just helping your bones but actually slowing down the cellular age, impressive!”
“If this is confirmed in future studies, this could mean that daily [vitamin D} supplements could actually help reduce risks for age-related diseases. This is a door for new medical guidelines in the future and will be a huge deal for preventive medicine.”
— Yoshua Quinones, MD
However, it’s also important to note the potential risks of vitamin D supplementation.
“While 2,000 units of vitamin D is unlikely to have any negative effects, there may be some risk to vitamin D supplements as they can cause kidney damage and other adverse effects in excessive quantities. Since vitamin D is fat soluble, it can accumulate in our bodies, causing toxicity. So, any potential, as yet unproven benefits of vitamin D need to be weighed against its known risks,” Cutler said.
