Despite 'fortifying' efforts, most processed pet food may leave your dog or cat deficient in many important nutrients
You could be forgiven for thinking it was a meal for a human being. There's the juicy meat and the sides of peas and carrots, all served on a pretty china plate with lettuce for garnish. Except that the recipient of the meal is a little doe-eyed Westie, and the tag line is: 'Love them back'.
'Love them back' is the latest television ad campaign for Cesar pet food, brought to you by the people who make Mars bars. Some 80 per cent of the cat- and dog-food market is now controlled by the big four of the processed human-food industry (Nestle's, Mars, Colgate-Palmolive and Procter & Gamble) and, consequently, most of today's pet food, despite the claims on the adverts, is as processed as a packet of sweets, containing an amalgam of byproducts of the meat, poultry and fishing industries, with processed carbohydrates, meat 'derivatives', basic supplements and chemicals like preservatives.
The Association of American Feed Control Officials (AAFCO), an organization composed of both state and federal officials, and industry insiders create 'profiles' of the ideal composition of pet foods to ensure that they are made up of the correct percentages of fats, proteins and carbohydrates. Pet-food manufacturers are then required to provide chemical analyses to show that their food meets these profiles.
Chemical analysis, however, cannot provide any useful information on the true bio-availability of the components of the food. James G. Morris and Quinton R. Rogers, both emeritus professors at the department of Molecular Biosciences at the University of California at Davis School of Veterinary Medicine who carried out a detailed assessment of the nutritional adequacy of pet foods, discovered that many of the common dietary ingredients used in pet foods have wide variations in terms of nutritional composition (J Nutr, 1994; 124 [12 Suppl]: 2520S-34S).
Dry foods, for instance, although blended with the aid of computer programmes to establish the correct amounts of protein, fats and carbohydrates, often include ingredients that are largely indigestible to animals. Soy, a common ingredient in dog food, for instance, adversely affects digestibility, particularly of certain amino acids, in the canine small intestine (Anim Feed Sci Technol, 2003; 109: 121-32). Many amino acids like lysine, which are vital for dogs, get degraded by food-processing, particularly under high heat. And when a food's phosphorus content mainly derives from corn and soymeal, as is often the case in dog food, it usually doesn't get absorbed (J Nutr, 1994; 124 [12 Suppl]: 2520S-34S). The high phosphorus content of the food also blocks the availability of magnesium for cats.
As byproducts of the processed human food industry, most of the ingredients in pet foods-meat byproducts, bone meal, tallow and corn, wheat or rice meal-are processed twice, first from human-food processing and then by the pet-food manufacturers, which mix up cocktails and then subject them to extremely high heat. This kind of extreme processing is known to kill or degrade many micronutrients.
In dry food, the fat-soluble vitamins (vitamins A, D, E and K) lose more than half their nutritional value well before the process is finished and the food hits the stores. But even in wet food, the high heats and processing destroy vitamins such as the B-vitamin thiamine.
Consequently, pet-food manu-facturers have to 'refortify' in an attempt to add back what they've destroyed during pro-cessing without adding too much. This is an inexact science, says PetfoodIndustry.com, resulting in 'occasional toxicities and def-iciencies' largely because levels of vitamins required by companion pets are only guessed at by comparing the needs of other single-stomached animals of comparable size, like pigs.
Many cats and dogs show signs of clinical deficiencies of zinc and copper largely because of the phytic acid, present in the grains used in prepared animal foods, that binds with zinc. In fact, puppies that have been reared entirely on commercially prepared pet foods show evidence of zinc deficiency (J Am Vet Med Assoc, 1991; 199: 731-4).
The University of California at Davis team also found that the type of copper added to pet foods has a bioavailability of next to zero. Given the lack of whole foods in pet foods-and the questionable condition of most food these days (studies have found that vegetables and meat have 30-93 per cent and 41-54 per cent fewer nutrients, respectively, than they did 50 years ago)-you may wish to consider nutritional supplementation for your cat or dog.
But before you rush out to buy doggy vitamins, make sure you read the labels. Some standard supplement preparations contain chemicals like BHT (butylated hydroxytoluene), a preservative also used in embalming fluid that has been linked to cancer.
The latest kind of supplement is actually a healthy mix of 'superfoods' that are ground-up food from 'human-grade' sources and can be added to either a raw or cooked pet-food diet.
Several companies in the UK and North America offer pre-prepared mixes that can be combined with fresh meat, one or two vegetables, some oil, an egg and a little warm water to become a nutritious food. These products can be cooked or added to raw food (see box, left).
Or you can make your own. Some owners supplement with omega-3 and omega-6 essential fatty acids to help their pets maintain a silky coat. Brewer's yeast, kelp and sprouts can also add nutrients to your dog's diet. For raw-food diets, some vets suggest ground-up eggshells as a calcium supplement (two-thirds of a large eggshell, or half a teaspoon per pound of boneless meat).
Dr Jeffrey Levy, a Massachusetts homeopathic vet who lectures around the States, offers recipes for two homemade supplements.
The first, which he calls the 'Vita Powder' supplement formula, is packed with vitamins and minerals. The second is an oil-based mix made up of omega-3 and omega-6 fatty acids plus vitamin E (see box, above). They're almost worth putting out on a china plate.
Here are Dr Levy's Vita Powder Mix and Oil Mix
Ingredients Dogs Cats
Vita Powder Mix
Nutritional yeast flakes 1 cup 1/2 cup
Kelp powder 1/4 cup 1 tablespoon
Alfalfa powder 1/4 cup 1 tablespoon
Lecithin granules 2 tablespoons 1 tablespoon
Garlic powder 1 tablespoon 1 tablespoon
Vitamin C 3000 mg 3000 mg
Vegetable oil Dogs (average 30 lb) Cats (medium-sized)
safflower) 1/2-1 tablespoon 1 teaspoon
Cod liver oil 1/2 teaspoon 1/4 teaspoon
Vitamin E 200 IU 100 IU
To adjust the oils for your pet's size, multiply the amount in the oil recipe above by the Oil Mix number below, corresponding to your pet's weight
Vita Powder Oil Mix
5-10 lb 1 tablespoon 1/2
30 lb 2 tablespoons 1
65 lb 4 tablespoons 2
100 lb 6 tablespoons 3
Small (5-8 lb) 1 1/2 teaspoon 3/4
Medium (8-12 lb) 2 teaspoons 1
Large (12-15 lb) 3 teaspoons 1 1/2
Ready-prepared food supplements
Available in the UK
u Missing link has an all-in one powder for cats or dogs that includes flaxseed, sunflower seed, blackstrap molasses, rice bran, freeze-dried liver, primary dried yeast, dried alfalfa, freeze-dried bone, dried carrot, fish meal, freeze-dried oyster, dried kelp, lecithin, spirulina, sprouted green barley, yucca, garlic, nettle and, for cats only, taurine. There is also a dog vegetarian product as well as speciality products, such as a version of Missing Link that is rich in glucosamine for dogs with joint problems. Available from www.missinglinkproducts.com (US site) and amazon.co.uk.
From the US and North America
u Sojourn Farms in Minneapolis, Minnesota (tel: +888 867 6567; www.sojos.com) has prepared a healthy supplement for dogs and cats made of grains, nuts, seeds, seaweeds and herbs, all of which can be worked into raw or cooked food. The company will post nationally and internationally.
u Essex Cottage Farms (www.efarms.cc) in Canada has a range of supplements made of stoneground grains, vitamins and minerals, and offers recipes that you can add to your pet's food. This company will also post internationally.
vol 23 no 9 December 2012