Vitamin A, also known as retinol, is necessary for all vertebrate species, humans and dogs included. Retinol is a fat-soluble vitamin found in many foods, supplements, and even human skincare products.
Canines store vitamin A in their fat cells, where it helps with many bodily processes from mucus production to cell growth and division. Dogs need vitamin A in all stages of life since their bodies cannot function properly without it — but more on that later. Now that we've established that vitamin A is vital for dogs, what does it do exactly?
Out of all the elements that make up a delicious food bowl, vitamin A deserves a special place on the "essential nutrients for canines" list. Why? The skin, the coat, the muscles, and the nervous system all depend on vitamin A for proper growth and function. Vitamin A plays a fundamental role in your dog's growth and well-being, which is why canine nutritionists recommend that dogs consume around 5,000 IUs (i.e., international units) of vitamin A per kilogram of food. Unless the food is packed with vitamin A, your dog will be at risk of skin and coat conditions, dull coat, and night blindness.
Therefore, we will dedicate today's article to vitamin A's role in the canine body, the dangers of vitamin A poisoning and deficiency, and the foods with enough vitamin A to ensure proper growth and development!
Learning About the Different Kinds of Vitamins
The vitamins found in our foods are distinguished into two categories: water-soluble and fat-soluble vitamins. Any excess of water-soluble vitamins, such as vitamins B and C, is filtered through the kidneys and passed through urine four to eight hours after ingestion. For this reason, your dog is not at risk of water-soluble vitamin poisoning.
On the other hand, any excess of fat-soluble vitamins, such as vitamins A, D, E, and K, is stored in the canine body's fatty tissue. Over time, excess fat-soluble vitamins can become poisonous and even cause growth abnormalities. For that reason, it's imperative that dog parents avoid fat-soluble vitamin supplementation unless prescribed by a veterinarian.
What is Vitamin A?
Vitamin A is a fat-soluble vitamin that also acts as a powerful antioxidant. As a result, it plays a critical role in maintaining your dog's vision, bone health, neurological function, healthy skin, and more.
Vitamin A is found in two primary forms:
- Active vitamin A (also called retinol, which results in retinyl esters);
Retinol comes from animal-derived foods and is a type of "preformed" vitamin A that can be used directly by your dog's body.
Beta-carotene is found in fruits and vegetables. Beta-carotene and other types of carotenoids found in plant-based products first need to be converted to retinol in order to be utilized by the body. Because the canine body cannot effectively convert beta-carotene, this is one of many reasons why your dog should not be eating plant matter.
LINK TO FULL STUDY: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5090096/
How Does Vitamin A Help Your Dog?
Although it has multiple benefits on the canine body, the three primary ways through which vitamin A helps your dog grow happy and healthy are:
The first and foremost benefit of vitamin A is healthy eyesight, especially during the night. Research shows that the canine body makes use of its vitamin A deposits whenever the retina loses proper function. Vitamin A is essential for communicating the information gathered through the retina to the brain. Without enough vitamin A, the pigment responsible for adjusting to light changes will decrease in production and cause vision issues. Over time, a vitamin A deficiency can lead to night blindness (i.e., poor vision in dim light).
#2: Stronger Immune System
Vitamin A lends a helping hand in fortifying the immune system by encouraging the production of white blood cells, which, in turn, help the body ward off invading bacteria and heal damaged cells. Your dog will be better equipped to fight infection and diseases with a stronger immune system.
#3: Growth and Development
There's a reason why a puppy cannot grow in a healthy manner without his mother's milk. During their first weeks of life, puppies do not possess the ability to store vitamin A in their liver. The mother's milk compensates for this inability with rich concentrations of vitamin A. For these reasons, puppies who do not feed on their mothers' milk for the first eight weeks of life manifest growth deficiencies and abnormalities that no additional amount of vitamin A in the adult life stage can fix. For adult dogs, vitamin A deficiencies can impede the canine reproductive function by causing improper ovulation in females and sterility in males.
Symptoms of Vitamin A Poisoning
When it comes to canine growth and nutrition, moderation is essential. Dog parents must understand that vitamin A over supplementation will only cause future problems down the road instead of assisting their dogs' health and proper development. As we mentioned earlier, dogs thrive with 5,000 IUs (i.e., international units) of vitamin A per kilogram of food or 2,2272 IU per pound of food. Any additional vitamin A will be stored in your dog's fatty tissue and lead to toxicity, manifested through:
- Absence of hunger;
- Abnormal bone growth;
- Joint stiffness;
Symptoms of Vitamin A Deficiency
The same applies to vitamin A deficiencies, whose symptoms manifest themselves in four distinct areas:
- Muscular deterioration;
- Night blindness: Without enough vitamin A, the retina will gradually lose its proper function, causing your dog to experience poor vision in dim light (i.e., night blindness).
- Skin and coat conditions: Vitamin A helps with skin growth and repair. Without enough vitamin A, your dog will gradually lose his coat, and his skin will become scaly and crusty.
- Reproductive disorders: vitamin A deficiencies can lead to improper ovulation in females and sterility in males.
Best Vitamin A Sources for Dogs
Now that we have a clear image of vitamin A benefits, as well as the dangers of over and under supplementation, let's talk about the best vitamin A sources for dogs:
You can't say "vitamin A" without automatically thinking about carrots, one of the richest sources of this vitamin with proven benefits on the canine immune system and skin and coat health. Carrots are rich in beta-carotene, the pigment responsible for the carrot's signature color. The canine body converts beta-carotene into vitamin A, which will improve eye health.
A small number of carrots will be enough to meet your dog's daily vitamin A needs. One hundred grams of carrots contain 10,191 IU of vitamin A (Source: USDA), more than enough for your dog's daily vitamin A intake. As the summer season quickly approaches, check out our carrot and frozen celery recipe! Not a fan of frozen treats? You can process the carrots and add them to your dog's food bowl. Trust us; he will love it!
