Is it true that the more you eat these foods, the darker your skin will be?

Author: Xue Qingxin, one of the first nutrition instructors of the National Health Commission, and a registered nutritionist in China

Reviewer: Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center

gossip

Most people want to have fair skin, after all, "a white complexion hides three flaws". There are endless whitening tips circulating on the Internet. In order to make themselves whiter, many people have put a lot of thought into it. As long as they hear that a certain food can whiten their skin, they must buy it and show it off.

Are there really foods that can whiten your skin? I also heard that some foods can make you darker the more you eat them, so people don’t dare to eat them. Is this true?

In this article, we will reveal the truth about "whitening or tanning" foods, and finally tell you what foods will actually make your skin "change color".

analyze

Are the legendary whitening foods useful?

There are many foods that can whiten your skin, such as milk, tomatoes, lemonade, pomegranates, blueberries, etc. In fact, eating them has little effect on whitening your skin.

· Milk : The milky white appearance of milk gives people the impression that it is very "whitening", but this idea of ​​"like cures like" is unscientific. The main components of milk are water, protein, fat, calcium, etc., which have no special effect on whitening. Even if you wash your face with milk or take a milk bath every day, it will not whiten your skin.

Tomatoes, lemonade, pomegranates, and blueberries : Rumor has it that the reason why eating them can whiten your skin is the same, that is, they are all rich in vitamin C.

Tyrosinase is very critical in the production of melanin. Vitamin C can theoretically inhibit the activity of tyrosinase and the formation of melanin, which has the so-called whitening effect.

However, theory is theory, and the actual effect that vitamin C in food can play is minimal. It may have some effect when used externally, but it does not mean that eating foods rich in vitamin C can also whiten your skin.

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Besides, the vitamin C content of tomatoes, lemonade, pomegranates and blueberries is not high. The vitamin C content of tomatoes and pomegranates is only 14mg/100g and 8mg/100g respectively, and the vitamin C content of blueberries is generally 10~34mg/100g. They are not as high as the vitamin C content of fruits we usually eat, such as strawberries, grapefruits, and kiwis. As for lemonade, although it tastes sour, its vitamin C content is very low, probably less than 10mg/100g.

In fact, skin color is closely related to genetic and environmental factors, and it cannot be changed by eating certain foods. It is really unreliable to expect to whiten your skin by eating certain foods.

“Foods that make you black when eaten”, is it true that we shouldn’t eat them?

1. Photosensitive foods

Some people who are too obsessed with skin whitening will not only eat more so-called "whitening foods", but will also deliberately avoid foods such as celery, coriander, fennel, amaranth, etc. that are said to "darken the skin".

This is because, according to rumors, these plants contain furanocoumarins, which are photosensitive foods. Eating them and then exposing yourself to the sun will darken your skin.

Furocoumarins are considered to be common compounds that cause phytophotodermatitis. They are a class of natural plant ingredients with phototoxicity, mainly found in plants of the Rutaceae family (such as citrus fruits) and the Apiaceae family (such as parsnips, parsley, celery, and carrots). Fresh parsley, grapefruit juice, grapefruit, lime juice, lime, and lemon juice contain high concentrations of furanocoumarins. When people ingest or come into contact with the skin of plants containing furanocoumarins, the furanocoumarins can be absorbed and enter the blood and skin.

When the skin is exposed to furanocoumarin compounds and irradiated by long-wave ultraviolet rays (UVA), the photosensitive substances will damage the cell membrane and cell DNA, leading to cell death and epidermal damage, and producing a non-immune mediated inflammatory response. The main manifestations are erythema, blisters, epidermal necrosis, and post-inflammatory pigmentation, which means that in theory, the skin will become darker.

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However, if we eat a normal amount, we don't need to worry about causing our skin to darken. Someone has conducted a study on this and recruited 4 volunteers for an experiment.

The volunteers ate 300 grams of celery root in a short period of time and were exposed to UVA for 10 minutes 2 hours after eating. No skin reaction was observed.

Combined with subsequent experiments, it is estimated that healthy people need to eat about 2 kilograms of celery root in a short period of time to produce phototoxic effects. According to our normal eating habits, eating celery root and other traditional vegetables will not cause phototoxic damage, so there is no need to worry about this.

In addition, compared to eating foods containing furanocoumarins, skin contact with such foods and then direct exposure to the sun may cause it to darken, or even develop erythema, blisters or bullae.

2. Soy sauce

In addition to these photosensitive foods, soy sauce has also been passed by many beauty-conscious friends in their diet, the reason being: soy sauce is dark in color, so eating it will also cause the skin to darken. This statement is not reliable!

These black ingredients in soy sauce will not cause the skin to darken, because they will be broken down after entering the digestive tract and will not be deposited on the surface of the skin to affect the skin color. What's more, we don't usually drink soy sauce, we just add a little to cook for seasoning, so there is no need to worry.

In fact, you don’t have to worry about what you eat will make your skin darker. If you want to prevent your skin from getting darker, the most important thing is to do a good job of sun protection.

These are the foods that will really make you “change color”!

Although the food we eat cannot "whiten" or "darken" our skin, some foods can make our skin turn yellow or orange-red. These are foods containing carotenoids.

Foods such as carrots, tangerines, papayas, mangoes, pumpkins, and chicory are rich in beta-carotene, which can be converted into vitamin A in the body and is beneficial to the health of our eyes and skin.

However, if you eat too much beta-carotene in a short period of time, excessive carotene will enter the body. The body cannot metabolize it for a while, and it will be deposited in the skin, turning the skin yellow and causing "hypercarotenemia."

Image source: Xiaohongshu

Tomato sauce, tomato juice, guava, watermelon, grapefruit, etc. are rich in lycopene, which is also a kind of carotenoid and has strong antioxidant capacity. However, if you consume a lot of foods rich in lycopene for a long time, it may lead to lycopeneemia, which is manifested as orange skin, turning yellow or orange.

Although eating too much of these two types of food can cause skin discoloration, this is only temporary and does not harm your health. As long as you stop consuming foods rich in carotene and lycopene for about a week, your skin will slowly return to its original color. Drinking more water can also speed up metabolism.

in conclusion

You can't make your skin whiter by eating and drinking, and you don't have to worry about what you eat causing your skin to darken. But don't eat too much of food rich in carotenoids at one time, such as tangerines, otherwise it will really make your skin turn yellow.

If you want to prevent your skin from getting darker, the most important thing is to do a good job of sun protection.

References:

[1] Xu Tianhua, Li Yuanhong, Zhu Xia, Jiang Lili, Gao Xinghua, Chen Hongduo. Clinical study on the whitening and wrinkle-removing efficacy and safety of L-ascorbic acid[J]. Chinese Journal of Aesthetic Medicine, 2009, 18(12): 1799-1801.

[2] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 1[M]. Peking University Medical Press, 2018

[3] Yuan Zhenhua. Risk assessment of human ingestion of phototoxic furanocoumarins[J]. Foreign Medicine (Hygiene), 1992, (05): 306-307.

[4] Liu Xin. Retrospective analysis of literature cases of phytophotodermatitis (with 10 case data) [D]. Lanzhou University, 2020. DOI: 10.27204/d.cnki.glzhu.2020.003522

[5] Jiang Mengru, Liu Changshu, Wang Sai. Research progress on sensory properties of soy sauce and its improvement technology[J]. Food and Fermentation Industries, 2019, 45(9): 295-300

Planning｜He Tong

Editor-in-charge｜Liu Yantong (internship)

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