Caffeine is the main exciting substance in coffee. In addition, it also contains fat and minerals such as magnesium, potassium and copper, as well as vitamin B, aromatics and toxins. That is to say, coffee has no nutritional value, but it has many advantages and disadvantages on the body due to the effect of caffeine.

1. The beneficial effects of drinking coffee on health:

For the nervous system: Caffeine can excite the brain, eliminate the feeling of laziness, make people feel relaxed and happy, and make people concentrate, think quickly and recall memories. Studies have proved that caffeine can speed up people's calculation and computer-playing, and make car drivers agile. But there is no scientific evidence to prove that caffeine has an effect on improving the quality of work.

Cardiovascular: Drinking coffee can make the heart beat faster, raise blood pressure, promote blood circulation and enhance myocardial contraction.

For urinary system: Caffeine can dilate renal blood vessels, increase the blood flow of glomerulus, thus increasing the water permeability and detoxification function of kidney. It can be said that coffee has diuretic effect.

For respiratory system: Caffeine can relax the smooth muscle around trachea, thus dilating trachea and increasing respiratory capacity. But caffeine can't be used as a medicine to treat asthma in clinic.

2. The influence of drinking coffee on physical disadvantages:

Drinking a lot of coffee affects appetite, which may cause vomiting and spasm, gastritis and thick tongue coating, which will make the body feel tired and weak.

Drinking a lot of coffee increases urine output, harms the bladder and may cause urinary tract infection.

Too much caffeine in the body has a negative effect on the nervous system, which can make people insomnia, trembling hands and slurred speech.

The latest research shows that when breastfeeding women drink coffee, caffeine will enter the child's body with the milk, making the child fidgety and unable to sleep.

Coffee is a risk factor for those with heart disease and high blood pressure. Studies in the United States show that drinking coffee can aggravate heart disease and high blood pressure. Caffeine intake must be controlled within 200 mg per day, that is, no more than 3 cups of coffee per day. Never give coffee to children. I advise you not to let teenagers under 15 drink coffee. Try not to drink or drink less coffee after 40. The latest animal experiments show that caffeine may be a carcinogenic factor. Breast-feeding women should not drink coffee.