High-fat diets are to blame for 80% of colorectal cancers

High-fat diets are the reason 80 percent of colorectal cancers in America, a new study claims.

Researchers at the Cleveland Clinic have found evidence that fatty diets stimulate tumor growth by activating a molecular pathway that feeds abnormal cells. 

Colorectal cancer, which starts in the colon or rectum, is the third most common cancer in the United States with more than 130,000 cases reported annually. In the last few years, federal reports have shown a surge in cases in under-55s.

The research team found that eating a diet high in fats - whether it's a greasy Western diet of fast food or a trendy diet of avocado toasts - could be driving rates up.

Dr Matthew Kalady, a colorectal surgeon who led the study, said: 'We have known the influence of diet on colorectal cancer. However these new findings are the first to show the connection between high-fat intake and colon cancer via a specific molecular pathway.'

While many high-fat diets are widely condemned as causing high cholesterol and rapid weight gain, the ketogenic diet has been touted as a healthy alternative that can help people to lose weight.

Celebrities including Kim Kardashian, Megan Fox, Adriana Lima and even health preacher Gwyneth Paltrow have lauded the ketogenic diet, which cuts out carbs so that the body's first instinct is to break down fat stores to trigger weight loss.  

Carbohydrates make up five percent of the diet, compared to a standard diet which contains 30-50 percent carbs.

However, the new study by the Cleveland Clinic warns that even this 'healthy fat' lifestyle creates fertile ground for tumors to grow in the gut. 

The research team, led by Dr Justin Lathia and Dr Matthew Kalady in the clinic's colorectal cancer program, injected lab mice with abnormal cells that are linked to colon cancer growth.

They then split the mice into two groups; one group was fed a high-fat diet and the other was fed a normal rodent diet. The team then monitored the rates of the tumors growing. 

Overwhelmingly, they found that the high-fat diet rapidly increased the growth of aggressive, cancerous cells in the mice, while their peers on a normal diet saw little change. 

It is all down to the high levels of vitamin A, the researchers discovered, which unlock a pathway making it easier for normal cells to mutate.

Dr Lathia explained: 'These findings provide insight into how environmental influences, such as diet, can alter cancer stem cell populations in advanced cancers.'

While changing a nation's diet is a huge challenge, Dr Lathia said the research could pave the way towards developing treatments to prevent a poor diet from fueling tumors.

In the study they managed to curb tumor growth by blocking the vitamin A pathway.  

'We can now build upon this knowledge to develop new treatments aimed at blocking this pathway and reducing the negative impact of a high-fat diet on colon cancer risk,' Dr Kalady explained.    

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