Tag: senior

old brown tabby
Behavior

Cognitive Dysfunction Syndrome (CTS) in Elderly Cats

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Old brown tabby cat
Photo by Jonas Jaeken on Unsplash

As our cats get older, they can show a variety of signs of aging. Some, like arthritis and a graying muzzle, you probably expect. But did you know that cats (and dogs) can get dementia, just like humans? Cognitive dysfunction in cats is not uncommon in old age [4]. About 30% of cats 11-14 years old and 50% of cats 15+ have changes in behavior unrelated to another health problem [4-6]. This is called Feline Cognitive Decline or Cognitive Dysfunction Syndrome (CDS) in veterinary terms.

What Does Cognitive Dysfunction Syndrome Look Like?

Sordo and Gunn-Moore use the acronym VISHDAAL to help explain the typical indications of cognitive dysfunction in cats. The letters are in order of how common the symptoms are. [5]

  • V is for Vocalization: excessive meowing or yowling, especially at night [1-5]
  • I is for Interactions: changes in the way your cat interacts with members of the household, such as an increased or decreased interest in petting and attention, irritability, aggression toward people/pets, or decreased responsiveness [1, 3, 5, 6]
  • S is for Sleep-wake cycle: changes in the cat’s sleep-wake cycle, particularly being awake during hours of the night when they used to sleep [1-6]
  • H is for House-soiling: that is, urinating and/or defecating outside the litterbox [1-6]
  • D is for Disorientation: being confused about place or time, e.g. getting lost in familiar locations, becoming somehow stuck in places they should be able to get out of easily, not remembering that they’ve just been fed, staring blankly into space [1-6]
  • A is for Activity levels: either decreased activity, e.g. less grooming, lack of interest in food or play, or increased activity in the form of restlessness [1-6]
  • A is for Anxiety: this can manifest in a variety of ways depending upon the individual cat and may contribute to other symptoms [1-6]
  • L is for Learning and memory: forgetting routines, commands, and familiar people, pets, or places [2-6]

Not every cat will exhibit every symptom, and CTS is a condition that changes and progresses over time [5, 6]. Some of the first signs of CTS may be subtle, and many cat parents mistake them for a normal part of aging that they can’t do anything about [1, 5, 6]. However, if you notice any of these symptoms in your senior cat, you absolutely should tell your veterinarian [1, 3]. The vet can confirm a diagnosis and come up with a treatment plan to make your cat’s last years as peaceful as possible.

Cara’s Story

Cara was one of my childhood cats. She was born under our front porch when I was five or six years old, along with two sisters and a brother. We kept her and her brother, Milo, and they were with us into my college years. Cara was always sort of an odd duck. She wanted attention only rarely, stuck her head in shoes, and stared down into the floor vents for extended periods of time. But when she got to be maybe eight or nine years old, she started getting weirder.

The garage was the cats’ home base, and when they wanted out there they would stand at the door and meow. But Cara started going up to any closed door in the house and meowing to go out. She started actually rubbing against us and demanding attention. She started peeing in the bathtub. Cara had kidney problems, as many old cats do, but we never could figure out why it was just the bathtub. She became much more vocal, as well, although if she was meowing in the middle of night, we never heard it since they slept in the garage. No one in my family knew that pets could get dementia until we saw it with Cara.

Diagnosing Cognitive Dysfunction Syndrome

CDS is a diagnosis of exclusion because many of the symptoms can also be caused by medical problems that are common in senior cats [1-3, 5, 6]. For example, pain from arthritis might cause irritability or decreased activity [1, 2, 5]. Vision or hearing loss might cause a cat to become disoriented [1, 2]. It’s important to rule out other medical causes through testing [5]. Only then can your veterinarian be sure that CDS is the culprit.

What Causes Cognitive Dysfunction in Cats?

No one knows for sure what causes CDS. Just like Alzheimer’s disease in humans, it is still somewhat of a mystery. Veterinarians have a few ideas, however. As cats get older, their brains accumulate certain kinds of age-related damage [4-6]. Their brains eventually shrink and lose neural connections, just like ours do [5]. Toxic beta-amyloid plaques and abnormal tau proteins build up in the brain over time [4-6]. Impaired blood flow and oxidative damage are also age-related changes that contribute to cognitive dysfunction in cats [4-6]. The brain is expected to deteriorate with age, just like the rest of the body [3]. However, handling dementia in your elderly pet isn’t as straightforward as some of the other conditions common in senior cats because it isn’t one-size-fits all.

