Tea Drinkers Have Lower Rates of Acid Reflux, 27,000-Person Taiwan Study Finds

If a burning ache creeps up your chest after meals and you already suspect it traces back to your gut, you have probably wondered whether your tea habit is helping or hurting. A new analysis of more than 27,000 adults in Taiwan found that habitual tea drinkers had a meaningfully lower rate of gastroesophageal reflux disease (GERD, the chronic form of acid reflux marked by recurring heartburn and regurgitation), but only under specific conditions. The benefit showed up for green and oolong-style tea, not black tea, and only at one to two cups a day, drunk every day rather than occasionally.

Key Takeaways

• Among 27,119 participants in the Taiwan Biobank, habitual tea drinkers had lower odds of GERD than non-drinkers (odds ratio 0.843, meaning roughly 16 percent lower odds).
• The protective link held only for semi-fermented (oolong-style) and non-fermented (green) tea; fully fermented (black) tea showed no association.
• The sweet spot was one to two cups a day (roughly 350 to 700 mL), drunk daily. Three or more cups a day showed no significant benefit.
• This is a single snapshot-in-time study; it cannot prove tea prevents reflux, and people already diagnosed with GERD are often told to cut caffeine, which could produce the same pattern in reverse.

Habitual Tea Drinkers Showed a Lower GERD Rate in the Taiwan Biobank

Researchers led by Cheng-Ming Kuo analyzed data from 27,119 adults enrolled in the Taiwan Biobank, a long-running population database that tracks the health and lifestyle habits of Taiwanese adults, and published the results in the International Journal of Medical Sciences (Kuo et al., 2026). Of the full group, 4,706 people (17.4 percent) had GERD, diagnosed by a standardized self-report questionnaire, and 22,413 did not. After adjusting for age, sex, smoking, hypertension and other factors, habitual tea drinkers had significantly lower odds of having GERD than people who did not drink tea at all: an odds ratio (OR, a measure of how much more or less likely an outcome is in one group versus another) of 0.843, with a 95 percent confidence interval of 0.779 to 0.911.

Why Reflux Sufferers Are the Ones Who Should Pay Attention

GERD affects an estimated 20 percent of adults in the United States and is driven mainly by the lower esophageal sphincter (LES, the ring of muscle that normally keeps stomach acid out of the esophagus) relaxing when it should not. Anyone managing chronic heartburn, or the related complications of esophagitis or Barrett's esophagus that can follow years of untreated reflux, has a direct stake in knowing what worsens or eases their symptoms. This study adds tea to a debated list of dietary factors tied to reflux risk. Caffeine itself has long been shown in controlled physiology studies to relax the LES and provoke reflux, an effect documented decades ago for coffee in the New England Journal of Medicine. Tea also contains caffeine, which is exactly why the researchers were interested in whether tea would show the same reflux-provoking pattern as coffee, or a different one.

Inside the 27,000-Person Taiwan Biobank Analysis

The strength of this study is its size and its granularity. Rather than lumping all tea together, the researchers classified it into fully fermented (black tea), semi-fermented (oolong-style) and non-fermented (green tea), and separately tracked how often and how much people drank. Only semi- and non-fermented tea were linked to lower GERD prevalence (OR 0.832); fully fermented tea was not (p equals 0.288). Frequency mattered too: only people who drank tea every day had lower odds of GERD (OR 0.847); weekly or monthly drinkers did not. Quantity followed a curve rather than a straight line. One cup a day (OR 0.881) and two cups a day (OR 0.765, the strongest of the dose-response figures in the study) were both linked to lower GERD, but three or more cups a day was not significantly associated with reflux risk at all. The pattern also held up fairly consistently across men and women, people under and over 65, and people with and without hypertension, which adds some confidence that this is a real statistical signal rather than a fluke in one subgroup.

