Saturday, July 21, 2012

vitamin B

Discovery of vitamin B:
The Englishman Sir Frederick Gowland Hopkins is given credit for approaching the discovery of the vitamin concept, when in 1906; he determined that food contains essential ingredients beyond carbohydrates, minerals fats, proteins and water. The term vitamin was first used for water soluble substance which was necessary for the nutrition of infants and which was separated from wheat germ, yeasts and milk. In fact this term was used after the first discovery of anti-beriberi factor by Casimir Funk in 1912. The first vitamin B discovered was vitamin B1 by Funk that was extracted from police rice husk. It was then isolated in pure and crystalline form by B.C.P Jansen in 1925.Casimir coined the term ‘vital amine’ to describe the class of chemicals that he and other researchers were studying, and the word was simplified to ‘vitamin’ by 1920.Three years after this discovery, Elmer Vernon McCollum and Marguerite Davis labeled it ‘water soluble B’ which British biochemist Jack Cecil changed to vitamin B in 1920.Casimir Funk (1884-1967), a Polish born American biochemist, collected all published literature in the issue of deficiency diseases. He was the first to isolate niacin, latter called vitamin B3.
B vitamins are a group of water-soluble vitamins that play important roles in cell metabolism. The vitamins were once thought to be a single vitamin, referred to as vitamin B. Later research showed that they are chemically distinct vitamins that often coexist in the same foods. In general, supplements containing all eight are referred to as a vitamin B complex. Individual B vitamin supplements are referred to by the specific name of each vitamin (e.g., B1, B2, B3 etc.). The B-group vitamins do not provide the body with fuel for energy. It is true though that without B-group vitamins the body lacks energy. The body uses energy-yielding nutrients such as carbohydrates, fat and protein for fuel. The B-group vitamins help the body to use that fuel. Other B-group vitamins play necessary roles such as helping cells to multiply by making new DNA.

List of B vitamins:

Vitamin B1 (Thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin niacinamide)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12

Health benefits:
The B vitamins are necessary to:
Support and increase the rate of metabolism.
Maintain healthy skin, hair and muscle tone.
Enhance immune and nervous system function.
Promote cell growth and division, including that of the red blood cell that help prevent anemia.
Reduce the risk of pancreatic cancer- one of the most lethal forms of cancer when consumed in food, but not when ingested in vitamin tablet form. All B vitamins are water-soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished regularly, since any excess is excreted in the urine. This can result in the urine produced being a bright green-yellow color. B vitamins have also been hypothesized to reduce the symptoms of attention deficit hyperactivity disorder.

Vitamin B deficiency and effect:
Several named vitamin deficiency diseases may result from the lack of sufficient B-vitamins. Deficiencies of other B vitamins result in symptoms that are not part of a named deficiency disease.

*Vitamin B 1: Deficiency causes beriberi. Symptoms of this disease of the nervous system include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, periods of irregular heart beat and swelling of bodily tissues. Heart failure and death may occur in advanced cases. Chronic thiamine deficiency can also cause Korsakoff’s  syndrome, an irreversible psychosis characterized by amnesia and confabulation.

*Vitamin B 2: Deficiency causes ariboflavinosis. Symptoms may include cracks in the lips, high sensitivity to sunlight, angular cheilitis glossitis (inflammation of the tongue), seborrheic dermatitis or pseudo- syphilis, pharyngitis (sore throat), hyperemia and edema of the pharyngeal and oral mucosa.

*Vitamin B 3: Deficiency, along with a deficiency of tryptophan causes pellagra. Symptoms include aggression, dermatitis, insomnia, weakness mental confusion, and diarrhea. In advanced cases, pellagra may lead to dementia and death (the 3(+1) Ds: dermatitis, diarrhea, dementia, and death).

*Vitamin B 5: Deficiency can result in acne and paresthesia, although it is uncommon.