How is Feline Cognitive Dysfunction Treated?

Tan cat laying on sidewalk
Image by Anna Armbrust from Pixabay

There is no cure for CDS, but there are things you can do to make things easier for your cat if they are diagnosed with it [3, 5, 6]. A lot of it has to do with adjusting your cat’s environment to make things easier for them [1, 3]. Keeping to a strict routine makes everything easier to remember and less stressful [1, 5]. Avoid major changes, such as introducing a new pet, if at all possible [2, 3]. If your cat is up all night, you can make a point to keep them active during the day and play with them in the evening hours [1]. Cats that are soiling outside the litterbox may be forgetting where the litter box is or how they’re supposed to use it [1]. Add more litterboxes in easy-to-see places [1-3].

Anxiety may be helped by giving your cat more attention, playing the radio at night/when you’re not home, or using a calming pheromone diffuser like Feliway [1, 3, 5]. Every cat is different, though, so expect some trial-and-error. Ask your veterinarian for recommendations based upon your cats specific symptoms [1, 5]. It may help to consult a cat behaviorist, too [1].

A special diet can sometimes help with CDS [2, 3, 5, 6]. Vitamin E and antioxidants are believed to aid an aging cat’s brain [2, 3, 5]. There are cat foods available that are high in these nutrients [5]. Ask your veterinarian or local pet store for a recommendation. You can also buy supplements, but be careful, because they are usually formulated for dogs and may not be safe for cats [5]. Only use a supplement that is clearly labeled as safe for cats!

Medication

There aren’t any medications specifically for cognitive dysfunction in cats yet; nonetheless, there are some that your veterinarian may prescribe. Anti-anxiety medication is one option [1-3, 5]. The drug selegiline/Anipryl is approved for CDS in dogs and is sometimes prescribed for cats [1, 2, 5, 6]. Not all cats with CDS require medication, however, and their needs can change over time. Take your senior kitty into the vet for regular appointments to reassess what their needs are [6].

Sources

  1. American Society for the Prevention of Cruelty to Animals. (n.d.). Older cats with behavior problems. ASPCA. https://www.aspca.org/pet-care/cat-care/common-cat-behavior-issues/older-cats-behavior-problems
  2. Cornell Feline Health Center. (2018, July). Cognitive dysfunction. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/cognitive-dysfunction
  3. International Cat Care. (2018, August 17). Senility, dementia or cognitive dysfunction syndrome. https://icatcare.org/advice/senility-dementia-or-cognitive-dysfunction-syndrome/
  4. Kornreich, B. (2022, September 27). Feline cognitive dysfunction syndrome (CTS). Cornell Feline Health Center Monthly Health Tips. [Email Newsletter]
  5. Sordo, L. and Gunn-Moore, D. A. (2021). Cognitive dysfunction in cats: Update on neuropathological and behavioural changes plus clinical management. VetRecord, 188(1), e3. https://doi.org/10.1002/vetr.3
  6. Stilwell, N. (2019). Unpacking feline dementia: A veterinary guide. Vetted, 115(5), 6-8. https://www.dvm360.com/view/unpacking-feline-dementia-veterinary-guide

Published October 1st, 2023

Science

Hyperthyroidism

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Thyroid disease is fairly common in cats, especially as they get on in years. The most frequent type of thyroid disease in older cats is hyperthyroidism [1, 4]. My parents’ elderly cat, Rosie, has it. So did my roommate’s cat Coco. And so do my best friend’s two ancient gray ladies. Even though hyperthyroidism is a common illness, I will attest that it can still be mystifying at times. It can impact a cat’s entire body, and it isn’t completely understood even by scientists and veterinarians. It is diagnosable and treatable, however. Sometimes, hyperthyroidism can even be cured.

Graphic of cat thyroid gland
The thyroid gland – Image from Cornell Feline Health Center

What is Hyperthyroidism?

