Post by muskyhusky on Oct 16, 2008 19:52:21 GMT -6
What do cancer, kidney disease, pancreatic disease, allergies, hair loss, blindness and immunodeficiency have in common? Preservatives used in dog food have been blamed for causing every one of these problems.
The nutrient that is most susceptible to spoilage is fat. Fat spoilage (oxidation) decreases the nutritional quality of the food, makes it less palatable to the dog, and can even make it unsafe to eat. Since most dog food contains high level of fat and fat-soluble ingredients (including vitamins A and E), it is critical to prevent oxidation to maintain quality, nutritional value and palatability. Canned dog food is protected from oxidation by its airtight storage, but dry food, even with modern packaging, must include preservatives to maintain quality and safety. Dry dog food needs preservatives, but which preservatives is the best?
Preservatives can be either artificial or natural. Both types work by preventing fat and other ingredients in the food from oxidizing. The most common artificial preservatives used by the pet food industry are ethoxyquin, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). Tocopherols (vitamin E) and ascorbic acid (vitamin C) are the most common natural preservatives.
The preservative that has caused dog owners the most concern is ethoxyquin. It is currently allowed in dog food at levels up to 150 parts per million (ppm). Although ethoxyquin has been used in animal feed for more than 30 years, in the last nine years the FDA has received many consumer reports about health problems occurring in dogs that were fed ethoxyquin-containing foods. Although several studies have not shown any adverse effects from using ethoxyquin in dog food at approved levels, consumer concerns have triggered further investigation into the safety of this preservative. A recent study by Monsanto, the major producer of ethoxyquin, indicated that the only problems caused by long-term, moderate-to-high ethoxyquin levels in food were mild increases in blood levels of liver enzymes and an increase in the levels of a normal red-blood-cell metabolite in the livers of lactating bitches, who generally eat more than other dogs. No reproductive abnormalities or other health problems occurred.
Although the liver findings referred to above are considered to be very mild and of no clinical significance, further investigation is needed. In July 1997, the FDA's Center for Veterinary Medicine sent letters to the manufacturers of ethoxyquin and to the pet food industry requesting that the maximum levels of ethoxyquin be lowered to 75 ppm in dog food. A study currently under way by the Pet Food Institute is designed to determine whether still lower levels (30 or 60 ppm) of ethoxyquin provide adequate antioxidant protection for dog food. The FDA will take appropriate action based on the results of this study.
Although vitamins C and E can both be used as preservatives, neither is as effective as the artificial preservatives. For example, one study found that dry dog food preserved with vitamin E spoiled faster than food preserved with ethoxyquin or BHA.
To provide alternatives to artificial preservatives or other ingredients perceived as unhealthy, many companies now market dog foods that are "all natural." The problem is that there's no legal definition of "all natural," "preservative free," or similarly named products. Manufacturers define products by what they believe these terms mean. In general, the implication is that no preservatives or artificial colors have been added and that natural preservatives, such as vitamin C or vitamin E, have been used, but this can vary from brand to brand. In addition, although these products may not contain added artificial preservatives, they may still contain low low levels of artificial preservatives that were already in the meat or fat-soluble vitamins obtained from suppliers.
The low levels of artificial preservatives in dry dog food pose an extremely small risk to the general canine population. Nevertheless, until the studies now being conducted produce conclusive information, some dog owners will choose to avoid artificial preservatives and give their dogs a naturally preserved dry dog food. Also, there is a small percentage of dogs that cannot tolerate artificial preservatives. For those dogs, owners can choose from a wide variety of canned and dry foods preserved with either vitamins C or E. If you do choose to give your dog a naturally preserved food, remember that it should be consumed within four to six months of the date of manufacture. The date should be listed on the label, but sometimes it's difficult to read or is listed only as a code. In these cases, call the manufacturer for further information (as you should do with any specific questions you have about the food). Although you should stay up-to-date on information coming to light regarding preservatives, be discerning about what pet food manufacturers and other people in the dog world tell you. A wise consumer judges the evidence and doesn't just listen to the hearsay.
