One cup of freshly brewed coffee a day is effective in protecting the liver, canned coffee and instant coffee are ineffective.

Japanese researchers have found that drinking a cup of freshly brewed coffee a day can improve liver function in patients with chronic hepatitis C, and that the more they drink, the more effective it is to protect the liver. But it should be noted that canned coffee drinks, instant coffee and decaffeinated coffee have no hepatoprotective effect.

Researchers at the affiliated Hospital of Osaka City University in Japan have found that drinking more than one cup of freshly brewed coffee a day can improve liver function in patients with chronic hepatitis C. the study was published in the December 11, 2013 issue of the American academic journal PLoS one.

The affiliated Hospital of Osaka City University investigated the relationship between the number of ALT enzymes (the number of ALT enzymes increases with the injury of hepatocytes, which is usually used as an indicator of liver function) and the frequency of coffee drinking in 376 patients with chronic hepatitis C at the age of 20 to 80 years. The results showed that most of the patients who drank more than one cup of freshly brewed coffee a day for a year maintained their ALT enzyme levels in the normal range compared with those who did not drink. And the more coffee you drink, the more effective it is to protect the liver. The researchers also found that drinking canned coffee drinks, instant coffee and decaffeinated coffee had no corresponding hepatoprotective effect.

Extended reading: what are the ingredients in roasted coffee beans, and what are their effects on the human body?

Caffeine: caffeine is the most eye-catching of all the ingredients in coffee. It belongs to a kind of phytoxanthine (animal muscle component). It has the same properties as theophylline contained in cocoa, green tea contains the same theophylline, and the percentage of reduction after baking is very small. Caffeine has a very extensive effect. It will affect various parts of the human brain, heart, blood vessels, gastrointestinal tract, muscles and kidneys. The right amount of caffeine will stimulate the cerebral cortex, promote sensory judgment, memory and emotional activity, and make the myocardial machinery more active. Vasodilation enhances blood circulation and improves metabolic function. Caffeine can also reduce muscle fatigue and promote digestive juice secretion. In addition to this, because it also promotes the kidney function to help the body expel excess sodium ions (chemicals that hinder the metabolism of water molecules), caffeine will not accumulate in the body like other narcotic and excitant substances (narcotic drugs, paint solvents, stimulants, etc.) and will be excreted in about two hours. The biggest bitterness of ─ in coffee flavor is caused by caffeine.

Tannic acid: after extraction, tannin will turn into a yellowish powder, which can easily blend into water. After boiling, it will decompose and produce pyrosylic acid, which will make the coffee taste worse. If the coffee is soaked and left for several hours, the color of the coffee will become stronger than when it was just soaked. And it is also less tasty, so there is the saying that "it is best to drink it as soon as possible."

Fat: the fat contained in coffee plays a very important role in flavor. It is found that there are many kinds of fat in coffee, the most important of which are acidic fat and volatile fat. Acidic fat means that there is acid in fat, and its strength varies with different types of coffee, and volatile fat is the main source of coffee aroma. Once the fat contained in roasted coffee beans comes into contact with the air, chemical changes may occur and the taste and flavor will become worse.