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Where Are Vitamins Metabolized?

author image Luci Coffey
A native Texan, Luci Coffey began writing for LIVESTRONG.COM in 2010. She is a registered nurse and has over thirty years experience in the health care industry. Coffey holds a Master of Science in nursing from the University of Texas and is nationally certified as an expert in health care quality.
Where Are Vitamins Metabolized?
Vitamins are present in all the food you eat. Photo Credit zneb076/iStock/Getty Images

As you were growing up, your mother no doubt told you to take your vitamins. But have you ever considered that every time you eat something, you are taking your vitamins? The human body cannot make vitamins on its own, so they must be obtained from the food you eat, or from a synthetic source, such as a vitamin supplement. If a vitamin is absent from the diet, or is not properly absorbed, serious deficiencies can develop.This is why vitamins are called essential nutrients.

Types of Vitamins

There are two groups of essential vitamins, each classified according to the materials in which they will dissolve. The fat-soluble vitamins are: A, D, E and K. This group of vitamins dissolve in fat before they are absorbed into the blood stream, and are stored in primarily in the intestines, liver and in fatty tissues. The water-soluble vitamins on the other hand, dissolve in water, are not stored in the body, and are eliminated regularly in urine and feces. Because of this property, this group of vitamins needs to be constantly re-supplied.The water-soluble vitamins are comprised of the B-complex group, and vitamin C.

Function of Vitamins in the Body

Vitamins contain no calories, but play a critical role in how your body works. Vitamins assist in the regulation of metabolic reactions in virtually every organ system of the body. If a vitamin is absent, or present in deficient amounts, it affects the metabolic balance within a cell. If this deficiency or imbalance becomes chronic, illness ensues. One well-known example of this is scurvy, which is caused by a deficiency of vitamin C. With the exception of vitamin C, all of the water-soluble vitamins assist enzymes that function in energy transfer, or in the metabolism of fats, carbohydrates and proteins. Some of the fat-soluble vitamins assist in maintaining the integrity and functioning of various cell membranes.

How Vitamins Are Metabolized

Vitamin metabolism is an extremely complex process involving numerous biochemical actions and reactions.The human body is comprised of approximately 60 percent water. Water is the main component of saliva, blood, cell plasma, and extracellular fluid.The digestive system uses water to break food down into smaller molecules, which are then transported and assimilated to various destinations for use. Vitamin metabolism begins with ingestion, followed by mechanical digestion, chemical digestion, and finally, absorption. Nutrient absorption occurs at cellular levels throughout the body.

Where Vitamins Are Metabolized

Where Are Vitamins Metabolized?
A well-balanced diet provides the best source of vitamins needed by the human body. Photo Credit MYDinga/iStock/Getty Images

The small intestine is not only the primary site of chemical digestion, but it also serves as a major site of vitamin absorption in the human body. Nutrients enter at a cellular level and are picked up and absorbed via blood capillaries and lymph fluids through the processes of active transport, diffusion and osmosis. The large intestine is where vitamin B-12 and vitamin K are metabolized. The fat soluble vitamins, once absorbed into the circulation, are carried to the liver and fatty tissues where they are stored.

Additional Considerations

Vitamins are necessary in order for the body to function properly.They are critical for growth and development, as well as for the prevention and cure of many health problems and diseases. While vitamin supplements cannot replace a balanced diet, in order to obtain the most benefit from vitamin supplements you should take them with food and plenty of water. For additional information about good dietary sources of vitamins, view The Food and Nutrition Information Center, U.S. Department of Agriculture web site.

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