Effect of a magnesium-deficient diet on serum and urine magnesium concentrations in healthy cats

Carol R. Norris, Mary M Christopher, Kimberly A. Howard, Richard W Nelson

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Objective - To evaluate the efficacy of using serum total and ionized magnesium (Mg) concentrations and urine Mg concentrations to identify Mg deficiency in cats. Animals - 6 healthy castrated male cats. Procedure - A Mg-replete diet was fed for 37 days, followed by a Mg-deficient diet for 37 days. On days 1, 3, and 7 of the last week of each diet, serum ionized and total Mg concentrations were determined; in addition, urine Mg concentration was determined each day of the last week. Serum total and ionized Mg concentrations were compared with urine Mg concentration, amount of Mg excreted during 24 hours (24-hour urine Mg excretion), ratio of urine Mg concentration to urine creatinine concentration (Umg:Ucr), and urinary fractional excretion of Mg (FEmg) to determine which variable best predicted Mg status. Results - Cats fed Mg-deficient diets had significantly lower serum total and ionized Mg concentrations and 24-hour urine Mg excretion values, compared with cats fed Mg-replete diets. Serum total Mg concentration was the best predictor of Mg status. Twenty-four-hour urine Mg excretion was a repeatable, reliable measurement and had the best correlation with serum total Mg concentration. Serum total Mg concentration also correlated with urine Mg concentration, Umg:Ucr, and FEmg. Conclusions and Clinical Relevance - Serum total and ionized Mg concentrations can be used to identify cats with dietary-induced Mg deficiencies. Twenty-four-hour urine Mg excretion and urine Mg concentration correlated best with serum total Mg concentration and, therefore, may be the most useful urine variables for identifying Mg deficiency.

Original languageEnglish (US)
Pages (from-to)1159-1163
Number of pages5
JournalAmerican Journal of Veterinary Research
Issue number9
StatePublished - Sep 1999

ASJC Scopus subject areas

  • veterinary(all)


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