Sugar in fruit juice may raise risk of cancer, study finds
Excessive consumption of sugary drinks – including juice – associated with the disease.
Drinking large amounts of fruit juice may raise your risk of cancer, according to a big study which has found a link between the regular consumption of all kinds of sugary drinks and the likelihood of developing the disease.
The study, carried out in France, is the first substantial piece of research to find a specific association between sugar and cancer. Sugary drinks such as colas, lemonade and energy drinks have been linked to obesity, which is a cause of cancer, but the French researchers suggest there could also be other reasons sugar could trigger it.
The study, published in the BMJ, finds the association with cancer is just as strong with fruit juices as it is with colas. “When the group of sugary drinks was split into 100% fruit juices and other sugary drinks, the consumption of both beverage types was associated with a higher risk of overall cancer,” it says.
Cutting down on the amount of sugary drinks we all consume, together with sugar taxes and restrictions on marketing, might help reduce the cancer burden, say the authors. That does not mean nobody should ever drink them. “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.
“The recommendation from several public health agencies is to consume less than one drink per day. If you consume from time to time a sugary drink it won’t be a problem, but if you drink at least one glass a day it can raise the risk of several diseases – here, maybe cancer, but also with a high level of evidence, cardiometabolic diseases.”
Fruit juices showed the same association with cancer as colas. “The main driver of the association seems to be sugar, so when we just look at the sugar content per 100ml, regular Coke or 100% orange juice, for instance, are quite the same. So it’s not so odd that we observe this association for fruit juices,” said Touvier.
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 study is observational, so it is not possible for the researchers to state that sugar is a cause of cancer. The authors call for that to be investigated further. They say there are plausible biological mechanisms, such as the effect of sugar on the visceral fat stored around vital organs such as the liver and pancreas, blood sugar levels and inflammatory markers, all of which are linked to increased cancer risk.
The data was collected through a long-running nutrition survey in France, called NutriNet-Santé, involving 101,257 healthy French adults, 79% of whom were women.
Those taking part had completed at least two 24-hour online validated dietary questionnaires, designed to measure their usual intake of 3,300 food and beverage items, and were followed up for a maximum of nine years. Over that time, nearly 2,200 cases of cancer were diagnosed, including 693 breast cancers. They found that a 100ml increase in sugary drink consumption was associated with an 18% increased risk of overall cancer and a 22% increased risk of breast cancer.
There was no link between artificial sweeteners and cancer, but the numbers using artificial sweeteners were too small to be conclusive.
“Clearly there is more work to be done and measuring dietary intake is challenging – however, 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. This highlights why our UK sugar levy and controls on the marketing of high-sugar products is so important, not only in terms of obesity but also possibly cancer prevention,” said Dr Amelia Lake, reader in public health nutrition at Teesside University.
Dr Graham Wheeler, a senior statistician at University College London’s cancer trials centre, said the study was large, well designed and added to the evidence of risk. But, he said, “whilst there was some evidence for an association between sugary drink consumption and the risk of developing breast cancer, the same association was not found for colorectal or prostate cancers. Further research into the biological mechanism between sugary drink consumption and specific cancers is needed to establish if one does indeed cause the other.”
• This article was amended on 11 July 2019 because Graham Wheeler works for University College London’s cancer trials centre, not for Cancer Research UK as an earlier version said. This has been corrected.