Melanoma: vitamin D supplements would reduce the risk of skin cancer

Is vitamin D, and its intake in the form of supplements, directly linked to the risk of developing skin cancer or rather to the fact of protecting yourself against it? In any case, this is the theory advanced by a study carried out in Finland, a country in which the inhabitants, in lack of sun, often need to supplement themselves with vitamin D.

Vitamin D levels tested on nearly 500 adults at risk of melanoma

To verify this causal link, the research involved 498 Finnish adults determined by dermatologists to be at high risk for skin cancers, such as melanoma, as well as squamous cell carcinoma and basal cell carcinoma. Study participants ranged in age from 21 to 79, including 253 men and 245 women, and were divided into three groups based on their intake of vitamin D supplements: non-use, occasional use, or regular use.

The researchers also wanted to know whether regular use of vitamin D supplements correlated with higher blood levels of vitamin D, known as serum calcidiol or 25-hydroxy-vitamin D3 which represents the “storage form” of vitamin D. vitamin D in the body.

After testing serum calcidiol levels in 260 participants, researchers found that regular vitamin D supplementation corresponded to the highest levels of serum calcidiol and non-supplementation to the lowest levels.

Vitamin D, calcidiol and cancer

For the study’s lead author, Dr. Ilkka T. Harvima, “The issue of vitamin D in the context of skin cancers is interesting, although highly controversial.” he recognizes. Indeed, the study suggests that vitamin D may protect against oxidative stress and DNA damage, which are associated with cancer risk. Vitamin D may also be involved in immune modulation, particularly in directing Treg cells [cellules T régulatrices] and Th2 in immune surveillance.

However, Dr. Kim Margolin, medical director of the melanoma program at Saint John’s Cancer Institute in California, not involved in the study, also reacted: “It’s almost impossible for me to believe that a single nutrient could have a statistically and clinically significant impact on the development of a disease that requires so many different intakes.” Additionally, not all experts agree that calcidiol is an effective indicator of vitamin D levels in the body.

What are the vitamin D recommendations?

Anyway, for the author of the study, there are good reasons to take vitamin D. However, it is advisable not to self-medicate and not to exceed national guidelines. As a reminder, according to the latest data from ANSES, dating from 2022, the average vitamin D intakes in the French population through food are:

• 5.2 micrograms/day for children 1 to 3 years old;
• 2.6 micrograms/day for children 4 to 10 years old;
• 2.9 micrograms/day for children 11 to 17 years old;
• 3.1 micrograms/day for adults 18-79 years old.