Tannins (tannic acid) are polyphenols that are present in many plant foods. Tea polyphenols and many tannin components were suggested to be anticarcinogenic. The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins...

See:

Article Tannins and Human Health: A Review

Article Assessment of Anti-nutritive Activity of Tannins in Tea By-p...

Article Tannin - classification, analysis and applications

Tannins (tannic acid) are polyphenols that are present in many plant foods. Tea polyphenols and many tannin components were suggested to be anticarcinogenic. The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins...

See:

Article Tannins and Human Health: A Review

Article Assessment of Anti-nutritive Activity of Tannins in Tea By-p...

Article Tannin - classification, analysis and applications

Tannin, which is found in tea, prevents the absorption of iron in food, but its effect ... on the absorption of iron from animal sources (meat, chicken and fish) is heme iron

Tannin: It is a multi-alcoholic alcohol that is a powerful drug and is found in black tea

And coffee, which works on iron deficiency in the human body, so it is advised not to drink any

Immediately after eating, the body can absorb iron and make use of it.

Green tea and white tea contain little tannin.

Thank you "very much" Nihada Ahmetovic and Zainab A Makawi for your contribution and your interaction with appreciation

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Tannin is the color and taste of tea, but it is associated with iron and reduces its absorption so prefer lemon juice with tea to benefit from iron.

I'm following answers

Very interesting discussion

Interesting question dear Dr. Fatima Faiq . Tannins are found in different plants such as strawberries, herbs,spices, legumes, nuts, etc. Tannisns do have diverse uses and are commonly consumed. As an instance in beers, gums, etc. They are also used as an oleo-chemical in industries such as leather, metal industries (anti corrosive), etc.

Tannin ( tanic acid) is consider as a polyphenols found in many plant in pomegranate it used for treat diarrhea for secretory diarrhea.

Tannin is a polycyclic alcohol that is a potent drug that either binds or reduces proteins in many other organic compounds, including amino acids and alkaloids. The astringent effect of tannins or tannins is due to the feeling of dryness in the mouth after consumption of red immature fruit. Similarly, the destruction or modification of time-tannins plays an important role in fruit maturity and wine age determination. They are usually divided into water soluble tannins, tannins and intensive tannins. Tannin is found in coffee, wine and fruit juices such as pomegranate.

A. Tannins are found not only in tea, where they are indispensable to the production of tea's flavor and color, but they are found in many foods, such as cheeses and nuts, and in drinks such as wine. A plant contains tannin as a defense, to prevent it from being eaten. The bitter taste, as well as interference with starch digestion, tends to make the plant unpalatable to many animals, though tannins are not concentrated enough in tea to interfere with digestion if they are used in moderation. For some of us, the bitter taste of tannin is pleasurable. However, as always, people react differently to various food components, and for some, tannins cause headaches.

Tannins are found in many plant species including tea. They impart a slight bitter taste

Great discussion and answers, thank you "very much" to everyone who sincerely contributed to answering the question with appreciation to all

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Tannins are water soluble phenolic compounds that tend to accumulate in roots and bark of plants and fruits, as well as in their leaves, although in smaller proportion. They are considered antinutritive substances because, in high concentrations, they can limit the absorption of some nutrients such as iron. However, tannins also have astringent and anti-inflammatory properties. Added to the above, they are attributed an antioxidant action since they are capable of trapping free radicals.

Tannins are a heterogeneous group of complex compounds of widespread occurrence in plants. They are organic compounds, chiefly glucosidal in nature, which have an acid reaction and are very astringent. Tannins vary greatly in amount from one species to another.

Tannins are potential antioxidants. They have been considered to be cardio- protective, anti-inflammatory, anti-carcinogenic and anti-mutagenic.Tannins are used in dyeing, photography, refining beer and wines as well as an astringent in medicines. Please take a look at these useful RG links.

Article Tannins are Astringent

Article Tannin: An Antinutrient with Positive Effect to Manage Diabetes

Article Tannins from Foods to Combat Diseases

Article Antihypertensive effects of tannins isolated from traditiona...

Article Antioxidant Phytochemicals for the Prevention and Treatment ...

