Study: Zinc Citrate Absorption Superior to Oxide

BASEL, SwitzerlandAccording to new research published in The Journal of Nutrition, zinc citrate showed superior absorption compared to zinc oxide and was on par with the nutritional benchmark zinc gluconate.

Despite the benefits of zinc citrate compared to soluble zinc salts and more neutral taste, no human absorption data was available to date.           

The randomized, double blind, crossover study was led by Rita Wegmüller and

Richard Hurrel of the ETH Zurich (J. Nutr. January 1, 2013 jn.113.181487). The study focused on 15 healthy young adults that received 10 mg of elemental zinc though a zinc citrate supplement. Researchers then measured the zinc gluconate or zinc oxide and the absorption using the double isotope tracer methodology.

Median fractional absorption of zinc from zinc citrate was 61.3 percent and was not different to that from zinc gluconate with 60.9 percent; however, absorption from zinc oxide was at 49.9 percent, significantly lower than from both supplements. Three subjects had little or no absorption from zinc oxide. This might be explained by the fact that zinc oxide is an insoluble compound which may not be dissolved sufficiently by people with low gastric acid production.

According to the authors of the study, zinc citrate could be a useful compound for zinc supplementation. Currently, WHO recommends the use of the water soluble compounds zinc sulfate, zinc acetate or zinc gluconate in the form of syrups or dispersible tablets to manage diarrhea. Zinc citrate might be a useful addition to this list and be especially suitable for chewable/crushable tablets since it has better sensory properties.

The study was supported by Jungbunzlauer International AG. Zinc citrate is produced in Jungbunzlauers Pernhofen, Austria plant and supplied to food, dietary supplement and pharmaceutical industries worldwide.