Research shows that roughly 42 percent of U.S. adults have a vitamin D deficiency. That number jumps to 82 and 69 percent, respectively, for Black and Hispanic Americans. So, is it any surprise that, following multivitamins, vitamin D is the most-taken supplement in the country? And that's very good news because, in addition to keeping your bones strong and your immune system healthy, vitamin D may also help you live longer, according to a new study.
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Vitamin D could protect cells from aging.
The new study, published in the American Journal of Clinical Nutrition, suggests that vitamin D supplements could protect against biological aging by maintaining telomeres, "protective caps at the ends of chromosomes that shorten during aging and are linked to the development of certain diseases," explains a press release.
Some of these age-related diseases include pulmonary fibrosis, liver fibrosis, aplastic anemia, tumorigenesis, and increased risk of certain cancers.
The four-year study included 1,054 participants aged 50 and older who had the telomere length of their white blood cells analyzed at years two and four.
Compared to the placebo group, those taking vitamin D3 supplements showed "significantly reduced telomere shortening over four years, preventing the equivalent of nearly three years of aging."
A third study cohort took omega-3 supplements, which previous small-scale studies have suggested could also protect telomere length, but this group showed no significant change to telomere length over the study period.
"Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter a biological aging process," said first study author Haidong Zhu, PhD, a molecular geneticist at the Medical College of Georgia, Augusta University.
In addition, previous research has shown that vitamin D supplements can protect against stroke, heart attack, and heart disease by "significantly" reducing systolic and diastolic blood pressure, improving total cholesterol levels, and improving glycemic parameters.
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How much vitamin D should you take?
Participants in the recent study received 2,000 IU/day (5 mL) of vitamin D. JoAnn Manson, MD, principal study investigator and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, told the New York Post that participants had no adverse side effects from the dose they received and that she considers this a safe amount.
However, the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) recommends that most adults take 600 IU daily, except those 71 and older, who can take 800 IU daily.
Manson added in speaking with the Post that appropriate vitamin D supplement doses are "a controversial topic."
"Blood levels for deficiency and recommended blood levels vary across organizations, labs, and countries," she said. "For example, the National Academy of Medicine suggests a level at or above 20 milliliters (mL), but some other organizations recommend 30 mL or even higher levels. There’s no consensus or agreement on the optimal level to aim for."
That's why Manson and her team hope to conduct further research into vitamin D's role in slowing down cellular aging.
In the meantime, if you're considering taking vitamin D supplements, speak to your healthcare provider first.
You can also up your vitamin D intake through the foods you eat, including salmon, canned tuna or sardines, egg yolks, mushrooms, cheese, and fortified dairy and cereals. Or, you can simply take a walk outside.
"Going out for a 15-minute walk a few times a week at midday is usually enough sunlight for the skin to synthesize vitamin D, and this can be incidental sun exposure, such as while running errands," Manson told the Post.
