title: Magnesium-deficient diet-induced reduction in protein utilization in rats is reversed by dietary magnesium supplementation.
abstract: We investigated the effect of dietary magnesium (Mg) level on protein utilization in rats. Male Wistar rats were fed a control diet (control group) and a Mg-deficient diet (Mg-deficient group) for 28 days. After 28 days, the diet of half of the Mg-deficient group (recovery group) was changed from the Mg-deficient diet to the control diet for either 7 or 14 days. After 28 days, final body weight, weight gain and food efficiency were significantly decreased due to the Mg-deficient diet. Apparent Mg absorption, Mg retention and serum Mg levels were also significantly decreased due to the Mg-deficient diet. Furthermore, the Mg-deficient group showed a significant increase in urinary nitrogen (N) excretion and significant decreases in N retention and serum albumin level. At day 7 and 14 after changing the Mg-deficient diet to the control diet, apparent Mg absorption, Mg retention and serum Mg levels were significantly increased in the recovery group as compared with those in the Mg-deficient group. However, with regard to final body weight, weight gain and food efficiency, no significant differences were observed between the Mg-deficient group and the recovery group. At day 14 after changing the diet, urinary N excretion was significantly decreased and N retention was significantly increased in the recovery group as compared with the Mg-deficient group. At day 7 and 14 after changing the diet, the serum albumin level was also significantly increased in the recovery group as compared with that in the Mg-deficient group. These results suggest that: 1) the Mg-deficient diet depresses protein utilization; 2) the Mg-deficient diet-induced impairment of protein utilization is reversed by dietary Mg supplementation; and 3) the Mg-deficient diet-induced growth retardation is not completely reversed after 14 days of Mg supplementation.
authors.affiliation: Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nemoto
authors.forename: H
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: M
authors.initials: M
authors.lastname: Uehara
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D004032:Diet; D019587:Dietary Supplements; D008274:Magnesium / Q000008:administration & dosage / Q000378:metabolism; D008275:Magnesium Deficiency; D008297:Male; D009584:Nitrogen / Q000032:analysis; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D011506:Proteins; D008274:Magnesium; D009584:Nitrogen