Nutrition for Senior Dogs and Cats: What Can We Prevent?

The longevity of dogs and cats has been steadily and undeniably increasing in recent years, linked to factors that include both the individual, through breed selection, and the evolution of Veterinary Medicine as a whole. In this context, preventive Veterinary Medicine has gained prominence, keeping pace with the growth in the number of companion animals, as well as the greater availability of veterinary goods and services for small animals, especially in Asia and Latin America.

Although senility itself is not considered a disease, but a natural stage of life, it involves physiological changes that should be identified, managed, and, when possible, prevented. Currently, cats are considered senior from 10 years of age, while for dogs this classification varies according to size and breed, so that large dogs reach senility earlier compared to small dogs. One of the possible justifications that correlate the larger size of dogs with a shorter life expectancy is the longer exposure of the animal to Insulin-like Growth Factor-1 (IGF-1), which promotes growth but potentially also reduces longevity.
 

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Changes in digestive capacity and, consequently, in the proper use of nutrients provided by food, can occur over the years. Studies suggest that the moderate addition of fiber, especially soluble fiber, improves food utilization in both dogs and cats. In addition to fiber, another macronutrient studied in old age is fat, whose digestibility does not appear to decline significantly in dogs, but rather in older cats. This reinforces the importance of monitoring progressive weight loss in this species as they age, as a fundamental pillar of nutritional management.
 

Another important point in the preventive management of companion animals concerns kidney health. A reduction in the glomerular filtration rate (GFR) is observed, especially in smaller dog breeds, an alteration even seen in humans with advancing age. In cats, there is a strong relationship between the development of chronic kidney disease and age (over 12 years), mainly associated with interstitial inflammation, tubular atrophy, and fibrosis. A distinguishing feature is that proteinuria is rare in the early stages of glomerulopathies. 
 

Understanding the classification of chronic kidney disease in senior dogs and cats according to the International Renal Interest Society (IRIS) is crucial, since loss of lean mass is expected in older animals, whether due to pre-existing disease or not. Therefore, it is essential to weigh the advantages and disadvantages of protein restriction in this age group. 
 

However, caution regarding high phosphorus intake in old age is a safe measure and is widely addressed by most quality commercial foods.
 

The addition of nutraceuticals to the diet is also a relevant issue. Studies with EPA and DHA have evaluated their anti-inflammatory capacity and potential to help control chronic diseases, such as heart disease, skin diseases, chronic kidney disease, osteoarthritis, and behavioral disorders, which are common conditions in senior dogs and cats. 
 

It is important to emphasize that the effects are related not only to the correct amount of EPA and DHA present in the products, but also to the continuous supply of the nutraceutical to maintain the benefits. 
 

Regarding nutraceuticals, it is known that the oxidative cellular damage that naturally occurs with age is related to the onset and worsening of various chronic conditions. Therefore, the addition of antioxidants in the management of elderly patients also offers advantages. 
 

One of the most widely used natural antioxidants is alpha-tocopherol (vitamin E), which acts by interrupting the oxidation cascade by preventing the spread of damage caused by free radicals in biological membranes. A study conducted in 2004 indicated that increased inclusion of vitamin E in the diet raises its serum concentration and reduces the amount of reactive byproducts generated by lipid oxidation (called alkenals), when compared to the group of dogs that did not receive supplementation. 
 

Both omega-3 fatty acids (EPA and DHA) and vitamin E can be incorporated directly into senior food formulations or administered orally separately. 
 

In addition to the benefits already mentioned, they also show positive results in supporting age-related cognitive dysfunction.
 

Finally, clinical manifestations of Cognitive Dysfunction Syndrome (CDS) are prevalent in the elderly animal population, reaching 28% of cases in dogs aged 12 years and increasing to 68% in dogs over 15 years, according to the perception of their owners. 
 

This concern also extends to older cats; studies that evaluated cats over 11 years old report a possible diagnosis of CDS in 35% of cases. In felines over 15 years old, more than 50% showed clinical signs of the disease. 
 

Paying attention to the early signs of CDS is essential, starting with more subtle changes, such as behavioral alterations and changes in the sleep-wake cycle, including the reversal of day-night activity, to manifestations of disorientation and impairment of basic functions, such as eating and defecation. Early intervention can ensure a better therapeutic response, delay disease progression, and even promote clinical improvement for the patient. 
 

Among the most promising strategies is the provision of energy sources capable of generating ketone bodies, since the brain's efficiency in using glucose as an energy source decreases with age. 
 

Conversely, the utilization of ketone bodies can be seven to nine times greater. The inclusion of medium-chain triglycerides (MCTs) in the diet constitutes a viable source for the generation of these ketone bodies, which cross the blood-brain barrier and the mitochondrial membrane, generating ATP through the Krebs cycle and phosphorylation. 
 

MCT oils are concentrated forms of octanoic and decanoic acids, usually derived from coconut oil or palm kernel oil. The concentration of these acids in the crude oil from these sources is low, around a maximum of 12%, which makes effective supplementation with coconut or palm kernel oil alone in the diet unfeasible. 
 

Therefore, the addition of MCTs to the diet should be done through the calculated administration of purified MCT oils or by using commercial diets that already contain this inclusion in the appropriate dose [20,24]. Correct MCT supplementation has demonstrated significant clinical improvement in patients diagnosed with CDS, especially in the early stages.
 

Advances in veterinary medicine have ensured longer lifespans for our dogs and cats, making it essential to understand the most frequent conditions and their prevention and treatment strategies. Proper nutrition, especially in ideal quantities and with ideal sources of protein and fiber, along with the addition of specific nutraceuticals, can provide quality of life not only for the patient but also for the caregivers who accompany their animals as they age. 
 

However, proper dosage calculation and the correct choice of sources are fundamental to ensuring the effectiveness and safety of these supplements.

By Erika Pereira, Monique Paludetti and Thais Ximenes
Source: Cães e Gatos