Introduction

Zinc picolinate (Figure 1) is a zinc salt of picolinic acid. It is available as OTC dietary supplements as a source of zinc to treat and prevent zinc deficiency. The absorption of zinc after oral administration of zinc picolinate is shown to be effective.This compound belongs to the class of organic compounds known as pyridinecarboxylic acids. These are compounds containing a pyridine ring bearing a carboxylic acid group.

Zinc Picolinate on Cisplatin-Induced Nephrotoxicity in Rats

Cisplatin-induced nephrotoxicity is related to an increase in lipid peroxidation, oxygen-free radicals,and inflammation in kidney. Zinc is an antioxidant and has anti-inflammatory action. To date, the protective role of zinc picolinate on cisplatin-induced renal injury has not been investigated. The purpose of the present study was to examine the effect of zinc picolinate on cisplatin-induced renal injury.Male Wistar rats (n=28, 8-week-old, weighing 200 to 220 g) were divided into four groups consisting of 7 rats each: control, zinc picolinate (6 mg Zn/kg BW i.p.), cisplatin (7mg/kg BW i.p., single dose) and cisplatin plus zinc picolinate. A single dose of cisplatin resulted in an increase in malondialdehyde, 8-isoprostane, and tumor necrosis factor-a levels of kidney and significantly deranged renal function (urea-N and creatinine; P﹤0.0001). Zinc picolinate treatment significantly reduced urea-N, creatinine, malondialdehyde, 8-isoprostane, and tumor necrosis factor-a-a levels. Concentration of zinc in kidney was increased significantly after zinc picolinate supplementation; however, Fe and Cu levels did not change. Expression of Bax in kidney increased with cisplatin administration, and this could be prevented by zinc picolinate treatment (P﹤0.001). However, bcl-2 expression did not change by zinc or cisplatintreatment (P﹥0.05). The expression of heat shock proteins 60 and 70 in kidney was increased after cisplatin treatment compared with the levels in the control (P﹤0.01), and this increase could be prevented by the zinc picolinatetreatment (P﹤0.05).These results suggest that zinc picolinate may be a potential preventive agent in cisplatin-induced renal injury through decreasing oxidative stress and inflammation.[1]

Zinc Picolinate in the Prevention of Leiomyoma in Japanese Quail

Epidemiologic studies suggest that zinc deficiency may be associated with increased risk of cancer. Researchers investigated the effects of zinc picolinate supplementation on the development of leiomyomas, malondialdehyde (MDA), 8-isoprostane, 4-hydroxyalkenal (HAE), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, and heat shock protein 70 (Hsp70) expression in Japanese quails. One hundred fifty quails (6 months old) were assigned to three treatment groups consisting of50 birds in each group. Birds were fed either a basal diet or the basal diet supplemented with 30 mg or 60 mg of zinc/kg of diet. The animals were sacrificed after 350 days, and the tumors were identified. Zinc picolinate supplementation did not affect the number of leiomyomas compared to control birds (P>0.05). However, the tumors in zinc-fed birds were smaller than those found in control birds (P=0.01) Serum MDA, 8-isoprostane, and HAE levels were lower in the treatment groups than in thecontrol group: MDA, 1.95 versus 0.93μmmol/L; 8-isoprostane, 108 versus 85 pg/mL; HAE, 1.55 versus 0.96 μmmol/L (P =0.01 for all three parameters). The concentrations of serum 8-OHdG, which is a marker of oxidative damage, in the groups were 28.5, 23.6, and 20.1ng/mL, respectively (P=0.01). Hsp70 expression was significantly decreased in zinc-treated birds (P<0.01). The results indicate that dietary zinc picolinate supplementation reduces the growth of spontaneously occurring leiomyomas of the oviduct in the Japanese quail. Clinical trials should be conducted to investigate the efficacy of zinc supplementation in the prevention and treatment of uterine leiomyoma in humans.[2]

Zinc Picolinate for Taste Disorders

A total of 73 patients with an idiopathic zinc-deficiency taste disorder completed a double-blind, placebo-controlled trial of the efficacy of zinc picolinate. Patients in the zinc treatment group (n=37) received 29 mg of zinc picolinate orally by capsule 3 times a day for 3 months.In this double-blind study, administration of zinc picolinate was significantly (p<0.01) more effective than placebo in improving taste function (as measured by the filter paper disk method) in patients with zinc-deficiency or idiopathic taste disorders. In addition, serum zinc level was found to increase significantly with 3 months of zinc picolinate therapy. These ?findings lead to the conclusion that administration of zinc picolinate is an effective treatment for patients with zinc-deficiency or idiopathic taste disorders.[3]

References

[1]Tuzcu M, Sahin N, Dogukan A, et al. Protective role of zinc picolinate on cisplatin-induced nephrotoxicity in rats. J Ren Nutr. 2010;20(6):398-407. doi:10.1053/j.jrn.2010.04.002

[2]Sahin N, Tuzcu M, Ozercan I, Sahin K, Prasad AS, Kucuk O. Zinc picolinate in the prevention of leiomyoma in Japanese quail. J Med Food. 2009;12(6):1368-1374. doi:10.1089/jmf.2008.0287

[3]Sakai F, Yoshida S, Endo S, Tomita H. Double-blind, placebo-controlled trial of zinc picolinate for taste disorders. Acta Otolaryngol Suppl. 2002;(546):129-133. doi:10.1080/00016480260046517