3 min read

Phosphorus for Dogs


By Emily Gantt

Published: 09/19/2023, edited: 09/20/2023

Reviewed by a licensed veterinary professional: Dr. Linda Simon, MVB MRCVS

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Phosphorus is an essential mineral that dogs need for healthy bones, teeth, and metabolism. By itself, phosphorus is highly unstable and is often combined with calcium in the body. These two minerals have an inverse relationship and work together and against each other to maintain homeostasis. 

Interestingly, low-phosphorus diets have been on the rise in the veterinary community. This begs the question: is phosphorus necessary after all? What functions does it play in the canine body? Read on to find out. 

Bulldog taking a pill


Phosphorus plays many vital roles in the canine body. This mineral works closely with calcium to help maintain the integrity of bones and teeth; in fact, the teeth and bones store 86% of the canine body's phosphorus.

Phosphorus combines with other minerals in the body, forming phosphates and compounds that help regulate normal bodily functions. One of the primary duties of phosphates is to fuse with lipids and proteins to form membranes in the body. Phosphorus compounds even help comprise nucleic acids in DNA and RNA, making them essential to the very fabric of your pup's being.

Phosphates assist in managing a dog's pH balance and are involved in the formation of essential nucleotides. Phosphorus also helps rid the body of dangerous toxins by stimulating the kidneys.

Dogs can receive up to 22.25 mg of phosphorus per kilogram of body weight each day. In terms of dog food, young dogs and small breeds need between 0.6% and 1.3% phosphorus. Bigger breeds like Labs need between 0.7% and 1%, depending on their age and activity level. 

foods containing phosphorus

Food sources

Dogs get their daily phosphorus intake solely through the diet since phosphorus is rapidly absorbed by the small intestines. Phosphorus is in many different food groups, including dairy, meats, and grains. It is also an ingredient in almost every commercial dog food. Here are just a few phosphorus-rich foods that dogs may enjoy:

  • Eggs
  • Whole wheat
  • Halibut
  • Salmon
  • Chicken
  • Beef
  • Lentils¬†
  • Potatoes

Signs of phosphorus deficiency in dogs

There isn't much research into phosphate deficiency in dogs, mainly because phosphorus is so closely linked with calcium. A phosphate deficiency is rarely seen without a calcium deficiency too. 

Interestingly, this inverse relationship between calcium and phosphorus can sometimes lead to a phosphate deficiency. If calcium levels are too high, phosphorus levels can plummet.

Dietary deficiencies of phosphorus are rare, but they can occur if a dog eats an improper diet or stops eating altogether. Symptoms of a phosphate deficiency include stunted growth, heart problems, and inhibited red blood cell function.

Some pet parents of dogs with kidney failure feed their dogs a phosphorus-deficient diet to try to prevent excessively high levels. The idea behind this diet is that by reducing phosphorus intake, you reduce the kidney's workload.

When Phosphorous levels are high in those with renal disease, vets will often prescribe a phosphate binder, which prevents the absorption of phosphate by the small intestines. 

Never feed your dog a low-phosphorus diet without the explicit instruction and supervision of a veterinarian. 

Treatment of phosphorus deficiency

In treating a phosphorus deficiency, care must be taken to ensure the right amount of phosphorus and calcium are being consumed in tandem, whether in the diet, or with supplementation or the addition of phosphorus and/or calcium-rich whole foods. Kidney function may be monitored and treated as necessary. In some severe cases, hospitalization may be necessary, and could involve intravenous mineral or insulin therapy. If anemia is present, blood transfusions may be given. 

Signs of phosphorus overdose in dogs

Overdosing on phosphorus is unlikely, though there is such a thing as too much. Excess phosphorus in the blood (also called hyperphosphatemia) is a symptom that is almost always caused by another condition.

Renal failure, low parathyroid hormone production, or overactivity of the parathyroid gland are common reasons for high phosphorus in the blood. Symptoms of elevated phosphorus include are linked with high calcium and include:

chocolate Labrador Retriever taking pill from veterinarian - phosphorus for dogs

Phosphorus supplements for dogs

Dogs who receive a balanced diet probably won't respond to phosphorus supplements, though there are some exceptions. Dogs fed homemade dog food may not meet their daily recommended intake of phosphorus and may require supplementation.

There are many different phosphorus supplements for dogs on the market, but most contain both calcium and phosphorus. These supplements may help maintain bone density in dogs who are getting older. Phosphorus supplements are not recommended for dogs experiencing kidney failure since this can cause the kidneys to work harder.

Never give a supplement without first consulting with your vet, as they can do more harm than good for certain dogs.

The symptoms of a phosphorus deficiency can be expensive to treat. To avoid high vet care expenses, secure pet health insurance today!

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