Phosphorus Content in Dog Food

Here's some of what is known about dietary phosphorus and dog foods:

Putting all this together, those of us with older dogs have a bit of a problem: Old dogs do best on a moderate to high protein diet, while it would be prudent to feed them a diet with relatively low phosphorus levels.

What are the recommended dietary phosphorus levels for dogs?

Optimum phosphorus ranges
Figures are in percentages as measured on a Dry Matter Basis
Source: Small Animal Clinical Nutrition 4th edition
Small/Medium Breed Puppies 0.6 - 1.3
Large Breed Puppies 0.6 - 1.1
Adult Dogs (Low Activity) 0.4 - 0.9
Adult Dogs (Normal Activity) 0.4 - 0.9
Adult Dogs (High Activity) 0.4 - 0.9
Older Dogs (>6 years) 0.5 - 0.7

AAFCO Minimum Phosphorus Levels
AAFCO Dog Food Nutrient Profiles (% dry matter basis)
Source: Selecting Nutritious Pet Foods by David A. Dzanis DVM, PhD, DACVN.


Growth and Repro. Minimum Adult Maintenance Minimum
Protein 22 18
Fat 8 5
Phosphorus 0.8 0.5
Maximum Phosphorus: 1.6% (Dry Matter Basis)
Note This chart presumes an energy density of 3.5kcal Metabolizable Energy/gram DMB (Dry Matter Basis). Rations greater than 4.0 kcal/g should be corrected for energy density; rations less than 3.5 kcal/g should not be corrected for energy.

How do you compare phosphorus levels in dog food?

There are two common measures of phosphorus. The first, which is listed in the "guaranteed analysis" on most dog food bags is the phosphorus percentage of the food "as fed". There are a few problems with using this figure to compare phosphorus levels in dog foods.

  1. The figure is usually listed as minimum rather than maximum phosphorus (the figure that is of more interest to those feeding senior dogs, for whom some moderation of dietary phosphorus levels is recommended.
  2. All things being equal, any food that is nutritionally dense (high calorie) is going to have higher 'as fed' phosphorus percentages than any low-calorie food. However, dogs will eat more of a low-calorie ration, so the actual phosphorus intake might be as high or higher.
  3. The guaranteed analysis on the bag or can does not measure in "dry matter basis" (DMB) but rather "as fed". You must recalculate the DMB before comparing the figures.

    For these reasons, the best way to compare phosphorus levels is to use the measure of actual phosphorus content in milligrams per 100 kilocalories. This equalizes the high-calorie and low-calorie foods. (Note, a kilocalorie or kcal is the unit that most of us layfolk refer to simply as "calorie".) Some dog food companies use the figure of phosphorus in grams per 1000kcals, but that is easy to convert into mg/100kcal.

    While phosphorus in mg per 100kcal makes the comparison between foods simple, it's not a common measure that most consumers request, so it's not listed on dog food bags and many companies don't even have that information available. It can be calculated from other figures that are reasonably easy to get: the dry matter basis phosphorus percentage and the calories per kilogram. For those brands that do not make the 'dry matter basis' figures available to consumers, you can calculate that information from the phosphorus percentage as fed, the calories per kilo, and the moisture content. Some companies will provide you with the actual moisture content as found in laboratory analysis - otherwise a maximum moisture content figure is usually given on the bag or can. The maximum moisture listed is going to be slightly higher than the actual moisture content of the food, but it's not that far off.

    I compiled the figures for phosphorus as well as some other figures for general nutrition for various dog foods. If you want to know why some brands are included and others not, one of the main criteria were how easy it was to obtain the figures. For example, Nestle/Purina customer support was excellent and easily available from a toll-free phone number. They had all the figures I wanted immediately available. Similarly, Natura, the company that makes California Natural and some other lines of food emailed me a comprehensive spreadsheet for their foods.

    By contrast, some of the brands had customer support folks seemed peevish that I wanted so much information or simply did not have these figures available. I emailed a few of the smaller brands, when the front-line support techs could not supply the figure of phosphorus per 100kcals, but I did not receive answers, even from Canidae, a company that has an staff nutritionist. In a few cases, such as that of "Sensible Choice" the information on the manufacturer's website differed from that given by the support staff, and the phosphorus amount per 100g were not available at all.

