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Vitamin C for Dogs: The Juicy Details - Dog with tongue out in the forest looking up at the sky

Vitamin C For Dogs: The Juicy Details

Most pet parents are familiar with vitamin C. Maybe you even start your day with a glass of fresh-squeezed orange juice, or chug Emergen-C when you’re fighting a cold! Because vitamin C is involved in several essential cellular and bodily functions in both people and animals, it offers many benefits.

But while we humans have to make an effort to include vitamin C in our diet, our furry family members actually don’t. Keep reading to find out:

Overview of vitamin C

Vitamin C, also known as ascorbic acid, is that amazing nutrient you've been told to consume when you have a cold. And for good reason — it's vital for overall health!

This water-soluble vitamin is naturally found in some foods and also available as a supplement. It supports the following bodily functions:

  • Skin & healing: Helps make collagen, a protein needed for healthy skin and wound healing. It also plays a role in strengthening blood vessels, teeth, gums, tendons, ligaments, and bones.
  • Protection: Acts as an antioxidant, defending cells from harmful free radicals. (Quick chemistry lesson: free radicals are atoms, molecules, or ions that have at least one unpaired valence electron. They’re formed as byproducts of normal cell processes or introduced from external sources, like tobacco smoke. Vitamin C neutralizes free radicals, helping to prevent cellular damage that can lead to premature aging and various health concerns.
  • Immunity: Supports the immune system and the body's ability to fight off illness.
  • Iron absorption: Helps the body absorb plant-based iron, like that found in spinach.
  • Brain health: Aids in making neurotransmitters (such as norepinephrine), which are signaling chemicals important to brain function and mood regulation.

Here's a juicy twist: while we humans can't synthesize our own Vitamin C and must get it from our diet, our dogs are able to make it themselves.

Dogs and their built-in vitamin C factory

Human bodies are truly amazing, sure. But now imagine you had a mini factory inside of you, making all the vitamins and minerals your body required. For dogs, this isn't far from the truth!

Dog with sunglasses on sitting on the floor

Dogs (and most other animals) are equipped with a natural biological process that allows them to synthesize vitamin C internally. This process provides pups with a steady source of this vital nutrient, even if they don't get any from their diet. Here's a simplified breakdown of how it works:

  • Starting point: Dogs use glucose, a type of sugar, as the foundation for making vitamin C.
  • Transformation: Inside the liver, glucose gets transformed step-by-step into vitamin C.
  • Special helper (GULO): Dogs have an enzyme called L-gulonolactone oxidase (GULO) that completes the final step of making vitamin C. Humans don't have a working version of this enzyme, which is why we can't make our own vitamin C.
  • Adjusting production: If a dog is sick or stressed, their vitamin C requirements may change, and their body can make more vitamin C to help cope.

Can dogs take supplemental vitamin C and minerals?

Dogs can have vitamin C. But another question is: do they need it? The Association of American Feed Control Officials, also known as AAFCO, does not include vitamin C among its nutrient requirements for dogs when considering the formulation for a complete and balanced diet.

Unlike dietary recommendations for humans, there isn't a fixed daily amount of vitamin C that dogs are known to require. This is because their bodies adjust their own synthesis based on their current needs. Healthy dogs who are eating a complete and balanced diet don’t need (and probably won’t respond to) vitamin C supplements.

In fact, supplementing your dog with vitamin C could actually do more harm than good in some cases. See below for more details.

There are few studies focusing on vitamin C supplementation in dogs. Some veterinarians use high-dose intravenous vitamin C in the treatment of certain cancers. Vitamin C is also part of the treatment protocol for acetaminophen (Tylenol) toxicity. It may also be beneficial for managing conditions such as arthritis, hip dysplasia, and fever, along with other treatments.

Dogs who are under physical or emotional stress due to illness, anxiety, activity level (like racing greyhounds), or life stage (e.g. lactation, pregnancy, growth, old age), may also benefit from vitamin C supplementation — but more research is needed.

Can dogs have vitamin C deficiency?

Vitamin C deficiency is extremely rare in dogs, especially if they are eating a complete and balanced diet. However, dogs who are stressed, sick, senior, pregnant, or nursing may have higher needs for vitamin C.

If you’re concerned that your dog is deficient in vitamin C or not getting the other vitamins, minerals, and nutrients that your dog needs, it’s vital to schedule an appointment with your vet.

What foods are high in vitamin C for dogs?

