Vitamins

Tagreed Osman

1

Vitamins

Are a group of organic nutrients required in small quantities for a variety of biochemical functions, forproper metabolism, to protect health, and for normal growth and activity of the body. Also for the prevention of a number of diseases.

Most vitamins cannot be synthesized by the body. They must be supplied in the diet.

Vitamins are usually classified as water soluble or fat soluble

2

Types of Vitamins:

1.Fat-Soluble Vitamins2. Water-

Soluble Vitamins:   

3

Fat-Soluble Vitamins: Properties: 

1. Fat soluble vitamins often have very specialized functions

Necessary for the function or structural integrity of specific body tissues and membranes.

Can be retained in the body, and are not leached out quickly.

Apolar hydrophobic compounds that can only be absorbed efficiently when there is normal fat absorption.

Unlike water soluble vitamins, an excess of a fat soluble vitamin can be just as harmful as a deficiency

 4

Water-Soluble Vitamins: Properties:

Act as catalysts and enzyme cofactors in metabolic processes and energy transfer.

Are not stored in the body (excreted fairly rapidly) and must be replaced each day.

These vitamins are easily destroyed or washed out during food storage and preparation (overcooking)

Water soluble vitamins do not accumulate in the body, so regular supplies are necessary

5

FAT – SOLUBLE VITAMINS

6

Vitamin A: Vitamin A is also known as

retinol Vitamin A Sources:

• Commonly found in cod liver oil, green vegetables, fruit dairy products, eggs, and liver

• Carrots indirectly serve as a source of vitamin A since they contain b carotene which the body readily converts to vitamin A

7

8

Vitamin A Functions:

Role in aiding in night vision. Retinol is oxidized to retinal, which

combines with the protein opsin to form rhodopsin. Rhodopsin is the active agent which converts light signals to electrical impulses that the optic nerve transmits to the brain

Vitamin A Deficiencies:

A deficiency in vitamin A results in night blindness.

The most serious deficiency results in a condition known as Xeropthalmia, a severe form of conjunctivitius or blindness.

Excess of Vitamin A: Carotenemia; Bleeding;

Hepatosplenomegaly (rare)9

2-Vitamin D (Calciferol)Sources: Dairy products, eggs, Fish liver oils. Synthesized by

sunlight action on skin. Unlike other vitamins, the body synthesizes vitamin D

in the skin through the action of ultraviolet light on 7-dehydrochlosterol

Vitamin D Functions: Vitamin D is an important regulator of calcium

metabolism. It is involved in the uptake of calcium and phosphate

ions from food into the body. It is necessary for the proper formation of bone

structures and teeth.10

Vitamin D Deficiencies: Rickets (children) Osteomalacia (adults)

Excess of Vitamin D : Hypercalcemia leading to

metastatic calcification and renal damage (rare).

3- Vitamin KFunction:• Blood clotting, Required for

synthesis of Prothrombin (II) and clotting factors VII, IX and X.

Sources:• Green leafy vegetables, liver;

Naturally produced by bacteria in the intestine.

Deficiencies:• Hemorrhagic disease

12

Water-Soluble Vitamins:1- B12 (Cyanocobalamin)

Food source: Red meats, Liver, eggs, dairy products and

fish

Function: Nucleic acid production Deficincy: Megaloblastic anemia (Pernicious

anemia);neuropathy.

13

Vitamin CSources: Citrus fruits, green leafy vegetables,

tomatoes

Function: Collagen formation in teeth, bone, and

connective tissue of blood vessels May help in resisting infection Absorption of iron, calcium, folacin Ascorbic acid is a great antioxidant Works with vitamin E as a free-radical

scavenger.

14

Vitamin C DeficienciesDeficincy: Scurvy (breakdown of skin, blood

vessels, and teeth) mpaired wound healing. *Vitamin C deficiency- often results

secondary to hyperparathyroidism

Excess: None known, minimal-possibly

urinary calculi, gastrointestinal complaints including diarrhea, nausea and abdominal cramps

15

Folic Acid (Folacin)

Source: Whole-wheat foods, green vegetables,

legumes, organ meats, fish, citrus fruits.

Function: Nucleic acid metabolism

Deficiency: Megaloblastic anemia (Pernicious anemia)

Excess: None

16

Other vitamins:1.Vitamin P (bioflavonoids, citrin): a. Helps increase strength of capillaries

found in the mesocarp (tasteless, spongy, white layer beneath the rind) of lemon fruit.

2.Vitamin F (unsaturated fatty acids): a. Is important in respiration of vital

organs. i. -helps maintain resilience and

lubrication of cells. ii. -helps regulate blood coagulation. iii.-is essential for normal glandular activity.

17

Other vitamins:1.Vitamin B13 (Orotic acid): Is needed for the metabolism of some B-vitamins

2.Vitamin B15 (Pangamic acid): Helps eliminate hypoxia helps promote CHON

metabolism stimulates nervous and glandular system

3.Vitamin B17 (Laetrile): – has been linked to cancer prevention

18