A groundbreaking UK Biobank study reveals that drinking 7-8 cups daily of water, coffee, and tea—in the right combination—is linked to a 28% lower risk of death. The secret? Balance matters as much as quantity.
We've all heard the advice: drink plenty of water. Coffee lovers have celebrated studies showing their habit might be healthy. Tea drinkers point to ancient traditions touting their beverage's benefits. But what if the real secret to longevity isn't choosing one over the others—but combining all three in just the right way?
A comprehensive new study published in the British Journal of Nutrition analyzed data from over 182,000 UK adults and discovered something remarkable. The people with the lowest risk of dying weren't necessarily the ones drinking the most water, coffee, or tea individually. They were the ones drinking a balanced combination of all three, totaling 7-8 cups per day.
The Study: A New Way of Looking at What We Drink
Researchers from Southern Medical University in China took a fresh approach to an age-old question. Instead of simply asking "Is coffee good for you?" or "How much tea should I drink?", they asked a more nuanced question: "What happens when you replace one drink with another?"
This might sound simple, but it's actually revolutionary. Most previous studies compared people who drank different amounts of coffee or tea without considering what else they were drinking. If someone added a cup of coffee to their daily routine, was it replacing a sugary soda (probably good) or a glass of water (maybe not as beneficial)?
Using a sophisticated analytical framework called "compositional data analysis," the researchers tracked 182,770 adults over an average of 13.3 years. They meticulously recorded what participants drank, accounting for coffee, tea, and plain water consumption through detailed 24-hour dietary recalls.
The Sweet Spot: 7-8 Cups Daily
The results were striking. People who consumed 7-8 total drinks (of coffee, tea, and water combined) per day had the lowest mortality risk. Compared to those drinking fewer than four cups daily, this group experienced a 28% reduction in the risk of death from all causes.
But here's where it gets really interesting—it's not just about hitting that 7-8 cup target. The ratio of what you're drinking matters enormously.
The Magic Ratio: Coffee, Tea, and Water in Perfect Harmony
When researchers dug into the data, they discovered that once people were drinking at least four cups of fluids daily, replacing plain water with coffee or tea provided additional health benefits. But the protective effects weren't the same for all combinations.
The optimal mix? Roughly 2 parts coffee to 3 parts tea, with water making up the remainder of your daily fluid intake.
People following this balanced pattern saw remarkable reductions in mortality risk:
- 45% lower all-cause mortality (dying from any cause)
- 41% lower cancer mortality
- 31% lower cardiovascular disease mortality
- 72% lower respiratory disease mortality
- 65% lower digestive disease mortality
These aren't small numbers. They represent some of the most substantial protective associations found in nutritional research.
Why the Combination Works
Both coffee and tea contain powerful bioactive compounds that protect health in different ways. Understanding why they work better together helps explain these impressive findings.
Coffee is rich in over 1,000 different compounds, including chlorogenic acids, flavonoids, and trigonelline. These substances have been shown to improve insulin sensitivity, reduce inflammation, and provide antioxidant protection. Previous research has linked moderate coffee consumption to reduced risks of type 2 diabetes, certain cancers, and cardiovascular disease.
Tea, particularly the black tea commonly consumed in the UK, contains its own arsenal of beneficial compounds. Polyphenols, catechins, and other antioxidants in tea have been associated with improved heart health, better blood vessel function, and reduced risk of metabolic diseases. Tea also provides L-theanine, an amino acid that may promote relaxation and mental clarity.
The researchers suggest that coffee and tea may complement each other, providing a broader spectrum of bioactive compounds than either beverage alone. Meanwhile, plain water remains essential for basic hydration and physiological function.
The Cautionary Note: More Isn't Always Better
While 7-8 cups appeared optimal, the study revealed an important caveat. When total daily intake of these beverages exceeded nine cups, replacing water with more coffee or tea was associated with a potential increase in cardiovascular mortality risk.
This finding underscores an important principle in nutrition: there's often a sweet spot where benefits are maximized, and going beyond it doesn't necessarily provide additional advantages—it might even be harmful.
What About Water?
Some might wonder: if coffee and tea are so beneficial, why drink water at all? The answer lies in adequate hydration and balance.
At lower intake levels (fewer than four drinks daily), the study found that substituting water with coffee or tea didn't provide clear benefits. This suggests that maintaining a base level of hydration is crucial before the protective effects of coffee and tea become apparent.
Additionally, while coffee and tea contribute to daily fluid intake, they also contain compounds that may have diuretic effects, especially in those who aren't regular consumers. Plain water remains the most straightforward way to meet basic hydration needs without any additional compounds or stimulants.
