The nutrition of dogs and cats acts directly on the brain, microbiota and immune system: here’s how to balance the ideal bowl between proteins, fats and fibre.
What if good nutrition for our dog or cat didn’t just affect their physical health? We probably wouldn’t have thought of it, but what our four-legged friend eats can also influence psychological well-being and behavior: «We must consider that 90% of serotonin, the hormone of well-being and good mood, is produced at the intestinal level. Chewing, on the other hand, increases the sensation of dopamine, linked to the motivation and reward system”, points out Sara D’Agostino, veterinarian specialized in nutrition and food education for dogs and cats.
Nutritional deficiencies and aggression: a connected ecosystem
D’Agostino even talks about some “particularly aggressive patients, for whom the problem resided above all in a deficiency of tryptophan, a precursor of serotonin which is obtained from foods with a high protein content”. These are perhaps extreme cases, but the message is valid for everyone: just like the human one, the organism of our animals is also a unique ecosystem, where everything is connected.
Quality nutrition
And in fact we are increasingly attentive to the nutrition of dogs and cats. This is also demonstrated by the fact that well-known cooking blogs publish recipes designed for them or that dozens of owners, on social media, tell how they composed the bowl taking into account all the necessary nutrients, at least in intention.
Since our pet became a full-fledged part of the family, there has been a slow but steady transition towards quality nutrition: we want his diet to have a long-term impact on his health and improve his well-being and longevity.
Pet food market: the growth of functional foods and supplements
We already see it starting from purchases in specialized shops, where we are attracted by words such as “whole”, “natural” or “for skin care”. A recent survey by Assalco (National Association of Companies for the Feeding and Care of Pets) tells us that we are willing to spend more: in 2025, we recorded a new increase of 2.5% compared to the previous year. And a good part of this economic commitment was allocated to protein supplements and functional foods, i.e. those that provide more targeted benefits, for example against aging or for joint health.
The increase in scientific studies on animal nutrition
This change in attitude is supported by research. On PubMed, the most important free archive for scientific literature in the biomedical field, the graphs show how publications relating to dog and cat nutrition have seen a surge: last year they were between 70% and 90% more, based on the keywords searched, compared to 2015.
Progress in nutritional science can now also be seen in this field and increasingly goes hand in hand with what is happening in human nutrition. But human nutrition, and this is a point that should not be ignored, is not the most suitable for our pets: we have different nutritional needs. Unfortunately, this also means that giving them our leftovers or sharing a piece of dinner might not be good ideas, despite the pleading looks.
Factors to consider for the ideal diet
If we then want to be sure of offering them the healthiest menu, let’s try to compose a balanced and complete bowl together. Compared to our diet, the first difference that can leave us a little lost is that there is neither a food pyramid nor a standard formula for the perfect meal. The key word here is personalization. The formulation of a correct diet in fact requires “a much broader evaluation than imagined”, explains Barbara Tonini, president of Siana (Italian Society of Animal Food and Nutrition). «The species, breed, age, weight and body composition, level of physical activity, the presence of pathologies, the results of blood and urine tests, any ongoing therapies, food preferences, but also the lifestyle and needs of the owner are considered».
Ideal weight and energy needs at different ages
Just to give an example: the nutritional needs of a puppy (1-2 years) will be different from those of an adult or elderly dog (7 years or more, depending on size).
A correct diet must help the animal to remain at an adequate weight or, in other words, “well proportioned, with palpable ribs and minimal abdominal fat accumulation”, as provided by the official guidelines established by Aafco (Association of American Feed Control Officials).
The fundamental importance of proteins
In that bowl, therefore, the largest portion will always be made up of proteins: cats select 52% of the metabolisable energy (i.e. actually usable by the body) from this nutrient, while dogs only 30%. The primary function of proteins is to provide essential amino acids, useful for synthesizing hormones and neurotransmitters, and nitrogen for the production of non-essential amino acids, which support energy metabolism and promote the health of the nervous system.
Taurine, in particular, is essential for felines: it is found mainly in meat and fish and its deficiency increases the risk of serious heart and vision problems.
More generally, reduced growth rates in puppies, weight loss or dull, ungroomed coats warn that protein intake is not sufficient.
