New Study Reveals Certain Cat Foods Could Damage Kidneys Within Weeks

A shocking new study carried out by veterinary scientists in Munich shows that high phosphorus in certain cat foods can damage kidney function in cats.

Before the investigation, scientists didn’t know why 35% of older cats suffered from chronic kidney disease. But the results of the new study suggest that excess phosphate in a cat’s diet could have dangerous effects on kidney function, and “could contribute to the high incidence of chronic kidney diseases in elderly cats,” according to Professor Ellen Kienzle, the lead investigator and author of the study. The new findings appear in the Journal of Feline Medicine and Surgery.

Tests of commercial cat foods available in Germany, carried out by the consumer organization Stiftung Warentest, revealed that, in particular, moist cat food formulas contain on average several times the amount of phosphorus required to keep cats healthy, which might be sufficient to “damage the healthy feline kidney within a few weeks,” the scientists revealed.

The majority of cats in Germany are fed complete prepared cat foods. Typically, cat foods, especially moist foods, provide, on average, four to five times the phosphorus maintenance requirements, but the maximum concentration of phosphorus in some cat foods covers nine times the maintenance requirement.

As the authors explain, phosphates in animal foods are in part derived from natural sources, mainly bone and cereals, “However, pet-food manufacturers also add inorganic phosphates to achieve the appropriate texture and extend shelf life.”

Now the authors plan to look at the impact of excess dietary phosphate on the health of dogs and it is now the subject of a dissertation in Kienzle’s working group. The initial results suggest that the concentration of phosphate in the blood rises significantly “following the intake of inorganic phosphates.”

How does this study relate to pets in the U.S.? While no one can say for certain, it’s possible, we may be able to extrapolate the results of the study presuming the pet food market in the EU is not that different than it is in the U.S., however, the EU follows maintenance requirements according to the National Research Council and the European Pet Food Industry Federation.


If you believe your pet has become ill from consuming a pet food, please provide the FDA with valuable information by reporting it electronically through their Safety Reporting Portal or call your local FDA Consumer Complaint Coordinator.

If you and your veterinarian think a pet food or treat is the source of a problem – save it – because your state agricultural or veterinary diagnostic lab may want to do testing. If you need more help, find out how to report a pet food complaint to the FDA.


… I have a small favor to ask. Poisoned Pets’ independent, investigative journalism takes a lot of time, money and hard work to produce. But I do it because I believe this work matters – because it might save your pets life.

If everyone who reads my reporting, who likes it, helps fund it, the future of Poisoned Pets would be much more secure. For as little as $1, you can support Poisoned Pets – and it only takes a minute. Thank you.

Please donate – even if it’s a teensy weensy amount – to help Poisoned Pets.


dog cat poisoned pets safe food warnings news recalls alerts

Poisoned Pets | Pet Food Safety News remains free (and ad-free) and takes me many, many hours of laborious work to research and write, and thousands of dollars a year to sustain. Help keep Poisoned Pets alive by making a donation. Thank you.




Mollie Morrissette

Mollie Morrissette, the author of Poisoned Pets, is an animal food safety expert and consumer advisor. Help support her work by making a donation today.

Comments (11) Write a comment


This site uses Akismet to reduce spam. Learn how your comment data is processed.