Tannins are a part of phytochemicals useful for diverse activities in the plant. They are not found in man but could be used by man. To cause harm tannin has to build up to intolerable concentrations

I never know about it before ... thanks

Tannin is responsible for the astringency, colour, and some of the flavour in tea.

https://www.webmd.com/vitamins/ai/ingredientmono-217/tannic-acid

Interesting question

Tannins are natural organic materials that are usually the by-products of the natural break down of decaying vegetation and sometimes the product of “natures” fermentation process as opposed to the tannins found in wines. They are created as water passes through peaty soil and decaying vegetation. This causes the water to have a faint yellow to tea-like color, and can cause yellow staining on fabrics, fixtures, china and laundry. Tannin may give an unpleasant aftertaste to water. It may also cause water to have a musty or earthy odor. Tannins are sometimes referred to as fulvic or humic acids and are more common in surface water supplies, lake or river sources and shallow wells than in deep wells. Water in marshy, low-lying, or coastal areas is also more susceptible to tannins.

https://en.wikipedia.org/wiki/Tannin

Tannins are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term tannin refers to the use of oak and other bark in tanning animal hides into leather.

https://en.wikipedia.org/wiki/Tannin

In greater amounts, tannic acid can cause side effects such as stomach irritation, nausea, vomiting, and liver damage and regular consumption of herbs with high tannin concentrations seems to be associated with an increased chance of developing nose or throat cancer.

Thank you "very much" Dear researchers and fellow academics for your effective contribution this kindness of you, with appreciation to all

Tannin is the cause of color and taste of tea but it is associated with iron and reduces its absorption.

Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.

The tannin compounds are widely distributed in many species of plants, where they play a role in protection from predation, and perhaps also as pesticides, and might help in regulating plant growth.[1] The astringency from the tannins is what causes the dry and puckery feeling in the mouth following the consumption of unripened fruit, or tea.[2] Likewise, the destruction or modification of tannins with time plays an important role when determining harvesting times.

Tannins are touted as excellent antioxidants, promoted by the tea industry as well as wine and cheese makers. Catechin, one of several thousand proanthocyanidins or polyphenols, is a type of tannin peculiar to tea. Several of these proanthocyanidins are found to lower total cholesterol and improve the ratio of "good," or HDL, cholesterol to "bad," or LDL, cholesterol. They also seem to lower blood pressure, reduce the risk of cancer, stimulate the immune system, and have anti-bacterial properties.

High-tannin tea has also been shown to reduce the need for blood removal from people with iron overload, or hemochromatosis. Hemochromatosis arises from a genetic defect that allows uncontrolled absorption of iron. Iron overload, affecting one person in 200, is a major factor in congestive heart failure, a rapidly growing burden on the health care system. In one study, drinking tea with meals and without lemon or milk was shown to be effective in preventing iron absorption. In animal studies, liver iron stores increased significantly on an iron-enriched diet but not when the animals consumed the same diet supplemented with tea.

Tannins are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds.

Tannin is a naturally occurring polyphenol found in plants, seeds, bark, wood, leaves, and fruit skins.

As a characteristic, tannin adds both bitterness and astringency in an unriped fruit. Several studies have highlighted that tannins act as antioxidants amd enduringly present in chocolate, nuts, apple juice, tea, pomegranate, grape juice.

Tea polyphenols and many tannin components were suggested to be anticarcinogenic. Many tannin molecules have also been shown to reduce the mutagenic activity of a number of mutagens. Many carcinogens and/or mutagens produce oxygen-free radicals for interaction with cellular macromolecules. The anticarcinogenic and antimutagenic potentials of tannins may be related to their antioxidative property, which is important in protecting cellular oxidative damage, including lipid peroxidation. The generation of superoxide radicals was reported to be inhibited by tannins and related compounds. The antimicrobial activities of tannins are well documented. The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins. Tannins have also been reported to exert other physiological effects, such as to accelerate blood clotting, reduce blood pressure, decrease the serum lipid level, produce liver necrosis, and modulate immunoresponses.

References

Tannins and human health: a review., Crit Rev Food Sci Nutr. 1998 Aug;38(6):421-64.

I have gone through your answers and would like to get a direct one pertaining to sorghum. I know we have tannin from sorghum. We consume sorghum... could it be that we are consuming harmful products?

Nice discussion!

I would like to add that tanins are also considered as anti-nutrients or antinutritional factors due to the fact that they interefere negatively with absorption of other nutrients like iron and proteins (amino acids) as mentionned by other scientists here. There it is advisable for consumers to be mindful of tanin concentration in food before consumption. We also know that processing methods like fermentation can reduce it concentration.

Thanks for response

Tannin: It is a multi-alcoholic alcohol that is a powerful drug and is found in black tea

And coffee, which works on iron deficiency in the human body, so it is advised not to drink any

Of them immediately after eating so that the body can absorb iron and benefit from it.

Green tea and white tea contain little tannin.

Interesting question