Will your skin really become darker if you eat too much soy sauce?

Hello, this is Science Popularization China. What are we going to talk about today? Let's talk about soy sauce. You must be familiar with soy sauce. It is one of the seven necessities of life: firewood, rice, oil, salt, soy sauce, vinegar and tea. Soy sauce is so important to us, but there are rumors that "eating soy sauce will make your skin darker." Or "when you have a wound, eating soy sauce will leave a scar." Is this true?

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To understand this question, we need to first talk about why people become darker. There is a type of cell in our skin called "melanocytes", which can synthesize melanin and then secrete it into the skin. The depth of our skin color is determined by the melanin content in the skin. If the content is high, it will be darker, and if the content is low, the skin will naturally be whiter.

At this point you may have a question: Soy sauce looks black, and I heard that it contains a kind of "melanin". If you eat too much, will it increase the secretion of melanin?

This is completely unnecessary. The names sound similar, but they are actually completely unrelated. Melanin in the skin is a biological pigment derived from amino acids. Its synthesis is affected by genetic information, ultraviolet rays, age, changes in hormone levels, and inflammation.

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The melanin in soy sauce is a natural pigment that is broken down after entering the digestive tract and has no chance to reach the surface of the skin to affect the skin color. This is just like when we eat green leafy vegetables, our skin will not turn green.

By the same token, whether or not a scar is left after an injury has nothing to do with soy sauce.

Okay, that’s all we have to say about soy sauce today. See you next time.

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Review | Feng Jun, Deputy Chief Physician, Dermatology Department, General Hospital of Datong Coal Mine Group Co., Ltd.