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Sunshine and vitamin D significantly reduce the risk of cavities
Last reviewed: 30.06.2025
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Experts from the American Sunlight, Nutrition, and Health Research Center (SUNARC), having analyzed the results of several studies, came to the conclusion that the sun and vitamin D significantly reduce the risk of tooth decay.
In the mid-19th century, scientists noticed that the dental health of American teenagers and young adults varied depending on where they lived. For example, while in Kentucky during the Civil War of 1861–1865, 8 out of a thousand people were not drafted into the military due to lack of teeth, in the New England region, the ratio was 25:1,000.
Research conducted by Clarence Mills and Bion East in the 1930s was the first to link the geographic variation in dental caries to sunlight exposure. The researchers used data from male adolescents aged 12 to 14. East later found an inverse relationship between the prevalence of dental caries and the annual number of hours of sunlight: those living in the sunny western part of the United States (3,000 hours of sunlight per year) had half as many dental lesions as those living in the cloudier northeast (2,200 hours).
Several studies conducted in Oregon in the 1950s found that tooth decay rates were lower in sunny areas of the state. This finding held up even after accounting for other factors that influence tooth decay rates. Scientists then hypothesized that UVB exposure kept teeth healthy by improving calcium absorption and metabolism.
Also interesting are the studies conducted in the 1920s and 1930s: May Mellanby and her colleagues from Sheffield (England) studied the role of vitamin D in dental health. The first experiments on dogs demonstrated that the vitamin stimulates dental calcification. Then the effect of the “sunshine” vitamin on dental caries in children was studied, and it turned out that the effect was beneficial. Additional experiments involving children from New York showed that 800 international units of vitamin D per day are needed to prevent dental caries.
The mechanism by which UVB rays reduce the risk of tooth decay is through the production of vitamin D and the subsequent production of cathelicidin, which attacks cavity-associated bacteria in the mouth. Cathelicidin is known to be effective against bacterial infections including pneumonia, sepsis, and tuberculosis.
Researchers say that serum 25-hydroxyvitamin D at concentrations of about 30 to 40 nanograms per milliliter (75 to 100 nmol/L) has a significant impact on the formation of dental caries. (The average white American has about 25 ng/mL; the average black American has 16 ng/mL.) To achieve this level, it is recommended to take 1,000 to 4,000 international units of vitamin D3 orally per day or to sunbathe at midday for 15 to 20 minutes, exposing 20 to 30 percent of the body surface to sunlight.
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