The latest research suggests the wider use of vitamin D could help to protect against bowel diseases.
University of Auckland scientists believe people are getting less vitamin D because of greater public awareness of skin cancer from sunlight.
Professor Lynn Ferguson says as a result gastrointestinal diseases such as colorectal cancer and inflammatory bowel disease are becoming increasingly common worldwide, including among children and adolescents.
She says wider use of vitamin D in foods and dietary supplements could help combat the problem.
RadioLIVE