Lack Of Vitamins

Vitamins are a diverse group of chemical compounds with a variety of functions in our body. Many of them are enzymes that allow progress of essential metabolic reactions in the body and thus controlling the metabolism of essential nutrients, maintaining the internal environment, immune system functions, blood clotting, etc.


Vitamins have one common characteristic – we are partially or totally dependent on their dietary intake as our body can not produce them or produces them with certain restrictions. This is for example the case of vitamin K that is partially produced by intestinal bacteria and of vitamin D, which is (besides its dietary intake) produced in the liver, kidneys and skin when exposed to sunlight.


Basic vitamins are divided into two groups - the water-soluble vitamins (B complex and vitamin C) and fat-soluble vitamins (A, D, E, and K). Water-soluble vitamins are excreted into urine and the organism is not so efficient in their storage. On the other hand, it is difficult to overdose by them. Fat-soluble vitamins are stored in adipose tissue and the body usually has significant stores. On the other hand, fat-soluble vitamins may more easily cause an overdose, rarely even with fatal consequences.


The mechanism of vitamin deficiency depends on the situation, but usually it is caused by an inadequate intake of food containing the vitamin. Risk factors include malnourishment, patients in prolonged critical conditions, chronic alcoholics (inadequate food intake and liver damage) and patients suffering from anorexia nervosa. Vitamin deficiency my be also related to malabsorption of nutrients, especially disrupted fat absorption is usually accompanied with inadequate absorption of vitamins A, D, E and K. Water-soluble vitamins can be excessively removed from the body by repeated dialysis in patients with chronic renal failure. Acute shortage of B vitamins occurs in so-called refeeding syndrome.


Below, I would like to mention vitamins whose deficiency is common or causes clinically important complications. For more information check the single links.