Key TakeawaysVitamin D is a fat-soluble vitamin that plays an important role in bone and immune health.When it comes to cancer prevention, there isn’t enough evidence to show whether vitamin D supplements can play a role.Focusing on their overall dietary practices and lifestyle habits are the best methods to reduce cancer risk.

Key Takeaways

Vitamin D is a fat-soluble vitamin that plays an important role in bone and immune health.When it comes to cancer prevention, there isn’t enough evidence to show whether vitamin D supplements can play a role.Focusing on their overall dietary practices and lifestyle habits are the best methods to reduce cancer risk.

Vitamin D, referred to as the “sunshine vitamin,” is routinely in and out of the spotlight. While it’s true the vitamin can support bone health and immune health, it’s less certain that it can reduce the risk and severity of a COVID-19 infection—though that’s something researchers have spent a great deal of time exploring.

Here’s what you may be hearing about, and how research does—and does not—support those claims.

Vitamin D and Cancer Prevention

People with more frequent sun exposure tend to have a lower risk of vitamin D deficiency and a lower risk of getting cancer.Plus, studies have reported lower cancer and cardiovascular deaths in regions with greater sun exposure.With that in mind, could a vitamin D supplement help stave off cancer in people who don’t see the sun as much?

JoAnn E. Manson, MD, DrPH, chief of the division of preventive medicine at Brigham and Women’s Hospital in Boston, is not so convinced. She explained people with lower cancer risk tend to be more active, and therefore spend more time outdoors. As a result, their vitamin D levels are often higher, since the bodycreates vitamin D3after absorbing UVB light from the sun.

“Vitamin D level is a marker for other factors that are related to cancer,” Manson told Verywell, adding that it’s not a direct indicator of cancer risk.

Plus, Manson has learned through her own research that the data supporting the use ofvitamin D supplementsto prevent cancer is not incredibly strong.

After evaluating over 25,000 subjects, the researchers didn’t find a strong relationship between vitamin D supplementation and cancer incidence.

“The research on vitamin D supplements to prevent cancer is inconclusive,”Sarah Anzlovar, MS, RDN, LDN, an intuitive eating dietitian at Sarah Gold Nutrition, LLC, told Verywell. She explained that if a person is deficient in this nutrient, supplements can help them achieve adequate blood levels, which is important for many health outcomes. But if a person is not deficient in vitamin D, there’s little to no benefit to taking supplements. In fact, too much vitamin D can actually be harmful.

How Much Vitamin D Do You Need?

Data does exist that suggests healthy vitamin D levels may be linked to a reduced risk of two specific cancers: colorectal and bladder.But more data is needed to make a firm recommendation.

Vitamin D and Cancer Progression

Very few studies have reported on vitamin D supplementation and cancer outcomes, whether a specific type of cancer or cancer in general. However, Manson says the data that does exist is strong.

Specifically, Manson said results of the VITAL trial show supplementation with 2,000 IU of vitamin D is associated with a 17% reduction of advanced cancers.

Other data shows positive outcomes as well, although the relationship is not incredibly strong. A Cochrane Systematic Review reported lower overall cancer mortality with vitamin D supplementation but concluded that the findingcouldbe due to chance.And a study evaluating over 25,000 people showed that vitamin D3 supplementation might reduce the risk of developing advanced cancer among adults with certain cancers.In the same study, for those diagnosed with breast cancer, vitamin D supplement use was associated with higher levels of self-reported quality of life.

Should You Take Vitamin D Supplements?

While having adequate vitamin D in the body is linked to a slew of benefits, and bears repeating that you shouldn’t rely on it to prevent cancer.

“Vitamin D should not be used as a standalone line of defense against cancer,” nutrition consultantLiz Shaw, MS, RDN, told Verywell. “Given that the etiology of cancer is unique for every individual who receives this diagnosis, it’s important to take a multifaceted approach to lower one’s risk for developing cancer. There is a genetic component to cancer as well—genes may play a significant role in development and progression.”

Both Shaw and Manson said healthy lifestyle habits, like a well-balanced diet, regular exercise, plenty of sleep, and sunscreen use are most important for cancer prevention.

What This Means For YouThere’s not enough evidence to suggest vitamin D can prevent cancer, but some evidence suggests it can stop cancer from getting worse. If you’re focused on cancer prevention, eating a well-rounded diet, exercising, and other healthy lifestyle habits are most helpful.

What This Means For You

There’s not enough evidence to suggest vitamin D can prevent cancer, but some evidence suggests it can stop cancer from getting worse. If you’re focused on cancer prevention, eating a well-rounded diet, exercising, and other healthy lifestyle habits are most helpful.

9 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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Lindqvist PG.On the relationship between sun exposure and all-cause mortality.Adv Exp Med Biol. 2020;1268:115-122. doi:10.1007/978-3-030-46227-7_5

Manson JE, Cook NR, Lee IM, et al.Vitamin D supplements and prevention of cancer and cardiovascular disease.N Engl J Med. 2019;380(1):33-44. doi:10.1056/NEJMoa1809944

Herrick KA, Storandt RJ, Afful J, et al.Vitamin D status in the United States, 2011-2014.Am J Clin Nutr. 2019;110(1):150-157. doi:10.1093/ajcn/nqz037

Mondul AM, Weinstein SJ, Layne TM, Albanes D.Vitamin D and cancer risk and mortality: state of the science, gaps, and challenges.Epidemiol Rev. 2017;39(1):28-48. doi:10.1093/epirev/mxx005

Bjelakovic G, Gluud LL, Nikolova D, et al.Vitamin D supplementation for prevention of cancer in adults.Cochrane Database Syst Rev. 2014;(6):CD007469. doi:10.1002/14651858.CD007469.pub2

Chandler PD, Chen WY, Ajala ON, et al.Effect of vitamin D3 supplements on development of advanced cancer: a secondary analysis of the VITAL randomized clinical trial.JAMA Netw Open. 2020;3(11):e2025850. doi:10.1001/jamanetworkopen.2020.25850

Andersen MR, Sweet E, Hager S, Gaul M, Dowd F, Standish LJ.Effects of vitamin D use on health-related quality of life of breast cancer patients in early survivorship.Integr Cancer Ther. 2019;18:1534735418822056. doi:10.1177/1534735418822056

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