- Liver cancer can be fatal, but experts are still working to understand how to best screen for and prevent liver cancer.
- Data from a recent study suggests that a diet high in processed fiber could increase some people’s liver cancer risk.
- Testing for the level of bile acids could help identify people at risk of developing liver cancer who may need a lower intake of fermentable fiber.
Sometimes, it can be hard to follow dietary recommendations despite new dieting ideas and trends.
Everyone’s dietary needs are different, which means that diets often need to be diverse and tailored based on individual needs and health risks.
A recent study published in Gastroenterology looked at diets high in fermentable fiber in mice and their associated risk for developing liver cancer.
The researchers found that the risk for developing liver cancer among mice with a specific congenital defect was substantial when they ate a diet enriched with fermentable fiber. The blood of these mice also had a high bile acid content.
Based on this and additional data from people, the researchers suggest that screening for bile acid levels may help to predict liver cancer risk. People with higher bile acid levels may need to exercise caution regarding the amount of fiber-enriched processed foods they eat.
What is processed fiber?
Fiber is a carbohydrate that provides certain health benefits to the body but doesn’t give many calories.
Fiber occurs naturally in several foods, including many fruits and vegetables. There are a few different types of fiber, which all provide specific health benefits.
Fermentable fiber refers to types of fiber that the bacteria in the gut can ferment and break down. In some cases, food manufacturers will add fermentable fiber to processed foods.
Brian Power, RD, nutrition expert and registered dietician, not involved in the study, explained to Medical News Today:
“Food processing techniques can make fiber fermentable, which means it can be broken down by gut bacteria and produce many byproducts that are good for your health.”
However, people in specific subgroups may need to use caution when it comes to diets high in fermentable fiber.
Fermentable fiber and liver cancer risk
According to the American Cancer Society, liver cancer accounts for over 700,000 deaths worldwide each year.
“Liver cancer is increasingly serious in the U.S. and is projected to be the third deadliest cancer within this decade,” Dr. Yiing Lin, Ph.D., a liver surgeon with Siteman Cancer Center at Washington University in St. Louis, not involved in the study, told MNT.
For the study, the authors researched how a few different components may be related to liver cancer risk.
Researchers examined mice that had a specific congenital defect called a portosystemic shunt, which impacts blood flow and exchange between the liver and the rest of the body. These mice had a higher risk for liver cancer.
When the at-risk mice ate fermentable fiber-enriched diets, their risk of developing liver cancer increased. Researchers theorized that this could be because the fermentable fiber diet contributed to a suppressed immune system.
What’s more, the mice had high levels of bile acids related to the portosystemic shunts. The liver makes bile acids out of cholesterol. Bile acids help the body digest and absorb fat.
While it was difficult to thoroughly study portosystemic shunts in humans, researchers could examine bile acid levels. They looked at the bile acid levels in men who developed liver cancer and matched these participants with controls that did not develop liver cancer.
They found that bile acid levels were about double for the men who developed liver cancer later in life. This indicates that screening for this could be helpful in the prediction of liver cancer.
Next, researchers looked at overall fiber intake and associated liver cancer risk in humans. Among men with high bile acid levels, high fiber intake was associated with an increased risk of developing liver cancer.
Overall, the study notes a potential screening method for liver cancer and the potentially cautious use of fermentable fiber in certain at-risk groups. Dr. Lin noted the following:
“The findings are that in the setting of congenital portosystemic shunts in mice, fermented fiber-rich diets increase the chance of developing liver cancer. In humans, congenital portosystemic shunts are not common, but shunts develop in patients with cirrhosis. The findings in the study could help patients with liver disease and decrease their chances of developing liver cancer by diet modifications or other interventions.”
Study limitations and continued research
The study had several limitations, and further research is needed before experts can genuinely understand how diets high in processed fiber influence liver cancer risk. First, the initial data is from mice studies, which can only provide so much information.
Power noted the following:
“The greater our understanding of the biochemistry involved in the breakdown of dietary fiber and its impact on health such as liver cancer, the closer we get to developing new, effective treatments. In the current study, the work puts our finger on the molecular basis for the link between fiber and liver cancer risk. But it does need care in interpretation. Especially when trying to apply evidence from mice to humans.”
The data from people was only from men, indicating further diverse follow-up is needed.
Researchers could not distinguish between fiber types in their data from human subjects. This means that further research is needed to understand if it is actually fermentable fiber that contributes to liver cancer risk.
Researchers also note that further research is needed on the prevalence of congenital liver shunts and how they impact liver disease and liver cancer.
Dr. Lin noted the following areas for research:
“The effects of a modified diet in humans with liver disease will need to be confirmed. These are challenging studies since liver cancer develops in subsets of people with liver disease, and the effects of diet modifications have to be tracked over long periods of time and can be a challenge to control. However, these are important questions to address since metabolic syndrome and its association with liver cancer are significant problems in the U.S.”
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