SOMERVILLE, Mass., Aug. 20 (Nationwide Times) — For people who regularly drink soda, sweetened sports drinks, lemonade or other sugary beverages, a new U.S. study adds to concerns about how those drinks may affect long-term health. Researchers found that people who consumed at least one sugar-sweetened beverage a day had 2.45 times the risk of developing stomach cancer compared with people who consumed fewer than one serving a month.
That figure describes a relative difference between groups. It does not show the absolute chance that any one person will develop stomach cancer. The study recorded 278 cases among 112,284 participants over the study period, but the researchers did not report the cancer rate for each beverage-consumption group in the materials summarized by Mass General Brigham.
The study was observational, meaning it identified an association rather than proving that sugary drinks or fructose cause cancer. Andrew T. Chan, the study’s senior author and a gastroenterologist and epidemiologist at Mass General Brigham and Massachusetts General Hospital, said the research cannot establish cause and effect and that more research is needed.
What did the study examine?
Researchers analyzed health and diet information from participants in the U.S. Nurses’ Health Study and the Health Professionals Follow-Up Study. The data covered 1986 through 2022 and included 112,284 participants, according to Mass General Brigham.
The study, by researchers at the Mass General Brigham Cancer Institute, was published in Gastro Hep Advances. The researchers examined participants’ reported intake of sugar-sweetened beverages and total fructose, a type of sugar found naturally in some foods and added to many drinks and processed products.
The sugar-sweetened beverages included carbonated drinks, punch, lemonade and sports drinks. Other descriptions of the study also included regular soda, energy drinks and juice with added sugar.
Among women in the Nurses’ Health Study, drinking more than one sugar-sweetened beverage a day was associated with a 3.04-fold higher risk of stomach cancer compared with very rare consumption. The association was also reported among men, although the supplied study summary does not provide the full sex-specific statistical results.
What does fructose have to do with the finding?
The researchers also found that higher total fructose intake was associated with a higher incidence of stomach cancer. The results do not establish whether fructose itself caused the increased risk, whether the finding reflects sugary drinks specifically or whether another part of participants’ diets or lifestyles contributed to the association.
Chan said the study found an association between sugary drinks and stomach cancer, but additional research is needed to determine whether the relationship is causal.
Did artificially sweetened drinks show the same association?
No increased stomach-cancer incidence was observed for higher consumption of artificially sweetened beverages after the researchers adjusted for other factors, according to Mass General Brigham. In the study, those beverages were defined as low-calorie carbonated drinks.
That result does not show that artificially sweetened drinks prevent cancer or are healthier in every respect. It means only that the study did not find an association with increased stomach-cancer incidence after adjustment.
How should the risk number be understood?
A 2.45-times higher relative risk can sound large, but it cannot be converted into an individual’s actual chance of developing cancer without knowing the baseline risk for the comparison group. The study summary does not provide absolute risks by beverage category, confidence intervals or an absolute risk difference.
The 278 documented cases represent about 0.25% of the entire analyzed cohort over the reported period. That calculation combines all beverage-consumption groups and therefore cannot be used as the risk for daily sugary-drink consumers or for people who rarely consume them.
Stomach cancer is uncommon compared with many other cancers, and the study’s results do not mean that a person who drinks a sugary beverage every day will develop the disease. They indicate that, within these U.S. cohorts, daily consumption was associated with a higher observed risk than very rare consumption.
What are the study’s limits?
Because the research was observational, participants were not randomly assigned to drink sugary beverages or avoid them. Researchers adjusted for other potential risk factors, but the supplied study summary does not list all of the factors included in the analysis.
The findings also do not show whether the association was driven by beverages, fructose, added sugar, a broader dietary pattern or another factor related to beverage consumption. The study population came from two established U.S. cohorts, so the results may not apply equally to every population.
The researchers described the work as the first study to show an association between sugar-sweetened beverage intake and stomach cancer in a U.S. population. Chan and his colleagues said further research is needed before the finding can be treated as evidence that sugary drinks directly cause the disease.