The thyroid gland is a small organ found in all vertebrates which produces the thyroxine (T4) and triiodothyronine (T3) hormones. In mammals, the thyroid is found in the throat and has two lobes. Thyroid hormones regulate a wide variety of bodily functions. When the thyroid produces too much T3 and T4, it’s called hyperthyroidism. Hyperthyroidism increases the body’s metabolism which can cause problems with many different organs and systems.

Cats typically develop hyperthyroidism when middle-aged or older [1, 2, 7, 8, 10]. Up to 10% of cats age 10 and older may have hyperthyroidism [1, 3, 8]. It’s uncommon in cats younger than that, however [1, 2, 7, 8]. Untreated hyperthyroidism is fatal, but today the prognosis for a cat with this disease is usually optimistic.

How is Hyperthyroidism Diagnosed?

If your veterinarian suspects hyperthyroidism, they will probably do a physical examination of your cat’s neck to see if they can feel that the thyroid is enlarged [1, 2, 4, 7]. The presence or absence of a suspicious lump isn’t enough for a diagnosis, however. Most of the time, the final diagnosis can be made with a total thyroxine, or TT4, blood serum test [10]. The vast majority of hyperthyroid cats will have very high T4 levels with a TT4 test, making the diagnosis clear right away [1, 2, 7, 10].

However, cats with hypothyroidism occasionally have T4 serum levels that fall within normal limits [1, 2, 7, 10]. T4 levels fluctuate, so your veterinarian may decide to try the test again in a few weeks [1, 7]. Or they might try other thyroid hormone blood tests. A thyroid scan is another option but must be performed at a specialty veterinary facility [7, 10].

What are the Symptoms?

Because thyroid hormones affect so many parts of the body, the symptoms of hyperthyroidism are varied and sometimes nonspecific. They include:

Graphic of cat with hyperthyroidism
Characteristic appearance of hyperthyroid cat – Image from Cornell Feline Health Center
  • Weight loss/muscle wasting
  • Increased appetite
  • Increased thirst and urination
  • Vomiting
  • Diarrhea
  • Hyperactivity
  • Unkempt fur
  • Aggression or irritability
  • Fast heartrate
  • Increased vocalization, especially at night
  • Weakness
  • Heat intolerance

Some cats demonstrate “apathetic hyperthyroidism,” where they are lethargic, anorexic, and depressed/dull instead of the more usual symptoms [1]. Hyperthyroidism is progressive, so symptoms may be very mild at first [2]. It’s also not uncommon for hyperthyroid cats to also have other diseases, especially since they tend to be older. Many of these symptoms can be symptoms of something else. The safest bet is to consult your veterinarian anytime your cat seems different or unwell.

Secondary Illnesses

An overactive thyroid can sometimes cause other organs to become diseased. The heart is particularly at risk. There is a form of heart disease known as thyrotoxic cardiomyopathy which is caused by the heart muscle working overtime to meet the demands of a metabolism on overdrive [10]. The heart muscle thickens as a result of pumping so hard, but then that makes it difficult for the heart to work properly [2, 4, 10]. This can lead to heart failure. Fortunately, successful treatment of the hyperthyroidism can improve and even reverse the cardiomyopathy [2, 7, 10].

Hyperthyroid cats frequently experience high blood pressure as a cardiac complication, too [2, 4, 10]. About 25% of the time, in fact [10]. In severe cases, the high blood pressure can damage their organs [2, 4, 10]. It can even lead to retinal detachment that renders them permanently blind [4, 10]. High blood pressure is no joke and needs to be managed alongside hyperthyroidism until the thyroid hormones are under control [2]. If the hyperthyroidism is resolved, the blood pressure usually takes care of itself [2, 10].

What Causes Hyperthyroidism?

Hyperthyroidism usually begins when the thyroid gland becomes enlarged [2, 10]. In cats, this is almost always the result of a benign tumor called an adenoma [2, 4]. In less than 2% of cases, the growth is cancerous [1, 10]. What causes the abnormal thyroid tissue growth to begin with, however, remains uncertain. Researchers have found evidence for both environmental and biological factors that may play a role.

