Can Cats Eat Walnuts? Are They Toxic?

Are walnuts safe for cats? These nuts are shaped like itty bitty brains and are considered a brain food for humans as well, among many other health benefits. But does this nut provide the same benefits for cats? Read on to learn if cats can eat walnuts.

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Last Updated: November 21, 2023 | 5 min read

Cat sniffing walnuts on a table

This article should not substitute contact with a veterinarian. Contact your local vet immediately if your cat is reacting poorly after consumption.

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As one of the healthiest superfoods on the planet, walnuts are known for their health benefits and are a satisfying, calorie-dense snack. Walnuts are rich in antioxidants and omega-3 fat. They have been linked to decreased inflammation, a healthy gut, low blood pressure, and more.

With all these benefits, you might wonder if walnuts are safe for cats. Can your furry friend benefit from this brain-building snack? We cover everything you need to know about cats’ nutritional needs and the efficacy of feeding walnuts to cats.

What Are Walnuts?

Walnuts are tree nuts that grow with a hard outer shell. Crack it open and get to the rich, earthy inner nutmeat. While there are about 20 species of walnut trees, you’re most likely to come across the English walnut or the California black walnut. Since walnuts are challenging to crack, many manufacturers do the work for you, selling shelled walnuts in halves or pieces.

Walnuts are popular for snacking and can be used in salads, granola, pasta, fruit bowls, and more. Walnut oil can be used in cooking (not high-temperature) and adds a nutty taste to a dish. Black walnut hulls are used in holistic medicine as a natural anti-parasite remedy. Furthermore, walnut meat has been studied for its anti-cancer activities and effect on cognitive decline.

Can Cats Eat Walnuts?

Can cats eat walnuts? While walnuts aren’t toxic to cats, you shouldn’t feed your feline walnuts. While eating a walnut isn’t harmful to cats, too many can cause digestive upset.

Are Walnuts Bad For Cats?

Can cats eat walnuts? No, they shouldn’t. Let’s look deeper into why walnuts are bad for cats and consider alternatives that offer similar nutritional benefits.

Cat Nutritional Needs

Cats—being obligate carnivores—have unique dietary requirements. While plant-based diets are healthy for humans, cats absorb nutrients most efficiently from animal sources. The ASPCA warns against feeding your cat a plant-based diet because it may result in nutrient imbalances and adverse health outcomes. While one cross-sectional study found no difference in the health of cats fed meat- and plant-based diets, providing your cat food from animal sources is generally recommended. According to the Association of American Feed Control Officials (AAFCO), cats need the following nutrients:

MacrosAmino AcidsFatty AcidsVitamins & Vitamin-like SubstancesMinerals
ProteinArginineLinoleic acid (LA)Vitamin ACalcium
FatHistidinealpha-Linolenic acid (ALA)Vitamin DPhosphorus
IsoleucineArachidonic acid (AA)Vitamin EPotassium
LeucineEicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA)Vitamin KSodium
LysineThiamine (B1)Chloride
MethionineRiboflavin (B2)Magnesium
Methionine-cystinePantothenic AcidIron
PhenylalanineNiacin (B3)Copper
ThreoninFolic AcidZinc
ValineVitamin B12Selenium

Cats utilize protein for energy, development, and overall body function. The building blocks of protein are amino acids. One of the critical amino acids for cats is taurine. The AAFCO lists taurine as a vitamin-like substance because, while it’s an amino acid, it is not used for protein synthesis. Cats are unable to synthesize taurine and must get it via their diet. So long as you feed your kitty a diet primarily of meat, they should get all their essential amino acids, including taurine. Many companies will even add extra taurine to ensure cats are getting a sufficient level of taurine.

Also, ideally from animal sources, cats use fats for energy and eyes, brain, skin, coat, and joint support. The building blocks of fats are fatty acids. Some fatty acids, like arachidonic acid, EPA, and DHA, are found primarily in meat. Quality sources of fat for cats include fish oil and beef tallow.

Finally, your cat uses carbohydrates for energy and digestive support. The AAFCO does not list carbs are an essential nutrient in a cat’s diet; however, the fiber from carbs can be beneficial for your cat’s digestive system when fed in moderation. Fiber supports the elimination of toxins and helps break down hairballs.

Other nutrients include water, vitamins, and minerals. Water carries nutrients throughout the body, regulates body temperature, supports joints, helps eliminate waste, and more. Vitamins and minerals support various body functions, including boosting the immune system, regulating hormones, repairing cells, and more.

