Losing weight can protect against a range of chronic conditions, but certain ways of shedding pounds could raise risk of deadly diseases. A new study warns that a hugely popular weight loss diet keto could increase risk of colon cancer, the condition fast rising among young people.
The study carried out by a group of Canadian researchers published in the Nature journal warns against low-carb diets such as keto to get rid of excess weight as this may promote the growth of toxic compounds linked to colorectal cancer in the intestine.
Low-carb diets are known to have metabolic advantage and are believed to increase your energy expenditure. This may help weight loss with higher efficiency. Many low-carb diets are also high in protein which can reduce appetite and boost metabolism.
The weight loss promise of low-carb diets
In the Keto diet, one consumes a very low amount of carbohydrates and replaces them with fat to help the body burn fat for energy. It helps reach body Ketosis, a metabolic state where it burns fat for energy instead of glucose.
Researchers in a new study highlight the adverse effects of insufficient carb intake saying this can cause E coli bacteria strain naturally present in the body to produce a toxin called colibactin, which could lead to abnormal growths called polyps to form in the colon, which could develop into tumours.
The study done in the mice shows how removing carbs completely from the diet can backfire and can increase risk of developing colon cancer. However, more human studies are needed to establish the connection.
It is to be noted that on the other extreme, a diet high in refined carbs can put one at risk of obesity, which is another risk factor for colon cancer.
What the researchers found
For the study, researchers analysed mice already affected with the bacteria Bacteroides fragilis, Helicobacter hepaticus or the E coli strain NC101. Bacteroides fragilis produces a toxin that causes colon inflammation and tissue damage, contributing to colon cancer. Similarly, studies suggest Helicobacter hepaticus may increase the risk of developing and dying from colon cancer in humans.
Both Bacteroides fragilis and Helicobacter hepaticus are naturally present in colon in humans. According to the study, the E coli strain NC101 has been found in about 60 percent of colorectal cancer cases. It is naturally found in the intestines and helps break down food compounds and produce vitamins. The mice were either fed a balanced, low-carb or Western-style diet.
Mice infected with E. coli NC101 and fed a low-carb diet were found to produce colibactin, a toxic compound that damages colon cell DNA and promotes the formation of polyps.
The team of researchers also found that a low carb diet group had thinner gut mucus layer in color as compared to others. Not having a solid mucus layer could mean more colibactin could reach the colon cells to cause genetic damage and drive cancer tumour growth.
Risks of carb elimination
Experts suggest that a lack of carbohydrates may raise cancer risk when combined with E. coli NC101 infection. However, the researchers also found that a fiber-rich diet, particularly one containing the prebiotic fiber inulin, could help counteract some of these harmful effects.
Prebiotic fibre can promote growth and activity of beneficial bacteria in the gut known as probiotics. This can support digestion, help promote gut health, and regulate bowel movements. The researchers did not find any notable association between the mice who had Bacteroides fragilis or Helicobacter hepaticus and were fed a low-carb diet with cancer.
What happens when you eat too many carbs
Eating too many carbohydrates can lead to several health issues, including weight gain, increased blood sugar levels, and a higher risk of developing type 2 diabetes. Excessive carb intake, especially from refined sources like white bread and sugary snacks, can also contribute to insulin resistance, inflammation, and poor gut health. Over time, this can raise the risk of heart disease, disrupt metabolic health, and even play a role in promoting certain cancers. Additionally, a diet overloaded with carbs can cause energy crashes, cravings, and digestive problems such as bloating and gas.
Benefits of fibre-rich foods in preventing colon cancer
Fiber-rich foods support gut health by promoting regular bowel movements and reducing constipation, which helps clear potential carcinogens from the colon. They also feed beneficial gut bacteria, producing short-chain fatty acids that reduce inflammation. Additionally, fiber helps regulate weight and blood sugar levels, both linked to lower colon cancer risk.
In nutshell, the study found that a lack of carbohydrates and fibre can significantly raise cancer risk when combined with certain E coli bacteria.