The following studies indicate the best/worst bioavailable forms of zinc supplements. I came across these while researching zinc:
Zinc Picolinate was found to be the most bioavailable form of those tested in the following study:
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract
The following studies indicate zinc-methionine is less bioavailable than thought. The reason is purported that the bond between elemental zinc and methionine is too weak to remain stable:
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract
http://www.ncbi.nlm.nih.gov/entrez/q...t_uids=2506318
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum
Full Text of PMID 10801947:
http://jn.nutrition.org/cgi/content/full/130/5/1378S
Quote:
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Methionine complexes of zinc have been used to improve zinc absorption from the diet, but besides improved carcass quality in steers (Greene et al. 1988 ), there is limited evidence for this. Hempe and Cousins (1989) found that the zinc-methionine complex reduces zinc absorption in ligated rat duodenal loops, which is in agreement with similar observations on intestines from swine and poultry (Hill et al. 1987 ). Because the proportion of absorbed 65Zn was similar in rats fed ZnC12 or zinc-methionine, they concluded that the zinc-methionine complex is not absorbed intact. Thus, the association of zinc to methionine may be too weak to make the complex "survive" passage in the upper gastrointestinal tract, and dissociation of zinc and reassociation with other ligands may occur.
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The above study was published by this person:
http://nutrition.ucdavis.edu/faculty/lonnerdal.html
A “less technical” summary of zinc information and bioavailability may be found as follows (includes study references):
http://www.bulknutrition.com/i9_Zinc.html