Food Science
Read our general notes on Risk Assessment
How does tannin affect iron absorption by the body? Does it do it by converting it to iron(III)? I am doing an investigation into iron content of vegetables and tablets.
Igloo writes
The reaction of tannin with iron(II) ions is not redox; it involves complexing. Tannins contain phenol groups, and these readily form complex ions with many metal ions, including Fe2+.
Because of their tannin content, drinks such as tea and coffee prevent iron absorption in the body because the tannin-iron complex is insoluble so cannot be properly absorbed.
Since tannins are also present in many vegetable foods the formation of such complexes may be a factor in the poor availability for absorption of much food iron.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
Rate this page or react
Share your views on this page, 2 ratings so far
, rated at 
updated: 06 December 2006
