Vitamins
Vitamins are essential organic compounds necessary for the body's growth and health. The body cannot produce them but requires them in specific amounts. They enter the body through natural food sources or through dietary supplements.
Digestion of Vitamins in the Body
After food containing vitamins is digested in the stomach and converted into bile, the various vitamin compounds dissolved in the bile travel to the small intestine. The small intestine absorbs the vitamins and transfers them into the bloodstream for transport to different parts of the body. This occurs through two main processes in the intestinal mucosa, which is connected to millions of tiny blood capillaries: active transport and relative diffusion.
The mucous membrane of the small intestine contains numerous protein carriers and protein channels, which cause a continuous, random movement of various molecules present in digestive juices, including vitamins. This movement is called relative diffusion. The active transport (absorption) of vitamins then begins from the small intestine through the mucous membrane and into the capillaries. Simpler vitamins bind to protein carriers, facilitating their passage into the capillaries. Complex vitamin compounds are digested and absorbed in the large intestine.
Vitamin Storage in the Body
Water-soluble vitamins: Excess vitamins are transported to the excretory system and excreted in urine. Examples include vitamins B and C.
Fat-soluble vitamins: Excess vitamins are stored in the liver and fat cells. Examples include vitamins A, D, E, and K.
Benefits of Vitamins for the Body
Vitamins are closely linked to the function of various body enzymes and are often referred to as coenzymes. Vitamin D regulates mineral metabolism, while vitamin A regulates cell growth and helps differentiate cells in structure and form. Vitamins E and C act as antioxidants. Other important vitamins for the body include maintaining regular metabolism and brain function, preserving emotional balance, strengthening teeth, contributing to bone formation, and promoting healthy skin and hair growth and preventing dryness.
Sources of Vitamins
Fresh and dried fruits and vegetables are the primary source of various vitamins and the only food source rich in vitamins. Fresh fruits and vegetables contain higher concentrations of vitamins. While we may obtain small amounts from the meat of animals that have been fed vitamin-rich fruits and vegetables, this is not sufficient as the sole source of the vitamins the body needs.