Should You Drink Coffee? The Real Pros and Cons

Coffee is the most consumed psychoactive beverage in the world. The headlines swing every few years between miracle drink and toxic habit. The body of evidence has actually settled into a fairly clean position: moderate coffee intake (3 to 4 cups per day) is associated with lower all-cause mortality, lower cardiovascular disease, and lower risk of type 2 diabetes in large meta-analyses. The 2017 BMJ umbrella review by Poole and colleagues collected the strongest signals.

The pros

• Mortality. The Poole 2017 BMJ umbrella review found 3 to 4 cups per day was associated with the largest relative risk reduction for all-cause mortality compared with no coffee.
• Cardiovascular disease. Modest reduction in CVD events, especially for moderate intakes.
• Type 2 diabetes. Both caffeinated and decaffeinated coffee are linked to lower diabetes incidence in cohort studies.
• Liver health. Lower risk of liver fibrosis, hepatocellular carcinoma, and non-alcoholic fatty liver disease.
• Cognition. Acute improvements in alertness and reaction time. Long-term cohorts suggest a modest reduction in Parkinson's disease and Alzheimer's risk.
• Performance. 3 to 6 mg/kg of caffeine 30 to 60 minutes before training improves strength and endurance in well-controlled studies.

The cons

• Sleep. Caffeine half-life is 5 to 7 hours. Coffee after 2pm pushes sleep onset and reduces slow-wave sleep in most adults.
• Anxiety. Sensitive individuals report panic, jitters, and palpitations above 200 mg per dose.
• Pregnancy. NHS recommends below 200 mg per day. Higher intakes are associated with low birth weight.
• Iron absorption. Coffee within an hour of meals reduces non-heme iron absorption. Important for adults with iron-deficiency anaemia.
• Acid reflux. Coffee can trigger or worsen reflux symptoms in adults with GORD.

A practical coffee plan

• 2 to 4 cups a day for most adults. Stop by early afternoon.
• Black, with milk, or with a small amount of sugar is fine. Daily syrup-laden coffees push calories and added sugar quickly.
• Time pre-training caffeine 30 to 60 minutes before the session.
• Stay below 200 mg per day if pregnant.
• Reduce or remove if it triggers anxiety, palpitations, reflux, or interferes with sleep.

Sources

1. Poole R, Kennedy OJ, Roderick P, Fallowfield JA, Hayes PC, Parkes J. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2017, vol 359, j5024.
2. NHS. Pregnancy and caffeine. nhs.uk