When it comes to questions difficult to do justice in a 15 minute consultation, diet is a biggy. As we increasingly become aware of the dietary influences over our own health, the hazards of processed foods, and the toxicity of chemical residues, many pet owners are keen to hear a vet’s opinion on what to feed. Confused by conflicting reports of the merits of fresh and commercial foods, they are often desperate for impartial advice. Sadly, too often, they are simply guided to the shelf of foods in the waiting room. The decision should be a lot more well-considered than this..
While we have little control over genetic causes of disease, understanding environmental causes of ill-health can be empowering. There are 3 main ways in which we come into contact with the environment: via our skin, inhaled into our airways, or ingested into gastrointestinal tract. To give you an idea of the potential impact of each:
- Skin is a tough and resistant barrier with the approximate surface area of a ping-pong table.
- The respiratory system, guarded by a nasal filtration system, has the surface area of a tennis court.
- The bowel, far more permeable and without a filter, has the area of a football field.
The stuff we swallow, our diet, the nutrients and all else it contains, easily represents the single most significant route of exposure to environmental factors impacting on the wellbeing of us and our pets. The detoxifying clearinghouse, the liver, stands as biologic monument to the continuous toxic insult inflicted on us by the contents of our gut.
Topping the list, as organ with largest volume of immunologic tissue in the entire body, the gut is constantly monitoring and responding to an Amazonia of foreign antigens. The immunologic challenge presented by a river of continuously changing microflora and putrifying foodstuffs, passing through the core of the beast, is nothing short of staggering.
The complexity of interactions between an ecosystem of billions of microbes, most not yet studied, feasting on a diet containing millions of chemical compounds, many not yet known, makes subtle impacts of diet on the greater organism a mystery, even in man.
We are only just begining to glimpse the role of the gut in immune regulation, and how it affects the development of autoimmune and allergic diseases. Fundamental questions like ‘How do food allergies cause skin lesions?’ remain unanswered, while the bigger picture, epidemiologic evidence is pointing clearly towards childhood sanitation and over-medication in the developed world. For more on this see The Hygiene Hypothesis.
Large studies of human populations have revealed hundreds of associations between diet and disease, including some of the biggies like cardiovascular, diabetes, cancers, and now even psychopathology. Similar relationships exist in animals, some identified by investigation into animal disease and nutrition, but most studied in laboratory rats and mice as models of human disease.
When a vet is presented with a dog with cancer, or a cat with heart disease, it’s difficult for them to know to what extent diet or other environmental factors were contributory. Apart from some diseases, long-known to be associated with diets too high or too low in a particular nutrient, most dietary effects remain unidentified.
Domestic cats and dogs, often served the same food, year in, year out, may be more susceptible to dietary impacts upon their health, compared to their owners who seek variety. Wholesale belief in the hype of any one side of the dietary arguement will place Fido at risk of a range of dietary associated diseases. Too many bones may give him obesity, broken teeth and constipation; too much commercial may put him in to renal failure. For more on this see The Argument for Dietary Diversity.
There is no single, simple answer to ‘What should I feed my pet?’. It will depend upon your finances, spare time, philosophies surrounding food and chemicals, and your pet’s specific needs, which are likely to change over time. When making a decision there are a range of issues to consider, each covered in separate posts. Scattered amongst them are recipes for you to try. Click on the links below for further detail..
- The elephant in the room is the Commercial pet food versus Fresh food debate. Given the vast majority of research into animal nutrition is conducted by pet food manufacturers, and some veterinary nutrition texts are written by industry, it’s often hard to know where the science ends and spin begins.
- The Argument for Dietary Diversity also looks into the fallout of the US pet food melamine contamination scandal of 2007.
- Growing animals, like our kids, have special dietary needs and it’s these animals that vets most often see with the catastrophic consequences of a fresh meat diet: puppies and kittens with fractures. The obvious issue is calcium requirement for growing bones, which is taken to extremes in rapidly-growing, large and giant breed dogs.
- Pregnant and lactating animals have special needs in regards to calcium and calories.
- Preservatives – Processed foods for man and animal contain the same preservatives, but poor regulation sees toxic levels of sulphites in some cat foods. A cautionary tale about industry self-regulation.
- Crippling your pet with kindness – The most common disease of nutrition is simply too much. In man, more than 60 diseases have been associated with obesity. Is it the same in animals? Weight gain, it’s causes and treatments.
- Cats with urinary tract disease – There’s plenty of diets designed to prevent it, but how effective are they?
- Kidney failure and Liver failure– How to keep a carnivore eating when protein turns toxic.
- Arthritis is not just a disease of the elderly, and it’s one of the best reasons for keeping your dog slim. Essential Fatty Acid supplements, glucosamines & chondroitins, tumeric and other nutraceuticals all deserve a mention.
- Bones of contention – The cooked versus raw debate, and their usefulness in prevention of dental disease and boredom.
- Tragically preventable – The most frequent cause of euthanasia of pet rabbits is related to poor diet.
- Food allergy – The incidence is skyrocketing in man and we don’t know why. Such allergies also exist in animals and can manifest as skin or gastrointestinal problems. Learn about the myths of food allergies in pets, and how to design an elimination diet. A tangential topic here is the Hygiene Hypothesis as an explanation for increasing hypersensitivities.
- Fibre comes in digestible and indigestible forms, and may help your dog with constipation or colitis, or your cat with furballs or megacolon.