Adults who consumed sugar-sweetened beverages more than once a day had more than twice the risk of developing gastric cancer compared with people who rarely drank them, while lower-frequency consumption was not associated with the same increase, according to a study of more than 112,000 participants.
By yourNEWS Media Newsroom
Drinking sugar-sweetened beverages every day may be associated with a substantially higher risk of stomach cancer, according to a large U.S. study that followed more than 112,000 adults using decades of health and dietary information.
Researchers from Massachusetts General Hospital and Harvard Medical School found that participants who reported consuming sugar-sweetened beverages more than once per day had more than double the risk of developing gastric cancer compared with those who rarely drank them.
The findings were based on participants in two of the nation’s longest-running health research projects, the Nurses’ Health Study and the Health Professionals Follow-up Study.
The analysis is among the first large investigations to examine sugar-sweetened beverages specifically in relation to gastric cancer over an extended period.
Researchers emphasized that the findings demonstrate an association and do not prove that sugary drinks directly cause stomach cancer.
The pattern, however, was concentrated among people for whom sugary beverages had become an everyday habit. Participants who consumed the beverages less frequently — including monthly, weekly and even several times per week — did not show the same elevated gastric cancer rates.
That distinction suggests frequency may be particularly important when evaluating the potential health consequences of sweetened drinks.
Decades of Dietary Data Used to Track Cancer Risk
The research combined information from two established prospective cohort studies that have generated extensive data on diet and chronic disease.
The Nurses’ Health Study began enrolling female nurses in 1976, while the Health Professionals Follow-up Study began tracking male health professionals in 1986.
Participants periodically completed detailed food-frequency questionnaires covering their usual consumption of foods and beverages.
The questionnaires included sugar-sweetened sodas, fruit beverages, sports drinks and artificially sweetened drinks.
Researchers then followed participants over time and recorded cases of gastric cancer.
Because the cohorts were monitored for decades, investigators were able to compare long-term beverage habits with later cancer diagnoses while accounting statistically for several established or suspected gastric cancer risk factors.
Those included age, cigarette smoking, alcohol use and infection with Helicobacter pylori, a bacterium strongly associated with certain forms of stomach cancer.
The large number of participants and lengthy observation period allowed researchers to examine relatively uncommon outcomes such as gastric cancer with greater statistical power than would be possible in a smaller or shorter study.
After accounting for other risk factors, the association between frequent sugar-sweetened beverage consumption and gastric cancer remained.
Risk Increase Appeared Primarily Among Daily Consumers
The strongest result involved participants drinking more than one sugar-sweetened beverage each day.
That group experienced more than twice the gastric cancer risk of participants who consumed the drinks rarely.
The association was present among both men and women, although researchers reported that the increase appeared somewhat stronger among women.
The findings did not show a steady increase in risk at every level of consumption.
People drinking sugar-sweetened beverages one to three times a month had gastric cancer rates similar to people who rarely consumed them.
The same was true for participants who drank them weekly.
Even those consuming sugary beverages four to seven times a week did not show the increase observed among people drinking more than one serving each day.
That pattern places particular emphasis on habitual daily consumption rather than occasional use.
A soda at an event, an occasional sweetened lemonade or a sports drink from time to time did not produce the same statistical association in the study.
The elevated risk became apparent when sugar-sweetened beverages were consumed every day and, specifically, more than once daily.
Artificially Sweetened Drinks Did Not Show the Same Association
Researchers separately examined artificially sweetened beverages and found no significant relationship with gastric cancer in this particular analysis.
That difference led investigators to examine whether sugar itself could help explain the association.
They analyzed total fructose intake and found that participants consuming greater amounts of fructose also experienced higher rates of gastric cancer.
Fructose is a naturally occurring sugar but is also a major component of high-fructose corn syrup, which is widely used to sweeten soft drinks and other beverages.
The combined findings suggest that the sugar content of beverages may be more relevant to the observed gastric cancer association than factors such as carbonation or sweetness alone.
The study does not establish the precise biological process responsible for the relationship.
Researchers nevertheless noted that high sugar intake can influence metabolic pathways involving insulin, inflammation and other biological processes that have been investigated in connection with cancer development.
Other Studies Have Connected Sugary Beverages With Cancer
The new findings add stomach cancer to a broader body of research examining possible links between sugar-sweetened drinks and malignancies.
A previous study published in the Journal of the American Medical Association found that women drinking at least one sugar-sweetened beverage per day had an 85% higher risk of liver cancer.
Other laboratory research has examined the interaction between glucose and fructose, the sugars combined in high-fructose corn syrup, and found evidence that they can influence colorectal cancer growth and spread.
Additional studies have associated sugar-sweetened beverages with colon tumors and with a greater risk of premature death from cardiovascular causes.
Michael Greger’s “How Not to Diet” has summarized research examining associations among sugary beverages, chronic disease and cancer.
Nancy Appleton’s “Killer Colas: The Hard Truth About Soft Drinks” has similarly discussed the metabolic effects associated with soft drinks and high-fructose corn syrup.
