There is more to food than a full stomach.
Nature had it all running quite smoothly. But since we took control of our dogs' nutrition it is now up to us to understand these things if we want to do it right.
Long before vitamins were identified there was evidence that certain foods are important to maintaining health.
Even though he wasn't the first scientist to isolate them, the formulation of the concept of vitamins is attributed to Polish biochemist Casimir Funk. He named these micronutrients vital (from the Latin vita for life) amines.
So what makes vitamins so important?
Vitamins do not serve as building blocks of tissues and they don't provide energy and yet they are vital to your dog's health. So what do they do?
Each vitamin plays a unique and irreplaceable role in the dog's body.
Some of them have a function similar to hormones and regulate metabolism or tissue growth. For example vitamin D helps regulate the balance of calcium and phosphorus in the body.
Some vitamins, such as vitamin E, function as antioxidants.
B vitamins are necessary for fat and protein metabolism, production of red blood cells and a healthy nervous system and more.
Each vitamin is unique but they are generally classified as either water-soluble or fat-soluble.
Fat-soluble vitamins need fat to be absorbed and can be stored in fat tissues. Water-soluble vitamins get absorbed through the intestines from which they enter the bloodstream. Any excess is excreted in urine.
The way vitamins are absorbed is tailored to fit their respective functions.
The important consideration is the relative risk of deficiency or toxicity.
Because fat-soluble vitamins are stored in the dog's body the risk of deficiency is relatively low, while the risk of toxicity is relatively high. For a dog to develop a deficiency in a fat soluble vitamin, he would have to eat a diet with low levels of that vitamin for a relatively long period of time.
With water-soluble vitamins it's the other way around. Deficiency is much more likely and appropriate amount should be provided regularly. Toxicities can develop, but a dog would need to receive very large amounts of the vitamin to overwhelm his body’s ability to excrete it in the urine.
Water-soluble vitamins are also more likely to be lost during cooking process.
Three fat-soluble and eight water-soluble vitamins are essential for dogs.
An essential vitamin is one that cannot be manufactured by the body from other nutrients. It must be consumed in the diet.
Fat-soluble vitamins essential for dogs are vitamin A, vitamin D and vitamin E.
Water-soluble vitamins essential for dogs are Thiamin (B1), Riboflavin (B2), Niacin (B3), Pyridoxine (B6), Pantothenic acid (B5), Folic acid (B9), Vitamin B12 and Choline.
What about vitamin C?
Vitamin C is not an essential nutrient for dogs, although it is for humans. Unlike us, a dog's liver can make vitamin C from glucose. There is an argument as to whether or not supplementing vitamin C could be beneficial for your dog. I think individual consideration is important.
Vitamins K and biotin are also not essential for dogs. These are manufactured by bacteria in the dog's intestines.
Bottom line about vitamins in your dog's nutrition?
Too much or too little can be equally harmful. Know what you're doing.
If you are feeding a high quality, nutritionally balanced food and your dog is a good eater, vitamin supplements are likely not be necessary and in fact could do some harm. If, however, you are feeding a home-cooked diet or your dog is a very picky eater, vitamin supplementation is a good idea.
It's your dog's health!
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