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Drinking coffee has consistently been linked to improved heart health and increased longevity. However, new research suggests that the timing of coffee consumption may play a key role in its benefits. According to a study published Tuesday in the European Heart Journal, limiting coffee to the morning may be the most beneficial — regardless of the quantity consumed or other influencing factors.
“This is the first study exploring how the timing of coffee consumption impacts health outcomes,” said Dr. Lu Qi, lead author and professor at Tulane University’s School of Public Health and Tropical Medicine, in a news release. “While dietary guidelines typically overlook timing, this study suggests it might be worth considering in the future.”
Previous research has indicated that moderate coffee intake is associated with reduced risks of type 2 diabetes, cardiovascular diseases, and premature death. However, factors such as genetics, sweeteners, and consumption levels have led to inconsistent or controversial findings.
Study Overview
The study analyzed dietary and health data from 40,725 adults aged 18 and older, collected through the National Health and Nutrition Examination Survey (1999–2018). Participants reported their dietary intake over the previous day, and a subgroup of 1,463 adults provided weeklong dietary records.
Researchers categorized coffee consumption into three time periods:
- Morning (4 a.m.–11:59 a.m.)
- Afternoon (12 p.m.–4:59 p.m.)
- Evening (5 p.m.–3:59 a.m.)
The study found two main patterns of consumption: morning-only and all-day. Over a median follow-up of nearly 10 years, there were 4,295 deaths (1,268 from cardiovascular disease and 934 from cancer).
Compared to non-coffee drinkers, individuals who drank coffee only in the morning had a 16% lower risk of premature death and a 31% lower risk of cardiovascular-related death. Those who drank coffee throughout the day saw no reduction in risk. These associations persisted even after adjusting for factors such as age, sex, income, physical activity, diet, and health conditions.
Interestingly, the amount of coffee consumed — whether less than one cup or more than three cups daily — did not alter the benefits for morning drinkers. Both caffeinated and decaffeinated coffee showed similar results.
Limitations and Considerations
The study’s observational nature means it can only establish associations, not causation. Vanessa King, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics, noted that while the findings are significant, they don’t prove that drinking coffee in the morning directly reduces mortality risk.
The study also had limitations:
- Dietary data relied on self-reports, which may include inaccuracies or biases.
- Long-term habits were not accounted for.
- The researchers lacked genetic data to examine caffeine metabolism rates.
- The morning coffee pattern might correlate with other healthy lifestyle behaviors, such as regular exercise or a diet low in processed foods.
Why Timing Matters
Timing may influence the body’s circadian rhythms and hormone levels. For instance, drinking coffee in the afternoon or evening could disrupt melatonin production, which regulates sleep and affects cardiovascular health. Coffee’s anti-inflammatory properties might be more effective in the morning, as certain inflammatory markers peak during that time.
Coffee also contains antioxidants that reduce inflammation and counteract free radicals, which are linked to cardiovascular risks.
Adjusting Coffee Habits
If you want to restrict coffee intake to the morning but find it challenging, consider addressing your sleep quality. A sleep specialist can identify conditions like sleep apnea, which may disrupt rest. You could also dilute afternoon servings with water to reduce caffeine intake gradually.
Checking thyroid function, vitamin D, and iron levels can help identify underlying causes of fatigue, said Sue-Ellen Anderson-Haynes, another dietitian and spokesperson for the Academy of Nutrition and Dietetics.
For non-coffee drinkers considering adding it to their routine, it’s essential to focus on an overall balanced and active lifestyle first.
Until more research confirms the optimal timing of coffee consumption, it’s best to follow your healthcare provider’s guidance on caffeine intake.