Did you know that more than one out of three people will develop cancer in their lifetime? According to cancer.gov, breast, colorectal, and lung cancers are the top three cancers in women while prostate, lung, and colorectal cancer top the list of cancers in males. With cancer so common, it’s not surprising that people are looking for safe, natural ways to lower their odds of developing this challenging disease.
Fortunately, there are ways to lower the risk of some forms of cancer, although not all cancers are preventable. These include eating a whole food diet, maintaining a healthy body weight, and staying physically active. Plus, limiting sun exposure may lower the risk of skin cancers.
But one downside to less sun exposure is a lower vitamin D level. Your skin contains vitamin D precursors that sun exposure activates. What role does vitamin D play in the risk of cancer?
Does Vitamin D Have an Effect on Cancer Risk?
Although some studies link taking a higher vitamin D level to a lower risk of some types of cancer, other studies fail to show this association. Despite the ambiguity, vitamin D has some characteristics that suggest it could be beneficial for cancer prevention. In animals, it promotes healthy cell growth and cell death when a cell is damaged. When cells have mutations, you want them to die, and vitamin D encourages cell death (apoptosis) of damaged cells.
So, vitamin D regulates how cells behave and promotes normal cell growth and development. Cancer occurs when cells mutate, so they can replicate out of control. Research also shows vitamin D reduces blood vessel growth around tumors, depriving them of oxygen and nutrients. Plus, vitamin D plays a key role in immune function and your immune system helps keep cancer cells in check.
Beyond its role in cell growth and immunity, vitamin D helps regulate calcium absorption from your gut and regulates how much calcium you lose through your urine. So, it plays a key role in calcium and phosphorus balance
Still, as the National Cancer Institute points out:
“Taken together, the available data are not comprehensive enough to determine whether taking vitamin D can prevent cancer.” That doesn’t mean vitamin D doesn’t play a role in cancer prevention but there is not enough evidence yet to support its benefits for prevention.
Some studies also suggest that vitamin D may reduce mortality in people with cancer and the evidence is stronger for improving mortality rates than lowering the incidence of cancer. Still, both areas need more research before scientists will recommend vitamin D for cancer prevention.
Most People Don’t Get Enough Vitamin D
Despite uncertainties about whether vitamin D prevents cancer or reduces cancer mortality, many people have a low or low normal vitamin D level. One study found an incidence of 41.6% of vitamin D deficiency in the United States population with greater rates in blacks and Hispanics.
Why the higher rate among dark-skinned individuals? Darker skin tones absorb less vitamin D from sun exposure than lighter ones. A person with pale skin only needs around 10 minutes of direct sunlight on their skin (with no sunscreen) daily while people with darker skin may need double or even triple this amount.
Factors associated with low vitamin D in the study were:
- Poor health
- No college education
- High blood pressure
- Low HDL-cholesterol
- Obesity
- Not consuming dairy products
Other research shows that living in an area with little direct sun exposure and being over 60 is correlated with lower vitamin D. For example, residents of nursing homes who rarely get outside and have age working against them are at a high risk of vitamin D deficiency. Food is not a good source of vitamin D, although you get small amounts from drinking fortified milk, yogurt, and cereal and consuming fatty fish, like wild salmon.
Sun exposure is still the best way to boost your vitamin D level. Since excessive sun exposure is risky to skin health and not all areas of the country offer enough direct sunlight, most people benefit from taking a vitamin D supplement of 1000 to 2000 IU daily.
Research shows it’s safe to take up to 4000 IU daily without developing toxicity. However, it’s best to consult your physician and check your vitamin D blood level before taking more than 2000 IU daily. If you supplement with vitamin D, look for cholecalciferol or D3, which may have better bioavailability than ergocalciferol or D2.
The Bottom Line
Are vitamin D and cancer-related and can you lower your risk by raising your vitamin D level? Further studies are ongoing to answer this intriguing question. It’s clear that you don’t want to be deficient in vitamin D, but you don’t want a very high level either.
Research suggests vitamin D benefits have a U-shaped curve. Mortality rises at both ends of the spectrum – too low and too high. That’s why it’s a good idea to check your blood level every 6 months, or at your doctor’s recommendation, to ensure you’re not too high or too low.
Know your family history too. Some cancers have a genetic component, although environmental factors and lifestyle play a greater role for some people. There’s much you can do to lower your odds of developing a malignancy.
References:
- Tagliabue E, Raimondi S, Gandini S. Vitamin D, Cancer Risk, and Mortality. Adv Food Nutr Res. 2015;75:1-52. doi: 10.1016/bs.afnr.2015.06.003. Epub 2015 Aug 5. PMID: 26319903.
- “Vitamin D and Cancer Prevention – NCI – National Cancer Institute.” https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/vitamin-d-fact-sheet.
- Gnagnarella P, Muzio V, Caini S, Raimondi S, Martinoli C, Chiocca S, Miccolo C, Bossi P, Cortinovis D, Chiaradonna F, Palorini R, Facciotti F, Bellerba F, Canova S, Gandini S. Vitamin D Supplementation and Cancer Mortality: Narrative Review of Observational Studies and Clinical Trials. Nutrients. 2021 Sep 21;13(9):3285. doi: 10.3390/nu13093285. PMID: 34579164; PMCID: PMC8466115″Vitamin D Deficiency – StatPearls – NCBI Bookshelf.” 18 Jul. 2022, https://www.ncbi.nlm.nih.gov/books/NBK532266/.
- Zittermann A, Gummert JF, Börgermann J. Vitamin D deficiency and mortality. Curr Opin Clin Nutr Metab Care. 2009 Nov;12(6):634-9. doi: 10.1097/MCO.0b013e3283310767. PMID: 19710612.
- “Strong Link Between Vitamin D Deficiency and Mortality.” 19 Sept. 2019, https://todayspractitioner.com/diabetes/strong-link-between-vitamin-d-deficiency-and-mortality/.
- “Cancer Statistics – NCI.” 25 Sept. 2020, https://www.cancer.gov/about-cancer/understanding/statistics.
- “Common Cancer Types – NCI – National Cancer Institute.” https://www.cancer.gov/types/common-cancers.
- Sergeev IN. Vitamin D-mediated apoptosis in cancer and obesity. Horm Mol Biol Clin Investig. 2014 Nov;20(2):43-9. doi: 10.1515/hmbci-2014-0035. PMID: 25460294.
Related Articles By Cathe:
5 Best Ways to Get Enough Vitamin D with Inadequate Sun Exposure
How Much Sun Exposure Do You Need for Optimal Vitamin D Status?
Is Vitamin D from the Sun the Same as Vitamin D from Food?
5 Surprising Things You Might Not Know About Your Vitamin D Level
What is the Ideal Vitamin D Level for Health?
How Much Vitamin D Do You Really Need?
Can You Get Enough Vitamin D from Sun Exposure Alone?
Can Vitamin D Improve Your Body Composition?