Diets high in processed fiber may increase cancer risk

The outcomes emphasize the necessity for day by day monitoring of bile acid ranges in the blood, and warning in fiber consumption in individuals with high bile acid ranges.

A research discovered that males with high fiber consumption and high ranges of bile acids in their blood had a 40% greater risk of creating liver cancer.

Many individuals use fiber-rich meals to shed pounds and battle power illnesses like cancer and diabetes.

According to a latest research from the University of Toledo, consuming an excessive amount of refined fiber may increase the risk of liver cancer in some individuals, particularly these with vascular malformations.

The conclusion said in the report revealed in the journal gastroenterologyUToledo provides to the rising information in regards to the underappreciated function our intestine performs in the event of illness.

“We’ve lengthy labored on the concept that all illness begins in the intestine,” mentioned Dr. Matam Vijay-Kumar, professor of physiology and pharmacology in the College of Medicine and Life Sciences and senior writer of the paper. “This research is a major advance in this idea. It can even assist determine people who find themselves at risk of creating liver cancer and may also help cut back this risk by making easy dietary modifications.

Kill Vijay Kumar and Beng San Yeo

From left, Dr. Matam Vijay-Kumar, Professor of Physiology and Pharmacology and Dr. Beng San Yeoh, Postdoctoral Fellow. Credit: University of Toledo

Expand analysis

The Vijay-Kumar crew has revealed a serious paper in the journal cell In 2018, they discovered that mice with immune system deficiencies developed liver cancer in massive numbers after being fed a eating regimen enriched with inulin.

Inulin is a purified, plant-based fermentable fiber bought in supermarkets as a health-promoting prebiotic. In addition, it’s usually discovered in processed meals.

Vijay-Kumar and colleagues discovered that though nearly all of inulin customers had improved metabolic well being, one in ten wholesome laboratory mice developed liver cancer after being fed a eating regimen containing inulin.

“It was very stunning that liver cancer is uncommon in mice,” mentioned Vijay-Kumar, director of the UToledo Microbiome Consortium. “The findings increase actual questions in regards to the potential dangers of some refined fibers, however we’re solely now understanding why the mice developed such aggressive cancers.”

A brand new research gives a transparent rationalization — and may have implications that transcend lab animals.

The Missing Link

As the crew continued to analyze, the researchers discovered that each one mice with malignant tumors had high concentrations of bile acids in their blood, a results of a beforehand undetected delivery defect known as a portosystemic shunt.

Normally, blood from the intestines goes to the liver, the place it’s filtered earlier than returning to the remainder of the physique. In a portosystemic shunt, blood from the gut is bypassed by the liver and returned to the physique’s common blood provide.

Vascular malformation additionally ensures that the liver repeatedly synthesizes bile acids. Those bile acids are finally spilled and enter the bloodstream as an alternative of coming into the intestines.

Blood away from the liver has high ranges of microbial merchandise that stimulate the immune system and trigger irritation.

To take a look at for irritation that may harm the liver, the mice react by creating a compensatory anti-inflammatory response that dampens the immune response and reduces the power to detect and kill cancer cells.

All of the mice with extra bile acid in their blood developed liver harm, whereas solely the inulin-fed mice developed hepatocellular carcinoma, a serious deadly liver cancer.

Interestingly, 100% of the mice with high bile acid developed cancer when fed inulin. None of the mice with low bile acids developed cancer on the identical eating regimen.

“Dietary inulin is sweet for lowering irritation, however it’s not good for the liver and might trigger immunosuppression,” mentioned Dr. Beng San Yeoh, a postdoctoral fellow and first writer of the brand new paper.

Dr. According to Bina Joe, University Distinguished Professor and Chair of the Department of Physiology and Pharmacology and co-author of the research, the high-impact publication highlights the pioneering analysis being finished at UToledo.

“The function of the intestine and intestine micro organism in well being and illness is an thrilling and vital space of ​​analysis, and our crew is bringing new insights to the chopping fringe of this discipline,” he mentioned.