Environment

There is a demonstrated association between diet and the chances of a cat developing hyperthyroidism. Too much iodine in the diet may make a cat susceptible [10]. Canned cat food is also associated with higher rates of hyperthyroidism [1, 5]. The results of a 1999 study suggest cats fed primarily canned food have a rate of hyperthyroidism 2 to 3 times higher than other cats [5]. Researchers still don’t know why canned food would lead to an overactive thyroid. Correlation is not causation, so there may be more going on here that we don’t understand yet.

Using cat litter has also been found to be a potential risk factor, with the same study showing triple the rate of hyperthyroidism in cats that use litter [5]. Again, although there is a potential link, there is as yet no explanation. From looking through a lot of research papers to write this article, I know that veterinary scientists are still hard at work trying to figure out feline hyperthyroidism. The disease just doesn’t want to give up its secrets easily.

Certain household chemicals are associated with higher rates of feline hyperthyroidism, too. Polybrominated diphenyl esters (PBDE), which are used as flame retardants, have been found in high levels in the blood serum of hyperthyroid cats [1]. According to the Environmental Protection Agency factsheet for PBDE, rodent studies have shown thyroid toxicity from PBDE exposure. Per- and polyfluoroalkyl substances (PFAS) are a versatile group of artificial chemicals with a wide variety of applications in industry and the home. Wang et al. found that PFAS levels, particularly perfluorooctanoic acid, were higher in hyperthyroid cats than the cats in the control group [9]. The Environmental Protection Agency lists tumor growth and thyroid hormone disruption among the effects of PFAS in animals.

Siamese cat in meadow
Siamese have a reduced rate of hyperthyroidism – Image by rihaij from Pixabay

Biology

Hyperthyroid cats may have defects in the way their cells communicate that lead to the adenomas and other tissue abnormalities that overproduce thyroid hormones. Cats with thyroid nodules sometimes have low levels of the G protein in their thyroids [1]. A lack of G protein can decrease the inhibition of cell growth [1]. Some cats with thyroid nodules or adenomas have a cancer-causing mutation, known as an oncogene, which could cause the excessive cell growth [1].

Certain breeds of cat are less likely to develop the disease: Siamese, Burmese, Tonkinese, Himalayan, Persian, Abyssinian, and British Shorthair [3, 5, 9, 10]. At one time, only the Siamese, Burmese, and Persian/Himalayan were known to have these decreased risk, so the benefit was thought to be associated with the color-point pattern or lighter coat colors [3]. This hypothesis ultimately didn’t hold up [3], but perhaps there is something special these breeds have in common which will one day come to light. The same study which discovered the three new resistant breeds also found that long-haired, nonpedigree cats have higher rates of hyperthyroidism [3]. This despite the extremely long-haired Persian and Himalayan’s decreased rate.

What Treatments are Available?

Radioactive Iodine

It might sound a little scary, but radioactive iodine is actually the gold standard for treating feline hyperthyroidism. This treatment can only be done in specialized veterinary clinics that are authorized to work with radioactive materials, so it may not be accessible or affordable for everyone [2, 7, 10]. It’s a great option if you can take it, though, because for about 95% of cats it cures their hyperthyroidism–even those few with cancerous thyroid tumors [1, 2].

Radioactive iodine therapy relies on the fact that the thyroid takes up iodine to synthesize thyroid hormones. The cat is injected with the radioactive version of iodine, I-131 [1, 2, 7, 10]. No anesthesia is required [2, 7, 10]. The cat’s thyroid absorbs the I-131, just like it would normal iodine, but the abnormal thyroid tissue that’s churning out T3 and T4 like crazy is hogging the iodine. So the radioactive molecules get sucked into the abnormal tissue and kill it, leaving alone the cat’s healthy tissues, including any healthy thyroid tissue [1, 2, 7, 10].

Although the procedure is quite safe for the cat, it can be dangerous for the people around the cat which is now shedding radioactive particles [2]. Cats have to be hospitalized for a week or two after radioactive iodine therapy so that their radiation levels can get low enough for release [1, 2, 7, 10]. Even then, special care has to be taken at home for a two weeks after [1].

