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Older Cats and Protein – A Delicate Balance

Nutrition Nuggets is the newest offshoot of petMD's Cat Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of cat nutrition.

Older Cats and Protein – A Delicate Balance

December 07, 2012 / (5) comments

Cats are true carnivores, and as such, they have relatively higher requirements for protein in their diets than do dogs. This is true during all of a cat’s life stages, but when they hit their senior years, the situation gets a little complicated.


Chronic kidney disease (CKD) is extremely common in older cats and can only be diagnosed via traditional means when the condition is quite advanced (when two-thirds to three-quarters of a cat’s kidney function is already lost). Since CKD is a chronic, oftentimes slowly progressive disease, it follows that many older cats have reduced kidney function that is not yet bad enough for our laboratory tests to diagnose.


Overfeeding protein, particularly poor quality protein, to cats with CKD worsens their condition. As a result, some senior cat foods have been designed to have reduced protein levels, presumably based on the assumption that many of these individuals have undiagnosed kidney disease and would benefit from a lower level of protein in their diets.


Not so fast. Another common problem in older cats is sarcopenia, the loss of skeletal muscle mass and strength associated with the aging process. Sarcopenia can have many causes including protein deficiency, systemic diseases, reduced activity levels, and musculoskeletal and neurologic disorders. There hasn’t been much research into the condition in animals, but one study did reveal that cats between the ages of ten and fourteen have a harder time digesting protein and other important nutrients like fat and energy.1 Also, studies in older people have shown that eating more protein can reduce muscle mass loss.2


So it appears that the owners of older cats are between the proverbial rock and a hard place, yes? Until more research into the optimal dietary protein levels for senior cats is done, I think the best solution lies in focusing more on protein quality rather than quantity. I typically recommend that the owners of healthy, older cats neither increase nor decrease the amount of protein in their pets’ diets but maintain the level that worked well for that individual in the past (after all, it got them to their golden years in pretty good shape).


I urge owners to pay extra attention to the quality of their older cat’s food. Check out the ingredient list. A highly digestible protein source like chicken should be listed first, indicating it is the predominant ingredient by weight. Eggs also have an exceptionally high biologic value for cats, meaning that the protein is actually utilized by the body rather than excreted as waste. It is this unused protein that results in the potentially detrimental extra work for the kidneys that we want to avoid in older cats.


To sum up, I think our best option, until future research proves otherwise, is to keep the amount of protein we feed older cats similar to that which they ate in their prime and to do all we can to ensure that it is coming from high quality and digestible ingredients.


Dr. Jennifer Coates



1. Some nutritional aspects of aging in cats and dogs. Taylor EG, Adams C, Neville R. Proc Nutr Soc. 1995. 54:645-656.

2. Amino acids and muscle loss with aging. Fujiita S, Volpi E. J Nutr. 2006. 136:277S-280S.

Image: Schubbel / via Shutterstock

Comments  5

Leave Comment
  • Kidney Failure
    12/07/2012 11:58am

    Chronic Kidney Failure seems to be pretty common in older kitties. If only there were a way to "head it off at the pass" before it becomes a problem.

  • 12/09/2012 07:19pm

    There certainly IS a way to head chronic kidney failure off at the pass. Chronic kidney failure in cats is due primarily to the cats consuming, over their lifetimes, excessive quanitities of dry food with inferior sources of protein and insufficient moisture. If cat owners would feed their cats wet food, with fresh meat being the primary protein source, they would be going a long way towards combating the threat of chronic kidney failure down the road in the cats' lives.

    It is the fault of cat food processors, like Hill's, which purposely mislead cat owners into believing the BIG LIE -- that dry food and non-meat protein is the best food for their pet cats. Hill's Science Diet Adult Indoor cat food contains NO MEAT ("Chicken By-Product Meal" is, by definition, not meat).

  • Kidney failure
    12/09/2012 07:21pm

    It's very nice to see Dr. Coates endorse adequate protein for cats. I'm convinced kidney failure in cats is caused by excessive carbohydrates in their food, i.e, dry foods. But once it occurs, a lack of protein, or low protein kidney diets, literally starve the cat to death because of their high protein need. Thanks again for endorsing a cat friendly diet.

  • Daily moisture from food
    12/09/2012 08:10pm

    A cat's daily moisture requirements should come primarily from its food. If you see your cat drinking frequently from its water dish, then the cat's kidneys probably already are affected.

    It's nice that you "urge owners to pay extra attention to the quality of their older cat’s food." It would be better if you urged them to do that beginning when the cats are kittens. If cats are fed high quality food, including fresh meat and adequate moisture content, throughout their lives, then chronic kidney failure could be the exception rather than the rule.

  • 06/04/2014 12:22am

    Yes, it is important to provide proper nutrition from day one. However, I refer you to the title of the article, "Older Cats & Protein..." Suggestions for food for kittens are not germane to the article. Dr. Coates has kept the article focused on the subject about which we need to read.
    I would, however, really appreciate a list of products which contain the kinds/amount of protein which would be good for older cats.


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