Serum Magnesium and Zinc Concentrations in Dogs with Inflammatory Bowel Disease
Magnesium and zinc are essential trace elements absorbed in the proximal small intestine. Reduced magnesium and zinc concentrations have been documented in human malabsorptive conditions such as Crohn's disease. Initial clinical signs of magnesium deficiency include vomiting and diarrhea, with progression to cardiac and neuromuscular abnormalities. Clinically relevant signs of zinc deficiency include acrodermatitis, poor wound healing and diarrhea. Currently, the effect of malabsorptive disease on magnesium and zinc concentrations in dogs is unknown.
The purpose of the study was to compare serum magnesium and zinc concentrations in normal dogs and dogs with inflammatory bowel disease. We hypothesized that, compared to healthy dogs, dogs with inflammatory bowel disease would have decreased serum magnesium and zinc concentrations. In a prospective clinical study, 16 client-owned dogs were evaluated for chronic gastrointestinal signs. Inflammatory bowel disease was diagnosed through histological evaluation of endoscopically obtained gastrointestinal biopsies. At the time of endoscopy, serum was collected for commercial magnesium and zinc analysis. Serum was also obtained from 16 age- (within six months) and sex-matched clinically healthy dogs. The median age of cases was 6.3 years (range: 1.5-15.4 years), and the median age of controls was 6.2 years (range: 1.5-14.9 years).
In dogs with inflammatory bowel disease, median serum albumin concentrations [1.3 gm/dl (range: 0.9-3.8 gm/dl)] were significantly lower than for control dogs [3.4 gm/dl (range: 2.6-4.2 gm/dl)] (p=0.003). Albumin concentrations were significantly correlated with total magnesium (r=0.636; p=0.008) and zinc (r=0.702; p=0.003) concentrations in dogs with inflammatory bowel disease. There was no correlation between albumin concentrations and total magnesium (r=-0.195; p=0.469) or zinc (r=0.139; p=0.608) concentrations in control dogs. Median total magnesium concentrations for dogs with inflammatory bowel disease [1.6 mg/dl (range: 0.8-2.4 mg/dl)] were significantly lower than for control dogs [2.1 mg/dl (range: 1.8-2.5 mg/dL)] (p<0.001). Median zinc concentrations for dogs with inflammatory bowel disease [0.66 ppm (range: 0.25-2.12 ppm)] were significantly lower compared to control dogs [1.00 ppm (range: 0.58-1.65 ppm)] (p=0.044).
This study suggests that magnesium and zinc deficiency should be considered in dogs with inflammatory bowel disease and secondary hypoalbuminemia. The clinical significance of these deficiencies in dogs with inflammatory bowel disease is currently unknown and should be further evaluated.