Vitamin D lowers the risk of skin cancer caused by arsenic exposure

Millions of people worldwide drink arsenic-polluted water regularly. Arsenic is a toxin that is known to cause different types of cancer, including skin cancer. According to a new study published in American Journal of Cancer Research, it looks as if the active form of vitamin D, calcitriol, can prevent the onset of arsenic-induced skin cancer in a special type of skin cells. Calcitriol also appears to be able to prevent other types of cancer caused by arsenic.

Around 140 million people in 50 different countries are exposed to arsenic regularly from their drinking water, and their arsenic exposure exceeds WHO’s threshold level of 10 µg/L. Because it is difficult for the body to break down and excrete arsenic, this constant exposure results in arsenic accumulation in the body and may cause skin cancer.
There is not much data concerning how to control the cancerous mechanism of arsenic. Also, methods on how to prevent and treat arsenic-triggered skin cancer have been lacking. But scientists from Shibaura Institute of Technology (SIT) and Nagoya University in Japan have studied vitamin D’s effect and are one step closer to a solution.

Active vitamin D regulates genes and proteins involved in cancer development

The type of vitamin D that we synthesize in our skin in response to sunlight exposure is inactive. By way of a two-step process, it is converted into the active form known as calcitriol (1,25-dihydroxcholecalciferol). Calcitriol is the form of vitamin D that binds to the vitamin D receptors of our cells (VDR), thereby enabling it to regulate around 10 percent of our genes. This is important for our immune defense and for a number of other functions.
Using in-vitro studies (lab studies), scientists have now managed to demonstrate that calcitriol counteracts arsenic-triggered skin cancer in a particular type of skin cells called keratinocytes. These skin cells are primarily found in the epidermis. Also, certain signaling molecules called kinase proteins that regulate different biological processes are related to the development of cancer cells and tumors. The new study of human keratinocytes revealed that calcitriol down-regulated the activation of these kinase proteins that are involved in skin cancer development.
In order to better the understand the interaction between calcitriol and arsenic, the researchers measured levels of arsenic in the keratinocytes. They found that when the keratinocytes were treated with calcitriol, arsenic levels plummeted. They also discovered that calcitriol dialed down the activation of certain genes (AQP/, 9, and 10) that are normally activated by arsenic.
Afterwards, the scientists looked at whether calcitriol could counteract arsenic-induced cancer development in cells other than the keratinocytes. For this purpose, they used epithelial lung tissue cells. The study also showed that calcitriol reduced the cancer development by 20 – 70 percent. In other words, calcitriol’s ability to counteract arsenic-induced cancers is not limited to skin cancer.

Vitamin D is relevant for long-term prevention and treatment

According to the scientists, environmental toxins contribute to the development of cancer and other diseases. Nonetheless, it may take years or decades for a person to develop cancer as a result of drinking arsenic-containing water. They therefore assume that calcitriol may help prevent and treat arsenic poisoning and cancer. It would be relevant for people in areas with arsenic-poisoned water to take vitamin D supplements as a way of lowering their risk of getting cancer 5 -10 years later.
The ability of vitamin D to prevent different cancer forms is good news for the millions of people worldwide who cannot avoid being exposed to arsenic from their drinking water. If they do decide to take a vitamin D supplement they must make sure to optimize their blood levels of the nutrient. optimized. If their main source of vitamin D is sun exposure, it is essential to take into account that the sun in some parts of the world is not sufficiently powerful during the winter period. Also, there are various limiting factors that can impair your vitamin D status such as spending too much time indoors, having dark skin, being overweight, or being old.

The body needs magnesium to activate and utilize vitamin D

In order for the body to convert inactive vitamin D into active vitamin D it needs magnesium to support different magnesium-dependent enzymes. Therefore, if you want to make proper use of vitamin D from sun exposure, from the diet, or from supplements, you also need to get enough magnesium.

References:

Ichiro Yajima, Akira Tazaki, Nobutaka Ohgami, Masashi Kato. Calcitriol inhibits arsenic-promoted tumorigenesis through regulation of arsenic-uptake in a human keratinocyte cell line. American Journal of Cancer Research, 2022

Shibaura Institute of Technology. Activated vitamin D3 treatment may reduce the risk of arsenic-mediated skin cancer. ScienceDaily December 15, 2022

Anne Marie Uwitonze, Mohammed S Razzaque. Role of magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association. 2018