TL;DR: Low-Phosphorus Diets for Dogs
Phosphorus is essential for healthy bones, energy, and cell function—but in dogs with kidney disease, too much can make things worse. Here’s what to know:
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What phosphorus does: Supports bones, muscles, nerves, and energy use.
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When less is needed: Mainly in dogs with chronic kidney disease (CKD) or certain rare conditions.
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Good low-phosphorus foods: White/brown rice, sweet potatoes, certain veggies/fruits, eggs (in moderation), and fish oil.
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Foods to avoid: Organ meats, dairy, nuts/seeds, grain alternatives like lentils, and unbalanced homemade diets.
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Diet options: Prescription kibble/canned food, fresh frozen diets, or vet-formulated homemade plans.
Pro tip: Always work with your veterinarian (and ideally a veterinary nutritionist) to ensure the diet is safe and balanced.
Phosphorus is a mineral that is important for bone development, energy regulation, and cell-based functions. All pets need phosphorus in their diet, which pet food makers must supply according to nutritional guidelines for healthy pets.
However, not all pets have the same needs. Those with chronic kidney disease and a few other select conditions might need a lower-phosphorus diet than their healthier counterparts. Low-phosphorus dog food is available by prescription from your vet, but kibble isn’t the only option.
Fresh diets, homemade dog food, and veterinary-formulated custom diets may be beneficial for pets that require a lower phosphorus intake in their diet.
Here is an overview of what phosphorus does, when to feed less phosphorus, what ingredients contain phosphorus, and how to choose a diet that supports your dog’s kidneys and overall health.
What is phosphorus?
Phosphorus is a mineral found in many foods that plays a vital role in your pet’s health. It helps support strong bones and teeth, supports muscles and nerves, and helps the body use energy.
Most pet foods contain phosphorus from ingredients such as meat, dairy, or grains. Your pet’s food might also have phosphorus salts added to ensure a healthy balance between calcium and phosphorus.
In healthy pets, the kidneys filter excess phosphorus from the bloodstream. If kidney function declines, phosphorus can build up in the body. Excess phosphorus may cause:
- bone loss
- soft tissue hardening
- hormone changes
- worsening kidney issues.
When do pets need low-phosphorus diets?
The most common reason a pet needs a low-phosphorus diet is chronic kidney disease (CKD). The condition usually occurs in older pets, whose kidneys can’t filter waste or conserve water as efficiently as they should. Waste products can build up, causing affected animals to feel sick.
Pets with CKD may also develop high phosphorus levels. Feeding less phosphorus in your dog’s diet can protect the kidneys’ remaining function. Other health problems that can raise phosphorus levels are uncommon, but can include:
- Tumor lysis syndrome — Dying cancer cells release phosphorus and other substances into the blood.
- Muscle damage — Muscle cells release excess phosphorus into the blood.
- Vitamin D overdose or parathyroid hormone imbalance — These conditions can change the balance of calcium and phosphorus.
If your pet has any of these conditions, your veterinarian may suggest switching to a low-phosphorus kidney care diet.
When to avoid a low-phosphorus diet
While low-phosphorus diets may be helpful for pets with kidney problems, they aren’t necessary for most other pets. In fact, feeding too little phosphorus to a healthy pet, especially a growing puppy or kitten, may cause weak bones, muscle loss, and poor growth or healing.
Some people believe that senior pets need diets that are “easier” on the kidneys. However, the best way to support aging in healthy pets is to feed a balanced diet that meets the standards set by the American Association of Feed Control Officials (AAFCO) for adult dogs.
Goals of a low-phosphorus diet
When veterinarians recommend reducing phosphorus in a dog’s diet, it’s important to avoid accidentally upsetting the balance of other essential nutrients.
A well-balanced low-phosphorus diet should address other health issues commonly faced by aging pets with kidney disease. To do this, these diets may contain:
- Reduced phosphorus to limit strain on the kidneys
- Sufficient but low protein levels compared to a standard diet
- Highly-digestible proteins and ingredients
- Low sodium to manage blood pressure and fluid balance
- Moderate fat and calories (kcals) to prevent weight loss or low energy
- Increased moisture to help flush toxins from the body
Because kidney disease can suppress your dog’s appetite, getting pets with CKD to eat can be a challenge. Low-phosphorus dog food should smell and taste appealing to your pet, as eating is crucial to preventing their disease and overall condition from worsening.