Radioactive iodine therapy may be a good option for cats that cannot undergo anesthesia. It also works well for cats with ectopic thyroid [7]. Ectopic thyroid is thyroid tissue somewhere other than the usual location of the thyroid gland such as under the tongue or in the chest [10]. It can be in locations that would be difficult to remove surgically. Radioactive iodine therapy doesn’t usually have complications, but for the rare cat it works too well and they become hypothyroid instead [2]. The solution to this is medication with thyroid hormones.

Medication

Hyperthyroidism cannot be cured with medication, but it can be managed with it. The medicine is called methimazole [1, 4, 7, 10]. Its brand names are Felimazole and Tapazole [4, 7, 10]. Methimazole is available as an oral tablet or a gel applied to the skin [1, 2]. It works by decreasing the production and release of hormones from the thyroid [2, 4]. It’s usually given twice a day [1, 4].

Cats may be given methimazole as a long-term method of managing their disease or to stabilize them before trying a more permanent solution [1, 4, 7]. Like all drugs, methimazole can have side effects. According to the Food and Drug Administration, the most common side effects of methimazole in cats are changes in appetite, lethargy, vomiting, diarrhea, skin lesions, itchiness, unusual vocalizations, weight loss, fur abnormalities, weakness, and agitation [4]. However, a small percentage of cats develop severe side effects with methimazole [1, 4]. Namely, liver disease, anemia, low blood platelets, and low white blood cell counts [1, 4, 7, 10]. Always report medication side effects, even seemingly small ones, to your veterinarian.

Two veterinarians holding white cat
Photo by Gustavo Fring from Pexels

Surgery

When Dr. Jean Holzworth first recognized feline hyperthyroidism in 1978, the only way to treat it was to remove the offending thyroid gland [1]. Although there are now other options, for some cats this is still the chosen course of treatment. For most cats, surgery cures their hyperthyroidism [2]. It can also be done at a regular veterinary surgery rather than the special facility required for radioactive iodine therapy, making it accessible to more people. Surgery requires a cat to go under anesthesia, however, and for older cats who often have other health problems, that can be a risky proposition [2, 10].

Surgery also carries a chance of complications. Complications aren’t likely, but they do happen. Most cats still have enough thyroid cells left after the surgery to keep up their T3 and T4 hormone levels, but some become hypothyroid and require medication [7]. Another possible complication is damage to the parathyroid glands, which are near or within the thyroid are necessary for maintaining normal calcium levels in the blood [2, 7]. If the parathyroid glands become damaged, the cat may develop low blood calcium and require supplemental calcium or vitamin D [1, 7]. Other complications include damage to nearby nerves or the larynx [1, 7].

Due to the risks associated with surgery and the availability of alternatives, it isn’t a very common choice anymore [2]. That being said, it might still be the right option for you and your cat. That’s something you would have to figure out with your veterinarian.

Diet

The research is still ongoing for diet as a means of controlling hyperthyroidism in cats [2]. For cats with health concerns that make other treatment options difficult or impossible, however, it can be the best–or only–choice despite being somewhat controversial. The principle is that limiting the amount of iodine in the cat’s diet to a small, controlled amount restricts the amount of hormones the thyroid can make. Cats fed a prescription iodine-restricted diet and nothing else should return to normal thyroid function [1, 7, 10]. Nothing else really means NOTHING else. No treats, don’t even put the prescription food in a bowl that has been used for other food or untreated water [1, 10]. The iodine-restricted diet contains only 0.2 parts per million of iodine [10]. That is a really, really small amount. It would not take much to throw off the balance.

