Tea or coffee? Harvard researcher's 30-year study on 50,000 women might settle the debate

In a revelation that could reshape your morning routine, a Harvard-backed study spanning over three decades and involving nearly 50,000 women has linked moderate coffee consumption with healthier aging and improved longevity. And no, tea or decaf doesn’t make the cut.

Led by Dr. Sara Mahdavi, a postdoctoral fellow at the Harvard T.H. Chan School of Public Health, the research presented at the American Society of Nutrition’s annual meeting suggests that caffeinated coffee—specifically—may play a pivotal role in preserving both mental sharpness and physical vitality well into old age.

How Coffee Came Into the Anti-Aging Spotlight
Beginning in 1984, the study followed 47,513 women, tracking their health outcomes, lifestyle choices, and daily beverage habits. Fast forward to 2016, and only 3,706 of them qualified as “healthy agers.” What counted as healthy aging? Reaching age 70 or older without major chronic illnesses, cognitive decline, or physical impairments—and with self-reported good mental health.

The standout factor? Coffee consumption. Women who drank at least one cup of caffeinated coffee daily were more likely to fall into the healthy aging group. Even more compelling: for every additional cup consumed per day (up to five), the chances of aging well increased by 2% to 5%. The benefits, however, tapered off after five cups—suggesting moderation is still key.

“Moderate coffee intake may offer some protective benefits when combined with other healthy behaviors,” said Dr. Mahdavi in a press release, adding that the findings reinforce—but don’t outweigh—the impact of exercise, a balanced diet, and avoiding smoking.

Not All Caffeine Is Created Equal
Interestingly, the benefits were exclusive to regular coffee. Tea and decaffeinated versions showed no significant impact on healthy aging, while soda—specifically cola—was associated with reduced positive health outcomes.

This isn’t the first study to give coffee a gold star. A separate study published in May 2024 involving 50,000 American adults found that one to three cups of coffee daily reduced the risk of death within the next decade by 15% compared to non-coffee drinkers.

But Dr. Mahdavi cautions that coffee isn’t a miracle brew. While it may help tip the scales toward graceful aging, its effects are modest when weighed against broader lifestyle choices. “The benefits from coffee are relatively modest compared to the impact of overall healthy lifestyle habits and warrant further investigation,” she said.

So, Should You Pour Another Cup?
If you’re healthy, active, and already enjoy your daily brew, science says—go ahead. Your coffee habit may be doing more than waking you up. It might just be helping you age better. But remember, more isn't always better. It's about striking the right balance—just like the perfect cup.