Best ingredients for low-phosphorus pet food
Certain foods naturally contain less phosphorus than others, making them better for commercial or home-prepared low-phosphorus diets. They include:
- Carbohydrates and starches — White rice, brown rice, and sweet potatoes are low in phosphorus, high in energy, and easy to digest.
- Non-starchy vegetables and fruits — Green beans, cranberries, and blueberries provide fiber and antioxidants with minimal phosphorus content.
- Whole eggs — Eggs are high-quality protein sources and more digestible than many meats. They contain moderate phosphorus, but may be used in small amounts in combination with other proteins.
- Fish oil — Omega-3 fatty acids, including EPA and DHA, are anti-inflammatory ingredients that support whole-body health. Vitamin E is often paired with fish oil to provide additional cell support. Fats and oils do not contain phosphorus.
Foods to avoid
High-phosphorus foods and poorly balanced formulas can undermine your renal support goals. Foods to minimize include:
- Organ meats and meat meals — Liver and kidney meat are densely nutritious, but high in phosphorus.
- Dairy — Milk and cheese contain phosphorus, and some dogs are also lactose intolerant.
- Nuts and seeds — Grain alternatives, such as lentils and chickpeas, which are often present in grain-free diets, contain less phosphorus than meat and seafood but more than traditional grains.
- Processed foods — Canned meat, fish, or beans, and other processed foods may contain high levels of phosphorus from preservatives.
- Unbalanced homemade diets — Removing ingredients from the diet to reduce phosphorus without replacing other nutrients may leave your pet with too much or too little protein, calcium, magnesium, vitamins, and other vital nutrients.
If you want to cook for your pet or can’t find a commercial diet that fits their health needs (e.g., allergies, diabetes, or stomach issues), a veterinary nutritionist must formulate or approve the recipe.
Choosing a low-phosphorus diet
Traditional kidney diets restrict phosphorus and come in convenient, shelf-stable forms like kibble or canned food. These are available from your veterinarian with a prescription and work well for many pets. However, they aren’t the only options.
Fresh food, including refrigerated or frozen kidney support diets, contains more moisture than dry food or kibble. This extra water helps to combat dehydration in dogs with kidney issues and is more easily digestible than processed foods. Fresh food might also encourage your dog to eat more because it tastes good!
Home-cooked diets are customizable for complex pet needs, but you’ll need to consult with your primary veterinarian and a veterinary nutritionist to ensure the diet is complete and balanced. Prepared fresh food diets provide the benefits of human-grade ingredients without having to worry about the diet’s nutrient balance.
When diet isn’t enough to reduce phosphorus levels or when a pet won’t eat the prescribed diet, veterinarians may recommend supplements that bind with phosphorus in your pet’s gastrointestinal tract so it doesn’t get absorbed.
Better nutrition for kidney health
A well-balanced low-phosphorus formula helps to manage kidney disease in pets, but there is no single food or formula that’s right for every pet. Prescription kibble or canned diets, home-prepared diets, and fresh kidney support diets offer options to meet a range of needs.
JustFoodForDogs also has a team of veterinary nutritionists standing by to consult with your family veterinarian and create a custom diet just for your pet. We’ll formulate a diet and send it to your door, so you can skip the meal prep and spend quality time with your pet, instead.
This content is for informational use only and does not replace professional nutrition and/or medical advice, diagnosis, or treatment. It is not a substitute for and should not be relied upon for specific nutrition and/or medical recommendations. Please talk with your veterinarian about any questions or concerns.
Sources
“Phosphorus Food Guide Protein.” n.d. https://kitchen.kidneyfund.org/wp-content/uploads/2021/04/Phosphorus_Guide_090419.pdf.
Cornell Feline Health Center. 2017. “Chronic Kidney Disease.” Cornell University College of Veterinary Medicine. October 16, 2017. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/chronic-kidney-disease.
Gardiner, John. 2018. “Nutritional Management of Chronic Renal Disease.” School of Veterinary Medicine. June 21, 2018. https://www.vetmed.ucdavis.edu/hospital/animal-health-topics/chronic-renal-disease.
Brown, Scott A. 2018. “Noninfectious Diseases of the Urinary System in Dogs.” Merck Veterinary Manual. June 15, 2018. https://www.merckvetmanual.com/dog-owners/kidney-and-urinary-tract-disorders-of-dogs/noninfectious-diseases-of-the-urinary-system-in-dogs#Kidney-Dysfunction_v3207925.
