Caffeine: Benefits and Risks for Health and Wellbeing

Abstract

Background: Tea contains a variety of compounds, including caffeine, which have a range of health impacts. The presence of caffeine in tea often raises questions about the benefits of its consumption, including potential effects on cognition, behavior, mood and exercise performance as well as areas of concern such as anxiety, stress, hydration and heart health. The aim of this review is to evaluate the benefits and risks of caffeine consumption with a focus on tea and other compounds present in tea, which may interact with caffeine. Methods: Evidence was considered from Randomised Controlled Trials (RCTs) published over the last 15 years investigating the effects of caffeine on cognition, alertness, behavior, hydration and mood. Systematic reviews, meta-analyses and expert panel reviews were included in the wider discussion. Results: Evidence suggests that caffeine intakes of 3-6mg/kg/bw/(body weight)/day may benefit cognitive function and exercise performance in adults. Many expert bodies state that there are no safety concerns with daily intakes of ≤ 200mg caffeine in pregnant women and ≤ 400mg in other adults. Evidence indicates that children and adolescents should limit their daily caffeine intake to 2.5mg/kg/bw. Tea contains a lower concentration of caffeine than most other caffeinated drinks as well as providing fluid for hydration and polyphenolic compounds for health, particularly cardiovascular health. L-theanine in tea moderates the potential negative impact of caffeine on stress and anxiety whilst improving attention and speed of mental performance. Conclusion: On balance, moderate amounts of caffeine provide benefits in terms of cognitive function, alertness and exercise performance in adults with minimal risk of adverse effects. Further research is required to determine safe, beneficial intakes in children and adolescents. Tea, with its lower caffeine content, in combination with flavonoid polyphenols, fluoride and L-theanine, may provide an acceptable benefit/risk ratio for people aged 4 years and over, assuming age-appropriate intakes of 1-8 daily servings.