There are many whole foods naturally containing high levels of vitamin C. If you’re interested in providing additional vitamin C for your pup, one way is to occasionally give fruits and veggies as treats. It’s important not to feed these in excess, though! Treats should make up less than 10% of your dog’s total diet.

Some yummy options that can provide the benefits of vitamin C for your pup include:

  • Bell peppers: High in vitamin C, they’re a crunchy treat.
  • Strawberries: Along with vitamin C, they offer fibers and antioxidants.
  • Broccoli: Contains multiple vitamins and detoxifying agents.
  • Brussels sprouts: They might be divisive at the dinner table, but they’re packed with nutrients.
  • Apple: While apples shouldn’t be given every day, as an occasional treat they might just help keep the vet away.

Always introduce any new food in moderation to gauge your pet's reaction. Cut these delicious treats into small pieces, and remove any hard pits or peels if present.

Strawberries in a bowl

Also, be sure to avoid foods that are dangerous or toxic to dogs, such as grapes, currants, onions, and more.

How much vitamin C is safe for dogs?

Some sources attest that dogs synthesize approximately 18 mg of vitamin C per pound of body weight per day.

In cases where additional vitamin C might be beneficial (like high-stress situations, injuries, or specific illnesses), the amount given as a supplement varies — but the total dosage per day can range from 100 to 500 mg for small dogs and 500 to 1,500 for larger dogs.

Due to the wide dose range, it’s especially important to check with your veterinarian before giving this supplement!

Side effects of vitamin C in dogs

Just like with any medication or supplement, there are potential side effects of administering vitamin C to your dog:

  • Digestive upset: Gastrointestinal upset such as diarrhea and vomiting can be side effects of vitamin C supplementation, especially if given in large amounts. Splitting the daily dosage between two or more meals can help to avoid this.
  • Calcium oxalate stones: There is some indication that large doses of vitamin C over extended periods can increase the risk of calcium oxalate stones in the urinary tract. Excess vitamin C is excreted through the urine in the form of oxalate. Too much excess vitamin C excretion, and your dog may be at risk for forming stones anywhere from the kidneys to the bladder. If you notice clinical signs such as increased frequency of urination, urinary accidents, pain with urination, or hematuria (bloody urine), consult your vet immediately.
  • Oxidation: While small amounts of vitamin C are known to play an important role as antioxidants, too much can actually promote oxidation of cells, thus causing further cell damage.

Considerations and recommendations

Now that you know more about Vitamin C, its important role in the body, and where it comes from, here are some key takeaway points for pet parents to consider regarding adding Vitamin C to their dog’s diet:

  • Natural synthesis: Remember that dogs naturally produce vitamin C in their liver, which means that they do not need it in their diet — except perhaps in some cases of stress or illness if advised by a licensed veterinarian.
  • Dosage: If you're considering giving vitamin C as a supplement, it's important to start with a low dose and observe any changes or reactions. The dose can then be adjusted based on the dog's size, health status, and specific needs, under the guidance of your veterinarian. Vitamin C supplementation is not needed for most dogs, and can lead to unnecessary side effects. Using fresh fruits and veggies as treats in moderation is a fun and tasty way to provide your dog with some extra vitamin C.
  • Consultation: Always consult with a veterinarian before introducing ANY supplement, including vitamin C, into your dog's diet. They can provide recommendations tailored to your dog's individual needs and circumstances.
Sad dog with eyes looking up while laying on a couch

Fun facts for readers who made it all the way to the bottom!

  • While most animals are able to synthesize their own vitamin C, some can’t. That list includes humans (alas), guinea pigs, fruit-eating bats, and some types of fish, birds, and primates.
  • Historically, a deficiency of vitamin C led to a disease called scurvy, which often affected sailors on long voyages due to the lack of fresh produce. Symptoms included fatigue, swollen joints, gum disease, and anemia. It wasn’t until the discovery of lemons and oranges as a remedy that scurvy became a preventable disease.
  • The highest natural concentration of vitamin C is found in the Kakadu plum, a fruit native to Australia containing 100 times more vitamin C than oranges. Kiwis and strawberries also have more vitamin C than oranges.
  • Cooking can reduce the amount of vitamin C in foods, so eat your veggies raw when you can for a vitamin-packed punch!
  • Some (human) skincare products use vitamin C for its antioxidant properties, aiming to protect skin from damage and reduce signs of aging.
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