Such findings do not mean every person who regularly drinks sugary beverages will develop cancer, nor do they establish sugary drinks as the sole or primary cause of the cancers examined.
Cancer generally results from complex interactions among genetics, age, environmental exposures, infections, lifestyle and numerous other factors.
The new gastric cancer research identifies beverage consumption as another factor warranting further investigation.
Researchers Caution That Observational Study Cannot Prove Cause
Despite the size and duration of the analysis, researchers stressed that the study has limitations.
Participants were not randomly assigned to drink sugary beverages or avoid them.
Instead, scientists observed existing habits and compared them with later health outcomes.
That observational design means researchers cannot determine with certainty whether the beverages themselves caused the increased cancer risk.
People who routinely consume large quantities of sugary drinks may also differ from infrequent consumers in other ways that affect health.
Statistical analysis can adjust for known variables, but researchers acknowledged that residual confounding from factors they did not measure or could not completely control remains possible.
Dietary information was also obtained through questionnaires, which rely on participants accurately remembering and reporting their consumption.
Still, the investigators said the association deserves attention because of its magnitude, the long follow-up period and the biological plausibility of metabolic pathways associated with high sugar intake.
The relationship with fructose intake provided additional evidence suggesting the finding may be related to sugar exposure rather than some unrelated characteristic of beverages.
Daily Habits May Matter More Than Occasional Consumption
One practical implication of the research is the apparent difference between occasional and habitual intake.
The data did not suggest that infrequent consumption carried the same increased gastric cancer risk as drinking sugar-sweetened beverages multiple times each day.
That makes the findings especially relevant to people for whom soda, sweetened juice drinks, energy beverages or sports drinks have become routine sources of daily hydration.
Reducing one recurring beverage can significantly decrease added sugar intake over months and years.
A person who ordinarily drinks a sugary soda each day could substitute plain water, unsweetened sparkling water or another beverage without added sugar.
Sparkling water flavored with a small amount of juice can provide sweetness while reducing the overall amount of added sugar.
People who routinely consume sports drinks after moderate exercise may also find that water is sufficient for hydration in many circumstances.
The goal suggested by the research is not necessarily complete elimination of every sweet beverage but greater attention to repeated daily consumption.
Sugar May Affect Several Biological Pathways
Researchers have several reasons for examining added sugar as a possible contributor to chronic disease.
Frequent intake of rapidly absorbed sugars can produce repeated increases in blood glucose and insulin.
Over time, chronically elevated insulin levels and insulin resistance can contribute to metabolic dysfunction.
High-sugar dietary patterns have also been associated with inflammatory processes.
Both insulin-related signaling and chronic inflammation have been studied for possible roles in the initiation and progression of certain cancers.
Obesity, which can be promoted by excess calorie intake from sugary drinks, is itself associated with elevated risks for numerous chronic diseases and several cancers.
Liquid calories may be particularly relevant because sweetened beverages can provide substantial amounts of sugar without producing the same feeling of fullness as solid foods.
That can make it easier to consume additional calories without consciously increasing meal size.
The current study does not establish which, if any, of those mechanisms explains the higher gastric cancer rates observed among daily consumers.
Further laboratory and clinical research will be needed to determine how sugar-sweetened beverages may affect stomach tissue and cancer development.
Diet Beverages Were Not Linked to Gastric Cancer in This Study
The absence of a significant association involving artificially sweetened beverages provides an important distinction within the findings.
In this analysis, diet drinks did not show the same gastric cancer risk as sugar-sweetened beverages.
Researchers cautioned, however, that the finding should not be interpreted as proof that artificially sweetened drinks are entirely without health concerns.
Other studies have examined artificial sweeteners in relation to cancer and metabolic health, producing ongoing debate over their long-term effects.
The present research addressed gastric cancer specifically and found no statistically significant association with artificially sweetened beverage consumption.
That result reinforces the need to interpret nutrition research narrowly rather than assuming findings involving one disease apply universally to every health outcome.
Long-Term Reduction in Sugary Drinks Could Carry Broader Benefits
Even if future research modifies or refines the estimated gastric cancer risk, cutting back on sugar-sweetened beverages may offer benefits beyond cancer prevention.
Lowering added sugar intake can help reduce excess calorie consumption and may support healthier blood glucose regulation, body weight and cardiovascular health.
For people drinking multiple sugary beverages every day, reducing consumption can represent a relatively simple dietary change compared with restructuring an entire eating pattern.
The study’s central finding was particularly focused: gastric cancer risk was not significantly elevated among occasional or moderate consumers but rose sharply among participants drinking sugar-sweetened beverages more than once daily.
That pattern does not prove cause and effect, but it gives researchers another reason to study how repeated exposure to high amounts of added sugar may influence long-term health.
With more than 112,000 participants followed across two major U.S. cohorts, the findings suggest that daily beverage choices may deserve greater attention in research on stomach cancer.
For consumers, the results provide another reason to view sugar-sweetened beverages as an occasional choice rather than an automatic part of every day.
Explainer Infographic
Comments