Hi stranger! Signing up for MypetMD is easy, free and puts the most relevant content at your fingertips.

Get Instant Access To

  • 24/7 alerts for pet-related recalls

  • Your own library of articles, blogs, and favorite pet names

  • Tools designed to keep your pets happy and healthy



or Connect with Facebook

By joining petMD, you agree to the Privacy Policy.

petMD Blogs

Written by leading veterinarians to provide you with the information you need to care for your pets.

The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.

ADVERTISEMENT

With so many brands of pet food for pet owners to choose from, commercial dog food makers pursue customers using crafted marketing strategies. By capitalizing on widespread perceptions, or misconceptions, owners have about pet nutritional needs, these companies have created a myriad of life-stage, lifestyle, and breed specific products to capture the market share.

This proliferation of “specially formulated” foods only further solidifies a more widespread belief in the need for such products. Some of these nutritional strategies are supported by scientific data confirming their value. Most are not. The notion that geriatric pets need special nutrition is a case in point. Older pets have the same needs as younger animals, unless they develop specific diseases.

Protein in Senior Pet Foods

Commercial food strategies for protein in senior diets have traditionally been either providing less protein or more protein. The case for less protein was founded in the belief that kidney function decreases with age, and that pets with kidney disease should be protein restricted. In fact, studies indicate that structural changes associated with aging in the kidneys of geriatric dogs do not result in decreased renal function.

Kidney disease and dysfunction is most often diagnosed in geriatric pets, but as these studies indicate, it is not a result of age but a result of developing kidney disease by whatever cause (mostly idiopathic, meaning we haven’t a clue). The majority of geriatric pets do not have kidney disease.

Old research suggested that if a pet has kidney problems, normal protein levels in food would accelerate kidney dysfunction. We now know that this is not true. Elevated protein levels in the diet does not speed kidney failure. Low protein diets are used with patients with advanced stages of kidney disease to alleviate the symptoms of elevated blood ammonia levels due to kidney dysfunction (Geriatric Pets Need More Protein). These low protein diets designed specifically for kidney disease are not appropriate for geriatric pets without kidney disease. Such diets could accelerate the natural muscle tissue loss that does accompany aging.

Most newer, commercial geriatric formulas feature slightly higher levels of protein than regular diets. This strategy is based on the recognition that aging does result in a progressive loss of muscle tissue, or sarcopenia. Some studies have suggested that high protein diets can bring about muscle production in geriatric dogs and cats. Other studies have suggested that increased protein in the diet merely slows muscle loss. And still other long term studies in dogs have documented no difference in the amount of sarcopenia with diets containing either 16.5 percent protein or 45 percent protein.

It appears that a diet containing between 16 and 24 percent protein is adequate for geriatric dogs. Not surprisingly, most non-senior dog food contains 24 percent or more protein. A survey of special geriatric diets suggests that these formulas contain only about 4-8 percent more protein than the already adequate regular dog food.

The story is similar with cat food, although the percentages are much higher given the higher protein needs of cats. I am not against extra protein. The point is this: Just because a pet is geriatric does not mean it needs more protein than that already provided in its normal diet.

If an animal has adequate muscle mass, extra protein cannot be stored and will be used in three ways: First, it can be used as energy. Second, it can be converted to sugar or glucose for energy. Or thirdly, that glucose can be converted and stored as glycogen or, more likely, fat.

Avoid geriatric foods that feature less protein than your present dog or cat food. But don’t pay more for a “senior food” with extra protein if your dog’s regular diet already contains 24 percent or more protein (as dry matter) and your cat’s regular food contains 35 percent or more protein (as dry matter).

To calculate protein level on a dry matter basis you will need the label from the food. In the guaranteed analysis on the label, take the percentage of protein content and divide it by the percentage of moisture content.

