Can Dogs Eat Spinach? Benefits, Oxalates and Preparation

Reading time: about 8 min

For years Faddy gave me a distinctly unimpressed look whenever I offered him fruit or vegetables. Then one day I offered him some frozen, chopped spinach, and to my surprise he took it enthusiastically. He even crunched it up. At the time I joked that perhaps he had decided to slow down ageing all by himself. Of course, I have no idea why he wanted it, but dogs’ food preferences can still surprise us.

I bought frozen chopped spinach from Härmavili and offered him one portion a day when he wanted it. That is our experience, not a daily serving recommendation for every dog: frozen portions vary in size, and a dog cannot judge nutritional balance or oxalate content by taste.

A small amount of spinach can be a suitable addition for a healthy dog that tolerates it. It provides water, fibre and various plant compounds, but it does not need to appear in every pet’s bowl. Dr Karen Shaw Becker’s discussion of spinach first made me interested in the subject. The valuable idea is to explore what fresh foods can offer, while still considering the amount, preparation and the individual animal’s health.

What does spinach actually provide?

Spinach contains beta-carotene, folate, vitamins K, C and E, other B vitamins and minerals. Researchers have also identified plant compounds such as quercetin, luteolin and spinacetin. Their antioxidant properties are a reason to investigate possible health effects. However, finding a compound in a food is not proof that a spoonful of spinach will prevent disease in a dog.

Free radicals are produced during perfectly normal metabolism too. The body has its own protective systems to regulate them; problems can arise when oxidative stress and antioxidant defences are out of balance. Diet may be one influence, but ageing and chronic disease cannot be explained simply as a shortage of antioxidants.

It is easier to assess nutrients by weighing food than by referring to an unspecified spoonful. According to USDA data for raw spinach, 10 grams provide approximately 2.3 kcal, 0.22 g of fibre, 2.8 mg of vitamin C and 19 micrograms of folate. This is an illustrative calculation, not a feeding recommendation. Values can differ for frozen or cooked spinach.

Dogs can use beta-carotene as a precursor to vitamin A. Cats, however, need preformed vitamin A in their diet and cannot rely on spinach for that purpose. Spinach’s iron content does not make it a treatment for anaemia either: the form of iron, its absorption and the cause of the anaemia all matter. Healthy dogs can synthesise vitamin C themselves. Spinach may contribute nutrients to a diet, but it cannot replace a complete food or therapeutic nutrition where that is needed.

Dietary fibre can affect stools and the activity of intestinal microbes. The appropriate amount and balance of soluble and insoluble fibre depend on the entire diet and the dog. We cannot derive a universal “4% fibre requirement” for all pets from an article about spinach. Nor is the crude-fibre figure on a food label the same as total dietary fibre.

Learning ability and body weight: important distinctions

Becker’s article makes an interesting reference to alpha-lipoic acid and learning in older dogs. In a 2007 study by Milgram and colleagues, beagles aged 7.6–8.8 years received a combination of alpha-lipoic acid and acetyl-L-carnitine for approximately two months. The dogs made fewer errors in two learning tasks, but there was no significant difference in a separate spatial-memory test.

This was a study in dogs, but it was not a study of spinach, nor a trial of alpha-lipoic acid alone. The authors’ proposed link with mitochondria and ageing does not establish that eating spinach slows cellular ageing. Nor can the amount of the supplement used in the study be translated into a homemade portion of spinach.

Thylakoids are membranes found in the chloroplasts of green plant cells. Preparations made from spinach membranes have been investigated in humans in relation to appetite and body weight. In one 2014 study, 38 women with overweight received either 5 g of a plant-membrane preparation or placebo for 12 weeks, alongside lifestyle guidance. Weight loss was greater in the preparation group. This does not show that ordinary spinach reduces appetite or treats overweight in dogs. Thylakoids are also not a single specific antioxidant.

These research directions are interesting. My own practical reason for offering spinach is simpler: in a suitable dog, a small serving can add variety and plant-derived nutrients.

Oxalates: when spinach may not be appropriate

Spinach is rich in oxalates. Some dietary oxalate binds calcium in the digestive tract, while some can be absorbed and excreted in the urine. The risk of calcium oxalate stones depends on factors including urine concentration, the excretion of calcium and oxalate, and individual susceptibility. A small ordinary serving of spinach does not mean that sharp crystals automatically form in the bloodstream.

