Effects of a high dietary level of zinc (Zn), copper (Cu) and iron (Fe) on lipid and mineral metabolism in aging male Sprague-Dawley rats fed 1% cholesterol (CHOL)

The authors report an inverse relationship of serum CHOL to dietary and serum Cu in rats fed without CHOL. Others report the relationship of some essential minerals with lipid metabolism indicating both deficiency and excess of essential metals associated with elevated serum lipids. The authors have extended their investigation to the relationship of varying levels of Zn, Cu and Fe to changes in lipid metabolism when diet is fortified with 1% CHOL. Six groups of 6 weanling rats were fed a purified dietary regimen +/- 1% CHOL containing Zn/Cu/Fe in ppm 20/5/37 (grs 1,2), 60/18/200 (grs 3,4) and 60/18/200 (grs 5,6) for 189-193 days. Changes in body wt, plasma Zn and Cu were minimal. Plasma Fe in grs 2,3,5,6 was higher than in grs 3 and 6. CHOl did not affect liver Zn or Cu. Liver Fe was highest in gr 2. Major effects observed were on liver lipids. Due to dietary CHOL, liver CHOL was elevated in all grs but less in gr 6 where Zn and Cu were high. Similar results were seen for liver total lipids and triglycerides. This suggests that feeding excessive amounts of Zn and Cu to growing rats reduces deposits of lipids in themore » liver while feeding excess Fe does not. The highest levels of Zn, Cu and Fe did not affect plasma CHOL.« less