Sugar consumption and cancers of the digestive tract.

In order to assess the relationship between dietary intake of sugar and cancers of the digestive tract a comprehensive search of the scientific literature was undertaken. Forty human studies (ecological, cohort or case-control) were found which assessed the intake of sugar or sucrose-containing foods and risk of cancer of the stomach, small intestine, colon or rectum. These were systematically reviewed and study quality criteria applied. No clear relationship between national or international estimates of sugar intake and risk of gastrointestinal cancers emerged. Two of eight studies for gastric cancer, and seven of 21 studies for colorectal cancer, reported risk estimates consistent with a positive association or trend for sugar consumption. Only one study was reported of the relationship between sugar intake and risk of small intestinal cancer. When study quality criteria were applied, none of the studies remaining showed a significant positive relationship between gastric cancer and intake of sugar, and of six studies of colorectal cancer only two showed a significant positive association. The balance of studies suggests that there is no relationship between intake of sugar and risk of developing cancer of the stomach. As a result of the limited number of well-conducted studies of small intestinal or colorectal cancer, however, there is insufficient information upon which to assess the degree of risk associated with sugar consumption and development of cancer of these sites.