What the Sweet Spot Might Mean for Someone Managing Reflux

The authors' own explanation for the curve is a biological hypothesis, not proof. Tea polyphenols, plant compounds with anti-inflammatory and antibacterial effects linked to the gut microbiome, are more concentrated in green and oolong tea than in black tea. The researchers suspect that at a moderate one to two cups a day, those mucosal anti-inflammatory effects may outweigh the mild LES-relaxing effect of tea's caffeine, while at three or more cups the cumulative caffeine burden may tip the balance back toward more reflux events. Nobody has tested that mechanism directly in this paper. If you already drink one to two cups of green or oolong tea a day, this study is a reason not to worry about it. It is not evidence that adding tea, or swapping in more of it, will treat existing reflux, and no tea variety, dose or schedule has been established as a treatment for GERD.

Why This Study Cannot Prove Tea Prevents Reflux

This is a cross-sectional study, meaning everyone was surveyed at a single point in time, so it can show an association but not which came first. The authors flag what may be the most important alternative explanation themselves: dietary counseling in Taiwan routinely advises reflux patients to cut back on tea and coffee, so people who already have GERD may have quit or cut down on tea because of their symptoms, rather than tea preventing reflux in the first place. Tea intake was also self-reported and estimated in standard servings rather than directly measured, and the entire cohort was drawn from one Taiwanese population, so it is unclear whether the pattern holds in other groups. The effect size is modest in absolute terms, too: the adjusted odds ratio translates to roughly 15.4 percent GERD prevalence among habitual tea drinkers versus about 18.0 percent among non-drinkers, a difference of about 2.6 percentage points. With more than 27,000 participants, even a small, clinically modest difference produces a statistically tight result, so the low p-values here should not be mistaken for a large effect.

What Comes Next

The researchers call for further work to test the biological mechanisms directly and to run interventional studies, actually assigning people to drink more or less tea, rather than relying on a single observational snapshot. Until that happens, this remains one cross-sectional study in one population: consistent with a real protective effect, but equally consistent with reflux patients simply drinking less tea after their diagnosis.

Common Questions

Does this mean tea causes less acid reflux? Not necessarily. The study only shows an association at one point in time. It is equally possible that people with GERD cut back on tea because they were told to, rather than tea preventing their reflux in the first place.

Which tea should I drink if I want the described benefit? The association only showed up for semi-fermented tea (oolong-style) and non-fermented tea (green tea). Fully fermented black tea showed no link to lower GERD in this study.

How much tea was linked to lower GERD risk? One to two cups a day, roughly 350 to 700 mL, drunk daily rather than weekly or monthly. Three or more cups a day was not associated with any benefit.

Is this the same thing as treating existing acid reflux? No. This is an observational study about prevalence in a general population, not a treatment trial. Nothing here shows tea reduces symptoms in people who already have GERD.

References

1. Cheng-Ming Kuo, Jiun-Hung Geng, Wen-Hung Hsu, Neng-Shen Chu, Szu-Chia Chen (2026). Habitual tea consumption is associated with a low prevalence of gastroesophageal reflux disease in a Taiwanese population study. International Journal of Medical Sciences. https://doi.org/10.7150/ijms.139922
2. Yen-Chen Anne Feng, Chia-Yen Chen, Tzu-Ting Chen, et al. (2022). Taiwan Biobank: A rich biomedical research database of the Taiwanese population. Cell Genomics. https://doi.org/10.1016/j.xgen.2022.100197
3. Definition & Facts for GER & GERD in Adults – NIDDK. NIH. https://www.niddk.nih.gov/health-information/digestive-diseases/acid-reflux-ger-gerd-adults/definition-facts
4. Sidney Cohen, Glenn H. Booth (1975). Gastric Acid Secretion and Lower-Esophageal-Sphincter Pressure in Response to Coffee and Caffeine. New England Journal of Medicine. https://doi.org/10.1056/nejm197510302931803
5. Jiaying Yang, Wei Chen, Jiayi Chen, Dengchao Xie, Yuefei Wang, Jihong Zhou (2025). Tea Polyphenol Epigallocatechin Gallate and the Gut–Health Axis: Unraveling Structural Characteristics, Metabolic Pathways, and Systemic Benefits. Advances in Nutrition. https://doi.org/10.1016/j.advnut.2025.100545