Daily vitamin D3 supplements slow telomere shortening in older adults by 25% over four years, potentially reducing the risk of age-related diseases and premature death. Digest
Telomeres serve as protective caps at the ends of chromosomes, and when they shrink too much, cells stop dividing and age. Shorter telomeres have been linked to an increased risk for age-related diseases and premature death. A recent study found that daily vitamin D3 supplementation slowed telomere shortening by about 25% over four years in older adults.
Researchers recruited 1,031 participants from the large VITAL trial who took vitamin D3 (2,000 IU daily), omega-3 fatty acids (1 gram daily), both, or a placebo for four years. The researchers measured each person’s telomere length at the start of the study, then again two and four years later.
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On average, telomeres shrank noticeably in the placebo group, but remained much more stable in the group taking vitamin D3. After four years, those taking vitamin D3 had telomeres preserved by an average of 140 base pairs—about 25% more than the loss observed in the placebo group. The benefits were most pronounced among participants under age 64 who didn’t smoke, maintained a healthy body weight, or weren’t taking medications for cholesterol, diabetes, or high blood pressure. Omega-3 fatty acid supplements had no apparent effect on telomere length.
These findings suggest that daily vitamin D3 supplements help slow cellular aging by reducing telomere erosion, particularly in people who are younger, healthier, or not already taking medications for chronic conditions. Learn more about vitamin D in our comprehensive overview article.