As you will see in the example below, you must first convert the moisture percentage to decimal. Do this by placing a decimal point in front of the percentage (e.g., 10% becomes .10; 81% becomes .81) and then subtract it from 1. You will then us the resulting number to divide the protein percentage. The final answer is the protein level on a dry matter basis.

Dry Food: Label says 24% protein and 10% moisture: 24%/ (1-.1) = 24%/.9 = 26.7%

Wet Food: Label says 9% protein and 81% moisture: 9%/ (1-.81) = 9%/.19 = 47.4%

As you can see with this example, the protein levels are already adequate.

Next week's blog will look at other geriatric changes targeted by commercial geriatric food formulas.

Dr. Ken Tudor

Image: Ysbrand Cosijn / via Shutterstock

Comments  5

Leave Comment
  • Good Information!
    04/18/2013 12:33pm

    Thanks for this useful information. I've been going back and forth on whether or not to switch to a food formulation for older dogs. Our girls (a Miniature Poodle and Japanese Chin - the Poodle is the older one,she's about 11 now) have been thriving on the food we've always given them (Science Diet regular formula). I've always tended to go along with the old adage "If it ain't broke don't fix it" lol, and so was hesitant to make any changes in their basic diet. This article pretty much confirms that my feelings are correct. The girls are healthy, energetic, playful and happy and maintain a proper weight on their current diet which, since I've read this, I will continue to feed them. Of course their diet is supplemented by wet food and treats (yes, my husband and I do spoil them but not to excess). Hopefully we will still continue to have them with us for many years to come - I can't imagine life without them!

    Again, thank you for this helpful and informative article.

  • 04/18/2013 02:49pm

    We never alter diets based upon age any more than we would do for humans. One of the cats we took in was limping along on only one kidney with borderline renal numbers but in all the years we had him, those numbers did not increase in spite of his need for a diabetic cat's diet that kept him off insulin for over a decade. Most of these trendy foods are a bit rediculous IMHO, just as they would be if we found them on human grocery shelves.

  • Marketing!
    04/18/2013 05:43pm

    The pet food companies seem to be stellar at marketing and knowing what will tug at the heartstrings of the humans who love their critters.

    I agree with Mahkidzrpupz - "If it ain't broke, don't fix it!"

    Without feeding everyone separately, it would be difficult to feed a "herd" of varying ages even if all are healthy.

    As I age, I don't plan to change my diet unless a health issue crops up. Why shouldn't my critters be fed using the same strategy?

  • Excess Protein
    04/19/2013 09:56pm

    I have been feeding a "senior" formulation that contains a whopping 42% protein as dry matter (based on your calculation above).

    Looks like this very high protein level could possibly be contributing to my dog's tendency to put on weight?

    " ... extra protein cannot be stored and will be used in three ways: First, it can be used as energy. Second, it can be converted to sugar or glucose for energy. Or thirdly, that glucose can be converted and stored as glycogen or, more likely, fat."

    I think it's time for me to rethink what I feed to him. Thanks for this eye-opening post.

  • 04/20/2013 01:10am

    One gram of protein is 4 calories, as is one gram of carbohydrate. If you pick a food with reduced protein, usually you find that the protein is replaced with higher fat content, which then means more calories. Portion control is always the first response to weight gain, and then reviewing the food's ingredients.

    As corn gluten meal contains a much higher proportion of leucine, and leucine has been found to create muscle rather than fat, I always like to see corn gluten meal as a SECONDARY source of protein in our sedentary house pets' foods. Muscle meat is always first on my list. I would expect that leucine would be even more helpful for older pets that have a harder time utilizing nutrients.

    The next nutrient I would look for would be good sources of fermentable fibers as they don't provide calories, or very few. Much better than replacing protein with fats.

Meet The Vets

  • Lifetime Credits:
  • Today's Credits:
Hurry Before All Seats are Taken!
Enroll
Be an A++ Pet Parent! Take fun & free courses to earn badges & certifications. Choose a course»

Top Current Topics