Vitamin Classification

The National Institute of Health has reported that our body needs to consume 13 different vitamins to maintain normal health. In this list of vitamins they include the vitamin B complex (folate, B12, B6, biotin, pantothenic acid, niacin, riboflavin and thiamine) as well as vitamins K, E, D, C and A. That is because each vitamin in the list is essential for different functions of the body. In most cases, people are able to get sufficient vitamins simply from consuming a diet that is well-balanced. How do we classify vitamins?

Vitamin Classification

Classification Standard

The main classification for vitamins is based on solubility as some are soluble in water while others are soluble in fat. The vitamins which are soluble in fat are stored by the body and therefore can accumulate. On the other hand, the kidneys flush out water soluble vitamins. Another way that some people classify vitamins is based on how they were obtained: either from food or naturally from food. This method, however, can become complicated because many of the foods we consume on a daily basis are vitamin fortified.

Fat-soluble Vitamins

Because the body stores fat-soluble vitamins in its cells, they are not flushed out as simply as the water-soluble vitamins. This means that they do not require as frequent ingestion as water-soluble vitamins but you still need sufficient amounts. It is important to remember that consuming too much of fat-soluble vitamins can cause toxicity. We are particularly sensitive to high levels of vitamin D as well as high levels of vitamin A specifically from animal sources. Simply consuming a balanced diet should provide sufficient fat-soluble vitamins.

Vitamin Name


Dietary Sources

Vitamin A

Vitamin A helps with healthy mucous membranes and skin, vision, tooth and bone growth and the health of the immune system.

From retinol (animal sources): liver, eggs, fortified margarine, butter, cream, cheese, fortified milk.

From plant sources (beta-carotene): dark orange vegetables (pumpkin, sweet potatoes, winter squash, carrots) and fruits (cantaloupe, apricots); dark green leafy vegetables.

Vitamin K

Vitamin K is required for correct blood clotting.

Vegetables from the cabbage family, leafy green vegetables, milk; it is also produced in the intestinal tract by the bacteria.

Vitamin E

Vitamin E is an antioxidant and helps protect the cell walls.

Nuts and seeds, egg yolks, liver, whole-grain products, wheat germ, leafy green vegetables and polyunsaturated plant oils (safflower, cottonseed, corn, soybean).

Vitamin D

Vitamin D is stored in the bones and is required to properly absorb calcium.

Fortified margarine, fortified milk, fatty fish, liver, egg yolks; the skin can also produce vitamin D when it is exposed to sunlight.

Water-soluble Vitamins

Water-soluble vitamins are able to freely travel throughout the body and any unneeded quantities are usually flushed out by the kidneys. Frequent small doses of water-soluble vitamins are required by the body and this type of vitamin is not as likely to approach toxic levels as fat-soluble vitamins are. In addition, vitamin C, choline, folate, vitamin B6 and niacin have higher consumption limits. Consuming high levels of vitamin B6 during long periods of time can cause nerve damage that is irreversible.

Most people are able to consume sufficient quantities simply by consuming a balanced diet. However some vegetarians as well as those over 50 years of age may require supplements for sufficient B12 intake.

Vitamin Name


Dietary Sources

Ascorbic acid (vitamin C)

Ascorbic acid is an antioxidant and it is a portion of an enzyme that is required for protein metabolism. It also helps with iron absorption and is important for the health of the immune system.

Only found in vegetables and fruits, especially: kiwifruit, mangoes, papayas, lettuce, potatoes, tomatoes, peppers, strawberries, cantaloupe and vegetables that are part of the cabbage family

Thiamine (vitamin B1)

Thiamine is a portion of an enzyme that is required for energy metabolism and it is important for nerve function.

Found in moderate amounts in all of the nutritious foods: nuts and seeds, legumes, whole-grain/enriched cereals and breads, pork

Riboflavin (vitamin B2)

Riboflavin is a portion of an enzyme that is required for energy metabolism. It is also important for skin health and normal vision.

Enriched, whole-grain cereals and breads, leafy green vegetables, milk products


(vitamin B3)

Niacin is a portion of an enzyme that is required for energy metabolism. It is also important for skin health as well as the digestive and nervous systems.

Peanut butter, vegetables (particularly leafy green vegetables, asparagus and mushrooms), enriched or whole-grain cereals and breads, fish, poultry and meat

Pantothenic Acid (vitamin B5)

Pantothenic acid is a portion of an enzyme that is required for energy metabolism

It is widespread in foods.

Pyridoxine (vitamin B6)

Pyridoxine is a portion of an enzyme that is required for protein metabolism. It also helps with the production of red blood cells.

Fruits, vegetables, poultry, fish, meat

Folic Acid

(vitamin B9)

Folic acid is a portion of an enzyme that is required for creating new cells (particularly red blood cells) and DNA.

Liver, orange juice, seeds, legumes, leafy green vegetables. It is now added to many refined grains.

Cobalamin (vitamin B12)

Cobalamin is a portion of an enzyme required for the production of new cells and it is important to the function of nerves.

Milk, milk products, eggs, seafood, fish, poultry, meat. It is not present in plant foods.


Biotin is a portion of any enzyme that is required for energy metabolism.

It is widespread in foods and can be produced by bacteria in the intestinal tract.

Considerations for Vitamin Intake

Choosing the Right Vitamin

When you select between the many multivitamins that are found on the market, you should remember that determining your ideal vitamins and supplements depends on the following:

  • Your current health
  • Your age
  • Your diet
  • Your gender
  • Your exercise regimen

Each of the above factors will determine the quantities of each vitamin and mineral that your body requires. An example is that a body builder who is a young male would probably need to increase their consumption of calcium, iron and protein to help maintain their bone and muscle strength. A young child that is sick, however, should increase their intake of vitamins B and C in order to help their immune system.

Before you choose the right multivitamin (both for you and for your family) you should talk to your doctor. They will tell you about the best brands available as well as the vitamins that are ideal for children, men and women.

Supplement Risks

Most people can take a single multivitamin each day and as long as it follows the recommended dosage they will not have any negative side effects. It is important to remember, however, that taking too much of any vitamin (especially fat-soluble ones) can be toxic for the body and increase a person’s risk of early death.

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