http://www.ncbi.nlm.nih.gov/pubmed/9759559

Tannins and human health: a review.

Chung KT1, Wong TY, Wei CI, Huang YW, Lin Y.

Author information

Abstract

Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that are present in many plant foods. They have been reported to be responsible for decreases in feed intake, growth rate, feed efficiency, net metabolizable energy, and protein digestibility in experimental animals. Therefore, foods rich in tannins are considered to be of low nutritional value. However, recent findings indicate that the major effect of tannins was not due to their inhibition on food consumption or digestion but rather the decreased efficiency in converting the absorbed nutrients to new body substances. Incidences of certain cancers, such as esophageal cancer, have been reported to be related to consumption of tannins-rich foods such as betel nuts and herbal teas, suggesting that tannins might be carcinogenic. However, other reports indicated that the carcinogenic activity of tannins might be related to components associated with tannins rather than tannins themselves. Interestingly, many reports indicated negative association between tea consumption and incidences of cancers. 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. We have also found that tannic acid and propyl gallate, but not gallic acid, were inhibitory to foodborne bacteria, aquatic bacteria, and off-flavor-producing microorganisms. Their antimicrobial properties seemed to be associated with the hydrolysis of ester linkage between gallic acid and polyols hydrolyzed after ripening of many edible fruits. Tannins in these fruits thus serve as a natural defense mechanism against microbial infections. The antimicrobial property of tannic acid can also be used in food processing to increase the shelf-life of certain foods, such as catfish fillets. 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. The dosage and kind of tannins are critical to these effects. The aim of this review is to summarize and analyze the vast and sometimes conflicting literature on tannins and to provide as accurately as possible the needed information for assessment of the overall effects of tannins on human health.

PMID:

9759559

[PubMed - indexed for MEDLINE]

Are the tannins in my tea bad for me? - The Austin Chronicle

www.austinchronicle.com/columns/2004.../208400/

The Austin Chronicle

Apr 30, 2004 - A. Tannins are found not only in tea, where they are indispensable to the ... They also seem to lower blood pressure, reduce the risk of cancer, ...

Health benefits of plant tannins - Medi BizTV

www.medibiztv.com/articles/health-benefits-of-plant-tannins

Tannins are a broad class of compounds that is present in tea, red wine, ... to protect and fight against various ailments like, protect heart diseases, cancer, etc.

Tannic Acid Preferentially Targets Estrogen Receptor-Positive

www.hindawi.com/journals/ijbc/2013/369609/

by BW Booth - ‎2013 - ‎Cited by 5 - ‎Related articles

Sep 27, 2013 - Abstract. Research efforts investigating the potential of natural compounds in the fight against cancer are growing. Tannic acid (TA) belongs to ...

Health Benefits of Tea | Organic Facts

https://www.organicfacts.net/health-benefits/.../health-benefits-of-tea.htm...

The health benefits of tea include relief from cancer, early aging, gum disorders, ... The alkaloids, like tannin and caffeine, which are present in tea, also help in ...

Tannic Acid Is an Inhibitor of CXCL12 (SDF-1α)/CXCR4 with ...

clincancerres.aacrjournals.org/content/.../3115.f...

Clinical Cancer Research

by X Chen - ‎2003 - ‎Cited by 60 - ‎Related articles

In addition to its chemopreventive effects, tannic acid also directly suppresses cancercell growth. In vitro, tannic acid inhibited the proliferation of various cancer ...

TANNIC ACID: Uses, Side Effects, Interactions and ...

www.webmd.com/.../ingredientmono-217-tannic%20acid.aspx?...

WebMD

Tannic acid is also taken by mouth and applied directly for bleeding, chronic diarrhea, dysentery, bloody urine, painful joints, persistent coughs, and cancer.

[PPT]TANNINS AND HUMAN HEALTH: Nutraceuticals effect of ...

www.pitt.edu/~super7/31011-32001/31131.ppt

University of Pittsburgh

TANNINS AND HUMAN HEALTH: Nutraceuticals effect of Tannin and its ... (+)Catechin prevents cancer (liver, lung, breast and colon cancer) in at least one of ...

Cancer 'Cure' - Tannic acid compositions for treating cancer (US ...

www.abovetopsecret.com/forum/thread369578/pg1

Jul 7, 2008 - 16 posts - ‎9 authors

In sum, the invention provides a pharmaceutical composition including tannic acid andtannin complexes, and a method of treating cancer with ...

Tannins, xenobiotic metabolism and cancer ... - Springer

link.springer.com/.../10.1007%2FBF03...

Springer Science+Business Media

by C Nepka - ‎1999 - ‎Cited by 56 - ‎Related articles

It has been shown that various tannins exert broad cancer chemoprotective activity in a number of animal models. This review summarizes the recent literature ...