Life expectancy for cats has risen, on average, to 14-16 years of age. We are living in the (human) generation which overall
sees the benefits of the acceptance and compliance of the general "cat owning" public with our recommendations in vaccination
protocols, nutritional counseling/the availability of nutritionally balanced feline-specific diets, and dental hygiene. And,
while we can always focus and expand our client education efforts, the veterinary community, and to a great extent industry,
have done a good job in client education! We should be proud of ourselves.
What is a "senior" or "geriatric" cat? In a cat," senior" ranges from about 9-12 years of age with "geriatric" after that:
these age ranges correlate roughly with human ages of 52-64 and 68 onwards (Chart 1).1 A cat may begin to manifest serious age-related disorders, (e.g. renal insufficiency) on average, around 8 - 9 years of
age. This does NOT make that individual old.... or less treatable. Aging comes equipped with a set of cellular changes that
are somewhat predictable and which need to be taken into consideration in our approach to health care, both preventative as
well as therapeutic. At any age there are changes and disorders, particular to that age group or stage of progression.
Aging is a complex process reflecting increasing damage at the cellular and organismal level. To paraphrase from Robbins:
Aging begins at the moment of conception, involves differentiation and maturation and, at some point, leads to the progressive
loss of functional capacity characteristic of senescence ending in death. This occurs at an organismal level as well as at
a cellular level. The former may be affected by genetics, social environment, nutrition, and the occurrence of age-related
diseases. Cellular aging, on the other hand, includes progressive accumulation of sub lethal injury (e.g., from free radical
damage), resulting in either cell death or diminished capacity of the cell to repair itself. We can impact these changes to
some degree through nutritional intervention.
Nutritional considerations of aging
What happens to body composition as cats age? Maintenance energy requirements (MERs) vary with age, genetic potential, health
status, and gender (intact or altered). MERs decrease with age in humans, dogs and rats. In cats, interestingly some reports
no change; when evaluated over longer periods, it has become apparent that MERs decrease until about 11 years of age. After
this point, however, MERs per unit body weight actually increase.
Cats in the middle ages ("senior"), under 12 years tend to overweight or obesity as energy needs decrease without concurrent
decrease in energy intake. Lean body mass (LBM: skeletal muscle, bone, skin and organs) decreases in cats, just as it does
in other species, with advancing age. As LBM is a primary driver of metabolism, all decreases in activity result in reduction
Studies in geriatric cats over 12 years of age show that fat digestibility decreases with age. Additionally, approximately
20% of cats over 14 years of age have reduced protein digestion. This is of clinical relevance when we try to design the optimal
nutritional regime for our older feline patients: protein and fat restriction may well be contraindicated. Especially if underweight,
older cats will benefit from a more energy-dense, highly digestible diet to help offset these age-related digestive and metabolic
Key to determining the appropriate diet for any given individual is a nutritional assessment. This should include determining
not only body weight at every visit, but also identification of body composition, most practically by using a body condition
score. Percentage weight change determination is helpful in detecting trends and alerting both the practitioner and the client
to incipient (or blatant) physiologic alterations. Use of a simple diet history form provides important information by revealing
not only food fed, but also brand and quantity and treats or supplements that this patient may have access to.