Main components and functions of coffee;

Caffeine: It has a particularly strong bitter taste and stimulates the central nervous system, heart and respiratory system. Moderate caffeine can also reduce muscle fatigue and promote the secretion of digestive juice. Because it can promote renal function, it has diuretic effect and helps the body discharge excess sodium ions. But too much intake can lead to caffeine poisoning.

Tannic acid: Tannic acid after boiling will be decomposed into wood vinegar, so the taste of coffee cooked for too long will become worse.

Fat: The most important ones are acidic fat and volatile fat.

Acidic fat: that is, fat contains acid, and its strength will vary with the type of coffee.

Volatile fat: it is the main source of coffee aroma and a substance that emits about 40 kinds of aroma.

Drinking coffee in moderation may have protective effects on the brain and heart. In fact, coffee is one of the risk factors of metabolic syndrome. If metabolic syndrome is not well controlled, patients are prone to cardiovascular diseases. The so-called metabolic syndrome refers to a group of characteristics related to metabolic symptoms in the same person, including waist obesity, hypertension, hyperlipidemia and so on.

Side effects of caffeine:

1, aggravating hypertension.

Caffeine is often combined with other simple painkillers because of its analgesic effect. However, if you take a lot of caffeine for a long time, if you already have high blood pressure, using a lot of caffeine will only make your situation worse. Because caffeine alone can raise blood pressure, if combined with emotional tension, it will have a dangerous multiplier effect. Therefore, people at risk of hypertension should especially avoid drinking caffeinated drinks when working pressure is high. Some people who have been drinking coffee for many years think that they are immune to caffeine, but this is not the case. A study shows that after drinking a cup of coffee, the blood pressure can rise for as long as 12 hours.

2. Induced osteoporosis

Caffeine itself has a very good diuretic effect. If you drink a lot of coffee for a long time, it will easily lead to bone loss, which will adversely affect the preservation of bone mass and may increase the threat of osteoporosis in women. However, the premise is that people who don't get enough calcium in food on weekdays, or people who don't exercise regularly, plus postmenopausal women, lose calcium due to insufficient estrogen. These conditions, combined with a large amount of caffeine, may pose a threat to bones.

3. When you are nervous, you add chaos.

Caffeine helps to improve alertness, sensitivity, memory and attention. However, if you drink more coffee than you are used to, you will have the same dose of stimulants, which will cause tension. For people with anxiety tendency, caffeine can aggravate the symptoms of sweating, palpitation and tinnitus.