Human Food Toxic to Dogs

Dogs have evolved for years to be man's best friend and historically that has meant sampling our food. While each dog is an individual and may have unique sensitivities, foods in the onion family, grape family, macadamia nuts, chocolate, coffee, xylitol products, and edibles should be avoided for all dogs. As a dog lover, you may be curious what happens when these are ingested by a dog, when you will see changes, and what to look for? Here is what we know:

Onion Family (all onions and garlic)

Foods in this family cause oxidant injury to red blood cells that result in hemolysis (RBC destruction) both in the blood vessels and in the tissues. The body compensates for loss of RBC by releasing cells from storage in the spleen and fast tracking production in the bone marrow. Once those options have been used the body cannot compensate any longer. Without enough RBC, there is a reduced ability to bring oxygen from the lungs to the body. The oxidative injury typically peaks at 24 to 72 hours with signs developing usually between day 2 and 5 days after exposure. Signs of onion toxicity include weakness, pale gums, high heart rate, and red brown urine.

Grape Family (Vitis spp) (includes raisins)

Grapes cause kidney injury that can lead to failure, but we do not know what causes it and if the injury is related to dose. Due to the unknowns and the poor prognosis of kidney failure, exposure is assumed to be toxic. There are individuals who report feeding dogs grapes with no consequence and dogs that have developed fatal kidney failure from a single exposure. I share this to help you understand why professionals take this so seriously and to acknowledge that with better understanding in the future this may well change. The kidney injury typically can be detected on bloodwork between 3 and 5 days after ingestion. Like many systems in the body, healthy kidneys have significant ability beyond what is needed. That means that your dog can have significant permanent kidney damage - estimated 70%- before changes are seen. This allows for some damage before illness develops, but also means in cases of toxic exposure, changes are not seen until significant damage is done. Signs of grape toxicity include vomiting, lethargy, increased drinking, increased/decreased/no urine production, and in rare cases tremors and seizures.

Macadamia Nuts

The cause of macadamia nut toxicity is unknown. Signs typically start within 3 hours of ingestion, peaking around 8 hours after ingestion and may resolve around 24 hours after ingestion when ingested alone in a healthy pet. Unfortunately dogs often ingest macadamia nuts with chocolate or xylitol complicating recovery. Signs of macadamia nut toxicity include weakness, ataxia, vomiting, tremors, increased temperature, and coma.

Chocolate/ Coffee and caffeine containing products

Chocolate and caffeine cause a chain of reactions that lead to catecholamine release, which act as a stimulant (think fight or flight response). Once absorbed from the intestines they circulate in the body, get filtered into the bile, bile is secreted into intestines and then can be reabsorbed, and the process repeats. The active metabolites can also be reabsorbed from the bladder. Signs often start quickly after ingestion and how long they last depends on how quickly treatment is provided to prevent reabsorption. Signs of chocolate or caffeine toxicity include weakness, tremors, seizures, increased heart rate and in severe cases coma and death.

Xylitol (aka Birch Sugar)

Xylitol is an artificial sweetener commonly found in peanut butter, gum, medications formulated for humans, and oral health products. Xylitol causes rapid increase in insulin which results in dangerously low blood sugar and in some cases liver failure. Signs usually present within 1 to 3 hours after exposure and take 1 to 3 days to recover with aggressive intervention. Signs of xylitol toxicity include weakness, ataxia (stumbling) and lethargy. Without intervention, risk of long term damage or death are significant.

THC products (edibles, topical, second hand inhalation)

THC has a profound effect on dogs. How quickly signs develop depends on how they were exposed, how much they got and for how long. Typically signs start within 1 to 3 hours of exposure and dogs recover within 24 to 72 hours, assuming they do not have continued exposure. Signs of THC exposure include change in coordination, change in mental status, low body temperature, and dribbling urine incontinence. Dogs on THC products often find themselves in additional trouble due to cognitive changes (ex: broken bones, ingesting other toxins).