Vitamin D has been touted as a cancer fighter, but a new study puts an actual number on the claim.

Researchers looked at the relationship between vitamin D serum levels and the risk of colon cancer and breast cancer. Study authors estimated how many cases of cancer worldwide could be prevented if vitamin D levels met targeted levels, and report 600,000 cases of colon cancer and breast cancer could be prevented, including 150,000 in the United States.

The study included data from surveys of vitamin D levels during winter months from 15 countries. Researchers used satellite measurements of sunshine and cloud cover in countries where levels of vitamin D were known. That data was then applied to 177 countries. This is how researchers determined an estimate that 600,000 cases of cancer could be prevented if vitamin D levels were at targeted levels. They say increasing vitamin D levels is particularly important for countries north of the equator.

Moderate sun exposure can increase a person’s vitamin D levels. Study authors write the optimal vitamin D levels are best achieved with a combination of diet, supplements and short intervals in the sun. Researchers recommend 10 minutes to 15 minutes in the sun each day, but warn it could be less for fair-skinned individuals. Study authors write this study reveals the need for prompt public health action to increase intake of vitamin D as an inexpensive tool for prevention of cancer.

— This article was reported by Ivanhoe.com.