Scientists has discovered that high-fat diets boosts the growth of stem cells in the intestines which increases the risk of cancerous tumors forming in the gut.
The new study carried out on laboratory mice that was solely fed with fatty food shows they were more likely than normally-fed mice to suffer changes to the cells of the gut lining that may lead to the formation of cancerous tumors. Which also explains the link between obesity, fatty food and cancer.
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According to the researchers, the findings could help to explain the changes to the body’s cells that account for the established link between fatty food and the higher-than-average rate of certain types of cancer in overweight people.
The lead author of the study published in the journal Nature, Semir Beyaz of Harvard Medical School explained further:
The epidemiological link between a high-fat diet and colorectal cancer has been reported for many years, but the underlying mechanisms were not known.
Our study for the first time showed the precise mechanisms of how a high-fat diet regulates intestinal stem-cell function and how this regulation contributes to tumor formation.
As the study discovered, the mice in the study were fed an exceptionally fatty diet, containing 60 per cent fat, for between 9 and 12 months – compared to a typical western diet of 20 to 40 per cent fat. The mice became up to 50 per cent heavier than normally-fed mice and developed more intestinal tumors.
The researchers found that the high-fat intake significantly increased the overall pool of intestinal stem cells – the “mother” cells that develop into the specialized tissue of the gut – as well as increasing the number of other cells that started to behave like stem cells.
It is these stem cells, and stem-like cells, that can begin to divide uncontrollably to become cancerous tumors, which appears to explain why high-fat diets increase the risk of colorectal cancers, the scientists said.
David Sabatini, professor of biology at MIT, explained:
Under a high-fat diet, these non-stem cells acquire the properties of stem cells so that when they are transformed, they become tumorigenic [tumor forming].
The researchers further noted that cancers develop as a result of changes to cells that cause them to divide uncontrollably. Stem cells are also able to divide continuously, but in a controlled way, so anything that converts an ordinary cell into a stem-like cell has the potential for creating tumors.
Omer Yilmaz of the Massachusetts Institute of Technology in Cambridge, Massachusetts, a co-author of the study said:
Not only does the high-fat diet change the biology of stem cells, it also changes the biology of non-stem-cell populations, which collectively leads to an increase in tumor formation.
We wanted to understand how a long-term, high-fat diet influences the biology of stem cells, and how such diet-induced changes that occur in stem cells impact tumor initiation in the intestine.
When the intestinal cells of the overweight mice fed a high-fat diet were removed and grown in a laboratory dish, they gave rise to “mini-intestines” much more readily than similar cells taken from ordinary mice.
Furthermore, the “progenitor” cells, which are derived by the division of stem cells, tend to revert back to a stem-like condition – they survived for longer and were also able to give rise to mini-intestines.
Dr. Yilmaz also said:
This is really important because it’s known that stem cells are often the cells of the intestine that acquire the mutations that go on to give rise to tumors.
Not only do you have more of the traditional stem cells on a high-fat diet, but now you have non-stem-cell populations that have the ability to acquire mutations that give rise to tumors.