The bioavailability of different zinc compounds used as human dietary supplements in rat prostate: a comparative study

Abstract

The normal human prostate accumulates the highest levels of zinc (Zn) of any soft tissue in the body. The pool of zinc available to the body is known to significantly decrease with age. It is suggested that dietary Zn supplementation protects against oxidative damage and reduces the risk of cancer. Zinc sulfate and zinc gluconate were the most frequently mentioned in per os administration in studies on Zn supplementation. The major aim of the study was to compare the bioavailability of different Zn compounds (sulfate, gluconate and citrate) in the prostate after their daily administration to male rats at three different doses (3.0; 15.0; and 50.0 mg Zn/kg b.w.) for 30 days. The results show that bioavailability in the prostate differs significantly between individual zinc preparations. A significantly elevated Zn concentration in the dorso-lateral lobe of the prostate, compared to controls, was found in the rats supplemented with two compounds only: zinc gluconate and zinc citrate. However, after administration of zinc gluconate, this effect occurred even at the lowest dose. The lowest zinc bioavailability in the prostate was found in the rats administered zinc sulfate: no significant Zn increase was seen in particular zones of the prostate. To sum up, the use of zinc gluconate is worth considering as a possible means of zinc supplementation in men.

The Effect of Zinc and Selenium Supplementation Mode on Their Bioavailability in the Rat Prostate. Should Administration Be Joint or Separate?

“…The zinc compound used for supplementation was selected on the basis of the outcome of an earlier study [15], in which zinc gluconate was found to exhibit the highest bioavailability in the rat prostate. After conversion, the applied zinc and selenium doses corresponded to the average level of recommended dose for supplementation in humans.…”

“…The prostate was divided into dorso-lateral (DL) and ventral (V) lobes as described previously [15]. The tissues were stored at −80 °C in cryo-tubes for further analyses.…”

“…Optimal daily level of zinc supplementation ranges from 30 to 85 mg [12,13,14]. Although it is not known whether dietary zinc intake affects intraprostatic zinc levels, our earlier studies on rats have indicated that oral administration of zinc significantly increases its concentration in the prostate, but its availability in this organ varies based on individual zinc preparations, which may be based on differences in absorption associated with zinc preparations [15]. Wegmüller et al (2014) notes that in humans, zinc gluconate, like citrate, should be recommended for the prevention of zinc deficiency [16].…”

Zinc inhibits the reproductive toxicity of Zearalenone in immortalized murine ovarian granular KK-1 cells

“…to their diet for 30 days. Only zinc gluconate and zinc citrate increased the zinc concentrations in the dorsolateral lobe of the prostate compared to controls 54 . In addition, Wegmüller et al used the double-isotope tracer method with 67 Zn and 70 Zn, and found that the median (IQR) fractional absorption of zinc from zinc oxide (49.9%) was significantly lower than that from zinc citrate (61.3%) and zinc gluconate (60.9%), but there was no marked difference between two organic zinc sources 55 .…”

Antidepressant, Anxiolytic and Neuroprotective Activities of Two Zinc Compounds in Diabetic Rats

“…The animals in the DSZ group received Zn sulfate supplementation and the animals in the DGZ group received Zn gluconate supplementation, both compounds orogastrically administered at a dose of 15 mg/kg body weight/day once daily for 4 weeks (Sapota et al, 2014). The dose choice used complied with the recommended maximum limit for rodents (National Academy of Sciences, 2001) and humans (Institute of Medicine, 2002) and it was calculated for each compound as a whole.…”