Foods rich in vitamin D may help protect younger adults against colon cancer, researchers report.
While colon cancer is decreasing overall, cases among younger adults have been on the rise. The trends dovetail with a decline in vitamin D intake from foods such as fish, mushrooms, eggs and milk.
There is growing evidence of a link between vitamin D and risk of colon cancer death, but little research on whether vitamin D intake is associated with the risk of young-onset (before age 50) colon cancer.
"Because vitamin D deficiency has been steadily increasing over the past few years, we wondered whether this could be contributing to the rising rates" of colon cancer in younger people, said study co-senior author Dr. Kimmie Ng, director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute in Boston.
The study found that vitamin D intake of 300 IU per day or more -- roughly equivalent to three 8-ounce glasses of milk -- was associated with roughly a 50% lower risk of developing young-onset colon cancer.
Higher vitamin D intake were also associated with a lower risk of potentially precancerous colon polyps detected before age 50.
The findings are based on data from more than 94,000 women who were part of a long-term study that began in 1989. They were 25 to 42 years of age when the study began.
The study -- recently published online in the journal Gastroenterology -- is the first to make the connection between vitamin D levels and risk of young-onset colon cancer, researchers said.
They didn't find a significant link between vitamin D intake and colon cancer risk after age 50, and they said more study is needed to determine if vitamin D actually provides greater protection against young-onset colon cancer than against it later on.
"Our results further support that vitamin D may be important in younger adults for health and possibly colorectal cancer prevention," Ng said.
She said it is critical to understand the risk factors associated with young-onset colon cancer so informed decisions about lifestyle and diet can be made and high-risk individuals can receive earlier screening.
The findings could lead to recommendations for higher vitamin D intake as an inexpensive addition to screening tests to prevent colon cancer in adults under 50, researchers said.
The U.S. National Cancer Institute has more on colon cancer prevention.
SOURCE: Dana-Farber Cancer Institute, news release, Aug. 17, 2021