Zinc is an essential trace element, and has shown benefit for protecting neurological functioning, eyesight, taste, smell and memory. Signs of zinc deficiency include hair loss, skin lesions and diarrhea. A common sign of zinc deficiency is white spots, bands, or lines on fingernails (leukonychia). About 25% of the world's population is at risk of zinc deficiency. Low zinc absorption can also be caused by various disease states such as diarrhea, chronic liver disease or renal disease, sickle-cell disease, diabetes and other chronic illnesses.
Zinc is often used as a supplement to support eye function, as the retina contains particularly high amounts of zinc, which is associated with RPE cells that degrade in age-related macular degeneration. Zinc supplementation may also be suggested for type II diabetes, as the ZnT8 protein is an important zinc transporter in alpha- and beta-cell functioning in the pancreas. Recently, Finnish researchers showed that diabetics that had lower blood levels of zinc and were more susceptible to fatal heart disease.
Zinc, however, is a "two-edged" sword. Excess zinc leads to copper deficiency and reduced iron functioning. It may also cause cause abdominal pain, nausea, vomiting and diarrhea. Excess Zinc can damage the very tissues that Zinc supplementation seeks to protect.
In order to reduce the risk of Zinc supplementation, two studies show that combining the Zinc with Oxaloacetate may be effective. In a study published in Neurochemical Research, scientists show that adding oxaloacetate greatly reduces the toxic effect of Zinc to RPE cells, and suggest that the combination is a more effective and safer way to treat a disease such as age-related macular degeneration.
See the abstract of this study here:
"Zinc and Energy Requirements in Induction of Oxidative Stress to Retinal Pigmented Epithelial Cells"
In a separate study published in Diabetologia, scientists show that both oxaloacetate and pyruvate protect pancreatic islet cell death caused by Zinc. While oxaloacetate is a potent antioxidant, the author suggests that the protective function of oxaloacetate is not due to antioxidant function alone, as other antioxidants were ineffective in protecting the islet tissues. The protective effect may be due to replenishing ATP levels.
See the abstract of this study here:
"Pyruvate inhibits zinc-mediated pancreatic islet cell death and diabetes"