*Vitamin B 6: Deficiency may lead to microcytic anemia (because pyridoxyl pho water retention, sphate is the cofactor for heme synthesis), depression, dermatitis, high blood pressure, water retention, and elevated levels of homocysteine.

*Vitamin B 7: Deficiency does not typically cause symptoms in adults but may lead to impaired growth and neurological disorders in infants. Multiple carboxylase deficiency, an inborn error of metabolism, can lead to biotin deficiency even when dietary biotin intake is normal.

*Vitamin B 9: Deficiency results in a macrocytic anemia, and elevated levels of homocysteine. Deficiency in pregnant women can lead to birth defects. Supplementation is often recommended during pregnancy. Researchers have shown that folic acid might also slow the insidious effects of age on the brain.

*Vitamin V 12: Deficiency results in a macrocytic anemia, elevated homocysteine, peripheral neuropathy, memory loss and other cognitive deficits. It is most likely to occur among elderly people, as absorption through the gut declines with age; the autoimmune disease pernicious anemia is another common cause. It can also cause symptoms of mania and phychosis. . In rare extreme cases, paralysis can result.

B vitamin sources:
B vitamins are found in whole unprocessed foods. Processed carbohydrates such as sugar and white flour tend to have lower B vitamin than their unprocessed counterparts. B vitamins are particularly concentrated in meat such as turkey and tuna, in liver and meat products. Good sources for B vitamins include kombucha, whole grains, potatoes, bananas, lentils, chili peppers, tempeh, beans, nutritional yeast, brewer's yeast, and molasses. Although the yeast used to make beer results in beers being a source of B vitamins, their bioavailability ranges from poor to negative as drinking ethanol inhibits absorption of thiamine (B1), riboflavin (B2), niacin (B3), biotin (B7), and folic acid (B9). In addition, each of the preceding studies further emphasizes that elevated consumption of beer and other ethanol-based drinks results in a net deficit of those B vitamins and the health risks associated with such deficiencies.
The B12 vitamin is of note because it is not available from plant products, making B12 deficiency a concern for vegans. Manufacturers of plant-based foods will sometimes report B12 content, leading to confusion about what sources yield B12. The confusion arises because the standard US Pharmacopeia (USP) method for measuring the B12 content does not measure the B12 directly. Instead, it measures a bacterial response to the food. Chemical variants of the B12 vitamin found in plant sources are active for bacteria, but cannot be used by the human body. This same phenomenon can cause significant over-reporting of B12 content in other types of foods as well. Vitamin B may also be delivered by
injection to reverse deficiencies. Another popular means of increasing one's vitamin B intake is through the use of dietary supplements. B vitamins are also commonly added to energy drinks, many of which have been marketed with large amounts of B vitamins.
In general, extra B vitamins are just flushed out of the system, although everyone's limit of absorption is different in regards to B complex vitamins, and no one knows how much is needed on an individual basis of these vitamins…"The elderly and athletes may need to supplement their intake of B12 and other B vitamins due to problems in absorption and increased needs for energy production. Both type 1 and type 2 diabetics may also be advised to supplement thiamine based on high prevalence of low plasma thiamine concentration and increased thiamine clearance associated with diabetes. Also, Vitamin B9 (folic acid) deficiency in early embryo development has been linked to neural tube defects. Thus, women planning to become pregnant are usually encouraged to increase daily dietary folic acid intake and/or take a supplement. However, for "most typical consumers of energy supplements or drinks, B vitamins are nothing more than a 'gimmick'."Even though the B-group vitamins are found in many foods, they are water soluble and delicate. They are easily destroyed, particularly by alcohol and cooking. Food processing can also reduce the amount of B-group vitamins in foods, making white flours, breads and rice less nutritious than their wholegrain counterparts.
The body has a limited capacity to store most of the B-group vitamins (except B12 and folate, which are stored in the liver). A person who has a poor diet for a few months may end up with B-group vitamins deficiency. For this reason it is important that adequate amounts of these vitamins be eaten regularly as part of a well-balanced, nutritious diet.

No comments:

Post a Comment