Polyphenols are Friends

Some people are concerned that polyphenols in some products could be dangerous for cats. It’s not true. They’re beneficial at the dosage levels in the products we sell.

By Dr. Dave Summers, Pet Valu Nutritionist

When used as directed, the levels of Apple Polyphenols in Wysong DentaTreat are safe for cats and dogs. Let me explain the basics about phenols.

Phenols are defined as a class of compounds consisting of a hydroxyl group attached to an aromatic hydrocarbon group. Polyphenols are simply many phenols attached together. However, understanding the chemistry is not essential to determining the safety of polyphenols for pets.

There are literally thousands of polyphenols found in nature, and almost all of them come from plants. Most polyphenols are very good antioxidants, much better than Vitamin E or C, and most have antimicrobial activity. A group of polyphenols, called flavonoids, are found in significant levels in fruits and vegetables. It is the flavonoids that provide most of the health benefits we associate with fruits and vegetables. In particular, the health benefits of blueberries, green tea, red grapes, cranberries, cherries, apples, and (of course!) red wines are due to their flavonoid content.

Cats & Polyphenols

If there are thousands polyphenols, there are probably tens of thousands of phenol compounds. Some phenol compounds are very toxic, and cats have been shown to be more sensitive than other animal species to these toxic effects. This is similar to a cat’s more pronounced sensitivity to garlic, when compared to dogs.

Most of the knowledge on the metabolism of phenols has come from the study of drugs containing phenols – particularly studies of Acetaminophen (Tylenol) and Salicylic acid (Aspirin). Metabolism occurs along specific pathways in the body, and enzymes are like the intersections in these pathways. In the pathway to metabolize drugs containing phenols, there is an enzyme called glucuronosyltransferase. Cats have a lower level of this enzyme than most animals, so cats can tolerate, and benefit from, low levels of phenol compounds. At higher levels the phenol compounds will saturate the glucuronosyltransferase enzyme, creating a backup of phenol compounds that will lead to toxic effects. Without a drastic medical intervention the cat will succumb to respiratory failure.

Dogs are also more sensitive to the toxic effects of Acetaminophen than most other animals. Acetaminophen levels of 100mg/kg body weight have been shown to have toxic effects in dogs, but the toxicity level in cats is estimated to be about three times lower than the level in dogs. This is approximately 30mg/kg of a cat’s body weight.

As a group of phenolic compounds, flavonoids are generally considered to be non-toxic. A study of the toxicity of apple polyphenols (which are mostly the non-toxic flavonoids) in humans showed doses at 200 times normal daily intake levels did not even show any negative effects. This means even if cats were 100 times more sensitive than humans, they would still be outside the range considered to be toxic.

Consider Dosage

You must consider dosage rate before you can discuss toxicity. The same applies to apple polyphenols, as there is no doubt that at some intake level they will be toxic, just like most other compounds. With Acetaminophen and other phenolic drugs the daily intake is usually measured in hundreds of mgs while the intake of polyphenols is usually measured in single digits. At their higher intake levels, drugs can readily saturate the metabolic pathway, whereas polyphenols at low intake levels do not. (This also helps to illustrate why Tylenol is so toxic to animals, yet polyphenols in foods and supplements are beneficial.)

To put it in perspective, DentaTreat used according to directions would contribute less than 1mg of polyphenols to the diet. Given the safety of the polyphenols in question, and the cat’s ability to metabolize low levels of polyphenols, there is no evidence that the level of natural polyphenols coming from apples is toxic to cats, or any other animal. Wysong has used this natural ingredient for some 30 years with no adverse results after in tens of thousands of pets have consumed it.