As a symbol of fashion and deliciousness, coffee is favored by countless women. However, drinking coffee without paying attention to timing can actually harm the body.
Coffee contains caffeine, which, once in the body, stimulates the sympathetic nervous system. This eliminates drowsiness, improves blood circulation, and makes the body feel warm and less fatigued, hence its "energizing" effect.
However, stimulation and excitement of the sympathetic nervous system have a negative effect on appetite; that is, appetite decreases. Therefore, drinking coffee before a meal can lead to a loss of appetite. Additionally, the stimulation of the stomach increases gastric acid secretion, which irritates an empty stomach and is detrimental to patients with conditions like stomach ulcers. This can be considered a negative effect of coffee. But when consumed after a meal, the increase in gastric acid secretion aids digestion. Therefore, drinking coffee after a meal is absolutely fine.
Furthermore, some believe that adding milk can mitigate its stimulating effects. However, how much a small amount of milk can neutralize caffeine is questionable. Unless it's a 50-50 mix of milk and coffee, like a café au lait, the effect might be minimal. For example, the café au lait consumed for breakfast, with more milk than coffee, can still help to moderate gastric acid secretion even when consumed on an empty stomach. [China Food]
The ideal time to drink coffee is after a meal, which is beneficial without any harm. One of the benefits is preventing allergic reactions. Allergies, such as asthma or allergic rhinitis, are caused by the excitation of the parasympathetic nervous system. By promoting the excitation of the sympathetic nervous system and suppressing the parasympathetic one, it helps prevent attacks. This is especially true for severe allergy sufferers, where even minor triggers can cause physical discomfort. Coupled with the psychological fear of allergies, an attack can easily spiral out of control. Therefore, it is recommended to use the benefits of caffeine: when an allergy or asthma attack is about to occur (as the patient can feel it), drinking a cup of coffee beforehand has a preventive effect. Besides the stimulating effects of caffeine, the psychological sense of security from "having already drunk coffee" also makes an attack less likely.
Of course, "too much of a good thing is bad," and even the best things should be taken in moderation. Otherwise, regardless of whether it's before or after a meal, excessive caffeine can cause side effects such as palpitations (a very fast heartbeat), and even mental fogginess and an unstable gait.
As a rule of thumb, two to three cups of coffee a day is advisable. Most people will start to feel nauseous after four or five cups, so be cautious. As a general principle, for any stimulating beverage, it is best not to exceed three cups per day.