Friday, February 8, 2013

Pet Toxins Part II: Garlic and Onions on #FurbabyFridays

Welcome back to Furbaby Fridays. Today I'm continuing the series on common pet toxins. Last week I talked about marijuana and this week I'm covering my all time faves...garlic and onions.  Many folks know that onions are toxic but these same folks refuse to jump off the supplemental garlic band wagon. Too often I've had to correct that Old Wive's Tale that garlic repels fleas.

It doesn't and it never has. It doesn't repel ticks, lice or any other blood sucking or biting parasite.

Now that's out of the way. Let's get on with the discussion shall we?

Garlic and onions come from the same species of plants. Allium species contain a wide variety of toxins called organosulfioxides. Through chewing or other trauma to the plant, these turn into a mixture of sulfur containing compounds. This is how the plants get their characteristic odors and flavors as well as their pharmacological they can affect the body. They are readily absorbed through the gastrointestinal tract and then metabolized into other chemicals that are considered to be highly reactive oxidative agents.  This toxicity is not diminished through cooking or if the plants spoil.  For our discussion, I'll just stick to the "usual suspects" and not discuss the wild onions and garlic plants.

I know some of you are shaking your head right now. You want to argue with me that if garlic is so toxic, why is it in some pet foods, recommended by some veterinarians as helpful to pets? Let me start off with this statement:

"ALL ingested garlic/onion will cause some degree of hemolysis in dogs and cats—it's only when sufficient red blood cells have been damaged to alter the overall oxygen carrying capacity of the blood and/or to cause hemoglobinuria (dark red-brown urine) that the toxicosis becomes clinically evident."  Sharon Gwaltney-Brant DVM, PhD  Diplomate, American Board of Veterinary Toxicology

 What the good doctor above is saying is that even the very small amounts used in making these pet foods and maybe in your left over beef stew will cause damage to the animals red blood cells. If the animal is otherwise healthy, it's body will end up destroying the affected cells and creating new ones every three usual.  Unfortunately, if there is any other medical condition that has already caused problems, the body may not be able to keep up with the repair. So even in these patients, the very small amounts are a big NO NO.

Garlic is FIVE TIMES more toxic than it's family member the onion. The toxic does of onions is 5 grams of onions per kg in weight of the animal. Garlic is 1gram per kg of body weight. That seems like a lot until you find out that 1 TEASPOON equals 5 grams. So 1 teaspoon of raw onions or raw/fresh garlic each weigh five grams.  Another thing to note here is that  garlic POWDER is 2 to 2.5x more potent than fresh garlic. So  if you cook with 1 teaspoon of garlic powder you are using the equivalent to 12.5 grams of fresh garlic.  Hang onto your hats folks: cooked onions are far more toxic on a per weight basis than raw for the simple fact that as you cook them, they condense. So 1 teaspoon of raw onions does NOT equal 1 teaspoon in cooked onions when you compare toxicity. Once cooked, you are condensing more toxin in a smaller volume.

Garlic can also be a potent cardiac and smooth muscle relaxant, dilate blood vessels and lead to hypotension. Both onions and garlic can be potent anti-thrombic agents: they prevent clot formation. So it really wouldn't be a great idea for you to give your big Labrador 3 or 4 cloves of garlic to boost his immune system on the morning he's going in for a fracture repair. This actually happened to one of my colleagues. They found out that there was a problem when they were shaving the dog for surgery and the skin started to ooze blood. That is NOT NORMAL! If they would have continued with the surgery, there could have been fatal consequences.

Baby food used to have onion powder in it and believe it or not it was one of the most toxic concentrations for animals if they were fed that long term. Lucky for us, most of the baby food companies have stopped putting it in there and veterinary hospitals can continue to use these foods to help entice finicky patients to get back to eating.  Why doesn't it affect humans the same way as it does animals? Our red blood cells are a heck of a lot more resilient than the dogs and even more so than the cat.  Cats if you haven't already figured out are just a whole other story all together! Every thing affects them to the nth degree more than any other species and in fact can kill them all that much faster too.

Jaundiced gums and lips of a cat
What signs would you see if your pet has ingested enough garlic or onions to make them clinically sick? Weakness, increased respiratory rate, increased heart rate, and very dark urine. You may even see jaundice or a yellow color to the gums, inside of the ears, all of the skin, and the whites of the eyes. Laboratory abnormalities that would show up would be very low PCV (red blood count), hemoglobinuria (why the urine has the dark color), hemoglobinemia (large amounts of hemoglobin free in the blood stream and not inside the red blood cells), red blood cell abnormality called Heinz Body anemia. What that last part is describing is a small accumulation of hemoglobin that had been denatured and it sticks to other red blood cells. These cells are recognized by the body as foreign and then marked for destruction by the spleen. If enough of these cells are destroyed, you get the low red cell count...anemia.

Take Home Message

While the small amount of garlic in pet foods made commercially and those in veterinary approved home cooked recipes can stimulate some of the changes biological changes listed above, it usually will NOT cause the hemolytic disorders in an otherwise healthy pet. It's when people start supplementing themselves using more than recommended by their veterinarians. This can be done by using additional raw garlic bulbs, but more so using the powders and dehydrated forms of onions.  More in these cases is definitely not better!

Toxicity can be cumulative in these over-supplemented cases because the body doesn't have enough time to destroy the affected cells and also produce new red blood cells before even more are destroyed.  

So instead of perpetuating the Old Wive's Tales, please, please PLEASE have these discussions with your own veterinarians to help you develop the best health care routine for your pets. Trust me, we would want to be proactive in your pet's health than have to see you on an emergency at 3am and have to tell you what you've been feeding your pet caused it's current illness. 

Some links you'll want to bookmark

Click here to go to the site


See you next week for another segment on common toxicities in pets.
~Dr. Tammy

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