Highly Refined Fiber May Increase Risk Of Liver Cancer In Some People: Warn Researchers

A new study offers explanation on the relationship between consumption of highly refined fiber and liver cancer risk.

It is often recommended to consume foods that are rich in fiber to maintain optimal weight and avoid chronic conditions like diabetes and cancer. However, it is advisable to avoid or limit consumption of refined fiber. This is because a new study has warned that too much intake of highly refined fiber like inulin may increase the risk of liver cancer in some people -- particularly those with liver problems including leaky gut liver.

Not only inulin is marketed as a health-promoting prebiotic, but it is also used as a common ingredient in many processed foods.

The study from The University of Toledo was published in the journal Gastroenterology.

All diseases start from the gut

Senior author Dr. Matam Vijay-Kumar from the varsity's College of Medicine and Life Sciences, noted that their study supports the idea that "all diseases start from the gut."

He believes that the discovery may help identify individuals who are susceptible to developing liver cancer years before any tumors start forming and allow them to reduce that risk with simple dietary modifications.

In their previous study, Vijay-Kumar and his team had found that consumption of inulin-containing diet led to development of liver cancer in some mice with immune system defects. Now, they have understood why the mice got such aggressive cancer.

Their new study explains the link between consumption of highly refined fiber and increased risk of liver cancer.

How refined fiber increases liver cancer risk?

Upon further investigation, the team found that all mice that developed malignant tumors had high concentrations of bile acids in their blood possibly caused by a congenital defect called portosystemic shunt. In this vascular defect, blood from the intestines bypasses the liver and returns to the rest of the body without filtration. This stimulates the immune system and causes inflammation. Then, a compensatory anti-inflammatory response develops mice then reduces their ability to detect and kill cancer cells.

In addition, presence of a portosystemic shunt triggers over production of bile acids, which eventually spill over and enter the blood instead of going into the gut.

All mice with excess bile acids in their blood suffered liver injury, but only those fed inulin developed hepatocellular carcinoma, a deadly primary liver cancer. However, mice with low bile acids developed cancer when given the same inulin-containing diet.

Dietary inulin may cause immunosuppression, which is bad for the liver, said first author Dr. Beng San Yeoh.

People with a leaky gut liver should be careful of what they eat

Following a statistical analysis, Vijay-Kumar's team also found that men who developed liver cancer had high blood bile acid levels, twice as high as men who did not develop liver cancer.

Intriguingly, they also found high fiber intake associated with lower risk of liver cancer in those with low serum bile acid levels, the same diet increases the risk of liver cancer in men with high bile acid levels.

Based on their finding, the experts stressed the need for regular blood bile acid level testing so that individuals with higher-than-normal levels of bile acids in their blood could be careful of their intake of refined, fermentable fiber.