A healthy dog occasionally eating a small amount and a dog with calcium oxalate stones receiving spinach daily are very different situations. The University of Minnesota Urolith Center advises avoiding high-oxalate spinach for dogs with calcium oxalate stones. For such a dog, I would not promise that boiling makes spinach safe. Cats with kidney disease, a history of urinary stones or a prescribed diet also need individual dietary advice.

Becker’s discussion suggests boiling and very limited quantities for animals prone to stones. My position at FendaF is more specific: I would not add spinach to the diet of an animal with a known calcium oxalate problem on my own initiative. There are other options, and spinach is not an essential ingredient.

Raw, steamed or boiled?

Chopping spinach finely and cooking it can make plant tissues easier to access during digestion. Boiling and discarding the cooking water generally reduces soluble oxalates more than steaming. In a 2005 food-chemistry study by Chai and Liebman, the reduction depended on the vegetable and the preparation method. This was not a dog-feeding trial and did not establish one cooking method as suitable for every animal at risk of stones.

The claim that “heating triples beta-carotene” needs clarification too. In a 1998 trial by Rock and colleagues, researchers compared changes in blood beta-carotene in eight women after eating raw or cooked and puréed carrots and spinach. The increase during the processed-vegetable period was on average three times greater, but the difference between the two preparation groups did not reach conventional statistical significance. The study did not show that heating creates three times as much beta-carotene in spinach, and it did not test dogs.

A healthy dog may tolerate a small amount of finely chopped, gently cooked and cooled spinach. Follow the preparation instructions on frozen products: “frozen” does not automatically mean “ready to eat”. A suitable portion, thawed and prepared, is easier to offer than a large, hard, frozen lump. There is no need for cream sauce, onion, seasoned mixtures or other strong flavourings.

Treats and nutritionally unbalanced extras together should generally account for no more than 10% of daily calories. This is a guideline for dietary balance, not a spinach-specific safety limit. Because spinach is low in calories, an unreasonable quantity could still fit below the calorie limit. Keep spinach a small addition even if the calorie calculation seems to leave room for more. You can find other suitable choices in our article on five foods to enrich your dog’s diet.

Cleanliness and origin

I prefer food from a trustworthy source and, where possible, organic or home-grown spinach. Yet an organic label does not mean a food is free of microorganisms. Wash fresh spinach, discard spoiled leaves, and store and prepare frozen products according to their instructions. Home-grown spinach can be washed, suitably prepared and frozen in small portions.

Pesticide residues and antibiotic-resistant bacteria are two different issues. Walia and colleagues found bacteria resistant to several antibiotics even on triple-washed, packaged baby spinach. This reinforces the importance of food hygiene, but it does not prove that pesticide spraying caused resistance in those bacteria, or that the findings describe every spinach product sold in Estonia.

Faddy’s enthusiasm for spinach remains a lovely personal memory. What I take from it is curiosity about foods that might suit our dogs, coupled with a willingness to observe the actual amount and how well an individual dog tolerates them.

Sources

• Bark & Whiskers, reviewed by Dr Becker (2026; original publication 2022). Can Pets Eat Spinach?. The original article’s integrative starting point; previous address petfoodfacts.mercola.com/vegetables/spinach.html.
• USDA Agricultural Research Service. FoodData Central — Spinach, raw, SR Legacy, FDC 168462. Data used for nutrient calculations.
• Milgram, N. W. et al. (2007). Acetyl-L-carnitine and alpha-lipoic acid supplementation of aged beagle dogs improves learning in two landmark discrimination tests. FASEB Journal, 21, 3756–3762. DOI 10.1096/fj.07-8531com.
• Montelius, C. et al. (2014). Body weight loss, reduced urge for palatable food and increased release of GLP-1 through daily supplementation with green-plant membranes for three months in overweight women. Appetite. Human study, not a spinach trial in dogs.
• Chai, W. and Liebman, M. (2005). Effect of different cooking methods on vegetable oxalate content. Journal of Agricultural and Food Chemistry, 53, 3027–3030. DOI 10.1021/jf048128d.
• Rock, C. L. et al. (1998). Bioavailability of beta-carotene is lower in raw than in processed carrots and spinach in women. Journal of Nutrition, 128, 913–916. DOI 10.1093/jn/128.5.913.
• University of Minnesota, Minnesota Urolith Center. Treatment recommendations — human foods and calcium oxalate.
• Walia, S. et al. (2013). Prevalence of multiple antibiotic-resistant Gram-negative bacteria on bagged, ready-to-eat baby spinach. International Journal of Environmental Health Research, 23, 108–118. DOI 10.1080/09603123.2012.708916.
• WSAVA Nutrition Committee (2024). Feeding treats to your dog.