A 2023 study on humans showed how endotoxins increase the risk of obesity and type 2 diabetes.  Researchers discovered that fat cells are significantly damaged by endotoxin – and that endotoxins reduce a white fat cell's ability to transform into the more metabolically-active brown-like fat cells, which drive weight loss.

The study also found that white fat cells in obese humans were less likely to transform into brown-like fat cells compared with fat cells from lean individuals, likely due to the higher levels of endotoxin found in the blood of the obese people in the study.  

We'll talk more about the relationship between obesity and diabetes in another blog post.  For now, let's talk about what endotoxins are and why our pets are likely at greater risk for endotoxin exposure than humans. 

What Are Endotoxins?

Endotoxins are molecules that exist inside a cell of gram-negative bacteria (like salmonella or E.coli).  Approximately two million endotoxin molecules are released  every time a single cell of gram-negative bacteria dies.

Endotoxin overload initiates and perpetuates widespread damage and disease. GI, liver, brain, kidney, cardiovascular, autoimmune and metabolic injury including obesity are tied to it.

In six to 12 hours, one cell of salmonella on room-temperature chicken can replicate to one million cells. When these one million cells die (during cooking or digestion in your dog's belly) they release two trillion endotoxin molecules.

Why Endotoxin Risk May Have Been Elevated For the Last Two Years

The current H5N1 bird flu is the deadliest in US history.  It began overseas in late 2021.  It reached the US in 2022 and as of this writing in March 2023, nearly 60 million US poultry have been culled.

Destroying flocks is a gruesome and inhumane act.  About 75% of those 60 million birds have been destroyed by turning up the temperature and shutting off the ventilation in their living areas.  They die over the course of a few hours.  The other 25% generally are killed by spraying them with fire retardants. 

Eventually the “soup” of dead birds, excreta, flies, and all manner of foulness is shoveled out.  The FDA permits this poultry to be sold as the “chicken” or “turkey” on pet feed labels.  It permits that poultry (along with those fire retardants) to be rendered into meals that also are pet feed ingredients.  And, the FDA permits those dead chickens or turkeys raised on organic farms to be sold as “organic chicken” or “organic turkey” on a pet feed label.

The toxicity of these ingredients is incomprehensible. Endotoxin is one of those toxins that occurs widely but rarely is discussed.

Endotoxins activate several immunocompetent cell’s signaling pathways. At unmanageable levels they can initiate and perpetuate damage to and inflammatory diseases of the gut.  

How much is unmanageable?  To answer that question, we should look at the whole picture of what our pets eat.

First, imbalanced feeding worsens the disease states caused by endotoxins –namely diets with poor protein nutrition and lots of saturated fats.  A large scale study of 90% of the pet foods on the market found that:

"the largest feed ingredient [in pet food] was corn... Adding animal byproduct meals (e.g., meat and bone meal and meat meal), soybean meal, and corn gluten feed/meal to corn’s share represented more than 90% of all feed tonnage provided...to pets in 2019."

Plant based proteins from corn and soy and rendered products are poor quality protein, and rendered fats are inedible saturated fats. Thus we need to accept that a diet which exacerbates endotoxin overload is precisely what most pets are eating.  To assume otherwise would be to accept that rendered fats are healthy fats; meat meals, corn gluten meal and soybean meal are quality protein; and "chicken" on a pet feed label means the same thing as the chicken humans eat.  (It does not.)

Second, increasingly feed additives – like many amino acids and vitamins – contain significant levels of endotoxins because they are manufactured from gram-negative bacteria.  The volume of additives pets eat is significant because the quality of many base pet feed formulations is so poor.  A study on pet food by Industry estimated that additives including synthetic premix supplements can comprise approximately 13% of what is in the bowl.  There are also concerns over the presence of antibiotic resistant genes in these kinds of feed additives.

Third, endotoxin entering the body is carried to the liver where it is inactivated. Increased endotoxin levels can damage the liver.  But more importantly, even when the amount of endotoxin reaching the liver is normal, the presence of another substance can interact with endotoxin to damage the liver. The other substances are not necessarily toxins - or present in toxic amounts.  Clearly rendered ingredients that go into pet feed can be highly contaminated.  But the presence in the liver of endotoxins along with substances like vitamin A, copper and iron, and many drugs can damage the liver too.  This is especially concerning given what we know about the nutritionally provoked canine illness of copper associated hepatopathy.

So what can you do as a pet parent to ensure your beloved companion is thriving? 

Kibble is responsible for the vast majority of pathogenic bacteria pet food recalls because of their inferior ingredients and processing.  And where there's pathogenic bacteria there is endotoxin.  

Choosing a human grade, species appropriate gently cooked food is an excellent start.  It would be ideal if this food comprises 100% of your pets' diet, but if that is not in your budget, then start small.  Science shows that replacing as little as 20% of a process pet-feed diet (like kibble, canned, or roll packed feeds) with human-grade whole foods has a positive impact on a pet's body.

Higher fat diets - especially ones containing long chain fatty acids - increase inflammation and the leaking of endotoxins into the bloodstream through intestinal mucosa according to scientific studies.  Refined carbohydrate meals can also induce endotoxemia.  

Conversely, diets that are rich in fiber and thylakoids, a natural compound found in dark leafy green vegetables, has been shown to protect against the damaging effects of endotoxins.  Fibers and thylakoids restrict the uptake of endotoxin by the intestinal cell by forming a protective barrier on the mucosal lining.  

Wanna get geeky?  Here are some interesting scientific reference materials for further exploration...

Endotoxin Producers Overgrowing in Human Gut Microbiota as the Causative Agents for Nonalcoholic Fatty Liver Disease: https://pubmed.ncbi.nlm.nih.gov/32019793/

Role of Metabolic Endotoxemia in Systemic Inflammation and Potential
Interventions:  https://pubmed.ncbi.nlm.nih.gov/33505393/