The Natural Choice - making an informed choice!
By: Sivan Zilber, clinical pet nutritionist
When it comes to feeding your beloved 4 legged furry family member, you have several options – feed commercial dry or canned pet food, make your own diet, or feed commercial raw, cooked or dehydrated/freeze dried. Raw and cooked (at low temperatures), either commercially or home prepared and dried commercial foods all fall under the category of natural nutrition.
This article takes an in-depth look at the main reasons why I believe you should consider switching to a natural diet, either home prepared (after consulting your vet or a pet nutritionist) or commercial from a respectable manufacturer.
Human and pets alike need to eat a diet that best suits their biological characteristics, or as it's called – a species appropriate diet. After reviewing thousands of years of nutrition, experts claim that a nutritionally balanced diet for dogs should contain around 80% protein, fats and bone sources and around 20% carbohydrates. Cats should eat around 90-95% protein, fats and bone sources and only 5-10% vegetables.
When you look at kibble you can straight away see that it's far too high in carbohydrates. An average macronutrient breakdown of dried dog food is approx. – 26% protein, 15% fat and 55% carbohydrates.
This means, most of the processed dry foods don't come close to the correct macronutrients rations and so it's biologically inappropriate.
Another major aspect that doesn’t meet biological needs is that dry foods contain under 10% moisture compared to a raw or even cooked diets which contains over 60% moisture. This fact is especially relevant for cats, for studies show that feeding exclusively on dry foods can cause chronic, mild dehydration which in time leads to increased stress on the kidneys, and ultimately decreased kidney function.
Contrary to popular belief, commercial dry and canned pet foods only became widely available in the 1950's. Both food preparation methods – extrusion and retort – use high temperatures (sometimes over 250 degrees Celsius) and this causes tremendous effects on the quality of the food.
Effects of heat
Research conducted by the national cancer institute, John Hopkins University in the US and the Queen Elizabeth Hospital in London had shown that cooking meat at high temperatures creates seventeen different carcinogenic (cancer causing) compounds that are collectively called heterocyclic amines (HCAs). These interfere with the body's genetic structure and are shown to cause cancer in animals.
Other research shows that heat processing causes sugar and amino acids to react together in what is known as the Maillard reaction (this is what gives food its brownish color). It affects the availability of essential amino acids, enzyme activity, as well as absorption and utilization of metals in the body. It is also responsible for the formation of potent mutagenic and carcinogenic heterocyclic aromatic amines (HAAs).
In 2002, researchers in Sweden and the US discovered that heating high carbohydrate food produces a chemical called acrylamide which is considered as a probable carcinogen. Animal studies show that it causes gene mutation, neurotoxic effects, and cancer.
Studies have shown that the preservatives BHT and BHA cause DNA breaks, mutations and chromosomal aberrations. They increase the risk of tumors and caused cancer in lab animals. Although banned by some European countries, they are still in use in the US.
Carrageenan is used as a stabilizer and thickening agent in canned pet food and may cause ulcers and cancer.
Another problematic preservative is Ethoxyquin which is linked to animal sterility, deformed offspring and lesions of the liver, kidney and bladder.
MSG, often used as a flavor enhancer, is a chemical transmitter that may harm brain cells and also connected to obesity and allergies.
These are just a fragment of the artificial ingredients found in pet food. Other additives include: antimicrobials, emulsifiers, palatants, binders, stabilizers, thickeners and more. The most popular artificial substances are added nutrients. More and more data accumulates that connect artificial substances to many concerning health issues, such as hyperactivity, fearfulness, stomach ulcers, colitis, inflammatory bowel disease, cancer and more.
Synthetic vs. natural nutrients
Heat treatment destroys the natural vitamins and minerals found in the food and so food companies need to add these back in synthetic form in order to meet nutritional guidelines.
