Published on June 9, 2025
The effect of vitamin D and inflammation on telomere length and aging
Key Points
- A new analysis of a recent randomized controlled trial found that, compared to participants taking a placebo, those who received 2000 IU of vitamin D3 per day experienced significantly reduced telomere shortening “preventing the equivalent of nearly three years of aging compared with placebo.”
- Previous research has found that higher vitamin D levels were associated with both increased leukocyte telomere length (LTL) and decreased inflammation (CRP), and that vitamin D levels remained significantly positively associated with LTL even after adjusting for age and other factors.
- When looking at the combined relationship of CRP and vitamin D status on LTL, there was a difference of 164.6 base pairs between those with the lowest vitamin D and highest CRP levels versus those with the highest vitamin D and lowest CRP levels – equal to 7.6 years of aging!
A recent publication based on data from the VITAL randomized controlled trial has been receiving a lot of media attention – and for good reason! This new analysis found that participants who took vitamin D supplements had less telomere shortening (used as a marker of biological aging) over the four-year study period. Compared to participants taking a placebo, those who received 2000 IU of vitamin D3 per day experienced significantly reduced telomere shortening “preventing the equivalent of nearly three years of aging compared with placebo.”
While observational studies over the years have demonstrated a similar effect, such as the one by Richards et al. summarized below, the VITAL trial was the first to do so using data based on a randomized controlled trial – adding to the confidence of findings from previous studies.
The Effect of Vitamin D and Inflammation on Telomere Length and Aging
Telomere length shortens naturally with age; however, an increased rate of shortening is linked to faster biological aging and a higher risk of many age-related diseases. Slowing this process may also slow down the aging process, adding years to life and health.
Leukocyte telomere length (LTL) specifically can be used as a predictor of aging-related disease and in identifying the cumulative burden or amount of lifelong oxidative stress and inflammation. Higher amounts of inflammation increase cell turnover, resulting in decreased LTL.
A study by Richards et al. looked to see if there was a relationship between LTL, vitamin D, and inflammation. They assessed vitamin D levels, C-reactive protein (CRP; a marker of inflammation), and LTL using data from 2160 adult women (ages 18 to 80 years old, average age of 49). The authors found that higher vitamin D levels were associated with both increased LTL and decreased inflammation (CRP), and that vitamin D levels remained significantly positively associated with LTL even after adjusting for age and other factors (P<0.0001).
The average LTL among those with the lowest vitamin D levels was 6.97 while the average among those with the highest vitamin D levels was 7.08; the difference of 107.1 base pairs was equivalent to 5 years of telomeric aging (P 0.0009).
Low Vitamin D with High Inflammation Increased Aging by 7.6 Years, According to Study Findings
This above difference was further accentuated by increased levels of systemic inflammation, as measured by CRP. The chart below shows the LTL based on both CRP level and vitamin D level. Note that CRP values of 2.0 mg/L and below were labeled as “Low CRP” and those above were labeled “High CRP.”
LTLs were longer among those with lower CRP levels compared to higher CRP levels. When looking at the combined relationship of CRP and vitamin D status on LTL, there was a difference of 164.6 base pairs between those with the lowest vitamin D and highest CRP levels versus those with the highest vitamin D and lowest CRP levels – equal to 7.6 years of aging!
The study also found that taking vitamin D supplements was related to longer LTLs, however, this finding was not statistically significant. To that point, the authors conclude that randomized controlled trials exploring how vitamin D supplementation affects LTL were necessary, such as the recent VITAL trail.
“Although these associations do not prove causality, they do suggest that vitamin D may play an important role in the modulation of LTL, which is related to aging and age-related diseases. Previous studies indicated that shortened LTL is an independent risk factor for coronary heart disease, and our results suggest that vitamin D, which is easily modifiable through supplementation, may possibly attenuate LTL degradation.”
Vitamin D and Inflammation – Two Important Measures of Health and Aging
Vitamin D is a known inhibitor of inflammation, and several previous studies have demonstrated this by showing an inverse association between vitamin D and CRP levels. The status of both are significantly related to the risk of many chronic diseases, and as we have seen in the studies above, vitamin D and CRP are also related to telomere length and the rate of biological aging.
Save 15% when measuring both vitamin D and CRP (along with any other health measure) with the code SAVE15.
Measure Your Levels Today!
Check your vitamin D, CRP, omega-3s and 6s, magnesium, and other important markers today as part of the vitamin D*action project.
Measure your:
- Vitamin D
- Magnesium PLUS Elements (including zinc, copper, selenium, mercury, cadmium and lead)
- Omega-3 Fatty Acids
- hsCRP (for Inflammation)
- HbA1c (for Blood Sugar)
- and more
Did you know that each of the above can be measured at home using a simple blood spot test? As part of our ongoing research project, you can order your home blood spot test kit to get your levels, followed by education and steps to take to help you reach your optimal target levels. Start by enrolling and ordering your kit to measure each of the above important markers, and make sure you are getting enough of each to support better health and wellbeing!
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How Can You Use this Information for YOUR Health?
Having and maintaining healthy vitamin D and other nutrient levels can help improve your health now and for your future. Measuring is the only way to make sure you are getting enough!
STEP 1 Order your at-home blood spot test kit to measure vitamin D and other nutrients of concern to you, such as omega-3s, magnesium, essential and toxic elements (zinc, copper, selenium, lead, cadmium, mercury); include hsCRP as a marker of inflammation or HbA1c for blood sugar health
STEP 2 Answer the online questionnaire as part of the GrassrootsHealth study
STEP 3 Using our educational materials and tools (such as our dose calculators), assess your results to determine if you are in your desired target range or if actions should be taken to get there
STEP 4 After 3-6 months of implementing your changes, re-test to see if you have achieved your target level(s)