In memory of Coco and Rosenberg

Works Cited

  1. Brewer, W. G., Jr. (2020, July 6). Treating feline hyperthyroidism. Blue Pearl. https://bluepearlvet.com/medical-library-for-dvms/treating-feline-hyperthyroidism/
  2. Cornell Feline Health Center. (2017, January). Hyperthyroidism in cats. Cornell University Collège of Veterinary Medicine. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/hyperthyroidism-cats
  3. Crossley, V. J., Debnath, A., Chang, Y. M., Fowkes, R. C., et al. (2017). Breed, coat color, and hair length as risk factors for hyperthyroidism in cats. Journal of Veterinary Internal Medicine, 31(4), 1028-1034. https://doi.org/10.1111/jvim.14737
  4. Food and Drug Administration. (2019, December 3). Hyperthyroidism in cats: There’s an FDA-approved drug to treat it. FDA.gov. https://www.fda.gov/animal-veterinary/animal-health-literacy/hyperthyroidism-cats-theres-fda-approved-drug-treat-it
  5. Kass, P. H., Peterson, M. E., Levy, J., James, K., et al. (1999). Evaluation of environmental, nutritional, and host factors in cats with hyperthyroidism. Journal of Veterinary Internal Medicine, 13(4), 323-329. https://doi.org/10.1111/j.1939-1676.1999.tb02189.x
  6. Peterson, M. E., Castellano, C. A., and Rishniw, M. (2016). Evaluation of body weight, body condition, and muscle condition in cats with hyperthyroidism. Journal of Veterinary Internal Medicine, 30(6), 1780-1789. https://doi.org/10.1111/jvim.14591
  7. Pet Health Topics. (n.d.). Hyperthyroidism in cats. Washington State University College of Veterinary Medicine. https://www.vetmed.wsu.edu/outreach/Pet-Health-Topics/categories/diseases/hyperthyroidism-in-cats
  8. Stephens, M. J., O’Neill, D. G., Church, D. B., McGreevy, P. D., et al. (2014). Feline hyperthyroidism reported in primary-care veterinary practices in England: Prevalence, associated factors and spatial distribution. Veterinary Record, 175(18), 458. https://doi.org/10.1136/vr.102431
  9. Wang, M., Guo, W., Gardner, S., Petreas, M., et al. (2018). Per- and polyfluoroalkyl substances in Northern California cats: Temporal comparison and a possible link to cat hyperthyroidism. Environmental Toxicology and Chemistry, 37(10), 2523-2529. https://doi.org/10.1002/etc.4239
  10. Williams, K., Downing, R., and Ward, E. (n.d.). Hyperthyroidism in cats. VCA Hospitals. https://vcahospitals.com/know-your-pet/hyperthyroidism-in-cats

Published April 25th, 2021

Updated June 14th, 2023

Cat Care

In Search of the Best Cat Food, Part III: Kitten, Adult, & Senior Diets

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

The pet food industry offers diets for every stage of a cat’s life, from formula for newborn kittens to senior cat food. The kitten milk-replacement is one thing, but what’s the difference between solid food for kittens, adults, and seniors? And what about the cat food that says it’s for “all life stages”? Today we look at the difference between diets for the various life stages and what really matters for your cat.

Cat and two kittens eating from bowls
Image by mariahuusgaard from Pixabay

Kitten Food

Before doing this research, I knew there was at least one difference between kitten food and any other cat food. I took Joon in when she was about four months old, and I was living with a roommate that already had a cat. Domino is a gorgeous tuxedo cat with spooky yellow eyes, and she was quite pudgy. My roommate had to put her on a diet, and Domino was not a fan. She kept eating Joon’s food, which Joon was too busy playing to care about. My vet told me I should be careful to keep her from doing this, because kitten food is high in calories.

It makes sense, doesn’t it? Kittens are still growing rapidly, and as they get older they use up a lot of energy playing as well. In fact, kittens may need up to three times as many calories as an adult cat each day (1, 2, 3)! And they have higher protein requirements than adults, as well, needing to get about 30% of all that energy from protein (2). Most of the rest of the calories need to come from fat to ensure that they get enough essential fatty acids for proper development (1). Kittens need lots of vitamins and minerals as well. Basically, like all babies, kittens need lots of nutrients in their diet so they can grow up big and strong. So kitten food is made more nutrient-dense than adult food.

The Association of American Feed Control Officials (AAFCO) requires kitten food to be at least 30% protein and 9% fat on a dry matter basis (4). A survey of 212 adult and kitten foods by IdleCat found that kitten foods actually averaged 40.77% protein for kibble and 49.11% protein for canned food (3). The fat content was a little closer to the minimum recommendation, but for both kinds of food was more than 21% higher than the average fat content of the adult foods (3). Carbohydrate and fiber content were lower to compensate (3). Vitamins and minerals weren’t measured in that survey, but in a well-balanced kitten food they should be present in higher amounts as well.

