Can Dogs Eat Walnuts?

Walnuts aren't the safest choice for dogs

Walnut pieces and nutcracker on cutting board, close-up
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While nuts are a good-for-you snack that's rich in nutrients for humans, the protein-packed legume isn’t necessarily the safest treat for dogs. Though it's hard to ignore your four-legged friend's longing eyes while you're munching on nuts like walnuts, it's best to keep this particular snack to yourself--the dangers of consuming walnuts for dogs ranges from intestinal blockages and GI distress to serious conditions like pancreatitis. Walnuts can be particularly hazardous for our pets because consuming too many walnuts can actually be as toxic to your pet as munching on a chocolate bar.

Are Walnuts Safe for Dogs?

If your dog happens to steal a walnut that fell of your kitchen counter, it's probably not going to hurt him. But the reason walnuts shouldn't be offered to your pooch is that they're susceptible to a particular type of black mold that can prove extremely toxic to canines. While it's not likely to occur in high-quality walnuts that you might find at the grocery store, walnuts that have been collected outdoors from trees aren't safe for pets.

However, walnuts have a high moisture content and can thus start growing fungi at any stage (whether they're shelled or not) during their growth process, from harvest to the store shelf. Some fungi that can grow on walnuts produce metabolites called mycotoxins, which are considered to be carcinogenic, which others produce tremorgenic mycotoxins, which can cause tremors and seizures. While it's possible to boil walnuts and thoroughly dry them to remove any potential mold, it might not be worth the effort for dogs.

A specific type of walnut that's particularly toxic to dogs is the black walnut. These nuts are native to Northeastern United States and Canada, and are toxic for both dogs and horses (but, interestingly, not cats).

What Happens if Your Dog Eats Walnuts

If your dog does accidentally ingest either a moldy walnut or black walnut, symptoms to watch out for including vomiting, tremors, and seizures, and your veterinarian will need to be contacted immediately because their condition can be fatal if left untreated.

Generally speaking, human foods like walnuts that are are high in fats can upset your pooch's stomach and lead to the usual symptoms of tummy troubles, including vomiting and diarrhea. In more serious cases, consuming walnuts can lead to the development of more serious conditions like pancreatitis or gastroenteritis. Pancreatitis is an inflammation of the pancreas that can be either acute or chronic, while gastroenteritis occurs when the gastrointestinal tract (particularly the stomach and intestines) becomes inflamed. Along with their high fat content, pre-packaged walnuts can also contain additives like salt or other seasonings that can be harmful to our pets. 

Assuming they don't contain any black mold, plain, store-bought walnuts themselves aren’t necessarily toxic to your dog in small quantities. However, they are one of the larger varieties of nuts, which means they can not only be difficult for Fido to digest but can potentially causes serious intestinal blockages, particular in smaller breeds. These blockages require surgery and could be fatal if not addressed right away. Additionally, if your dog happens to eat a shelled walnut there's a higher possibility of the shell causing a blockage.

Are There Health Benefits of Walnuts for Dogs?

Nuts like walnuts are full of healthy fats, protein, fiber, and vitamins and minerals, which have been proven to do everything from lower cholesterol and blood sugar to reduce blood pressure in humans. Fresh walnuts, in particular, are packed with protein, antioxidants, and omega oils. But can our four-legged friends reap the same benefits? Experts say our canine counterparts unfortunately can't take full advantage of the health benefits of nuts.

The other issue is that even if Rover could take advantage of some of the health benefits of walnuts, the negative impact of their high fat content will override them--to put it into perspective, an ounce of walnuts contains about 18 grams of fat, and an average 30-pound dog should only be consuming about 14 grams of fat total per day. And combined with the possibility of any form of funghi, the risks of walnuts outweighs the potential benefits.

Are Other Nuts Safe for Dogs?

Generally speaking, veterinarians don't recommend any nuts for dogs, but the only ones that are considered to be somewhat less harmful are peanuts, cashews, and almonds. These nuts all contain nutrients like fiber and protein, but still can carry a risk of causing stomach distress or intestinal blockages...and you have to be especially careful with any nuts that contain flavorings like salt. You should never offer your dog macadamia nuts, as they are considered to be particularly toxic for dogs.