Endocrine Abstracts

JOINT417

Background: Cortisol, a stress hormone regulated by the hypothalamic–pituitary–adrenal (HPA) axis, plays a crucial role in maintaining physiological balance. Caffeinated beverages, such as coffee, tea, and energy drinks, are widely consumed worldwide and are known to influence cortisol secretion. Understanding the effect is vital for assessing the health implications of caffeine intake, particularly regarding stress regulation and overall well-being.

Objective: To evaluate and compare the effects of coffee, tea, and other caffeinated drinks on cortisol secretion, highlighting the magnitude of cortisol increase, caffeine content, and beverage-specific characteristics.

Methods: A comprehensive review of 15 studies conducted between 2000 and 2024 was performed. The studies assessed cortisol secretion in response to caffeine consumption, including coffee, tea, and energy drinks, across diverse populations. The analysis focused on the percentage increase in cortisol, number of participants, and caffeine content in each beverage category.

Results: The studies revealed notable differences in cortisol responses based on beverage type and caffeine content:

• Coffee: Represented in 10 studies with ~2500 subjects, coffee, with a typical caffeine content of 80–120 mg per 8-ounce cup, caused the strongest cortisol increase of 50% above baseline. Examples include espresso, Americano, cold brew, and drip coffee.

• Tea: Covered in 3 studies with ~800 subjects, tea (20–60 mg caffeine per serving) showed a milder cortisol increase of 20%. Examples include black tea (e.g., Earl Grey, English Breakfast), green tea, matcha, and iced tea. Tea’s effects are moderated by L-theanine, which promotes relaxation.

• Other Caffeinated Drinks: Represented in 2 studies with ~300 subjects, energy drinks (e.g., Red Bull, Monster) and sodas (e.g., Coca-Cola, Pepsi) exhibited a moderate cortisol increase of 30%, with caffeine content ranging from 30 to 300 mg per serving. Additional ingredients like sugar and taurine may influence cortisol responses.

Discussion: Coffee elicited the highest cortisol response due to its high caffeine concentration, while tea’s effects were milder, likely due to L-theanine’s calming properties. Other caffeinated drinks exhibited intermediate effects, depending on caffeine dosage and additional ingredients. Habitual caffeine consumers showed attenuated cortisol responses, suggesting tolerance over time.

Conclusions: Caffeine consumption significantly impacts cortisol secretion, with coffee showing the strongest effect, followed by other caffeinated drinks and tea. Tea’s stress-buffering properties and moderate cortisol response make it a suitable option for individuals sensitive to stress. Future studies should explore the long-term implications of caffeine-induced cortisol elevation and its role in stress and health management.