Fats, carbohydrates and the role of fiber for the microbiota
Inactivity, on the other hand, could be a symptom of a lack of fats, nutrients that not only serve to provide energy, but help absorb some vitamins and provide essential fatty acids, including omega-3 and omega-6, which keep skin and fur healthy. The former are found in flaxseed oil, oily fish and algae oil, the latter in corn and soybean oils and, for cats, in animal fats. The rest of the energy comes from carbohydrates, a source of glucose for the brain and red blood cells, and fiber.
«Today we know that fiber is not only important for intestinal regularity, but plays a fundamental role in maintaining a healthy and balanced microbiota», specifies Tonini. The microbiota, that set of bacteria and microorganisms that live in the intestine, has become a focal point of research and has a more important role than we imagined.
It is not just used for digestion: it keeps the immune defenses in training, helps regulate the metabolism and can even influence the animal’s behavior. Also for this reason, we talk about the gut-brain axis: a direct communication line along which the gut sends signals to the rest of the body. There are also others, for example towards the liver and towards the skin, and this is the reason why a balanced bacterial flora translates into a healthier and, at times, more serene animal.
The connection between microbiota and general health
Some substances contained in fruit and vegetables also contribute to keeping this ecosystem in shape, such as flavonoids, polyphenols and carotenoids, which nourish the so-called good bacteria and help the body defend itself.
«In pets, the microbiota has a very similar role to the one it has in humans», explains Giacomo Biagi, from the Department of Veterinary Medical Sciences of the University of Bologna and member of the Scientific Advisory Board of Fediaf, the European federation representing the pet food industry. “And the impact is also measurable on other organs of the body far from the digestive system, as well as on the animal’s well-being in general.”
Consequences and pathologies linked to an incorrect diet
The results of a balanced diet are therefore measurable, while an inadequate diet is the cause of various health problems.
The question is raised by Alessia Candellone, who as a veterinary gastroenterologist often has to deal with «patients who carry out a series of in-depth investigations in an attempt to find a solution to gastrointestinal problems. But analyzing the path that has been taken better, we notice how too little importance has been given to the dietary aspect.”
Therapy for chronic diseases
«Think, for example, of chronic enteropathies in dogs (long-term gastrointestinal disorders, often causing diarrhea or weight loss, Ed.)», adds Tonini: «today we know that in a very high percentage of patients, nutritional management represents the cornerstone of therapy, while the use of drugs is only necessary in a more limited percentage of subjects. The same goes for many other clinical conditions that are also common in cats, such as obesity, chronic renal failure, food allergies, diabetes, heart disease and some liver diseases.”
Weaning and the “gastroenterological fate” of the animal
Nutritional management and food education begin already during weaning, which can take up to two years of life. Alessia Candellone, who is also co-founder of Lampovet, a digital platform specialized in veterinary telemedicine, talks about «the patient’s gastroenterological fate which is decided in this phase because a series of evolutionary mechanisms linked to the formation of the intestinal microbiota occur and the interaction with the immune system is established. An effective image is that of the inventory: the immune system reviews the various substances it comes into contact with and classifies them as safe or unsafe, consequently learning to modulate the level of response. The greater the variety of foods he knows, the lower the risk of developing allergies in the future.”
The risks of leftovers and toxic foods
Now that we have assembled the bowl, it will perhaps be clearer why a diet based on leftovers is unbalanced and potentially lacking in the nutrients necessary for dogs and cats. But can’t we even share a piece of pizza or a bite of grilled sausage with them?
«It is one of the most widespread and understandable habits from an emotional point of view», replies Tonini. «And the problem is not so much the single bite, but the sum of all the small tastes distributed throughout the day. Many owners greatly underestimate the calorie intake of extras, which can lead to overweight and intestinal disorders.” Don’t forget, then, that some foods such as chocolate, grapes or avocado can be toxic, as can high doses of garlic and onion.
Also avoid the classic cooked bone to nibble on: it increases the risk of injuries and intestinal obstructions.
Allowed foods and scientific care of your four-legged companion
«The case is different for some simple or healthy foods, such as raw or cooked vegetables, unseasoned meat and fish. These can be included in the daily ration, as long as they are administered in defined quantities”, concludes Tonini. A more scientific approach to the bowl, therefore, is not simply a set of rules, but a continuous attention towards those who in all respects are our life companions.