- Written by Dr. Lisa Freeman, DVM -
(Dr. Freeman is a veterinary clinical nutritionist at Tufts University)
www.executec.com/food.htm
The nutrient that is most susceptible to spoilage is fat. Fat spoilage (oxidation) decreases the nutritional quality of the food, makes it less palatable to the dog, and can even make it unsafe to eat. Since most dog food contains high level of fat and fat-soluble ingredients (including vitamins A and E), it is critical to prevent oxidation to maintain quality, nutritional value and palatability. Canned dog food is protected from oxidation by its airtight storage, but dry food, even with modern packaging, must include preservatives to maintain quality and safety. Dry dog food needs preservatives, but which preservatives is the best?
Preservatives can be either artificial or natural. Both types work by preventing fat and other ingredients in the food from oxidizing. The most common artificial preservatives used by the pet food industry are ethoxyquin, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). Tocopherols (vitamin E) and ascorbic acid (vitamin C) are the most common natural preservatives.
The preservative that has caused dog owners the most concern is ethoxyquin. It is currently allowed in dog food at levels up to 150 parts per million (ppm). Although ethoxyquin has been used in animal feed for more than 30 years, in the last nine years the FDA has received many consumer reports about health problems occurring in dogs that were fed ethoxyquin-containing foods. Although several studies have not shown any adverse effects from using ethoxyquin in dog food at approved levels, consumer concerns have triggered further investigation into the safety of this preservative. A recent study by Monsanto, the major producer of ethoxyquin, indicated that the only problems caused by long-term, moderate-to-high ethoxyquin levels in food were mild increases in blood levels of liver enzymes and an increase in the levels of a normal red-blood-cell metabolite in the livers of lactating bitches, who generally eat more than other dogs. No reproductive abnormalities or other health problems occurred.
Although the liver findings referred to above are considered to be very mild and of no clinical significance, further investigation is needed. In July 1997, the FDA's Center for Veterinary Medicine sent letters to the manufacturers of ethoxyquin and to the pet food industry requesting that the maximum levels of ethoxyquin be lowered to 75 ppm in dog food. A study currently under way by the Pet Food Institute is designed to determine whether still lower levels (30 or 60 ppm) of ethoxyquin provide adequate antioxidant protection for dog food. The FDA will take appropriate action based on the results of this study.
Although vitamins C and E can both be used as preservatives, neither is as effective as the artificial preservatives. For example, one study found that dry dog food preserved with vitamin E spoiled faster than food preserved with ethoxyquin or BHA.
To provide alternatives to artificial preservatives or other ingredients perceived as unhealthy, many companies now market dog foods that are "all natural." The problem is that there's no legal definition of "all natural," "preservative free," or similarly named products. Manufacturers define products by what they believe these terms mean. In general, the implication is that no preservatives or artificial colors have been added and that natural preservatives, such as vitamin C or vitamin E, have been used, but this can vary from brand to brand. In addition, although these products may not contain added artificial preservatives, they may still contain low low levels of artificial preservatives that were already in the meat or fat-soluble vitamins obtained from suppliers.
The low levels of artificial preservatives in dry dog food pose an extremely small risk to the general canine population. Nevertheless, until the studies now being conducted produce conclusive information, some dog owners will choose to avoid artificial preservatives and give their dogs a naturally preserved dry dog food. Also, there is a small percentage of dogs that cannot tolerate artificial preservatives. For those dogs, owners can choose from a wide variety of canned and dry foods preserved with either vitamins C or E. If you do choose to give your dog a naturally preserved food, remember that it should be consumed within four to six months of the date of manufacture. The date should be listed on the label, but sometimes it's difficult to read or is listed only as a code. In these cases, call the manufacturer for further information (as you should do with any specific questions you have about the food). Although you should stay up-to-date on information coming to light regarding preservatives, be discerning about what pet food manufacturers and other people in the dog world tell you. A wise consumer judges the evidence and doesn't just listen to the hearsay.
- Written by Dr. Lisa Freeman, DVM -
(Dr. Freeman is a veterinary clinical nutritionist at Tufts University)
www.executec.com/food.htm
