30-Year Study Reveals Coffee's Surprising Effect on Women Over 70

Newsweek

2 days ago

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Women who consume caffeinated coffee in midlife may boost their odds of aging well, according to a 30-year study.
The findings suggest that a daily cup of coffee may do more than energize—it might support physical and mental health into an aging adult's golden years.
The research, which was presented at the NUTRITION 2025 conference by Harvard T.H. Chan School of Public Health fellow Dr. Sara Mahdavi, analyzed data from the Nurses' Health Study, which began in 1984 and focused on nearly 50,000 women aged 45-60.
Stock image: Two cups of coffee.
Stock image: Two cups of coffee.
Photo by Farknot_Architect / Getty Images
"Coffee is one of the most widely consumed beverages globally and its relationship with long-term health has generated both scientific curiosity and public debate," Mahdavi told Newsweek in an email.
"Given its rich mix of bioactives, we wanted to examine how midlife intake may relate to healthy aging outcomes decades later—especially in a well-characterized cohort with repeated dietary measures."
Researchers found that women who drank regular, caffeinated coffee—not tea or decaf—had a modest, but measurable increase in the likelihood of meeting criteria for "healthy aging" by age 70.
These criteria included being free from 11 major chronic diseases, having intact physical function and mental health, and reporting no memory complaints.
"Caffeine likely plays a role, but it's not the only factor," Mahdavi said.
"Caffeinated coffee contains a broader range of bioactive compound—including certain polyphenols and diterpenes—that may be altered or diminished during decaffeination.
"It's also possible that individuals who drink decaf differ systematically in health or behavior, though we adjusted for many of those variables."
What To Know
On average, women in the study who aged in a healthy way consumed around 315 mg of caffeine daily—roughly equivalent to three small cups of coffee.
Each additional cup was tied to a 2-to-5% increase in the odds of healthy aging, up to a threshold of five small cups per day.
The researchers noted that, for most people, two cups of coffee per day are generally safe and potentially beneficial.
By contrast, soda consumption was associated with a 20-to-26% reduction in the likelihood of healthy aging, which suggests not all caffeine sources offer similar benefits.
"The clearest takeaway was how consistent the findings were," Mahdavi told Newsweek.
"Even after accounting for factors like smoking, [body mass index] and overall diet quality, moderate caffeinated coffee intake in midlife remained positively associated with healthy aging.
"By contrast, cola consumption was associated with a substantially lower likelihood of aging well—nearly four times the magnitude, in the opposite direction."
Health Benefits of Coffee
Previous research has linked coffee consumption to a range of health benefits, including a reduced risk of several chronic conditions.
Studies published in journals such as The New England Journal of Medicine and Circulation (NEJM) have found associations between regular coffee consumption and lower rates of Type 2 diabetes, Parkinson's disease, stroke and cardiovascular disease.
A 2012 study in NEJM involving more than 400,000 participants found that people who drank coffee had a lower risk of death over the study period, whether it was caffeinated or decaf.
A 2017 umbrella review in The BMJ found that coffee consumption was, "more often associated with benefit than harm," for a range of health outcomes.
However, researchers have also cautioned that drinking too much coffee may pose risks for people with certain conditions, or low caffeine tolerance.
"Not all beverages are equal when it comes to long-term health," Mahdavi said.
"Moderate caffeinated coffee—1-to-3 cups per day—may support healthy aging, but more importantly, it can be part of a broader lifestyle that includes nutrient-rich foods, regular physical activity and avoiding harmful exposures.
"The study adds to the growing body of evidence that everyday dietary choices, even in midlife, matter for how we age."