Category: Nutrients

Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans.

Functions of Vitamin C

Vitamin C is necessary for the formation of collagen, the connective tissue in skin, ligaments, and bones. Vitamin C speeds the production of new cells in wound healing, protects your immune system, helps you fight off infection, and plays a role in the syntheses of hormones and other body chemicals. The vitamin aids in forming red blood cells and preventing hemorrhaging and bleeding gums.

 It maintains the activity of white blood cells which act as bacteria fighters. Vitamin C acts as an inhibitor of histamine, a compound that is released during allergic reactions and reduces the severity of allergic reactions. Vitamin C has shown protective effects against heavy metal exposure, pesticides, and food additives such as nitrates which have been associated with cancer. The vitamin is an antioxidant, protects LDL cholesterol from oxidative damage, supports the immune system, and helps prevent cancer. Recent studies have shown vitamin C affects nitric oxide activity, which is important in the dilation of blood vessels beneficial in preventing artery spasms leading to heart attacks and in lowering blood pressure.

Chemical name of Vitamin E is tocopherol, derived from toco, meaning related to childbirth.

RDA- 30 IU ; Optimal Intake- 100-300 IU

Vitamin E comprises of family of eight naturally occurring compounds – 4 tocopherols and 4 tocotrienols. Alpha-tocopherol is the only Vitamin E active in human body and the most common form of vitamin E in food. Vitamin E is a fat-soluble vitamin, absorbed in the presence of bile salts and fat. From the intestine, it is absorbed into the lymph and transported in the bloodstream as tocopherol to the liver where high concentrations are stored. It is also stored in the fatty tissues, heart, muscles, testes, uterus, blood, and adrenal and pituitary glands.

Chemical Names- Menadione, Phytomenadione
RDA- 80 mcg; Optimal Intake- 100-150 mcg

In 1929, Henrik Dam first noted that Vitamin K played critical role in blood clotting and name it Vitamin K for Koagulation. Vitamin K belongs to family of compounds known as quinines. These include phylloquinone from plants and menaquinones from animal sources. Phylloquinone is most biologically active form. Vitamin K absorption depends on normal consumption and digestion of fat. The vitamin is absorbed in the upper intestinal tract with the aid of bile salts, transported to the liver and stored in small quantities

Several forms (vitamers) of vitamin D have been discovered. The two major forms are vitamin D2 or ergocalciferol, and vitamin D3 or cholecalciferol. These are known collectively as calciferol.

Adequate intake levels of vitamin D have been established by the Food and Nutrition Board at the Institute of Medicine of The National Academies. These intake levels are based only on age (i.e., they are the same regardless of weight, gender, pregnancy, or lactation) – Birth to 50 years, 5 µg (200 IU); 51–70 years, 10 µg (400 IU); 71+ years, 15 µg (600 IU). These intake levels are based on the assumption that the vitamin is not synthesized by exposure to sunlight. Vitamin D from food is absorbed from the upper part of small intestine along with dietary fat and transported to liver. In skin ultra violet radiation from Sun converts cholesterol derivative to cholecalciferol which is transported to Liver, where it is converted to calcidiol, which is convereted into Vitamin D in kidneys.

The first nutritional deficiency disease to be clearly recognized was probably nightblindness. The ancient Egyptians, as mentioned in the Papyrus Ebers and later in London Medical Papyrus, recommended juice extractd from cooked liver to be applied to the eye to cure nightblindness. These observations and writings date even before 1500 B.C. Ancient Greeks have also recommended both ingestion of cooked liver for cure of night blindness. It was however in 1913, that Vitamin A was recognized as the first fat soluble vitamin and essential nutrient for growth and survival of the body. In 1930, it was established that carotene pigment in carrots, fruits and some vegetables is converted to Vitamin A in the body.
Vitamin A or retinol is found in food of animal origin, while carotene is provided by foods of both plant and animal origin. Vitamin A can either be ingested or synthesized within the body from plant carotene.

Approximately 80% of Vitamin A is absorbed in human system. It is passed along with fat through the lymphatic system into the bloodstream. The absorbtion of vitamin A increased if it is taken with fats. Women absorb Vitamin A faster than men. During diarrhea, jaundice and abdominal disorders, Vitamin A absorption is poor. Vitamin A is stored in liver. A healthy person can store about 100 mcg of Vitamin A per gram of liver. Of the Vitamin A absorbed, about 20-50 percent either combines with or burns down into products that are excreted within about one week in the faeces and urine. Remaining 20% of Vitamin A which is not absorbed is extracted within one or two days into the faeces.

Functions of Vitamin A: The best defined function of Vitamin A is its role in vision. It provides the required stimulation for vision in the retina. In addition, Vitamin A is required for growth, reproduction and maintenance of life. It builds up resistance to respiratory and other infections, and ckeeps the mucous linings and membranes of the body, especially those of the eyes, lungs, stomach, and intestines, in healthy condition. It prevents eye diseases. It aids in the secretion of gastric juices, and the digestion of protein. It also plays a vital role in preventing and clearing up infections of the skin and in promoting healthy hair, teeth and gums. Vitamin A increases permeability of blood capillaries and thereby contributing better tissue oxygenation. It also helps prevent premature ageing and senility, increase life expectancy, and extends youthfulness.