The Takeaway:
Phosphorus is important when its given naturally (not in a synthetic form) and when its provided in the proper amount.
High levels of phosphorus can be quite harmful to the kidneys and worsen kidney disease.
The kidneys normally filter extra phosphorus from the blood, but when the kidneys are damaged and not functioning properly, phosphorus levels can increase. High phosphorus levels can increase kidney function loss, which increases the severity of your cat’s kidney disease.
Now that I’ve explained the harm in too much phosphorus I need to explained why cats need some phosphorus to begin with.
Phosphorus is needed for the growth, maintenance, and repair of all tissues and cells within your cats body. Phosphorus is also needed to help balance and use other vitamins and minerals like vitamin D, iodine, magnesium, and zinc. So without it the body can’t utilize or metabolize vitamin D well.
This is why pet food manufacturers add in synthetic phosphorus to their food along with other nutrients due to their original ingredients having lost vitality during heat processing. Or in some cases the ingredients started out deficient as well. Either way its added back into the food synthetically in a premix of different vitamins and minerals.
Some of these premixes have had lethal levels of vitamin D. Generally speaking dogs and cats do not metabolize many pharmaceuticals and more important synthetic vitamins as well. This is a fact and we know that our dogs and cats cannot take all of the herbs, pharmaceuticals and even eat the same foods we can. Some are actually toxic to them.
More doesn’t always mean better, especially with fat soluble vitamins these are the vitamins that dont flush out and stay stored in your body for longer periods.
Phosphorus is important when its given naturally (not in a synthetic form) and when its provided in the proper amount.
When we feed a raw diet containing bone for example and the bone is less than 10% of the overal volume of the recipe, it is generally considered safe for cats with ckd. The issue occurs when we feed a processed food with synthetic phosphorus added or add in 15%-25% bone which is higher than a dog or a cat without a medical issue require.