Recently, the Clean Label Project released new testing data on contaminants in commercial dog food — and the results raised serious questions about what’s really in our dogs’ bowls.
They tested 79 of the top-selling dog foods across three categories:
- Dry (kibble)
- Air-dried/freeze-dried
- Fresh/frozen
The focus? Heavy metals like lead, arsenic, cadmium, and mercury, along with industrial contaminants such as phthalates and acrylamide.
The headline finding
Dry dog food tested highest in heavy metals and contaminants.
Compared to fresh/frozen foods, dry foods showed dramatically higher levels of:
- Lead
- Arsenic
- Cadmium
- Mercury
Fresh/frozen foods tested lowest overall. That doesn’t mean every kibble is toxic. But it does raise a bigger issue: Chronic exposure. Most dogs eat the same food, every day, for years.
Why Heavy Metals Are Concerning for Dogs
Heavy metals occur naturally in soil and water. Small amounts are unavoidable. The problem isn’t one meal — it’s accumulation over time.
Dogs are particularly vulnerable because:
- They often eat the same formula daily.
- They consume more food per pound of body weight than humans.
- They often stay on one brand for years.
When metals accumulate faster than the body can eliminate them, they can contribute to:
- Liver stress
- Kidney strain
- Neurological effects
- Oxidative damage and inflammation
This process is called bioaccumulation — and it’s why small amounts, repeated daily, deserve attention.
Why Dry Food Tested Higher
Ultra-processed foods like kibble go through:
- High-heat extrusion
- Dehydration
- Long shelf-life stabilization
- Addition of synthetic vitamin/mineral premixes
The more processing steps involved, the more opportunities there are for contaminants to concentrate or enter the supply chain.
Fresh/frozen foods typically:
- Use whole ingredients
- Undergo less extreme processing
- Contain fewer synthetic additives
The result in this testing? Lower contaminant levels on average.
What Pet Parents Can Do
This isn’t about panic. It’s about reducing risk over time.
Here’s how:
1. Add fresh food to the bowl
Even replacing 25–50% of your dog’s dry food with fresh can reduce repeated exposure.
2. Rotate fresh and dry proteins
Different ingredients accumulate contaminants differently. Rotation prevents the same exposure pattern day after day.
3. Choose dry dog food brands that test
Transparency matters. Ask brands:
- Do you test finished batches?
- Will you share results?
- Where do ingredients come from?
The Bigger Takeaway
We can’t eliminate environmental contaminants completely. But we can:
- Reduce ultra-processing
- Increase ingredient transparency
- Feed food that looks like food
The Clean Label Project’s findings don’t say “everything is dangerous.” They say: how food is made matters.
And for dogs who eat the same thing every day for years — that matters a lot.