Dogs and cats used to be fed raw meat and bones and some left over vegetable scraps from the table in the past, but since the introduction and popularity of highly processed pet foods since the 1960’s, their diet has shifted from predominantly scraps to processed foods (Billinghurst, 2009).
Due to the modern diet of processed food for dogs (and cats), there are many more chronic disease to be dealt with, in general veterinary practice today, than a few decades ago (Billinghurst, 2009; Syme, 2011). Processed kibbled food need to be of a much higher carbohydrate content to maintain its structure and rely on additives and preservative as well as flavours for palatability (Billinghurst, 2009). In America pet food is required to contain certain minimum amounts of macro- (Carbohydrates, Protein and fats) and micro-nutrients (minerals, vitamins) commonly referred to as the AAFCO standards (AAFCO, 2020), which is commonly adapted in Australia (own observation), but there are no maximum amount limits specified (Billinghurst, 2009). When looking at the ingredients and processing of most dog food brands it become evident why there is an increase in chronic disease, in the following section a few nutrients that are commonly found in excess in these processed foods will be discussed in relation to their health impacts on our pets. Most processed dog foods contain excessive amounts of calcium, phosphorous, protein, magnesium and sodium (Billinghurst, 2009).
The first ingredient is the macro nutrient carbohydrate. As much as 50% of the energy (Calories) in processed foods are from carbohydrates, compared to only 6% of energy in the primordial diet (Dogs Naturally Magazine University, 2020). High calories, in the form of soluble carbohydrates in moist pet food can lead to obesity (Billinghurst, 2009). The cereals used in processed food are too high compared to what their ancestors would have consumed in the wild. This higher cereal content cause health issues such as obesity, pancreatic insufficiency, diabetes, arthritis, bladder stones, dental and skin issues as well as cancer to name a few (Billinghurst, 2009).
Canned dog food is 80% water (Billinghurst, 2009). Due to the excess in water content, these foods actually do not contain much nutrients per weight, therefore it needs to be fed in great quantities, making it a very expensive food (Billinghurst, 2009).
Excessive calcium is found in processed food, which can cause bloat and skeletal problems in puppies and kittens (Billinghurst, 2009). Commercial dog food contains from 3 to 11 times more calcium than what is required in the dogs’ diet (Billinghurst, 2009). Excesses in calcium can cause zinc, iron, copper and phosphorous deficiencies (although phosphorous is not a deficiency issue here, as most foods contain too much) due to competing mineral absorption, this could also affect the trace minerals’ (selenium and chromium) absorption (Billinghurst, 2009). Excesses in calcium contribute to skin issues, reproductive issues and immune system dysfunction, especially due to the deficiency in zinc it causes (Billinghurst, 2009). Puppies, especially from arctic breeds, can suffer in their growth, caused by a zinc deficiency (Billinghurst, 2009). The soluble calcium found in dry food also attacks the dental health of dogs, causing gum and dental issues such as excessive tartar formation (Billinghurst, 2009). Tartar contains a high bacterial load, thus creating a dysbiosis in the microbiota of the mouth, leading to gum and teeth decay, infections and eventually loss of teeth (Billinghurst, 2009). The bacterial load from the mouth gets absorbed throughout the body and increases the toxic load, leading to disease, especially kidney and heart disease, but other organs such as lungs, uterine lining and prostate are also negatively impacted by the bacterial load as well (Billinghurst, 2009). Excess calcium in a diet can also cause bloat in dogs (especially in the deep chested breeds such as Alsatians), due to an overproduction of the hormone gastrin, causing both ends of the digestive tract to swell, thus stopping gasses from escaping (Billinghurst, 2009).
Excessive amounts of protein in a diet can cause kidney disease, due to the kidneys working too hard to eliminate the excess protein metabolites (Billinghurst, 2009). Excesses in phosphorous (5 to 9 times the requirement) add to this compounding effect on the kidneys as the imbalance of the phosphorous / calcium ratio further damages the kidneys (Billinghurst, 2009). If there were no kidney damage, then the kidneys would be able to eliminate excess phosphorus, but as the kidneys are damaged, it accumulates these excesses (phosphorous / calcium) and this then further damages the kidneys and other organs where these minerals are deposited (Billinghurst, 2009).
Excessive magnesium is implicated in bladder stones (Billinghurst, 2009).
Too much salt can cause cardiovascular issues such as high blood pressure and heart disease (Billinghurst, 2009). The excess salt also damages the kidneys, thus causing not only heart disease but also kidney disease (Billinghurst, 2009).
Excessive additives added to processed foods, cause all kinds of health issues, such as skin issues, hyperactivity, allergies and other hypersensitivity reactions (Billinghurst, 2009). The amount of additives compared to the size of the or of dog can be disproportionally large compared to weight (much like with adults and children). Artificial colours are especially implicated in health issues such as behaviour and cancers (Syme, 2011).
As seen from the above section, processed foods can have not only deficiencies, but also dangerous excesses, in certain nutrients, not regulated by law, which has far reaching implications in our pets’ health, causing illness and other morbidities in their old age. The onset and development of excess nutrients are not always immediately apparent and has a slow insidious effect on the pet’s health. The current regulations and suggested recommendations for processed pet foods do not take into account the quality of food, as long as the numbers stack up (individual nutrients) then it is OK to be used as pet food – you can almost get away with feeding water, coal, sump oil and leather, because the numbers would stack up, but this does not make a safe food (Billinghurst, 2009). Accumulated excesses over time causes systemic inflammation, which in turn will drive disease and cause our pets to become ill.
AAFCO, 2020, Association of American Feed Control Officials, website viewed 17 June 2020, https://www.aafco.org/
Billinghurst, I, 1993, ‘Give your dog a bone. The practical common sense way to feed dogs for a long and healthy life’, Warrigal Publishing, Bathurst.
Brown, R, G, 1994, Understanding Advertising in Pet Nutrition, Canadian Veterinary Journal, 35 (4), viewed 16 June 2020, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1686757/
PFIAA, 2020, Pet Food Claims…What do these Packs Really Mean?, viewed 12 June 2020, https://pfiaa.com.au/pet-food-claims-what-do-these-packs-really-mean/
Syme, B, 2011, ‘Scientific Guide to Natural Nutrition Scientific Guide to Natural Nutrition, A Natural Choice for Healthy Pets’, viewed 10 June 2020, https://vetsallnatural.com.au/
Anneke is a Degree qualified Naturopath, with a passion for animals and natural health. She has been using natural health solutions with her children and pets since 2001 and after doing many equine treatment courses, decided to follow her heart and started her formal education as a human naturopath in 2014, graduated in 2018 after 4 years of full time study. Upon graduating she enrolled into various equine and small animal therapy courses and in a Diploma of Holistic Animal Care (equine and companion animals) to further cement her knowledge in animal care.