D-fending the Colon: Bile component triggers vitamin D receptor
By John Travis
The protein that enables cells to respond to vitamin D also helps the gastrointestinal tract protect itself from an especially dangerous acid in bile, a new study suggests.
This unexpected finding about the protein–the vitamin D receptor–may help explain animal experiments and human-population studies suggesting that diets rich in vitamin D reduce the incidence of colon cancer.
“The vitamin D receptor probably evolved as a bile acid sensor of some kind,” says study coauthor David J. Mangelsdorf of the Howard Hughes Medical Institute at the University of Texas Southwestern Medical Center in Dallas.