Kitten food is also made to be easier for small mouths with developing teeth to eat. Canned kitten diets are typically softer, and the kibble comes in smaller pieces (1). However, the nutritional differences are what is most likely to impact a cat’s health. Adult cat food is usually not nutrient-dense enough for kittens, although it will do temporarily in a pinch (5). Conversely, as my vet told me, kitten food can cause adult cats to gain too much weight. Depending on the nutrients included, the extra vitamins and minerals could even cause toxicity in an adult cat (1). A few bites here or there is unlikely to cause anybody any harm–Domino is certainly none the worse for it–but kittens need kitten food and adults should be kept away from it as best we can.

Cats are considered kittens up to one year of age, with the exception of some large breeds. Maine Coons do not reach maturity for up to two years. If you are unsure how long to keep feeding your cat a kitten diet, check with your veterinarian.

Tortoiseshell cat eating from bowl
Image by sweetlouise from Pixabay

Adult Cat Food

Adult cat foods are formulated to maintain a grown cat’s weight and health. Growth and development never completely stop. All organisms continue to make new cells, repair damaged tissues, and progress through their life cycle as long as they live. However, an adult cat uses much less energy than a kitten to do these things, so they need far fewer calories and other nutrients relative to their body weight. This is reflected in the nutritive content of adult cat food.

The AAFCO divides their standards for cat food into two categories: “growth and reproduction,” for kittens and pregnant or lactating queens, and “adult maintenance” for the average, older, and sterilized adult cat (6). The minimum protein content for adult maintenance is 4% lower than the recommendation for kittens and queens. The fat minimum is the same, but 5 out of 12 mineral recommendations are lower for adults, as well as Vitamin A (4). These minerals and vitamin can cause toxicity in excess, which is more likely in adult cats who use less of the nutrients than a growing kitten or a queen who is growing kittens.

Cats are typically considered “adults” from the age of one year to seven years, although this varies some by breed and individual cat (7). Those of us with rescue cats often don’t know exactly how old they are, so you and your vet may have to play it by ear to decide when the time seems right to start treating your cat like a senior.

Senior Cat Food

In the United States, the AAFCO is the government body responsible for licensing pet food, and as previously indicated, they don’t issue standards for senior cat food. The consequence of this is that senior cat food is very similar to adult cat food, with some slight modifications that won’t color outside the AAFCO adult cat food guidelines (8). Whether this is a bad thing or not is hard to say. A lot remains unknown about the needs of senior cats. Due to lack of research, many of the decisions made about how to feed senior pets have been made based on what is known about aging humans (9). Even so, there have been improvements in senior cat diets over the years.

But some cats may not need to go on a senior diet at all, or not until much later in life. If an older cat is keeping up their body weight and muscle condition on their adult diet, there’s no need to change them to a senior diet (8). If a senior kitty begins to gain or lose weight or lose muscle mass and no associated health problem is found, a change in diet may be in order (8). However, senior cat diets can be pretty different from one another. Of course, cats with age-related health problems may be put on a diet specific to their needs. If your vet recommends just plain senior cat food, however, the variability in formulations can be overwhelming.

Fat tortoiseshell cat
Cats sometimes gain weight as they get older – Image by Quinn Kampschroer from Pixabay

It used to be the case that senior cat food was low protein, low fat, and high fiber (8), and the myth that senior cats need a diet low in protein still persists. Some health conditions may call for a low-protein diet, but a normal senior cat may suffer greater muscle loss with less protein (9).

Whether or not senior cats need more protein than adult cats is still unclear, however, and may depend upon the individual cat. If they are notably losing muscle mass, then a high-protein senior diet may be the solution (10). There are still senior diets made with low amounts of protein, all the way to those with enhanced protein, so it pays to check the label. Remember that it’s the dry weight of the nutrients that you need to compare, as the amounts on pet food labels are given in minimum and maximum percentages instead of absolute quantities. Check out this page for a rundown of how that math works.

