Artificial sweeteners are used to replace sugar in food and drinks. There are a variety of artificial sweeteners available, including saccharin, aspartame and cyclamate. While there is evidence to link high-dose artificial sweetener use with cancer in animals, there is no evidence to support such a link in humans.
Studies of laboratory rats in the 1970s linked high doses of saccharin with the formation of bladder stones that can lead to bladder cancer. These results however could not be replicated in mice and it has been determined that the increase in bladder cancer risk in rats is due to the physiology of the rat urinary system. Human studies that examined the rates of cancer among populations who are more likely to consume artificial sweeteners (diabetics) found that the risk of cancer was no higher than the general population.
Aspartame safety concerns were raised in the 1990s with a report that suggested that the increase in number of people with brain tumours may be associated with the introduction and use of artificial sweetener in the United States (US). However, an analysis of the US National Cancer Institute statistics showed that the incidence of cancers began to rise eight years prior to the approval of aspartame and mainly among people aged 70 and older, a group not exposed to the highest doses of aspartame. Subsequently, the National Cancer Institute examined data from the Diet and Health Study of more than half a million retirees and found that increasing consumption of aspartame-containing beverages was not associated with the development of cancer.
Studies of laboratory rats in 2005 found that rats given high doses of aspartame were more likely to develop lymphoma and leukaemia. However, the doses given to the rats in this study were the equivalent of between 8 and 2,083 cans of diet soft drink daily. It was concluded that the acceptable daily intake for aspartame was safe. A survey conducted by the Food Standards Australia and New Zealand (FSANZ) in 2003 concluded that Australian consumption was well below the levels at which adverse health effects could occur. A large safety evaluation study published in 2007 reviewed the health effects of average current consumption levels and found no evidence linking aspartame to cancer incidence.
According to the International Agency for Research on Cancer (IARC), there is insufficient evidence to conclude that cyclamates cause cancer in either humans or animals. IARC is a part of the World Health Organisation which convenes international expert working groups to evaluate the evidence of the carcinogenicity (cancer causing properties) of specific exposures. Cyclamates were banned in the US in 1969 by the Food and Drug Administration (FDA) after studies in rats suggested that cyclamate might increase the risk of bladder cancer in humans. However, re-examination of cyclamate’s carcinogenicity and the evaluation of additional data concluded that cyclamate does not cause cancer. Cyclamates are still banned in the US; however the FDA’s concerns about cyclamate are not related to cancer.
The FSANZ conducted a safety assessment of cyclamates which concluded that a daily intake of 11mg/kg body weight is not associated with an increased risk of cancer. Exposure assessments by FSANZ have found that all people over 12 years of age and 95% of children aged 2-11 consume cyclamates within this acceptable daily intake. To remedy the over-consumption of the remaining 5% of children, FSANZ is reducing the maximum amount of cyclamates allowed in flavoured drinks by almost half. FSANZ believes this will eliminate over-consumption of cyclamates in children.