What are vitamins and types

VITAMINS: Vitamins are Organic compounds that are required in small quantities to fulfill various biochemical functions. In general, they cannot be synthesized by organisms and must come from the diet. Their most prominent role is to act as co-factors of enzymatic reactions.




Vitamins Recommended Dietary Allowances (RDA) 

Level of intake of essential nutrients adequate to prevent and avoid the nutritional deficiency is at least 97% of the population.

CLASSIFICATION OF VITAMINS

1. Water soluble vitamins: These are vitamins soluble in water and oil. Water soluble vitamins are stored in small quantities in the body.

water soluble vitamins includes: Vitamin C (ascorbic acid), Complex B,Vitamin B1(Thiamine), Vitamin B2 (Riboflavin), Vitamin B3 (Niacin), Vitamin B5 ( Pantothenic Acid ),  Vitamin B6 (Pyridoxal), Vitamin B8 (Biotin) Vitamin B12 (Cobalamin), Folic Acid.
Now let discuss the water solubble vitamins first.



Vitamin B1 (Thiamine): is Present in grains, pork, legumes, seeds and nuts.
Vitamin B2 (Riboflavin): is Present in dairy, meat, chicken, fish and legumes. RDA: 1.1-1.3 mg / day. Although Riboflavin deficiencies causes problems like delay in growth, eye disturbances, myelin degeneration and muscle weakness.

Vitamin B3 (Niacin):  Vitamin B3 is Present in red meat, chicken, fish and whole grains. RDA: 14-16 mg / day.
Niacin can be synthesized from amino acid tryptophan and is not strictly a vitamin. The synthesis requires B1, B2 and B6. 60 mg of tryptophan are needed to synthesize 1 mg of niacin.
Pellagra is caused by the insufficiency of niacin in diet, associated with populations fed with a diet based on corn. Its characteristic symptoms are: dermatitis, diarrhea and dementia. Currently this disease is very rare and is seen in alcoholics or patients with significant absorption disorders.
Vitamin B5 (Pantothenic Acid):
A Present in meats, grains, legumes, chicken, meat, fish, eggs, brown rice, fruit, nuts. RDA: 1.3 mg.

Vitamin B8 (Biotin) RDA: 30 µg , Present in liver and egg yolk, being also synthesized by bacteria of the intestinal flora.

Folic Acid (Pteroyl glutamic acid) Present in cereals, legumes, citrus fruits and green leafy vegetables. RDA: 400 µg / day.



Vitamins B12 (Cobalamin):Vitamins B12 (Cobalamin) is Hematopoietic type of vitamins. Vitamins B12 RDA: 2.4 µg / day. Cobalamin is synthesized exclusively by microorganisms. Cobalamin is only found in foods of animal. Its deficiency causes pernicious anemia by blocking folate metabolism.

Vitamin C (L-ascorbic acid): Vitamin C is also Hematopoietic type of vitamins. It is also called L-ascorbic acid. It is present in citrus, potatoes, broccoli, spinach, strawberries, tomatoes, bell peppers.

Vitamin C was isolated in 1928. In 1932 Szent-Gyorgyi demonstrated that it is the anti-scurvy agent. In 1934 Haworth managed to synthesize it artificially. In 1934 Roche started selling Redoxon (international brand name for vitamin C).  RDA: 75-90 mg / day.


Scurvy disease is Caused by vitamin C deficiency. In scurvy there is a weakening of the capillaries that causes  bleeding, gum problems and loss of teeth. There are infections, joint problems, anemia, weakness,  mood disorders and even death.  Scurvy was a serious problem at the time of the great  maritime expeditions. 



2.Fat soluble vitamins: They are stored in the body, which can cause toxicity when accumulation in excess. Fat soluble vitamins are also called Liposoluble vitamins. It include Vitamin A (retinol), Vitamin D3 (calcitriol), Vitamin E (α-tocopherol), Vitamin K (menaquinone).

They are only well absorbed when the absorption of lipids is normal. They are transported by blood bound to lipoproteins. 

Vitamin A: is found in foods of Animal origin. Carotenoids are found in plants and constitute provitamin A, as they can be cleaved to form retinoids (derivatives of vitamin A). RDA: 700-900 µg / day UL: 3000 µg / day.
Vitamin A is essential for maintenance of epithelial tissues, for the adequate synthesis of keratin and for synthesis of glycoproteins that moisturize the epithelia. Vitamin A has an antioxidant role. 

Vitamin A deficiencies lead to: Night blindness, xerophthalmia (dryness of  cornea and conjunctiva of the eye), Sight loss, follicular hyperkeratosis (excessive development of keratin in hair) ,susceptibility to infections and anemia. Also Consuming too much vitamin A can be toxic.

Vitamina D3 (colecalciferol): It is not strictly a vitamin since, in addition to ingested, it can be synthesized in the skin at the expense of ultraviolet light and 7-dehydrocholesterol (intermediate in cholesterol synthesis). The natural sources of Vitamin D3 are water fish salty, liver and egg yolk ,RDA: 5 µg / day.

Vitamin D Regulation of absorption and homeostasis of football.

It acts via nuclear receptors that affect the gene expression. It is indeed a hormone. Its deficiency leads to rickets in children (skeleton disorder: softening and deformation of the bones) and osteomalacia in adults (creating deficiency of mineral in bones, more susceptible to fractures). RDA: 10–20 micrograms per day.

Vitamin E (α-tocopherol): There many other types of vitamin E but α-tocopherol is the one which human needs. Some of sources of α-tocopherol are: olive oil, sunflower oil, and safflower oil, nuts, whole grains, and green leafy vegetables. RDA: 15 mg / day.The deficiency of vitamin E causes: joint problems and vibration sensation in the body.

Vitamin K: Vitamin K helps in preventing excessive bleeding. Vitamin K is a group of compounds but the most important for humans are vitamin K1 and vitamin K2. Vitamin K1 is present in green leafy plants and vegetables. The sources of vitamin K2 are:  meats, cheeses, and eggs. The deficiency of Vitamin K leads to the uncontrolled bleeding.

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