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Sugary drinks may ‘represent a modifiable risk factor for cancer prevention’
Consumption of sugar-sweetened beverages appeared associated with a significantly increased risk for cancer, according to results of a large prospective study published in The BMJ.
Researchers also observed a link between consumption of 100% fruit juices and cancer risk.
“If these results are replicated in further large-scale prospective studies and supported by mechanistic experimental data — and given the large consumption of sugary drinks in Western countries — these beverages would represent a modifiable risk factor for cancer prevention, beyond their well-established impact on cardiometabolic health,” Eloi Chazelas, a PhD candidate in epidemiology at Sorbonne Paris Cité Epidemiology and Statistics Research Center in Paris, and colleagues wrote.
The findings add to the body of evidence that suggests benefits of limiting consumption of sugar-sweetened beverages, according to Colleen Doyle, MS, RD, managing director of nutrition and physical activity for the American Cancer Society.
“There have been many studies that link sugar-sweetened beverage consumption to excess weight,” Doyle told HemOnc Today. “Because of the impact that overweight and obesity have on cancer and other chronic disease risk, many organizations — including the American Cancer Society — have suggested reducing consumption of [these beverages] and have worked collaboratively to make it easier to do so.”
Significant associations
Global consumption of sugary drinks has increased by more than 40% since 1990.
Prior studies have shown the impact of sugary drinks on cardiometabolic health, including increased risk for weight gain, type 2 diabetes, hypertension and cardiometabolic death.
Epidemiological evidence on the potential impact of sugary drinks on cancer risk is limited and inconsistent. However, researchers have pointed to “mechanistic plausibility” based on the link between sugary drinks and obesity — a key cancer risk factor — as well as the potential for high glycemic index or glycemic load and the possibility that chemical compounds in sugary drinks may contribute to carcinogenesis, according to study background.
Chazelas and colleagues conducted a population-based prospective cohort study designed to investigate the relationship between consumption of sugary drinks or artificially sweetened beverages and risk for first cancer.
The analysis included 101,257 healthy adults (mean age, 42.2 years; 78.7% women) in the French NutriNet-Santé cohort recruited between 2009 and 2017. Repeated 24-hour dietary records documented participants’ usual consumption of 3,300 food or beverage items, including sugary drinks — including sugar-sweetened beverages and 100% fruit juices — and artificially sweetened (ie, diet) beverages.
Researchers assessed associations with overall cancer, as well as breast, colorectal and prostate cancers. Investigators accounted for established cancer risk factors, including age, sex, family history, smoking status, physical activity and educational level.
Median follow-up was 5.1 years (range, 0.003-8.8).
Average daily consumption of sugary drinks was higher among men than women (90.3 mL vs. 74.6 mL; P < .001).
Researchers validated 2,193 first cases of cancer during follow-up (mean age at diagnosis, 58.5 years). These included 693 breast cancers, 291 prostate cancers and 166 colorectal cancers.
Results showed a 100-mL-per-day increase in consumption of sugary drinks appeared associated with a statistically significant increased risk for overall cancer (HR = 1.18; 95% CI, 1.1-1.27) and breast cancer (HR = 1.22; 95% CI, 1.07-1.39).
Investigators found no association between sugary drink consumption and either prostate cancer or colorectal cancer; however, they noted the numbers of cases for these malignancies were more limited.
Consumption of artificially sweetened beverages did not appear associated with cancer risk; however, Chazelas and colleagues noted consumption level in the cohort was relatively low.
A subanalysis showed consumption of 100% fruit juice appeared significantly associated with risk for overall cancer (HR = 1.12; 95% CI, 1.03-1.23).
The effect of sugar on visceral fat, blood sugar levels and inflammatory markers — all of which could contribute to elevated cancer risk — may explain the findings, researchers wrote. The effects of other chemical compounds — including additives in some sodas — also may be a factor, they added.
The investigators acknowledged limitations of their study, including its observational nature, the potential for misclassification of beverages and their inability to guarantee detection of every new cancer case.
However, they noted their study was strengthened by its large sample size and adjustments for a variety of potentially influential factors.
“These data support the relevance of existing nutritional recommendations to limit sugary drink consumption, including 100% fruit juice, as well as policy actions — such as taxation and marketing restrictions targeting sugary drinks — [that] might potentially contribute to the reduction of cancer incidence” Chazelas and colleagues wrote.
Take-home messages for providers, patients
Although the study does not prove a direct association between cancer risk and consumption of sugary drinks, the findings suggest such a link, Doyle said.
“The take-home message is that people should reduce consumption of sugar-sweetened beverages,” Doyle told HemOnc Today. “From a cancer perspective, we know that if you don’t smoke, the most important things you can do to reduce your risk for cancer are to watch your weight, be physically active, eat a healthy diet — that includes limiting sugar-sweetened beverages — and limit alcohol consumption.”
The American Cancer Society’s guidelines on nutrition and physical activity include recommendations to reduce consumption of sugar-sweetened beverages. The society has worked with other organizations on initiatives to incorporate a recommendation in federal dietary guidelines to reduce consumption of these beverages, limit access to them in schools and workplaces, list calorie contents for sugar-sweetened beverages and other items on menus, and advocate for taxes on these products in certain areas.
Oncologists and other health care providers who care for patients diagnosed with cancer should be encouraged to ask about their consumption of sugar-sweetened beverages, Doyle said. These conversations should include discussion of sports drinks, which can contain higher levels of sugar than soda.
“There is no evidence that high sugar intake increases the progression of cancer — that sugar ‘feeds’ cancer,” she said. “But an important aspect to keep in mind — particularly for people undergoing treatment — is that the majority of sugar-sweetened beverages are essentially empty calories, providing no nutritional value.
“Maintaining good nutritional status is important during treatment, and we should be encouraging individuals undergoing treatment to get the biggest nutritional bang for the buck — consuming nutritious, nutrient-dense food and beverages,” she added. “Even though some individuals may need to increase their caloric intake during treatment, this can be done without consuming excessive amounts of beverages — and/or foods — high in sugar.”
The findings also are relevant to cancer survivorship.
“Some of the most important health-related goals cancer survivors ... can set [after treatment] are to watch their weight, live a physically active life and eat a healthy diet,” Doyle told HemOnc Today. “These are important goals for everyone to set, but especially for survivors to help reduce their risk for recurrence and development of second primary cancers. Our recommendations — based on the existing evidence — are that cancer survivors follow the guidelines that have been established for cancer prevention, including watching their weight and eating a healthy diet that includes limiting added sugar.” – by Mark Leiser
For more information:
Colleen Doyle, MS, RD, can be reached at American Cancer Society Inc., 250 Williams St., Atlanta, GA 30303.
Reference:
Chazelas E, et al. BMJ. 2019;doi:10.1136/bmj.l2408.
Disclosure: The authors report no relevant financial disclosures. Doyle reports no relevant financial disclosures.