1. Remember that coffee should not be taken with tea. Tannic acid in tea and coffee can reduce the absorption of iron by 75%. It is advisable to take it with warm boiled water;

2. Tannic acid in tea and coffee will reduce calcium absorption. Therefore, the time for drinking tea and coffee is best to choose between two meals;

3. Caffeine-containing drinks and foods will cause nausea, vomiting, headache, rapid heartbeat and other symptoms after being drunk in large quantities by pregnant women. Caffeine will also enter the fetus through the placenta, affecting fetal development;

4. Many doctors believe that drinking 1~2 cups of coffee, tea or carbonated drinks every day will not affect the fetus. But for the sake of caution, it is best for pregnant women to ban it. Caffeine can lead to an increase in abortion rate, so you should drink decaffeinated drinks;

People who want to lose weight should not drink more coffee. Common coffee partners contain more milk, sugar and fat. Coffee itself may stimulate the secretion of gastric juice and improve the digestion and absorption of food. Not only can it not slim down, but it will also make people fat.

6. Children should not drink coffee. Caffeine can excite children's central nervous system, interfere with children's memory and cause ADHD.

7. Strong tea, coffee and carbonated drinks are also risk factors for the formation of digestive tract ulcer;

8. Adding caffeine when you are nervous helps to improve your alertness, sensitivity, memory and concentration. But if you drink more coffee than you are used to, you will have the same dose of stimulants, which will cause nervousness. For people who are prone to anxiety disorders, caffeine can cause symptoms such as sweaty palms, palpitations and tinnitus to worsen;

9. Intensifying hypertension Caffeine is often combined with other simple painkillers because of its analgesic effect. However, if you take it in large quantities for a long time, if you already have hypertension, using a large amount of caffeine will only make your situation worse. Because caffeine alone can raise blood pressure, and if it is combined with emotional tension, it will have a dangerous multiplication effect. Therefore, people at risk of hypertension should especially avoid drinking caffeinated drinks when working pressure is high. Some people who have the habit of drinking coffee all the year round think that they are immune to the effect of caffeine, but this is not the case. A study shows that after drinking a cup of coffee, blood pressure can rise for up to hours.