Zinc supplementation and amino acid-nitrogen metabolism in patients with advanced cirrhosis

Author(s):Marchesini G, Fabbri A, Bianchi G, Brizi M, Zoli M
Source:  Hepatology 1996; 23:1084-92

Description:  Zinc is a necessary trace element in liver cell activity. Zinc deficiencies are common in patients who have advanced cirrhosis. When there is liver damage, the nitrogen from proteins, or the amino acids that form proteins, cannot be metabolized and disposed of as efficiently as they are normally. One of the nitrogen waste products that builds up to abnormal levels in the blood is ammonia, while in healthy people, the nitrogen takes the form of urea. Since alanine is a commonly found amino acid in proteins, it was used in this experiment. Sixteen patients with advanced cirrhosis were given alanine. Half (eight) of the patients had been treated with zinc supplements for three months before the alanine was administered. The patients who had been given zinc before the alanine were able to dispose of the nitrogen from the alanine in a normal way, but the other patients could not. Urea levels were higher in the patients with zinc treatments than with the control patients, but ammonia levels were higher in the untreated controls. Those patients who had taken zinc supplements also had improved mental function.

Explanation of what all that said:

Glucagon: A protein hormone that is produced from the pancreas in responseto low blood sugar levels.

The experimental patients were given 200 mg of zinc sulfate three time a day for three months. There were no signs of side effects from these zinc supplements.

To monitor how each patient metabolized nitrogen-containing compounds, each of the 16 patients was given intravenous alanine for 4.5 hours. Urine and blood samples were collected.

The results showed that both groups of patients had reduced zinc levels to begin with. However, those who got supplements showed 60% increases of zinc in their blood by the end of the three months. After alanine was given, the patients who had received zinc had half the glucagon levels of the controls and 30% more insulin in their blood. The ammonia levels in the zinc-treated group were 30% lower than in the control group. Other liver function tests were significantly improved. Mental function tests based on several parameters also improved greatly in the patients with zinc supplement treatment.

Two patients who had received zinc supplements were tested again six months later to measure zinc levels in the blood. At this time, their zinc levels had dropped back down to where they had been before supplements had started.