That’s why we stick to the amount recommended by experts for adult cats of around 0.6 grams of calcium and 0.5 grams of phosphorus per 100 grams of food – which corresponds to a ratio of 1.2 to 1.
How much is too much phosphorus in cat food?
Notwithstanding the lack of an official upper limit, the National Research Council (NRC) has recommended an upper limit range of 2. 5-3. 5 g/1000kcal ME. Recent studies conducted in the previous few years have demonstrated that a diet comprising three Signs of renal disease were caused by 6g of phosphorus per 1000 kcal of metabolizable energy (ME) and a low calcium to phosphorus ratio.
Additionally, I’m having trouble finding any information regarding the sodium content of these foods. It is not included in the “Guaranteed Analysis” unless it is listed as something else than sodium. How much sodium should my cat be getting, how low can it go before it’s too little, and how much is too much? Where can I find this information on the bag of cat food?
In a wet food I looked at, the phosphours level was MINIMUM 0.25%. This seems very high to me, considering that the wet food I have is MAX 0.20% Is it? If so, what is a good goal to look for when choosing wet foods? Here is the food: http://houndgatos.com/rabbit-catfood.aspx
Additionally, I’m not entirely sure how to treat versus prevent kidney disease. After further research, I concluded that high-quality protein is beneficial even for cats with kidney problems. Some claim that low protein should be used in treating it, but cats should have a very high level normally. Does this mean that the high-protein diet that cats need also slowly kills their kidneys? Am I correct in thinking this?.
I’ve been researching kidney disease prevention strategies for my nine-year-old cat extensively. I’m going to start giving her more wet food and less dry food in her diet. I want to know how much sodium and phosphorus she should be eating. since I’m having trouble finding a clear response online
Just for the heck of it, heres a picture of the lovely lady. http://imgur.com/e8lSdQZ
Can a High Phosphorus Diet Harm My Cat?
Although phosphorus is a necessary mineral, excessive amounts can be harmful. Cats with pre-existing chronic kidney disease (CKD) have been shown to deteriorate more rapidly when fed diets high in protein and phosphorus. This has led to the development of a primary therapeutic approach for cats in renal failure, which involves feeding them a diet low in sodium and phosphorus but high in high-quality protein at a neutral pH.
CKD in cats is not a very well-understood process. Early studies on the subject of protein’s role in renal disease led to the adoption of a low-protein diet in some veterinary diets in an attempt to stop the disease from progressing from its early stages. In just the last 4-5 years, a great deal more research has been done to examine the impact of dietary phosphorus on the kidney health of otherwise healthy cats, despite the possibility that there are numerous unrelated underlying causes.
A landmark study published in 2018 set the ball rolling for further follow-up studies to look more closely at dietary phosphorus in cat foods. Published in the Journal of Feline Medicine and Surgery, researchers found that feeding a diet very high in phosphorus (about 5 times that of the recommended allowances by the NRC) to healthy cats showed markers of kidney damage were seen after only 30 days. The diets were freshly prepared, but calcium and sodium monophosphate were both used to reach the high phosphorus level.
The same year this study was published, petfoodindustry.com published a short article entitled “High phosphorus cat food may hurt kidneys”, citing recent findings from the study.
Since then, a number of additional studies have been published examining the specifics of how dietary phosphorus may affect a cat’s kidneys and the threshold levels at which they would become dangerous.
A couple of the same authors from the landmark study published another the same year looking at types of inorganic phosphates included in cat foods. Their findings supported that inorganic phosphates have a much higher bioavailability and absorption than organic phosphorus and that sodium monophosphate led to higher stress on the kidneys than calcium monophosphate.
In the British Journal of Nutrition, researchers found that feeding a diet with an inorganic phosphate content of 3.6g/1000kcal combined with a low calcium-to-phosphorus ratio led to changes in the kidneys and ill effects within 4 weeks. Interestingly, a normal calcium to phosphorus ratio did not lead to these changes. These findings highlighted the importance of not just the total phosphorus level in food, or how much is inorganic vs. organic, but also the balance of calcium and phosphorus in the diet.
The next year in 2019, a study published in the Journal of Veterinary Internal Medicine evaluating phosphorus content in commercially available cat foods presented the concerning findings that 33% of the 82 diets they analyzed had phosphorus content exceeding 3.6g/ 1000kcalME.
They also stated some of the following conclusions:
- Phosphorus content in high-protein diet groups was higher than that of levels in healthy cats that have been linked to kidney dysfunction.
- No associations were found between phosphorus and non-traditional protein foods (i.e., foods that contain unusual protein sources like rabbit or kangaroo).
- There was no relationship found between high phosphorus levels and canned foods alone.
- An inverse calcium to phosphorus ratio could be a sign that the diet contains a larger amount of inorganic phosphorus.
- 7 diets contained phosphorus greater than 4. 8g/1000kcal ME, the majority of which are raw diets heavy in bone derivatives and protein.
- There was no relationship between the cost of the diet and the amount of phosphorus in the food.
The same year in 2019, a study published in Veterinary Medicine and Science looked more specifically at phosphorus content in commercial wet foods for cats. Researchers evaluated 35 commercial wet foods from Europe. All contained phosphorus (and sodium) levels above minimum requirements set by FEDIAF.
While it’s common to go above and beyond the minimum requirements to ensure adequate intake of phosphorus, five out of the twelve cat diets evaluated exceeded the three 6g/1000kcal of phosphorus, which numerous research studies have reported.
In 2020, researchers looked at different types and amounts of dietary phosphorus on the kidney health of cats, publishing their findings in the Journal of Veterinary Internal Medicine. Their main takeaway finding was that an inverse or low calcium-to-phosphorus ratio combined with use of highly soluble inorganic phosphates are associated with markers of kidney injury.
These researchers also concluded a couple of other important points:
- There was no proof linking commercial diets to kidney damage in general. Nonetheless, certain commercial diets have low calcium-to-phosphorus ratios and high phosphorus content in comparison to recommended levels.
- When highly soluble phosphates containing sodium are added to diets in amounts equal to or greater than 0, blood serum phosphorus levels rise. 5g of phosphorus per 1000kcal ME.
- There is little correlation between blood serum phosphate levels and dietary phosphorus. Only 1% of the body’s total phosphorus is found in serum phosphate, and this can be influenced by intestinal absorption and the movement of phosphorus in and out of bones and cells.
- The calcium to phosphorus ratio of a diet also influences phosphorus levels, and bioavailability in phosphorus sources can differ greatly.
Also Read: Cat Calorie Calculator
FAQ
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