Researchers recently analyzed the literature to determine the association between whole grain intake and digestive tract cancer. They concluded that a diet high in whole grains may reduce the risk of digestive cancer.
“Digestive tract cancer has become one of the major diseases that threaten human health. The occurrence of digestive tract cancer is related a variety of factors, of which approximately 5–10% can be attributed to genetic defects, whereas and the remaining 90–95% can be explained by unfavorable environment conditions or an unhealthy lifestyle,” the study authors explained.
The researchers identified studies published before March 2020 in database and other sources using the following key words: “grains” or “cereal” or “wheat” or “corn” or “rye” or “oats” or “oatmeal” or “bread” or “barley” or “bran” or “germ” or “colorectal cancer” or “colon cancer” or “rectal cancer” or “CRC” or “colorectal carcinoma” or “gastric cancer” or “stomach cancer” or “esophagus cancer” or “esophageal squamous cell carcinoma.”
The meta-analysis included 35 studies on colorectal cancer (n=18), gastric cancer (n=11), and esophagus cancer (n=6); a total of 2,663,278 participants and 28,921 cases were included. When comparing participants with the highest intake of whole grains versus the lowest, whole grain intake was inversely correlated with colorectal cancer (risk ratio [RR]=0.64; 95% confidence interval [CI], 0.84 to 0.93; P < 0.001), gastric cancer (RR=0.64; 95% CI, 0.53 to 0.79; P < 0.001), and esophagus cancer (RR=0.54; 95% CI, 0.44 to 0.67; P<0.001). In subgroup analysis of colorectal cancer in the case-control studies and studies with a sample size < 500, there was no significant correlation, nor was there a significant correlation in subgroup analysis of gastric cancer in the cohort studies and American population studies. None of the studies had a profound effect on the sensitivity analysis findings. There was no publication bias found in the colorectal cancer and esophagus cancer studies.
The results were published in Nutrition Journal.
“In conclusion, intake of higher whole grains can reduce the risk of colorectal cancer, gastric cancer and esophageal cancer. However, it should be more cautious to interpret the association of whole grains and gastric cancer because there is a high heterogeneity and significant publication bias,” the study authors concluded, recommending, “More high-quality study is needed in the future to clarify dose-response relationships and to assess the relationship between whole grains and digestive tract cancer.”