    The following chart has the phosphorus content in mg/100kcal for those brands that provided that figure. The dry matter basis phosphorus percentage is also included for comparison, as well as figures for DMB protein, fat, and the caloric content, which is the Metabolizable Energy in kcals per gram, as measured in dry matter basis.

    The dry matter basis figures were provided by the manufacturers in all cases except for that of Pedigree - they didn't have DMB figures available, so I calculated that using the maximum moisture listed on the bag.

    mg per
    "Life Stage"
    K/D (Hills Veterinary Diet) 55.2414.919


    Diamond Low-Fat/Senior140.5018.49.3


    Science Diet Senior144.5819.515.4


    Science Diet Maintenance Chicken and Rice148.6023.314.8


    Science Diet Maintenance Beef154.6223.314.8


    Science Diet Maintenance Original159.6424.715.8


    Science Diet Adult Large Breed Maintenance165.6623.8614.43


    Science Diet Adult Light170.5624.48.9


    Science Diet Maintenance Lamb Meal and Rice184.7422.815.94.01


    Innova Senior186.7219.898.843.49Maintence
    Eukanuba Adult Maintenance (and Adult Small Bite)196.9226.216.94.33All Life Stages
    Pro Plan Adult Lamb and Rice197.8928.9919.444.59Maintenance
    Eukanuba Adult Large Breed202.8525.1914.413.92Maintenance
    Pro Plan Performance202.9734.4823.564.82All Life Stages
    Purina ONE Chicken and Rice205.9531.8519.254.62All Life Stages
    Eukanuba Adult Premium Performance2071.0031.421.24.45All Life Stages
    Iams Large Breed Adult Maintenance208.9124.3114.074.03All Life Stages
    Diamond Premium Adult Maintenance210.9029.420.2


    All Life Stages
    Iams Active Maturity (Senior)213.9025.31113.89


    Purina ONE Beef and Rice216.9829.9619.94.54All Life Stages
    Eukanuba Senior Maintenance218.9526.9811.783.99Maintenance
    Eukanuba Senior Large Breed221.8726.9811.783.93Maintenance
    Pro Plan Adult Chicken and Rice2211.0128.5220.384.56Maintenance
    Iams Puppy2241.0432.0719.874..29


    Nutro Natural Choice Senior227.88 [max. 1.1]23.2312.73.88Maintenance
    Nutro Natural Choice Large Breed Weight Management228.85 [max. 1.4]21.259.943.74Maintenance
    Pro Plan Reduced Calorie228.9128.269.433.98Maintenance
    Science Diet Large Breed Puppy229.843010.73.41


    Pedigree Mealtime with Lamb and Rice230




    All Life Stages
    Pro Plan Adult Beef and Rice2301.0130.4418.784.51Maintenance
    Pro Plan Senior233.9531.2314.774.08Maintenance
    Purina ONE Lamb and Rice2351.0930.4920.154.66All Life Stages
    Nutro Natural Choice Large Breed Puppy235.9431.815.94


    Growth and Maintenance
    Innova Dog2391.1026.5215.474.17All Life Stages
    Pro Plan Puppy Chicken and Rice2391.1131.6221.23


    All Life Stages
    Purina Dog Chow240.9023.3812.974.00All Life Stages
    Nutro Max Weight Control Formula241.9118.8010.693.78Maintenance
    Pro Plan Puppy Lamb and Rice2431.1131.2621.63


    All Life Stages
    Pro Plan Adult Turkey and Barley2451.0527.9218.344.28Maintenance
    Purina ONE Reduced Calorie246.9528.639.613.87Maintenance
    Pro Plan Puppy Beef and Rice2471.1131.2120.60


