A large-scale study published in the British Journal of Nutrition found that drinking a mix of coffee, tea, and water is linked to the lowest overall mortality risk.The optimal mix was a 2:3 ratio of coffee to tea, which researchers associated with significantly lower risks of death from respiratory, digestive, cardiovascular, and cancer-related diseases.Researchers cautioned that the study was observational and relied on self-reported data, meaning it can’t prove causation — but it offers insight into how a balanced beverage routine may support long-term health.

You probably already know that drinking water is critical to your health. After all, humans can survive only about three days without it. However, according to a recent study published in the British Journal of Nutrition, you might want to consider drinking more than just plain water throughout the day. 

In September, researchers shared the results of a comprehensive study examining the optimal drink rotation throughout the day to help you live longer and lower your risk of developing certain health issues. To determine which drinks and in what amounts could help achieve this, the team used data from the UK Biobank, a massive population-based study that includes more than half a million people. 

In this latest study, the team analyzed all participants who completed at least one 24-hour dietary recall, which detailed their food and drink intake over a day. After reviewing the data, they included more than 182,000 adults.

If you’ve been trying to decide between coffee, tea, or plain water, new research says you don’t actually have to choose. Scientists studying more than 182,000 adults found that those who drank all three — especially in the right balance — lived the longest.

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The team, News Medical explained, analyzed data including demographic factors, medical history, and dietary information from 2009 to 2012, and measured outcomes over 13 years, including mortality and the specific causes of death. They discovered that drinking seven to eight cups a day (a mix of coffee, tea, and water) is associated with the lowest mortality rate. Notably, they also found that a specific combination of water, coffee, and tea provided the highest benefit. Specifically, the team reported that the greatest benefit occurred when people consumed coffee and tea in a 2:3 ratio, meaning about 2 parts coffee to 3 parts tea. This mix was linked to the lowest risk of death from all causes, as well as specific diseases like cancer, heart disease, respiratory issues, and digestive problems.

As News Medical further detailed, the team drilled down several causes of death and found that respiratory disease mortality saw the most significant drop when people followed that specific ratio, linking it to a 72% lower risk of death compared to other patterns. It also found that following the 2:3 ratio was associated with a dramatic 65% reduction in digestive disease–related deaths and a reduced risk of cardiovascular disease mortality and cancer-related deaths. 

There are, however, a few main caveats. The researchers found that replacing water with coffee and tea, and drinking only four daily drinks, showed no benefit, and that when total daily drinks exceeded nine, replacing plain water with more coffee or tea was associated with a potentially higher risk of cardiovascular death. 

There are other limitations to this study. For one, it relies on people self-reporting what they ate and drank, and people have unreliable memories, even if they’re trying to self-report accurately. The authors also note that because this was an observational study, they cannot say the drinks are specifically what caused the lower risk of premature death. Still, the researchers hope their research can inform future studies and, one day, provide people with better guidance on what to sip throughout the day for better nutrition.

Reviewed by

Lauren Manaker MS, RDN, LD, CLEC: Lauren is an award-winning registered dietitian and three-time book author, with more than 22 years in the field.