A Comparison of the Metabolic Effects of Zinc-Amino Acid (ZnAA) Versus Zinc Gluconate

Food consumption affects zinc metabolism within the body. Lowe and colleagues demonstrated that zinc is directed out of plasma and into tissues, such as into the liver, postprandially . It is likely that zinc absorbed with a meal is directed to the liver via the portal circulation whereas that zinc taken in the fasted state is more readily directed to peripheral blood plasma. Zinc taken with food is more likely to be bound to components of the food matrix and, therefore, it is not absorbed as efficiently by Zip4 ionic zinc transporters in the upper gastrointestinal tract. Some of the zinc in the food matrix may, however, be co-absorbed with amino acids over the whole length of the small intestine . Co-absorption of zinc with amino acids may explain the greater effects of zinc taken with food on omega-6 fatty acid desaturation . The investigators propose that this effect may be maximized by providing supplemental zinc complexed with amino acids. Since the zinc amino acid complex likely mimics the absorption and retention of zinc bound to protein in food, the investigators further propose that zinc, bound to amino acids taken in the fasted state will be directed into the cellular compartments more efficiently than zinc associated with gluconate. The primary aim in this study is to determine whether providing a zinc amino acid complex has a greater effect on indices of essential fatty acid desaturation compared with zinc gluconate when the zinc complexes are taken in the fasting state. The investigators hypothesize that taking a zinc amino acid (Zn-AA) complex in a fasted state daily for two weeks has a greater effect on the Fatty Acid Desaturase 1 (FADS1) activity compared with zinc gluconate. Also, if the uptake of ionic zinc gluconate into cellular compartments is reduced in comparison to Zn-AA because the zinc gluconate is retained in the plasma, two weeks of a daily zinc gluconate will have a greater effect on fasting plasma zinc concentrations compared to a Zn-