    All Life Stages
    Iams Chunks (same as Mini-Chunks)2491.1027.41164.06


    Diamond Maintenance2501.0023.913.7


    All Life Stages
    Diamond Professional Formula2501.1034.123.4


    All Life Stages
    Diamond Puppy2501.1035.323.4


    All Life Stages
    Purina Dog Chow Little Bites250.9522.3712.273.77All Life Stages
    California Natural Lamb Meal & Rice2521.1224.0712.493.99All Life Stages
    Nutro Natural Choice Large Breed Adult255.70 [max 1.40]30.214.983.97Maintenance
    Nutro Natural Choice Large Breed Senior255[max 1.0]25.3814.33.93All Life Stages
    Pedigree Puppy2601.0230.8611.36



    Purina Fit and Trim260.8328.386.493.10Maintenance
    Purina Hi-Pro2601.1529.5417.624.26All Life Stages
    Purina Puppy Chow Large Breed2601.0230.1913.93


    Growth and Maintenance
    Nature's Recipe Allergy - Vegetarian266.9820.739.703.69Maintenance
    Purina Dog Chow Senior 7 Plus270.9927.8311.283.63Maintenance
    Purina Puppy Chow2701.0829.9515.55


    Growth and Maintenance
    Purina ONE Large Breed Puppy Formula2731.0834.4711.673.97Growth and Maintenance
    Nutro Natural Choice High Energy2771.2034.4822.644.53All Life Stages
    Diamond Lamb and Rice Puppy2801.1030.316.5


    All Life Stages
    California Natural Reduced Calorie2861.1019.698.84


    Purina ONE Puppy Formula2871.3331.1220.664.64All Life Stages
    Nature's Recipe Easy to Digest Chicken Oat & Barley2881.1728.2417.184.05


    Science Diet Puppy2971.2229.419.4



    Nature's Recipe Senior Lamb Meal & Rice298.8917.059.142.97


    Innova Puppy3001.5528.7313.264.00All Life Stages
    Purina Beneful3001.2028.8913.953.97All Life Stages
    Diamond Lamb Meal and Rice Adult3101.2026.215.7


    Growth and Maintenance
    Come and Get It3131.1724.213.303.43


    Nutro Max Puppy3151.3131.4119.234.15All Life Stages
    Nutro Max Adult3251.3129.7718.054.02All Life Stages
    Nutro Max Mini Chunk3251.3129.7718.054.02All Life Stages
    Nutro Max Natural3251.3129.7718.054.02All Life Stages
    Nutro Natural Choice Chicken Meal and Rice3391.3124.2814.54


    All Life Stages
    Nature's Recipe Joint & Hip Formula3441.2923.3713.373.75


    Nutro Natural Choice Lite3551.2117.177.093.40Maintenance
    Alpo Lamb Meal Rice and Barley3571.2123.6815.13.59All Life Stages
    Alpo Puppy3611.2131.713.63.64Growth
    Nature's Recipe Adult Lamb Meal & Rice3641.3823.5513.653.78


    Pedigree Large Crunchy Bites (also Small Crunchy Bites)370






    Alpo Beef and Chicken3721.2422.4712.123.35All Life Stages
    Nutro Natural Choice Dental Care Adult3961.4623.2714.33.70All Life Stages
    Nutro Natural Choice Puppy4031.4029.4914.313.78

    All Life Stages

    Nutro Natural Choice Lamb Meal and Rice4061.5324.4714.39


    All Life Stages
    Pedigree Meaty Chunks with Rice and Vegetables4201.5923.869.09



    Nature's Recipe Easy to Digest Lamb, Rice & Barley4231.5625.3711.933.69


    Nutro Premium Nutrition Dog Food4251.5829.9714.41


    All Life Stages
    Nature's Recipe Venison Meal and Rice4291.625.0812.823.72


    Nature's Recipe Puppy4701.8025.8628.26



    Nature's Recipe Puppy Lamb Meal & Rice4701.828.2616.733.84


    The figures in the above table were collected in March 2002 and the Natura figures were revised in April 2003 when more detailed data was provided.

    The Hills Prescription Diet food k/d, designed for dogs with chronic renal failure or other kidney problems is included simply as a reference level. I am not recommending that anyone feed k/d to a dog who has not been diagnosed with renal failure.

    Here are some links that might be useful:

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    Copyright 2002, 2003 Stacy Pober.
    Golightly Greyhounds

    Revised, 22 April 2002, SP