Soda and Fruit Juice Linked to Cancer in Major Study of Sugary Drinks—But Artificially Sweetened Beverages Aren't

Consuming sugary drinks could raise the risk of developing cancer according to scientists, who say policies to crack down on such products could cut rates of the disease.

A study published in The BMJ. found products like sugar-sweetened drinks and 100 percent fruit juices were linked to the disease, which 1.6 million people in the U.S. were diagnosed with in 2016.

To understand the potential risks posed by drinking sugary and artificially sweetened drinks, French researchers looked at data on 101,257 adults who were taking part in the ongoing NutriNet-Santé cohort study. The participants were healthy, and had an average age of 42 when they were recruited.

When they first joined the study, participants detailed variables like their sociodemographic status, age, sex, education level, weight, whether they smoked, how much they exercised, their health and what they ate.

The participants filled out an online questionnaire on whether they ate 3,300 different items. Researchers followed up with respondents for a maximum of nine years. A total of 2,193 participants had their first cancer diagnosis in that time.

Drinking sugary drinks—defined as sugar-sweetened beverages and 100 percent fruit juices—was linked with an overall risk of cancer or breast cancer, the authors wrote

A 100mL per day increase in the amount of sugary drinks an individual consumed was linked with a 22 percent increased risk of breast cancer from the baseline, and an 18 percent increased risk of cancer overall.

Meanwhile, the team found no link between artificially sweetened drinks and the risk of cancer.

The authors concluded that the results suggest "sugary drinks, which are widely consumed in Western countries, might represent a modifiable risk factor for cancer prevention." Policies like sugar taxes and marketing restrictions on the product might cut rates of cancer.

Studies already show sugary drinks are linked with obesity, a higher risk of developing type 2 diabetes and a greater risk of high blood pressure, as well as dying from heart disease and stroke, the scientists said.

For instance, research in 2010 estimated around 178,000 deaths worldwide each year associated with diabetes and cardiovascular diseases were linked to the consumption of sugary drinks.

Mathilde Touvier, co-author of the paper and research director at INSERM and principal investigator of the NutriNet-Santé cohort, told Newsweek the link between fruit juices could be explained by the fact they generally contain high levels of simple sugar comparable to regular soda, and their glycemic indexes are higher than that of whole fruits.

She explained the harmful effects of sugar on cardiometabolic health are well-established. In contrast, the association between sugary drinks and cancer risk has been less investigated.

"Indeed, sugary drinks are convincingly associated with the risk of obesity, which in turn, is recognized as a strong risk factor for many cancer sites. Analyses of this study suggest that overweight and weight gain may not be the only drivers of the association between sugary drinks and cancer risk, but that the relationship observed was also strongly driven by its sugar content," argued Touvier.

However, as the study was observational, the findings don't prove sugary drinks cause cancer and confounding factors could be at play, although these were accounted for in the analysis, she said.

Co-author, PhD student Eloi Chazelas of Sorbonne Paris Cité Epidemiology and Statistics Research Center, told Newsweek: "Public health authorities encourage limiting sugary drink intake (less than one glass per day). The only beverage that is recommended ad libitum is water."

Katie Patrick, a health information officer of charity Cancer Research UK who was not involved in the work, told Newsweek: "Previous research has shown a link between drinks high in sugar and excess weight—a proven cause of cancer—and interestingly these new findings suggest that sugary drinks and cancer could also be linked regardless of weight. But we need more evidence to back up this up, and to explain how it might happen before jumping to any conclusions."

She continued: "There were also lots of differences in this study between the group drinking the most sugary drinks and the group drinking the least, so we need to make sure it's definitely sugary drinks that are affecting cancer risk. But there's already plenty of evidence that cutting down on sugary drinks, which includes things like soft drinks and fruit juices, is a good idea."

Allison Hodge, an associate professor at Australia's University of Melbourne and senior research fellow at Cancer Council Victoria, found a similar association for sugary soft drink consumption with 11 obesity-related cancers in a separate study.

Hodge, who did not work on The BMJ paper, told Newsweek the association with 100 percent fruit juice may come to a surprise to some as juices contain vitamins and are included in many government dietary guidelines. She said the high levels of sugar may explain the link.

Critiquing the study, she argued: "Because of the relatively young cohort there were not many cancer cases, and it may have been relevant to look only at obesity-related cancers for which there is a clear hypothesis for an association mediated through obesity."

Offering a take-home message, Hodge continued: "This is more reason to reduce consumption of sugary drinks and replace them with water, and consume whole fruits to obtain the vitamins that it provides."

Amelia Lake, reader in public health nutrition at Teesside University, who was also not involved in the research, commented that the study adds "to the overall picture of the importance of the current drive to reduce our sugar intake.

"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 article has been updated with comment from Allison Hodge.

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A stock image showing soda. Scientists have warned sugary drinks could cause cancer. Getty