Blood vessels dilate after drinking

There are a large number of capillaries distributed under the human skin. These capillaries are generally invisible to the human body. Only after being stimulated in some way will the capillaries dilate and obvious symptoms appear. The reason why your face turns red after drinking alcohol is that the special ingredients in the alcohol stimulate the capillaries, causing capillary dilation. Today I will explain to readers the relevant principles of capillary dilation after drinking.

Blushing after drinking, also known as "alcohol flush reaction", is the blushing phenomenon that occurs after drinking. Generally speaking, it is related to acetaldehyde dehydrogenase in the body.

After alcohol enters the human body, it will undergo a series of metabolic reactions: "ethanol - acetaldehyde - acetic acid - carbon dioxide, water, and fat." In the first two conversion processes, alcohol dehydrogenase and acetaldehyde dehydrogenase are required respectively. These two enzymes are responsible for oxidizing ethanol into acetaldehyde and oxidizing acetaldehyde into acetic acid, respectively, to facilitate the metabolism of alcohol. If these two enzymes are not secreted enough in the body, the face will turn red when drinking.

Redness in the face is caused by the dilation of capillaries in the face. The blood vessels in the human body are controlled by two nerves, one is the sympathetic nerve that can promote vasodilation, and the other is the parasympathetic nerve that can inhibit vasodilation. Normally, these two nerves coordinate with each other to control the contraction and expansion of blood vessels, but when the acetaldehyde content in the body rises, it will excite the sympathetic nerves and inhibit the parasympathetic nerves. If the skin on your face is thin, you will look red after drinking.

Some people's faces turn red after drinking, while others do not. This is because not everyone has acetaldehyde dehydrogenase in their bodies. People who blush immediately after drinking have highly efficient alcohol dehydrogenase in their bodies, but lack acetaldehyde dehydrogenase, which causes ethanol to stimulate the sympathetic nerves after being converted into acetaldehyde. The lack of acetaldehyde dehydrogenase will cause acetaldehyde to remain in the body for too long, because at this time the decomposition of acetaldehyde needs to be slowly converted into acetic acid through the action of the liver P450 enzyme system and then enter the TCA cycle.

Therefore, blushing after drinking does not represent how much a person can drink. It is just because the lack of acetaldehyde dehydrogenase in the body causes the blood vessels in the face to dilate.