Tannin Vs. Iron
It is proved that Iron deficiency remains a global health concern, as nearly 1 billion people suffer from iron-deficiency anemia (IDA). Sufficient iron stores are required for normal growth and development, and IDA has been associated with loss of productivity; reduced intellectual functioning, increased prematurity, and perinatal, childhood, and maternal mortality.
The absorption, incorporation, and use of iron in the body is a firmly regulated process in which the homeostatic regulation of iron is predominantly mediated through absorption and recycling. Nearly 90% of iron stores are reserved through senescent RBC recycling; nutritional intake accounts for the remaining 10% only.
Antinutritional factors such as tannins and phytates in cereals have been found to negatively affect the bioavailability of minerals such as iron when consumed in large quantities. It is established that tannins decrease iron availability before absorption through the formation of insoluble antinutritional-mineral complexes.
Tannins are often cited as contributors to the high incidence of deficiency. In spite of that, tannin-rich diets such as wine and tea may have potential beneficial cardiovascular and cancer-fighting properties because of the antioxidant activity of tannins.