Green tongue, orange skin, black poop...maybe they're all caused by what you eat!

"Doctor! The child is urinating blood! Is there something wrong with his kidneys?"

"Doctor! My stool today looks black. I checked online and it said that this is black stool and it may be caused by intestinal bleeding!"

"Doctor! My skin has become very yellow recently. Is it because my liver function is not good? I want to check it out!"

This is a sound often heard in the clinic.

As science becomes more popular, people's knowledge of medicine increases day by day, and the embarrassing situation of seeing danger everywhere comes along. Some people directly associate red urine with hematuria, some people regard dark stool as bloody stool, and some people equate yellow skin with jaundice.

When I went to the hospital to see a doctor, I realized that I was just scaring myself. The truth is that "misfortune comes from the mouth". So today we will talk about the colorful changes in body organs caused by "eating".

Image source: Internet

1. Skin discoloration

Which foods can cause yellowing of the skin if consumed in excess?

The first thing that comes to mind is carrots and oranges. Yes, because these foods have a high carotene content, consuming a large amount of them will increase the concentration of beta-carotene in the body. Some beta-carotene is converted into vitamin A, also known as retinol, which is essential for human vision, skin, and immune health; while the excess amount will be deposited in the skin, making the skin appear yellow or orange.

Image source: Pixabay

Why does beta-carotene appear yellow, rather than black, purple or pink? This is because the molecular structure of carotene determines the way it absorbs and reflects light, which makes it absorb shorter wavelength blue light and reflect or transmit longer wavelength yellow light, thus showing a yellow appearance.

Of course, this accumulation of carotene is mostly harmless to the body, and as you reduce the intake of such foods, your body color will gradually return to normal.

Speaking of yellowing, some beauty lovers asked, what foods can make the skin darker?

Here we have to first bring up our old friend who makes your skin darker: sunlight. The ultraviolet rays in sunlight damage skin cell tissues and accelerate the production of melanin, thus darkening the skin. And there is a category of food, which we call photosensitive food. They are more photosensitized than other foods, that is, their ingredients or compounds may interact with sunlight or ultraviolet rays, reduce the skin's ability to resist the sun, and make the skin darken faster. This type of food includes lettuce, celery, mustard greens, leeks, rapeseed, spinach, figs, oranges, lemons, carrots, snails, etc. Under the attack of ultraviolet rays, the skin has nowhere to hide, and it is not only more likely to get tanned, but also more likely to get sunburned.

2. Tongue discoloration

Speaking of color change, ice cream lovers in front of the screen must be familiar with the "Green Tongue" ice cream. In addition to its elastic texture, the green tongue it gives to everyone who loves it is also the reason why people can't put it down.

Image source: Internet

The main reason why these foods cause changes in the color of the tongue and lips is artificial pigments, including edible blue (a common name in snack ingredient lists is "bright blue"), edible red 40 (often labeled "tempting red"), etc. These pigments can act on the cells and tissues on the surface of the tongue, and make the tongue further present different colors through physical adsorption, chemical reactions, etc.

In addition to artificial colors, the foods we eat from nature also contain pigments. For example, fruits such as blackberries, blueberries, and raspberries contain a lot of anthocyanins, which may cause the tongue to appear dark purple after consumption. For example, fruits and vegetables such as oranges and carrots contain a lot of carotenoids, which may cause the tongue to appear yellow after consumption.

3. Discoloration of urine and stool

Because of the presence of bile in our body, food will undergo a series of reactions with it, causing normal human stool to appear brown or dark brown.
However, the color of stool may also change depending on the food you eat. If you ate a lot of red foods such as red pitaya and strawberries the day before, your stool may appear red or orange-red. This is mainly because the red part of the red pitaya is composed of anthocyanins and other natural pigments. Anthocyanins are a type of water-soluble plant pigment that are mostly red and purple in color. When it passes through the digestive tract, part of it may be absorbed, while the other part is excreted with the intestines, making the stool appear red.

Image source: Pixabay

If you have eaten a lot of chicken blood, duck blood or oral iron supplements the day before, your stool may appear black. The main reason is that chicken blood, duck blood and other animal blood contain hemoglobin, which contains iron. After being metabolized by the gastrointestinal tract, these iron elements may form black iron salt substances, which will make the stool appear black when excreted with the stool.

If you eat foods such as Oreo cookies, the cocoa ingredients and some inabsorbable artificial pigments may also cause black stools. The cocoa ingredients that cause the stool to turn black are closely related to our old friend, anthocyanins. Anthocyanins may form red or black compounds under the action of gastric acid, affecting the color of stools.

In addition to feces, urine is also not immune to this. The factors mentioned above, such as fruits and foods containing food additives, can affect the color of urine. For example, red foods such as pitaya, beets, and red amaranth (Chinese vegetables) will cause red urine after consuming a large amount. This is mainly because these fruits and vegetables are rich in water-soluble plant pigments - betalains, which are red to purple. After entering the human body, it is not easily digested and absorbed, and instead is discharged through the urinary tract, dyeing the urine red.

4. Other color changes

Of course, in addition to these foods, medication intake and illness may cause changes in the color of the skin, stool and urine.

For example, kidney tumors and stones can cause urinary tract damage and bleeding, which can cause hematuria. During anti-tuberculosis treatment, oral ethambutol may cause urine to appear orange or red.

Image source: taken by myself

Gastrointestinal bleeding caused by diseases such as gastric and duodenal ulcers, gastric cancer, intestinal polyps, and digestive tract diverticula can cause black or red stools. Long-term use of nonsteroidal anti-inflammatory drugs (such as acetaminophen, ibuprofen, and aspirin) may damage the gastric mucosa, leading to ulcers and bleeding, and ultimately causing black stools.

Anemia can cause the skin to appear pale. Diseases such as hepatitis, cirrhosis, and bile duct obstruction can cause bilirubin to accumulate in the body, causing the skin to appear yellow. Of course, there are also some autoimmune diseases such as systemic lupus erythematosus, which can cause the skin to turn red.

It can be seen that although food is one of the common causes of body color changes, this change may also be a sign of certain diseases or drug use. The mechanism by which they cause changes in the color of the skin, sclera, and urine and feces is relatively complex. There are colors of the components after drug metabolism, and there are also colors after reactions with urine and feces. In any case, we need to seek medical attention in time to avoid delaying treatment.

There is no such thing as a free meal in life. It may turn into a drop of red, a ball of black, or a touch of yellow... no matter how big or small, every bite counts!

Source: Chongqing Science and Technology Museum

Author: Wei Yi, one of the top ten science popularization ambassadors in the country.

Statement: Except for original content and special notes, some pictures are from the Internet. They are not for commercial purposes and are only used as popular science materials. The copyright belongs to the original authors. If there is any infringement, please contact us to delete them.