The body absorbs synthetic nutrients differently than it does the natural ones. This is because real food contains not just a single nutrient but rather a whole range of vitamins, minerals, co-factors and enzymes that allow for optimal use by the body. Without these, the body doesn’t use synthetic vitamins as well. The result is that a minute amount of a vitamin in its whole food form is tremendously more functional, powerful, and effective nutritionally than a large amount of a chemically pure, vitamin. For example, a single carrot contains about 200 nutrients and phytonutrients which work together synergistically in order to be properly absorbed and integrated into the body.
Moreover, because the molecular structure of synthetic vitamins is different, they are received by the pet's body as drugs and so they can over time potentially disrupt normal metabolic functions.
Synthetic fat soluble vitamins (Vitamins A, D, E and K) could even be dangerous because they can build up in the liver and fatty tissues and cause toxicity. This is because you get a high, concentrated serving of the vitamin rather than the small amount that you would get from a food-based form.
As for the water soluble vitamins C and Bs, these are not stored by the body and any excess is excreted in the urine. But does this fact make them safer?
A study designed to examine the effect of synthetic vitamin C on training efficiency in animals showed that against the popular assumption that as an antioxidant, it may help protect the muscles from oxidative damage caused by exercise, supplementation with vitamin C ascorbate actually devastates the muscle by increasing oxidative stress and suppressing some critical cellular mechanisms of adaptation to exercise. This action also disrupts the body's immune system, lowering the capacity to resist infection and disease.
Lastly, let's take a look at consuming mega doses of synthetic vitamins from an evolutionally point of view. Animal studies have shown that our pet's bodies are inherently designed to get maximum nourishment from minimum food. Researchers believe that this is due to what they call survival genes (or longevity genes) which are meant to increase the ability to survive when food is scarce by upgrading dogs and cat's energy utilization, strengthening their muscles, and improving their capacity to resist stress and starvation.
This means that anything that causes excess or imbalance in our pet's body can be toxic and inflammatory.
Allow me to repeat this final point – excess and imbalance can be toxic and inflammatory – and let's look at commercial dry and canned foods – they have an excess of carbohydrates, excess of preservatives and thickening agents, excess of synthetic substances… they are excessively dry, overly processed, and more…
This isn’t balanced nutrition as nature intended our pets to eat and we have the responsibility as their caregivers to make the most informed choices for them.
Unlocking the canine ancestral diet: healthier dog food the ABC way
Gomez-Cabrera MC, Domenech E, Romagnoli M, Arduini A, Borras C, Pallardo FV, Sastre J, and Vina, J. Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance. American Journal Clinical Nutrition. 2008 Jan; p. 87(1), p. 142-9.
Davies KJ, Packer L, Brooks GA. Biochemical adaptation of mitochondria, muscle, and whole-animal respiration to endurance training. Arch Biochem Biophys 1981; p. 209, p. 539-54.
Chi-Tang Ho. Maillard Reaction and Health Aspects. Mol. Nutr. Food Res. 2006, p. 50, p. 1099 – 1100.
Timothy A. Allen, David J. Polzin and Larry G. Adams, "Renal Disease", small animal clinical nutrition, 4th edition, Walsworth publishing company, 2000, p. 582.
Facts about Vitamin A and Carotenoids, from the National Institutes of Health's Office of Dietary Supplements.
Schultze R. Kymythy, Natural Nutrition for Cats
Chassaing, B. et al. Nature http://www.dx.doi.org/10.1038/nature14232 (2015).
Gomez-Cabrera MC, Borras C, Pallardo FV, Sastre J, Ji LL, Vina J. Decreasing xanthine oxidase-mediated oxidative stress prevents useful cellular adaptations to exercise in rats. J Physiol 2005;567:113-20.
Chemicals in Meat Cooked at High Temperatures and Cancer Risk -https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet
Marshall RJ, Scott KC, Hill RC, et al. Supplemental vitamin C appears to slow racing greyhounds. J Nutr 2002; p. 132.
Vitamin A Toxicity from http://www.vitamindcouncil.org/newsletter/2008-december.shtml