How to Apply These Findings to Your Life
Based on this research, here's a practical approach to optimizing your daily beverage routine:
Start with hydration basics: Ensure you're drinking at least 4 cups of fluids daily. This can include water, coffee, or tea.
Aim for 7-8 cups total: This appears to be the optimal range for maximum health benefits. One cup typically equals about 8 ounces or 240ml.
Balance your coffee and tea: If you drink both, aim for roughly a 2:3 ratio (for example, 2 cups of coffee and 3 cups of tea).
Don't overdo it: More than 9 cups daily may start to reduce benefits, particularly for heart health.
Consider your individual needs: Caffeine sensitivity, medical conditions, medications, and personal preferences all matter. Some people metabolize caffeine differently due to genetic variations.
A sample daily beverage routine might look like:
- Morning: 2 cups of coffee (black or with minimal additions)
- Midday: 1 glass of water
- Afternoon: 3 cups of tea (spread throughout the afternoon)
- Evening: 1-2 cups of water
What This Study Doesn't Tell Us
It's important to understand the limitations of this research. This was an observational study, meaning it found associations but cannot definitively prove that the beverage combination caused the reduced mortality. People who drink balanced amounts of coffee and tea might differ from others in ways not fully captured by the statistical adjustments.
The study relied on self-reported dietary data, which can be imprecise. It also didn't capture important details like how beverages were prepared—whether people added sugar, milk, cream, or sweeteners makes a significant difference in the health impact of these drinks.
The participants were predominantly from the UK, where black tea is the norm. In populations that primarily consume green tea or other varieties, the findings might differ. Additionally, the UK Biobank participants tend to be healthier and more health-conscious than the general population, which may limit how broadly these findings apply.
The Bigger Picture: Beverages and Healthy Aging
This study fits into a larger body of evidence suggesting that what we drink matters for longevity. Multiple large-scale studies have now shown that moderate coffee and tea consumption are associated with better health outcomes and longer lifespans.
A 2018 UK Biobank study found that even people who drank 8 or more cups of coffee daily had lower mortality risk, regardless of how their genes affected caffeine metabolism. A 2022 study of nearly 500,000 people found that tea drinkers consuming 2 or more cups daily had lower mortality risk, with benefits extending to heart disease, stroke, and respiratory disease deaths.
What makes this new research particularly valuable is its focus on the combination and substitution effects—providing more nuanced, actionable guidance than simply saying "coffee is good" or "drink more tea."
Practical Considerations
For coffee drinkers who don't like tea, or vice versa, this research doesn't mean you need to force yourself to consume beverages you don't enjoy. Both coffee and tea individually have been associated with health benefits in numerous studies. The key takeaway is that a balanced approach with adequate total fluid intake appears optimal.
If you're thinking about adjusting your beverage consumption based on these findings:
Talk to your doctor first if you have cardiovascular conditions, anxiety disorders, sleep problems, or are on medications that interact with caffeine.
Make gradual changes: If you're not currently a coffee or tea drinker, don't suddenly start consuming large amounts. Build up slowly to allow your body to adjust.
Pay attention to additions: The health benefits observed in these studies typically involved beverages consumed with minimal additions. Loading up coffee or tea with sugar, syrups, or cream can negate potential benefits.
Consider timing: Drinking caffeinated beverages too late in the day can disrupt sleep, which is crucial for health. Most experts recommend avoiding caffeine within 6 hours of bedtime.
Don't forget food: Beverages are just one component of overall health. A balanced diet, regular exercise, adequate sleep, stress management, and not smoking remain fundamental to longevity.
The Bottom Line
This comprehensive UK Biobank study provides compelling evidence that a balanced daily beverage routine—combining coffee, tea, and water for a total of 7-8 cups per day—is associated with significantly lower mortality risk across multiple causes of death.
The most protective pattern appears to be a mix of about 2 parts coffee to 3 parts tea, with water filling in the remainder of your hydration needs. This combination may provide complementary bioactive compounds that support heart health, reduce inflammation, and protect against age-related diseases.
While more research is needed to confirm causation and understand the mechanisms, these findings offer practical guidance for anyone looking to optimize their daily beverage choices. The key insight? When it comes to coffee, tea, and water, the winning strategy isn't choosing one over the others—it's finding the right balance among all three.
Your morning coffee ritual, afternoon tea break, and plain water throughout the day might not just be pleasant habits. Together, they could be contributing to a longer, healthier life.
Study Reference: Shi C, Wang Y-K, Yan M-Q, et al. Relative associations of coffee, tea, and plain water with all-cause and cause-specific mortality: a prospective cohort study. British Journal of Nutrition. 2025:1-29. doi:10.1017/S0007114525104248
