Homeostastis and Zinc: I'm researching some literature on the subject. A reference article, often cited, is Johnson et al., 1993.
http://ajcn.nutrition.org/content/57/4/557.longThis is a very interesting article on the homeostasis of zinc and the treshold below which homeostasis fails and deficiency comes about.
Some concentration units in the article are micro-moles/day, which multiplied by 65.38, the atomic mass of zinc, results in micrograms per day (and this multiplied by 0.001 is milligram/d), the usual unit. OK, I'm reading values are often converted.
The authors start with these data (current RDI = 11 mg/d):
FDA RDI in 1993 = 15 mg/d
'Adequate amount'= 10.3 mg/d
low amount= 4.4 mg/d
pretty low amount= 2.45 mg/d
very low amount=1.4 mg/d
The result is that almost all of the subject started to manifest zinc deficinecy at the pretty low or low tresholds.
Everyone was all right with 4.4 mg/day, which is about less than an half times the current RDI of 11 mg/day.
It must be told that the Zn supplied in teh study was highly available. In such case, conclusions of the rticle is that 3.4 mg /d is an adequate amount.
For us vegetarians it may not be so, although I would tend to believe that 5 mg/d would be in most cases (adult.males-average bodyweight) an adequate quantity.