Beyond the lab, the UToledo analysis may present insights that would assist clinicians determine individuals at risk for liver cancer earlier than the tumors develop.

In people, portosystemic shunts are comparatively uncommon, with just one in 30,000 documented circumstances at delivery. However, on condition that they normally don’t trigger any noticeable signs, the precise incidence may be a number of occasions greater. Portosystemic shunt usually happens after cirrhosis of the liver.

This high bile is theoretical[{” attribute=””>acid levels might serve as a viable marker for liver cancer risk, Vijay-Kumar’s team tested bile acid levels in serum samples collected between 1985 and 1988 as part of a large-scale cancer prevention study.

In the 224 men who went on to develop liver cancer, their baseline blood bile acid levels were twice as high as men who did not develop liver cancer. Statistical analysis also found individuals with the highest blood bile acid levels had a more than four-fold increase in the risk of liver cancer.

The research team also sought to examine the relationship between fiber consumption, bile acid levels, and liver cancer in humans.

While existing epidemiological studies don’t differentiate between soluble and non-soluble fiber, researchers could look at fiber consumption in concert with blood bile acids.

There are two basic types of naturally occurring dietary fiber, soluble and insoluble. Soluble fibers are fermented by gut bacteria into short-chain fatty acids. Insoluble fibers pass through the digestive system unchanged.

Intriguingly, researchers found high total fiber intake reduced the risk of liver cancer by 29% in those whose serum bile acid levels were in the lowest quartile of their sample.

However, in men whose blood bile acid levels placed them in the top quarter of the sample, high fiber intake conferred a 40% increased risk of liver cancer.

Taken together, Yeoh and Vijay-Kumar say the findings suggest both the need for regular blood bile acid level testing and a cautious approach to fiber intake in individuals who know they have higher-than-normal levels of bile acids in their blood.

“Serum bile acids can be measured by a simple blood test developed over 50 years ago. However, the test is usually only performed in some pregnant women,” Vijay-Kumar said. “Based on our findings, we believe this simple blood test should be incorporated into the screening measurements that are routinely performed to monitor health.”

And while the researchers are not arguing broadly against the health-promoting benefits of fiber, they are urging attention to what kind of fiber certain individuals eat, underscoring the importance of personalized nutrition.

“All fibers are not made equal, and all fibers are not universally beneficial for everyone. People with liver problems associated with increased bile acids should be cautious about refined, fermentable fiber,” Yeoh said. “If you have a leaky gut liver, you need to be careful of what you eat, because what you eat will be handled in a different way.”

References: “Enterohepatic Shunt-Driven Cholemia Predisposes to Liver Cancer” by Beng San Yeoh, Piu Saha, Rachel M. Golonka, Jun Zou, Jessica L. Petrick, Ahmed A. Abokor, Xia Xiao, Venugopal R. Bovilla, Alexis C.A. Bretin, Jesús Rivera-Esteban, Dominick Parisi, Andrea A. Florio, Stephanie J. Weinstein, Demetrius Albanes, Gordon J. Freeman, Amira F. Gohara, Andreea Ciudin, Juan M. Pericàs, Bina Joe, Robert F. Schwabe, Katherine A. McGlynn, Andrew T. Gewirtz and Matam Vijay-Kumar, 18 August 2022, Gastroenterology.
DOI: 10.1053/j.gastro.2022.08.033

“Dysregulated Microbial Fermentation of Soluble Fiber Induces Cholestatic Liver Cancer” by Vishal Singh, Beng San Yeoh, Benoit Chassaing, Xia Xiao, Piu Saha, Rodrigo Aguilera Olvera, John D. Lapek Jr., Limin Zhang, Wei-Bei Wang, Sijie Hao, Michael D. Flythe, David J. Gonzalez, Patrice D. Cani, Jose R. Conejo-Garcia, Na Xiong, Mary J. Kennett, Bina Joe, Andrew D. Patterson, Andrew T. Gewirtz and Matam Vijay-Kumar, 18 October 2018, Cell.
DOI: 10.1016/j.cell.2018.09.004

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