Consuming a diet high in whole grains and certain types of dietary fiber may reduce the risk of developing the most common liver cancer, hepatocellular carcinoma (HCC), a large study in JAMA Oncology suggests.
High-fiber diets have been linked with lowering the risk of health problems that predispose people toward HCC, such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease. Hypothesizing that a high-fiber diet may reduce the risk of HCC itself, researchers analyzed fiber intake in two groups of participants who filled out food questionnaires about every four years for an average of 24 years.
The researchers identified 141 people with HCC out of 125,455 participants. They found the risk of HCC significantly lower in the participants who consumed the most grains compared with those who ate the least. The protective effect of dietary fiber was more strongly associated with whole grains and possibly with cereal fiber; there was no association seen between fruit and vegetable fiber and HCC risk.
The study, which was published in 2019, does have a number of caveats. There were insufficient data on chronic hepatic infections in the participants to be certain this didn’t affect outcomes, and the number of people who developed HCC was relatively small. Also, as an observational study, it was subject to dietary misclassifications that result in overestimating or underestimating associations. But if future studies confirm these findings, eating more whole grains may be a sound strategy for protecting against HCC.