A new study published Wednesday in the medical journal BMJ looked at more than 100,000 French adults and found that drinking 100 milliliters of a sugary drink per day, which equates to about a third of a typical can of soda, increases a person's overall cancer risk by 18 percent. It followed them for a maximum of 9 years, between 2009 and 2018, to assess their risk for all types of cancer, and for some specific types including breast, colon and prostate cancer.
People who drink a lot of sugary drinks have a higher risk of developing cancer, although the evidence can not establish a direct causal link, researchers said on Thursday.
The study found no increased cancer risk from sugar-free drinks, although so few of the people studied consumed them that the results may not be significant, the researchers said.
"So this means if 1,000 similar participants increased their daily sugary drink intake by 100ml, we'd expect the number of cancer cases to rise from 22 to 26 per 1,000 people over a five-year period". "As usual with nutrition, the idea is not to avoid foods, just to balance the intake", said Dr Mathilde Touvier, who led the research, from Inserm, the French national institute of health and medical research.
Researchers in France monitored participants' daily consumption of sugar and artificially sweetened beverages, as well as 100% fruit juices.
"Surprisingly perhaps, the increased risk of cancer in heavier consumers of sugary drinks was observed even among consumers of pure fruit juice - this warrants more research", Johnson told the Science Media Centre in the UK.
But public health agencies say that fruit juices are a little bit better because they contain some vitamins and a little bit of fibre, she added. The authors call for that to be investigated further.
Gavin Partington, director-general of the British Soft Drinks Association, said the study "does not provide evidence of cause, as the authors readily admit".
The research spanned a five-year period, starting when the participants were aged 42 on average.
Researchers in France found that downing a small glass of 100 percent fruit juice or soda - about 3.3 ounces worth - a day was linked to an 18 percent increased risk of cancer and a 22 percent increase in breast cancer.
There was no link between artificial sweeteners and cancer, but the numbers using artificial sweeteners were too small to be conclusive.
"The message from the totality of evidence on excess sugar consumption and various health outcomes is clear - reducing the amount of sugar in our diet is extremely important".
"While this study doesn't offer a definitive causative answer about sugar and cancer, it does add to the overall picture of the importance of the current drive to reduce our sugar intake", said Amelia Lake, reader in public health nutrition at Teesside University.