Senior formulas may be low-calorie, hence the traditional wisdom of making them high-fiber, and for some cats this is appropriate. Generally, cats tend to have progressively slower metabolisms up to eleven years of age and are prone to obesity during middle age, around years six to eight (11). Once they get older than that, they often start to lose weight and may need high calorie diets (11).

Sometimes a vet may actually put a senior cat on a kitten diet if weight loss is a major issue, simply to get enough calories into them (8). In milder cases, a more calorie-dense senior food may be the way to go. If your cat has the opposite problem, well, low-calorie is where it’s at. Both obesity and being underweight can cause significant health problems or be symptoms of them, so keep a close eye on the body condition of older cats. If something changes, always have a vet check for disease before trying to treat the problem with diet alone.

There are other variables as well, such as dietary phosphorous and sodium, which sometimes matter for senior cats if they have certain health problems (9). If your cat has any health issues but they don’t require a medical diet, ask your veterinarian if there is anything you should be on the lookout for when choosing their food.

All Life Stages Cat Food

In order for a pet food to claim that it is “complete and balanced” for all life stages, it must meet the standards set by the AAFCO for both the growth and reproduction and adult maintenance stages. Because the minimums for certain nutrients are higher in the growth/reproduction stage, and there are only a few maximums, “all life stages” food may be too nutrient-dense for some adult cats (12). The food has to have enough nutrients for every stage of life, so it makes sense that what you end up with is more like the food intended for kittens and queens. They have higher nutrient requirements.

Opinions are divided, but I found that veterinarians seemed most inclined to think that food for all life stages was really not appropriate for adult or senior cats (12, 13). Pet food companies had the more mixed advice. Personally, I think all life stages food is great for keeping on hand if you find a stray cat or kitten you need to assist, as you never know what age they might be, and the extra nutrients are probably not a bad idea. It’s not what I would feed my cats at home, though.

Works Cited

  1. Paretts, S. (n.d.). What is the difference between kitten and cat food? The Nest. https://pets.thenest.com/difference-between-kitten-cat-food-6832.html
  2. ASPCA. (n.d.). Cat nutrition tips. link here
  3. John, B. (2019, November 19). Kitten food vs. adult cat food: What are the differences? IdleCat. https://theidlecat.com/kitten-food-differences/
  4. Association of American Feed Control Officials. (2014). AAFCO methods for substantiating nutritional adequacy of dog and cat foods: Proposed revisions edited per comments for 2014 official publication. PDF
  5. Syufy, F. (2019, November 4). How to choose the best kitten food. The Spruce Pets. https://www.thesprucepets.com/choosing-best-kitten-food-552267
  6. US Food and Drug Administration. (2020, February 28). “Complete and balanced” pet food. link here
  7. Chewy Pet Central. (2019, November 13). Cat food for all ages: How (and what) to feed your cat during every stage of life. https://petcentral.chewy.com/ages-stages-cat-food/
  8. Chewy Pet Central. (2019, December 10). The best senior cat food: A guide to feeding your older cat. https://petcentral.chewy.com/best-senior-cat-food/
  9. Freeman, L.M., Linder, D.E., and Heinze, C.R. (2016, March 8). When should I switch my pet to a senior diet? Tufts Clinical Nutrition Service. https://vetnutrition.tufts.edu/2016/03/when-should-i-switch-my-pet-to-a-senior-diet/
  10. Pittari, J., et al. (2009). American Association of Feline Practitioners: Senior care guidelines. Journal of Feline Medicine and Surgery, 11(9), 763-778. https://doi.org/10.1016/j.jfms.2009.07.011
  11. PetCoach. (n.d.). Do senior cats have different nutritional needs? https://www.petcoach.co/article/nutritional-needs-of-senior-cats/
  12. Coates, J. (2014, April 25). Are life stage dog foods credible? PetMD. https://www.petmd.com/blogs/nutritionnuggets/dr-coates/2014/april/debate-over-all-life-stage-dog-foods-31604
  13. Rock Veterinary Clinic. (n.d.). Understanding pet food labels. https://www.rockvetclinic.org/post/understanding-pet-food-labels.html

Published July 26th, 2020

Updated November 1st, 2020