Walnut Nutritional Breakdown

According to WebMD, one serving of walnuts—about seven—contains the following:

  • 185 calories
  • 2.5 grams monounsaturated fat
  • 1/7 grams saturated fat
  • 4.3 grams protein
  • 3.9 gram carbohydrates
  • 1.9 grams fiber
  • .7 grams sugar

Walnuts are also a magnesium, iron, folate, potassium, and calcium source. Walnuts can add up to 65 percent fat and are very calorie dense.

Walnut Nutrient Concerns

The high-calorie content of walnuts may lead to weight gain, which is associated with an increased risk of other health problems, including:

  • diabetes
  • gallbladder disease
  • high blood pressure
  • high LDL cholesterol
  • obesity
  • osteoarthritis

A cat eating multiple walnuts may also experience adverse effects due to this nut’s high-fat content. While fat is a crucial nutrient, it is also harder to digest. Symptoms of digestive distress include:

  • Bloating and gas
  • Diarrhea
  • Fatigue
  • Vomiting

But what about just a tiny piece? Do cats benefit from the fats in walnuts at all? You may have heard that walnuts are chock-full of omega-3 fatty acids, and the reason that they must be suitable for cats. Unfortunately, it’s not that simple. The source of the omega-3 makes a big difference.

While walnuts contain a significant amount of omega-3s, these omegas are from alpha-linolenic acid (ALA), a vegetable source of omega-3 fatty acids. ALA is a precursor to EPA and DHA. While all these fatty acids are essential for a cat’s diet, EPA and DHA provide the most health benefits for pets. Since ALA is a precursor to EPA and DHA, we must consider the conversion rate. In humans, the conversion of ALA into EPA is 1-10% and 0.5-5% into DHA. For cats, it’s even lower. Cats can synthesize small amounts of omega-3 acids from their precursors but not enough to receive the therapeutic benefits of these fatty acids.

Food Allergies In Cats

According to VCA Animal Hospitals, typical cat food allergies include beef, chicken, fish, or dairy; however, cats can be allergic to any food. An allergic reaction occurs when the immune system goes into overdrive due to a perceived health threat. Food allergies may develop anytime after three months of age. Before introducing any new food or treat, monitoring your cat’s reaction is essential. Stop feeding your cat food if you notice any signs of food allergies, including itchingbiting skin, vomiting, and diarrhea.

Risks Of Feeding Walnuts To Cats

Besides the nutritional concerns associated with feeding your cat walnuts, other risks include:

  • Choking: If a walnut isn’t broken into tiny pieces, it could become a choking hazard.
  • Fungus: Moldy walnuts can be a source of tremorgenic mycotoxins, which causes muscle tremors, ataxia (uncoordinated movements), rapid heart rate, rapid respiratory rate, vomiting, seizures, and death.

What To Do If Your Cat Eats Walnuts

If your cat eats walnuts, contact your veterinarian for assistance. Your vet will likely ask how many walnuts your cat ate and advise you from there. Watch your cat for changes in behavior, eating, and elimination habits. Make sure to tell your vet if the walnuts were moldy. Your vet will run tests to confirm exposure and offer a treatment plan.

Walnut Alternatives For Cats

Walnuts are a quality source of omega-3 fatty acids for humans but should be avoided by cats. EPA and DHA act as anti-inflammatories and support the brain, eyes, joints, skin, and more. For cats, consider these treats that are packed with omega-3s:

  • Freeze-dried capelin: These all-natural fish treats from Arya Sit! are made from 100% capelin fish and are a source of omega-3, along with omega-6, taurine, calcium, zinc, vitamin A, and Vitamin D.
  • Fish oil: Nordic Naturals Omega-3 Pet is made from wild-caught anchovies and sardines. This oil provides 156 mg EPA and 92 mg DHA per milliliter.
  • Six fish freeze-dried blend: Orijen Six Fish treats are made from Atlantic mackerel, flounder, monkfish, Atlantic herring, Acadian redfish, and silver hake. Each treat contains just one calorie, making it a diet-friendly option for your pet.

Frequently Asked Questions

What Other Human Foods Should I Avoid Feeding My Cat?

Some human foods are toxic for cats (grapes and raisins, cherries, chocolate, onions, and garlic). Processed meats, like bacon and pepperoni, should also be avoided. Some foods, like sweet potatoes and cottage cheese, are likely okay in moderation.

What Human Foods Are Safe For Cats?

Meats like steak and turkey are safe for cats to eat. Low-calorie fruits like blueberries and cranberries are also safe and provide additional health benefits. Other human foods that cats can eat include watermelon, carrots, shrimp, and ham.

Final Thoughts

Can cats eat walnuts? While walnuts aren’t toxic to cats, they aren’t healthy either. Like other nuts, walnuts have a high-fat and high-calorie nutritional content. Too many walnuts can lead to digestive distress, weight gain, and other health problems.

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