Aside from a healthy concentration of vitamin A, eggs contain numerous nutrients that will strengthen your dog's immune system, such as:
- Protein (one medium egg contains 5.7 grams of protein);
- Vitamin B12;
- Riboflavin (helps digestive enzymes break down food and turn it into energy);
- Selenium (support the proper metabolic function);
- Fatty acids;
- Folic acid (necessary for certain metabolic functions, such as DNA synthesis and red blood cell production).
#3: Sweet Potatoes
Vitamin A, vitamin C, iron, and potassium: these are but a few of the nutrients found in sweet potatoes! Instead of saving them for the next Thanksgiving, it's time for you to add more sweet potatoes to your dog's food bowl. But how will your dog enjoy this super veggie's health benefits? It's all about adequate preparation. Avoid feeding raw sweet potatoes (and any other potatoes, for that matter) in order to avoid oxalate and solanine poisoning. Also, steer clear of the potato's skin, plants, and leaves because of their high toxicity levels. Instead, turn to roasting and pureeing to process the sweet potatoes in a healthy way. Furthermore, sweet potatoes are rich in fiber, so feed a moderate amount to your dog in order to avoid digestive issues.
Sweet potato nutrient breakdown (Source: USDA):
- Calories: 89;
- Carbohydrates: 20.5 g, 7% DV;
- Fiber: 3.3 g, 12% DV;
- Sugar: 6.4 mg, 13% DV;
- Potassium: 471.3 mg, 10% DV;
- Iron: 0.7 mg, 4% DV;
- Vitamin A: 953.6 μg, 106%;
- Vitamin C: 19.4 mg, 22% DV.
The dietary benefits of cantaloupes are astonishing. Aside from the tremendous amount of vitamins A, C, and B6, as well as potassium, folate, and dietary fiber, cantaloupes are low in calories and high in water content, traits that make cantaloupes amazingly healthy snacks! However, these benefits shouldn't be taken as an invitation to as many cantaloupes as possible to your dog. The cantaloupe rinds (i.e., the outer skin layers) can cause digestive upsets and even become choking hazards. Furthermore, cantaloupes are high in sugar; too many cantaloupes might result in weight gain and diabetes. Be sure to feed cantaloupes to your dog in moderation.
Kelp is a natural superfood for any dog. It contains a vast array of nutrients, such as protein, iodine, calcium, sulfur, magnesium, iron, sodium, and potassium, as well as vitamins A, B, E, and D. Furthermore, kelp provides a healthy amount of iodine to help the thyroid gland function properly and keep your dog's health, metabolism, skin, and coat in great shape. Don't forget that kelp is also beneficial in the dental health realm, as it enhances the production of amylase, one of the enzymes responsible for breaking down plaque and keeping your dog's teeth pearly white.
#6: Cod-Liver Oil
Cod-liver oil is the last to make our "vitamin A-rich" food list. With its impressive concentrations of vitamins A and D and omega-3 fatty acids, cod-liver oil helps dogs regulate calcium metabolism and the utilization of phosphorus. Your dog's cardiovascular system, as well as the joints, skin, and fur, will benefit from cod-liver oil supplementation.
Dog parents can purchase cod-liver oil both in liquid and capsule form for supplementation. You can break the exterior capsule shell to allow the liquid to mix with the food or add the oil directly to the food bowl. Healthy daily amounts of cod-liver oil are:
- 10-15-pound dogs: 1/4 teaspoon
- 25-pound dogs: 1/2 teaspoon
- 50-pound dogs: 1 teaspoon
- 75-pound dogs: 1 1/2 teaspoons
- 100-pound dogs: 2 teaspoons
Upping your raw fed dog's intake of vitamin A foods is the best way for them to reap the benefits of this important micronutrient.
Below are some of the top vitamin A (retinol) sources:
- Beef liver: 713% DV per serving, 1 slice: 6,421 mcg (713% DV) 100 grams: 9,442 mcg (1,049% DV)
- Lamb liver: 236% DV per serving, 1 ounce: 2,122 mcg (236% DV) 100 grams: 7,491 mcg (832% DV)
- Egg yolks: 5% DV per serving, 1 large egg: 245 international units
- Cod liver oil: 150% DV per serving, 1 teaspoon: 1,350 mcg (150% DV) 100 grams: 30,000 mcg (3,333% DV)
- King mackerel: 43% DV per serving, 388 mcg (43% DV) 100 grams: 252 mcg (28% DV)
- Salmon: 25% DV per serving, 229 mcg (25% DV) 100 grams: 149 mcg (17% DV)
- Bluefin tuna: 24% DV per serving, 214 mcg (24% DV) 100 grams: 757 mcg (84% DV)
- Trout: 8% DV per serving, 1 filet: 71 mcg (8% DV) 100 grams: 100 mcg (11% DV)
A Parting Reminder
Vitamin A is one of the nutrients that deserve a fair share of your dog's nutrient intake. If you've noticed signs of vitamin A deficiency, contact your veterinarian immediately and work out a supplementation plan to bring back your dog's vitamin A to healthy levels. However, don't forget that vitamin A lies at the other end of the spectrum, so keep your dog's vitamin A intake within moderate levels. For more advice on dog nutrition, health, and training, make sure that you contact us and check out our blog!
To help more dog parents discover why, what, and how to feed their dogs the healthiest of foods, Volhard Dog Nutrition and its nutritionists are now offering online consultations! Speaking to a Volhard nutritionist will help you understand the inseparable relationship between healthy food, a healthy body, and a healthy mind. If you're interested in contacting one of our Volhard nutritionists, don't hesitate to check out our consultation page!