Could Vitamin D Help Us Age Better?

Recent Study Says… Maybe

Image Caption: [1]

Written by: Max Mislow ‘28

Edited by: Allison Shea ‘28

How can we slow down the aging process? This challenging question has been at the forefront of scientific research for centuries. Between genetic factors, lifestyle choices, or even the environment one lives in, there are a multitude of things to consider when discussing what contributes to cellular aging [2]. To address this, scientists from all different backgrounds have been investigating the different aspects of cellular aging. Just this year, in fact, researchers at the Medical College of Georgia concluded a 4-year long clinical study investigating the effects of vitamin-C and marine omega-3 fatty acid supplementation on one of the main mechanisms of cellular aging: telomere shortening.

What Exactly Are Telomeres?

Telomeres and chromosomes go hand in hand. Chromosomes are structures found inside the nucleus of a cell that are made up of DNA tightly coiled around proteins. Specific sections of DNA along chromosomes are called genes, which contain every piece of genetic information in an organism. 

Image Credit: [3]

Telomeres act as protective caps on the end of chromosomes, preventing chromosomes from fusing with other chromosomes, degrading over time, or being mistaken for damaged DNA [3]. While telomeres serve a whole host of essential cellular functions, they also naturally shorten with each cell division. After telomeres become too short, the cell can no longer divide and enters senescence (a state of cellular aging). The process of telomere shortening has been strongly linked to an increased risk of developing age-related conditions such as cardiovascular disease, chronic kidney disease, types 1 and 2 diabetes, Alzheimer’s, Parkinson’s, and more [4].

The VITAL Trial:

The VITAL Trial was a large-scale clinical study that aimed to see if daily supplements of vitamin D3 or omega-3 fatty acids (like those found in fish oil) would affect telomere length. Researchers in the VITAL trial employed a randomized, double-blind, placebo-controlled methodology in a group of over 1000 participants [5]. This means that participants were randomly assigned to different treatment groups, and neither they nor the researchers knew who was receiving the real supplements and who was getting the placebo (fake pill). The aim of a study design like this is to reduce bias and ensure results are accurate. The study contained four treatment groups [5]:

	Group 1	Group 2	Group 3	Group 4
Treatment	2 x Placebo	Real Vitamin D3 + Omega-3 Placebo	Vitamin D3 Placebo + Real Omega-3s	Real Vitamin D3 + Real Omega-3s

The first group received a once daily dose of vitamin D3 and a placebo for the omega-3 fatty acids. Another group received real omega-3 fatty acids and a placebo for vitamin D3. One group received both real vitamin D3 and real omega-3s, and the final group received two placebo pills, one for vitamin D3 and the other for omega-3s.

Image Credit: [6]

To conduct the analysis, the researchers collected blood samples at three key time points: at the start of the study (baseline), after two years, and after four years. The treatment dosage was a daily intake of 2,000 IU of vitamin D3 and 1 g of marine omega-3 fatty acids [5]. The LTL (leukocyte telomere length) was measured using qPCR, an accurate laboratory technique that gives precise and consistent results. The researchers then observed the change in LTL over time and compared the differences between the four groups. They also adjusted for other potential influences on telomere length, such as age, sex, BMI, and smoking status, to isolate the true effect of the supplements [5].

The Results: Vitamin D vs. Omega-3s:

The study found a significant difference between the effects of the two supplements on telomere length [5]. When compared to the placebo group, daily supplementation with 2,000 IU of vitamin D3 significantly reduced LTL attrition over the four-year period. The vitamin D3 group had LTLs that were about 0.035 kb (a measurement of DNA length) higher per year of follow-up compared to the placebo group, which equates to a total reduction in telomere attrition of 140 DNA base pairs over the study period. In contrast, the study found no significant effect of marine omega-3 fatty acid supplementation on LTL at either year 2 or year 4 [5]. 

Ultimately, the VITAL Trial researchers concluded that daily supplementation with vitamin D3, with or without omega-3s, might have a role in counteracting telomere erosion or cellular senescence, and while it isn’t definitive, it's an exciting step forward for the field of aging science!

Bibliography

1. Drug Discovery from Technology Networks [Internet]. [cited 2025 Sept 21]. The 3D Structure of Telomerase: Uncovering Its Role in Human Disease. Available from: http://www.technologynetworks.com/drug-discovery/articles/the-3d-structure-of-telomerase-uncovering-its-role-in-human-disease-300278

2. Cleveland Clinic [Internet]. [cited 2025 Sept 21]. Premature Aging: Signs, Causes & Prevention. Available from: https://my.clevelandclinic.org/health/symptoms/23105-premature-aging

3. BSc SM. News-Medical. 2019 [cited 2025 Sept 21]. What are Telomeres? Available from: https://www.news-medical.net/life-sciences/What-are-Telomeres.aspx

4. Huang X, Huang L, Lu J, Cheng L, Wu D, Li L, et al. The relationship between telomere length and aging-related diseases. Clin Exp Med. 2025;25(1):72.

5. Zhu H, Manson JE, Cook NR, Bekele BB, Chen L, Kane KJ, et al. 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. The American Journal of Clinical Nutrition. 2025 July 1;122(1):39–47

6. Resnick B. Vox. 2017 [cited 2025 Sept 21]. The weird power of the placebo effect, explained. Available from: https://www.vox.com/science-and-health/2017/7/7/15792188/placebo-effect-explained