Daily Sugary Drinks Linked To More Than Double The Risk Of Stomach Cancer

Diet Soda Comes Out Clean, But Regular Sugary Drinks Linked to Stomach Cancer Risk

A large, long-running study now suggests one common part of the American diet deserves closer attention: sugary drinks.

Researchers tracked more than 112,000 adults over several decades and found that people who drank at least one sugar-sweetened beverage per day had about two and a half times the risk of developing stomach cancer compared to those who almost never touched the stuff. That finding held up for both men and women. Diet sodas and other artificially sweetened drinks showed no significant association, though scientists caution the picture on artificial sweeteners is still evolving.

Stomach cancer is the fourth leading cause of cancer death worldwide. Known risk factors include smoking, heavy drinking, and a common stomach bacterial infection. Diet is increasingly coming under scrutiny, and this study, published in the journal Gastro Hep Advances, adds sugary beverages to that conversation.

The Study Tracked 112,000 Adults for Decades

To understand how researchers arrived at these findings, it helps to know just how long this data has been collected. Researchers drew from two major, ongoing health studies based at Harvard: the Nurses’ Health Study, which began enrolling female registered nurses in 1976, and the Health Professionals Follow-up Study, which began enrolling male health care professionals in 1986. Together, these studies have followed participants for decades, tracking diet, lifestyle habits, and health outcomes through regular questionnaires sent every two to four years.

For this analysis, researchers focused on 112,284 participants in total, about 68,000 women and nearly 43,000 men. Beverage intake was recorded using detailed diet questionnaires that asked how often participants consumed specific drinks. Sugar-sweetened beverages included regular carbonated sodas, punches, lemonades, and sports drinks. Artificially sweetened beverages meant low-calorie carbonated drinks, like diet sodas. Participants were sorted into five groups based on how frequently they drank these beverages, from never drinking them to consuming more than one serving per day.

Researchers then tracked who got diagnosed with stomach cancer from that first questionnaire through the early 2020s, double-checking every case against medical records and cancer registries. Out of more than 3.2 million combined years of tracking, 278 people ended up with stomach cancer: 140 women and 138 men.

Only the Daily Habit Moved the Needle on Risk

Among people drinking at least one sugary beverage per day, the risk of stomach cancer was 2.45 times higher than in those who almost never drank them. Women who drank that amount daily had about three times the risk compared to women who rarely consumed sugary drinks. Men who drank that much daily had roughly twice the risk compared to their counterparts who didn’t. People who only had sugary drinks a few times a month or a few times a week didn’t see their risk climb in any meaningful way. It was the daily habit that made the difference.

Researchers also looked at fructose, the type of sugar that sweetens these drinks. People who ate or drank more fructose overall also had higher rates of stomach cancer, especially among women, though the study couldn’t pin down whether fructose itself is the culprit or just travels alongside soda drinking.

The Stomach Bacteria H. pylori Did Not Explain the Pattern

One natural question: could soda drinkers just happen to carry a common stomach bug that’s already known to raise cancer risk? That bacteria, Helicobacter pylori, is one of the most well-established causes of stomach cancer and is widespread around the world.

Researchers checked for H. pylori in a subset of around 940 participants. Roughly a third tested positive, but sugary-drink habits had nothing to do with who tested positive and who didn’t. Since that check only covered a fraction of the full group, though, researchers couldn’t completely rule out the bacteria’s role in the bigger picture.

This Is the First Study to Link Sugary Drinks to Stomach Cancer

Nobody knows exactly how sugary drinks might fuel stomach cancer, but researchers have some educated guesses: weight gain, insulin problems, hormone shifts, inflammation, damage to DNA, or an upset in the gut’s bacterial balance. The study authors are upfront that this part remains an open question.

Earlier research had hinted at something but never quite nailed it down. One study tied sugary drinks to a type of esophageal cancer without finding the same for the stomach. A Japanese study found no link at all, though it lumped 100% fruit juice in with sugary drinks, unlike this one.

Sugary drinks have already been linked to higher rates of colon, breast, and liver cancer. Stomach cancer now joins that list, at least based on this one large study. It doesn’t prove sugary drinks cause stomach cancer, but it gives researchers a real reason to keep digging into what a daily habit might be doing over the long run.

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Disclaimer: This article is based on findings from a single observational study and is intended for general informational purposes only. It is not medical advice. The study shows an association, not a proven cause-and-effect relationship, and further research is needed to confirm these findings. Readers with questions about their own diet or health should speak with a doctor or registered dietitian.

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