Are you concerned about nutrition for your hypothyroid dog or overweight dog? Your high-exercise dog? Your dog who eats a high-carb or high-fat diet?

For these issues and overall optimal health for all dogs, as dog parents we need to know the benefits of vitamin B2/riboflavin, what happens with riboflavin deficiency, and how to feed riboflavin in your dog's daily diet.

What is vitamin B2/riboflavin

B complex vitamins are water soluble vitamins, and just like other B vitamins so is B2. That means dogs have limited ability to absorb and store vitamin B2 in their bodies, so it's best to provide it daily.

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What vitamin B2/riboflavin does for our dogs

Metabolizing fat, carbs, protein

Vitamin B2/riboflavin is required for the metabolism of fat, carbohydrates, and protein. It has a special role in fat metabolism - so dogs who are losing weight or are canine athletes likely require more vitamin b2/riboflavin for optimal health status. Diets higher in fat should also have increased vitamin b2/riboflavin.

Why it matters for skin, eye, & brain health

Vitamin B2/Riboflavin is most known for its role in fat metabolism, but it is also important for your dog's skin, eye, and brain health. The B vitamins work together, so often a deficiency of one vitamin B will affect the other. In this instance, low levels of vitamin B2/riboflavin can negatively affect Pyridoxine status.

Antioxidants, such as vitamin B2/riboflavin, can fight free radicals and may reduce or help prevent some of the damage they cause. Vitamin B2/Riboflavin is also needed to help the body change vitamin B6 and folate into forms it can use. It is also important for growth and red blood cell production.

Vitamin B2/Riboflavin works throughout all our bodies playing an important role in cellular energy. Its role in mitochondrial energy metabolism in both dogs and humans can have wide-ranging impact on wellness (in humans, riboflavin is proving to be effective in helping prevent migraine headaches, for just one intriguing example). 

Where to find vitamin B2/riboflavin in foods

Dietary riboflavin is found in the following foods: turkey, salmon, yogurt, spinach, eggs, beef, pork, tuna, cheese, and mushrooms. Vitamin B2/ riboflavin is also found in fortified cereal grains, breads and other grains.

Toxicity

There is low risk for toxicity from riboflavin because there is a limit to what your dog can absorb. As with all nutrients, only provide as much as needed for optimal health regardless of toxicity risk.

Recommended dietary allowance for vitamin B2/riboflavin

The recommended dietary allowance (RDA) for riboflavin for dogs is 0.1 to 1 mg/kg body weight/day, depending on age and activity level. For example, a 20 lb dog would require between 2-20 mg riboflavin per day.

Be sure to check the specific guidelines provided by your veterinarian for your dog's riboflavin needs (always a good idea before considering vitamin supplements/nutritional supplements).

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Riboflavin deficiency - causes & impact

Extreme riboflavin deficiencies have been reported through controlled, purified diets that ultimately resulted in muscular weakness, ocular damage, and death.

However, we need to be aware of even a marginal riboflavin deficiency or suboptimal status. Vitamin B2/Riboflavin is more bioavailable from animal foods than from plant foods. Kibble diets high in plant-based food may provide suboptimal riboflavin levels in an inferior form.

Commercial kibbles typically have B complex vitamins including riboflavin supplementation, but it would certainly be a “won’t hurt, may help” approach to provide your dog with animal-based, fresh sources of riboflavin if you are feeding a heavily processed food.

Risk factors in creating a riboflavin deficiency

Riboflavin is very sensitive to UV light, so cooking food exposed to light (typically how we all cook, of course) can cause losses. Homemade cooked diets often need B complex vitamin supplementation compared to raw diets- but it certainly depends on what is being fed.

Vitamin B2/Riboflavin requires adequate protein for absorption- another reason to try to incorporate high quality animal-based proteins when feeding foods like kibble.

Other conditions that can negatively impact Riboflavin status include thyroid conditions, chronic kidney disease, and suboptimal magnesium intake.

It's quite possible many dogs are receiving suboptimal riboflavin intake because:

• Many dogs are overweight.
• Many dogs eat high carbohydrate diets.
• Some dogs may not be eating a performance dog food that provides the extra riboflavin needed.
• Some dogs losing weight may not be eating a dog food that provides the extra riboflavin needed.
• Many raw fed dogs are often fed high fat diets (unknowingly). Fat displaces riboflavin as riboflavin is not found in fat.

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Where to find riboflavin in foods

Dietary riboflavin is found in the following foods: turkey, salmon, yogurt, spinach, eggs, beef, pork, tuna, cheese, and mushrooms. Vitamin B2/ riboflavin is also found in fortified cereal grains, breads and other grains.

To avoid primary riboflavin deficiency, you can find healthy amounts of riboflavin (along with other B vitamins and vital nutrients) in meats and some dairy.

High quality riboflavin food sources:

• Liver
• Kidney
• Heart
• Some dairy products (lower in riboflavin if processing exposes it to light)
• Eggs
• Salmon
• Red meat

Adding riboflavin food sources to kibble

Eggs, lean red meat, heart, and dairy products (if tolerated by your dog) are all great ways to boost riboflavin intake. Liver, while a great source of riboflavin, should only be added carefully because it is so rich in other nutrients. If you aren’t using nutrient guidelines, stick to the safer choices to avoid throwing off nutrient balance.

Homemade diets

Cooked diets very often are supplemented with B Complex supplements because of the losses of many B vitamins. Certainly, cooked homemade diets without organ meats and lean meats could be short in riboflavin.

Homemade raw diets

Homemade raw diets typically have enough riboflavin because of the inclusion of liver, meat, and other organ meats. However, if the raw diet is high in fat and your dog has low energy requirements, this may result in suboptimal riboflavin intake.

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Steps to evaluate vitamin B2/riboflavin in your dog's diet

1. Does your dog have any sort of condition or lifestyle that affects his or her riboflavin requirement? (Always consult your vet and/or canine nutritionist if your dog has a special reason for a high dose riboflavin requirement.)
2. If you feed a homemade diet, cooked or raw, can you identify where the riboflavin is coming from?
3. If you're feeding milk, does your milk come in containers that block out light?
4. If you're feeding a homemade diet, have you checked how much fat you are feeding?

Next up in the Basic Nutrition Channel on Dogly

Now that you have a good understanding of vitamin B2, keep going in our vitamin B series with the next essential vitamin step-by-step guide on vitamin B3/niacin.

Or hop over to the Basic Nutrition Channel if you'd like to ask a question in the Community discussion and start any of the other step-by-step guides in Needed Nutrients. If you ever need more personalized nutrition guidance, please reach out!

Sources & Reading

DSM in Animal Nutrition

Canine and Feline Nutrition

NRC nutrient requirements