Magnesium & Lower Urinary Tract Disease

What is the role of magnesium in Feline Lower Urinary Tract Disease?
The answer to this question is complex. Struvite crystals found in some cases of FLUTD contain three elements: magnesium, ammonium, and phosphate. This led to the belief that the more magnesium in the diet, the greater the chance of struvite crystal formation, and the higher the risk of FLUTD. Research in the 1970s showed that very high magnesium diets could cause obstruction in cats, if the magnesium was in the form of magnesium oxide. Based on this research, the magnesium was identified as the cause of blockage in cats. However, this research failed to identify that the magnesium oxide has another effect. It causes alkalization of the urine in the bladder.

Other researchers continued the magnesium study by feeding diets using magnesium in the form of magnesium chloride at high levels. No struvite crystals formed and no blockages occurred. This form of magnesium acidified the urine. This research showed that while magnesium may play a role in struvite stone formation, it is not the whole story! What is important is the acidity or pH of the urine of the cat. Acidity interferes with the formation of struvite crystals and alkalinity contributes to crystal or stone formation. Today, diets intended to prevent formation of struvite stones ensure appropriate amounts of magnesium and help acidify the urine. However, this addresses only a portion of cats with FLUTD. This remains a medical condition against which much research is focused.