Do Vitamin D Supplements Lengthen Telomeres?

Are there any supplements that can protect our telomeres? Nearly every supplement study to date has failed. None of the fish oil trials successfully delayed telomere shortening, nor did extra virgin olive oil, B vitamins… or zinc supplements… There are ten studies on vitamin D and telomeres, but only two double-blind, randomized, placebo-controlled trials.

The first was a four-month study of overweight African Americans in Georgia who started out with low vitamin D levels (14 ng/ml). They were randomized to 60,000 IU once per month, which is roughly equivalent to my 2,000 a day recommendation for those getting inadequate sun exposure. (The safety and efficacy of daily, weekly, or monthly dosing—1,000 daily versus 7,000 once a week versus 30,000 once a month—appear to be the same.) Compared to those randomized to placebo, the subjects who got the actual vitamin D experienced a significant boost in telomerase activity. Does that translate to longer telomeres?

For that, we turn to the other study, which was performed in China on individuals with vitamin D blood levels of 19 ng/ml, closer to the U.S. unsupplemented average of 24. Researchers randomized older adults to a year of 800 IU of vitamin D a day or placebo and found that those on placebo experienced a bit of their telomeres disappearing over that year, while the subjects on the daily vitamin D had a significant lengthening of their telomeres.