Artificial sweeteners may not be a healthier alternative to sugar, with international researchers identifying a possible association between consuming the sweeteners and an increased risk of cancer.
Artificial sweeteners, which are readily available in New Zealand's supermarkets, are used to maintain or add sweetness in foods and drinks while reducing the sugar content and corresponding calories. Many foods and beverages containing artificial sweeteners are consumed by millions of people each day - however, the safety of these additives has been a subject of debate.
Now, a new study - published this week in PLOS Medicine by researchers at the French National Institute for Health and Medical Research (Inserm) and Sorbonne Paris Nord University - suggests that some artificial sweeteners are associated with an increased risk of common cancers.
To evaluate the potential carcinogenicity of artificial sweeteners, researchers analysed data obtained from 102,865 French adults participating in the NutriNet-Santé study. The NutriNet-Santé study is an ongoing web-based cohort initiated in 2009 by the Nutritional Epidemiology Research Team (EREN). Participants enrol voluntarily and self-report their medical history, sociodemographic, diet and information on their health and lifestyle.
Analysing 24-hour dietary records, the team gathered data regarding the participants' intake of artificial sweeteners.
The researchers then conducted statistical analyses to investigate the associations between the consumption of artificial sweeteners and the risk of cancer. They also adjusted for a range of variables including age, sex, education, physical activity, smoking, body mass index, diabetes and family history of cancer, as well as baseline intakes, including energy, alcohol, sodium and sugar.
The team found that enrollees consuming larger quantities of artificial sweeteners - particularly aspartame and acesulfame-K - had a higher risk of developing common cancers compared to those who didn't consume artificial sweeteners. Higher risks were observed for breast cancer and obesity-related cancers in particular.
The study had several limitations, including that the participants' dietary intakes were self-reported. Selection bias may also have been a factor, as participants were more likely to be women (78.8 percent of the cohort); middle-aged (average 42.2 years); have higher levels of education; and exhibit health-conscious behaviours. The study was also observational and cannot establish cause-and-effect, meaning additional research will be required to confirm the findings and clarify the underlying causes.
However, the authors say their findings do not support the use of artificial sweeteners as safe alternatives for sugar.
"Our findings do not support the use of artificial sweeteners as safe alternatives for sugar in foods or beverages and provide important and novel information to address the controversies about their potential adverse health effects," the authors said.
"While these results need to be replicated in other large-scale cohorts and… clarified by experimental studies, they provide important and novel insights for the ongoing re-evaluation of food additive sweeteners by the European Food Safety Authority and other health agencies globally."
Lead author Charlotte Debras added: "Results from the NutriNet-Santé cohort suggest that artificial sweeteners found in many food and beverage brands worldwide may be associated with increased cancer risk, in line with several experimental… studies.
"These findings provide novel information for the re-evaluation of these food additives by health agencies."
Commenting on the findings, Dr Alan Barclay, an Honorary Associate at the University of Sydney, noted that the study had found some "small associations" between dietary sweetener consumption and common cancers, in particular breast cancer.
"Overall, this new research is novel and the results interesting," Dr Barclay said.
"However, it does not prove that intense sweeteners as a class, or specific sweeteners such as aspartame or Ace-K, cause cancer in humans. More high-quality research (e.g. randomised controlled trials) is required to answer this question definitively.
"Dietary intake was assessed well, but intense sweeteners are also consumed in medicines, supplements, mouth washes, toothpastes, and other non-food sources, and these were not assessed in this particular study. Therefore, we do not know how well this study captured participants' total intense sweetener intake."
Food Standards Australia New Zealand monitors and reviews the safety of all food additives used in foods and beverages and all available intense sweeteners - additives used to replace sugar - are considered to be safe.
On average, Australians consume more than 10 percent of their energy from free sugars, Dr Barclay noted. Free sugars are defined by the World Health Organization as all simple sugars, such as fructose and glucose, that are added to foods by the manufacturer, cook, or consumer - plus sugars naturally present in honey, syrups, and fruit juices.
"Therefore, Australians should continue to replace added sugars with intense sweeteners where appropriate."
