There is growing awareness and concern about the levels of heavy metals and other contaminants in pet food:
- CNN has reported “alarming risk of heavy metals and other contaminants” in dry kibble based on independent laboratory testing.1
- Clean Label Project reports high levels of heavy metals and other contaminants in 100% of the dry kibble tested.2
- Wall Street Journal reports increases in chronic disease in pets that are attributed to heavy metals in ultra processed kibble.3
- Two European articles present risks for lead due to residual gun shot in raw game meat.4,5
Certain heavy metals are considered essential nutrients in the canine and feline diet, such as iron, copper, and zinc. While essential nutrients, even these can pose health risk if too much is present in the diet.
Other heavy metals are considered contaminants and should be avoided, such as arsenic, cadmium, mercury, and lead.
Test Results
In all testing, kibble contained the highest levels for all contaminants. Air and freeze dried products contained moderate levels of contaminants. Fresh pet foods contain the lowest levels, especially products using “human grade” ingredients.
Here is how kibble compares to fresh/frozen for these contaminants:
For those who like to see the detail:
Sources of Heavy Metals
Standards for pet food are much more lenient than those for human food, and many ingredients that contain levels far higher than what are acceptable for human food are allowed to be used in pet food. For example, Zinc Hydroxychloride is an AAFCO approved feed ingredient, but test have shown levels of cadmium, arsenic, mercury, and lead well above what would be allowed in human food.
Fresh pet foods using only “human grade” ingredients will have the lowest levels since they must meet the human food standards. Novel proteins, such as game meats – such as pheasant or beaver – may have some risk of lead contamination due to harvesting methods.
Health Risks
Let’s look at some heavy metal specific illnesses:
- Copper is stored in the liver. Excess copper in the diet can lead to liver disease such as copper-associated hepatopathy.
- Lead in the diet can cause blood abnormalities, neurologic disorders, and cancer.
- Cadmium in the diet can lead to a variety of health issues, including gastrointestinal issues and kidney damage.
- Mercury in the diet can lead to neurological issues, gastrointestinal problems, and kidney damage.
- Arsenic in the diet can lead to gastrointestinal issues and nerve damage.
Studies show that all of these substances can accumulate in the kidney and liver and contribute to chronic disease including cancer which is a leading cause of death in dogs. (AVMA reports that 1 in 4 dogs will develop cancer during their lifetime.)
Pets on a steady kibble diet have the highest risk for these health issues since they are consuming these contaminants with every meal.
Fresh and frozen foods reported the lowest levels of heavy metals of any category. This is due to the higher quality ingredients in fresh or frozen pet foods, especially those that meet human food standards. These ingredients have already been tested and approved for human consumption.
Summary
For those who want to minimize their pets’ health risk due to consumption of heavy metals, choose pet foods made with human quality ingredients.
[link to article “Other Contaminants in Pet Food”] [Link to article “Why Kibble Is So Popular”] (needs to be written) [Link to article “Why More People Are Choosing Fresh” ] (needs to be written)
Sources:
1 Dog food contains ‘alarming’ levels of lead, mercury and other contaminants | CNN
2 Extremely High Levels of Hard Metals Found in Dog Food – Clean Label Project
4 https://www.mdpi.com/2813-9372/1/1/2
5 https://www.wtm.at/smart_users/uni/user94/explorer/43/wtm000044.pdf
Other Contaminants in Pet Food
