Atkins diet linked to bowel cancer risk
Tuesday, 19 Jun 2007 09:16
Some people reduce carbohydrate intake to lose weight
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Eating a very low carbohydrate diet could increase the risk of developing bowel cancer, research has suggested.
Diets such as Atkins produce weight loss by cutting out carbohydrates from foods such as bread and pasta and eating more protein-rich foods.
A new study from researchers at Aberdeen's Rowett Research Institute warns that following such a diet results in a four-fold reduction in the numbers of certain types of bacteria in the gut of obese men.
This finding is said to be significant as these bacteria produce a substance called butyrate, which has been shown to play an important role in keeping the gut healthy including helping prevent colorectal (bowel) cancer.
Writing in the Applied and Environmental Microbiology journal, the researchers argue their findings raise important questions about the impact of the prolonged use of very low-carbohydrate weight-loss diets on gut health.
They studied 19 healthy, obese men who were given three diets containing different levels of carbohydrates – low, medium and high. Two of the diets also included a high portion of protein.
Stool samples were analysed for the amount and type of bacteria, and for butyrate.
Lead researcher Professor Harry Flint said the observed changes in butyrate production are "the largest ever reported in a human dietary trial" and provide "strong evidence" that butyrate depends upon carbohydrate in the diet.
"We can't be sure from this study about the impact of butyrate production on gut health, but there has been quite a lot of work done which shows that butyrate stops cancer cells from growing, and so helps prevent colorectal cancer," he added.
"If low carbohydrate diets are to be consumed for long periods of time, it may be important to ensure that there is enough of the right sort of carbohydrate in the diet which can be used by the bacteria to produce compounds such as butyrate, which are beneficial for human health. This means making sure you continue to eat plenty of sources of fibre – such as fruit and vegetables."