The effects of coffee on the human body depend mainly on intake and individual differences. Moderate consumption of coffee (1-3 cups per day) may bring benefits such as refreshing the mind, increasing the metabolic rate, and reducing the risk of some chronic diseases; however, excessive intake may lead to anxiety, insomnia, heart palpitations, or digestive discomfort. Special populations (e.g. pregnant women, people with stomach problems, etc.) need to carefully control their intake.
Potential Benefits of Coffee
1. Central Nervous System Stimulation
Caffeine, the core ingredient in coffee, enhances alertness and concentration by blocking adenosine receptors and reducing fatigue signaling. Studies have shown that moderate intake improves short-term memory and reaction time.
2. Metabolism and Exercise Performance
Caffeine is often used as a pre-exercise aid as it promotes lipolysis, increases basal metabolic rate in the short term (about 3-11%) and enhances muscular endurance.
3. Antioxidant and Chronic Disease Prevention
Coffee is rich in chlorogenic acid and polyphenols, which have antioxidant effects. Long-term moderate consumption may be associated with reduced risk of type 2 diabetes, Parkinson’s disease, liver cancer, etc.
Risks of excessive or inappropriate consumption
1. Nervous system effects
Daily intake of more than 400 mg of caffeine (about 4 cups) may trigger anxiety, tremors or insomnia. Sensitive people (e.g., those with anxiety disorders) need to be more restrictive.
2. Digestive problems
Coffee stimulates the secretion of gastric acid, which may cause heartburn or acid reflux when consumed on an empty stomach. Symptoms may be aggravated in patients with gastric ulcers and irritable bowel syndrome.
3. Cardiovascular and bone health
Excessive caffeine may briefly raise blood pressure or cause heart palpitations. In addition, oxalic acid in coffee may interfere with calcium absorption, but the effect is small with normal diet.
Precautions and Individual Differences
1. Reasonable Intake
The daily recommendation for healthy adults is no more than 400 mg of caffeine (about 2-3 medium Americanos). Pregnant women need to limit to 200 mg.
2. Time and manner of consumption
Avoid consumption within 6 hours before bedtime to minimize sleep disturbance. It is recommended to serve with small amounts of food to minimize stomach irritation. Adding too much sugar and cream may negate the health benefits.
3. Special people need to be careful.
Patients with high blood pressure and arrhythmia should consult their doctors; long-term medication users need to be aware of the interaction between caffeine and drugs (e.g. some antibiotics and antidepressants).