A team of researchers from Georgia State
University's Institute for Biomedical Sciences conducted the study in mice. The
study showed that regular consumption of dietary emulsifiers exacerbated tumor
development in mice. The study was led by Drs. Emilie Viennois, Didier Merlin,
Andrew T. Gewirtz, and Benoit Chassaing.
‘Emulsifiers in processed foods can alter the gut microbiota and cause intestinal inflammation, promoting colorectal cancer development.’
Gut Microbiota and Colorectal Cancer
Gut microbiota is the diverse population of microorganisms
found in the human intestines. Studies have shown that gut microbiota plays
a key role in driving colorectal cancer
. Gut microbiota also plays a
role in two most common forms of inflammatory bowel disease (IBD) - Crohn's disease
and ulcerative colitis. IBD causes colitis-associated cancer
by promoting intestinal inflammation. Low-grade inflammation is a condition
that is more prevalent than IBD and is observed in many cases of colorectal
Between Dietary Emulsifiers and Colorectal Cancer
Earlier studies conducted by Georgia State research
team showed that regular consumption of dietary emulsifiers could promote
inflammation in the intestine.
Dietary emulsifiers are detergent-like
molecules incorporated into processed foods that alter the composition of gut
microbiota. Emulsifiers in food promote bacterial translocation across the epithelial cells.
"The incidence of colorectal cancer has been
markedly increasing since the mid-20th century. A key feature of this disease
is the presence of an altered intestinal microbiota that creates a favorable
niche for tumorigenesis," said Viennois, assistant professor in the Institute
for Biomedical Sciences.
"The dramatic increase in these diseases has
occurred amidst constant human genetics, suggesting a pivotal role for an
environmental factor," said Chassaing, assistant professor in the
Institute for Biomedical Sciences.
The research team hypothesized that dietary
emulsifiers might affect the gut microbiota in a way that promotes colorectal
cancer. The researchers conducted the study in mice to test the possibility.
Effect of Emulsifiers in Gut Microbiota
Two commonly used dietary emulsifiers- polysorbate
80 and carboxymethylcellulose- were given to mice. The doses were as same as
the emulsifiers that are incorporated into the majority of the processed foods.
The researchers observed that consumption of
emulsifiers changed the species composition of the gut microbiota that made it
more pro-inflammatory, leading to cancer induction and development.
Altered gut microbiota resulted in bacteria
expressing more flagellin and lipopolysaccharide, which activate
pro-inflammatory gene expression by the immune system.
The study found that consumption of dietary
emulsifiers made the animals more susceptible to develop colon cancer as it
created a pro-inflammatory environment, which is associated with an altered
proliferation/apoptosis (cell death) balance. The development of colon tumor
was associated with an altered gut microbiota.
In mice devoid of microbiota (germ-free mice), the
effects of emulsifiers were not seen. When microbiota from emulsifier-treated
mice was transplanted into germ-free mice, it altered the intestinal epithelial
cells' homeostasis. The study suggested that altered microbiota played a
central role in tumor development.
The researchers concluded that microbiota
interactions cause low-grade inflammation that can promote colon
carcinogenesis. The research team is taking the study further by investigating
which bacteria triggers cancer development, as well as the mechanism of altered
microbiota-induced cancer promotion.
The findings of the study are published in the
journal Cancer Research.
Colorectal cancer starts in the colon or rectum,
which are parts of the large intestine. Globally, colorectal cancer is the
fourth leading cause of cancer-related deaths. It is the most common type of
cancer in the United States. In 2012, colorectal cancer claimed about 700,000
lives. Obesity, physical inactivity, unhealthy diet, smoking and heavy use of
alcohol are some of the causes of colorectal cancer. Regular screening is one
of the most powerful weapons to prevent colorectal cancer. Avoid consumption of
such as sauces, canned
foods, processed meats, to reduce the risk of developing colorectal cancer.
- The perfect mixture: emulsifiers make our food enjoyable - (http://www.eufic.org/article/en/food-safety-quality/food-additives/artid/emulsifiers-food/)
- Can colorectal cancer be prevented? - (http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-prevention)