Sunday, July 29, 2012

About vitamin K

History, about vitamin K:
In 1929, Danish scientist Henrik Dam investigated the role of cholesterol by feeding chickens a cholesterol-depleted diet. After several weeks, the animals developed hemorrhages and started bleeding. These defects could not be restored by adding purified cholesterol to the diet. It appeared that—together with the cholesterol—a second compound had been extracted from the food, and this compound was called the coagulation vitamin. The new vitamin received the letter K because the initial discoveries were reported in a German journal, in which it was designated as Koagulationsvitamin. Edward Adelbert Doisy of Saint Louis University did much of the research that led to the discovery of the structure and chemical nature of vitamin K. Dam and Doisy shared the 1943 Nobel Prize for medicine for their work on vitamin K (K1 and K2) published in 1939. Several laboratories synthesized the compound(s) in 1939.

The precise function of vitamin K was not discovered until 1974, when three laboratories (Stenflo et al., Nelsestuen et al., and Magnusson et al.) isolated the vitamin K-dependent coagulation factor prothrombin (Factor II) from cows that received a high dose of a vitamin K antagonist, warfarin. It was shown that, while warfarin-treated cows had a form of prothrombin that contained 10 glutamate amino acid residues near the amino terminus of this protein, the normal (untreated) cows contained 10 unusual residues

Thursday, July 26, 2012

Vitamin E

The first use for vitamin E as a therapeutic agent was conducted in 1938 by Widenbauer. Widenbauer used wheat germ oil supplement on 17 premature newborn infants suffering from growth failure. 11 out of the original 17 patients recovered and were able to resume normal growth rates. Later on, in 1948, while conducting experiments on alloxan effects on rats, Gyorge and Rose noted that the rats receiving tocopherol supplements suffered from less hemolysis than those that did not receive tocopherol. In 1949, Gerloczy administered all-rac-α-tocopheryl acetate to prevent and cure edema. Methods of administration used were both oral, that showed positive response, and intramuscular, which did not show a response. This early investigative work on the benefits of vitamin E supplementation was the gateway to curing the vitamin E deficiency caused hemolytic anemia described during the 1960s. Since then, supplementation of infant formulas with vitamin E has eradicated this vitamin’s deficiency as a cause for hemolytic anemia.

The eight forms of vitamin E are divided into two groups; four are tocopherols and four are tocotrienols. They are identified by prefixes alpha-, beta-, gamma-, and delta-. Natural tocopherols occur in the RRR-configuration only. The synthetic form contains eight different stereoisomers and is called all-rac-α-tocopherol.

α-Tocopherol is an important lipid-soluble antioxidant. It performs its functions as
antioxidant in what is known by the glutathione peroxidase pathway and it protects cell membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. This would remove the free radical intermediates and prevent the oxidation reaction from continuing. The oxidized α-tocopheroxyl radicals produced in this process may be recycled back to the active reduced form through reduction by other antioxidants, such as ascorbate, retinol or ubiquinol. However, the importances of the antioxidant properties of this molecule at the concentrations present in the body are not clear and it is possible that the reason why vitamin E is required in the diet is unrelated to its ability to act as an antioxidant. Other forms of vitamin E have their own unique properties; for example, gamma-tocopherol is a nucleophile that can react with electrophilic mutagens.

Compared with tocopherols, tocotrienols are sparsely studied. Less than 1% of PubMed papers on vitamin E relate to tocotrienols. The current research direction is starting to give more

Tuesday, July 24, 2012

Vitamin D

 History of vitamin D:
American researchers Elmer McCollum and Marguerite Davis in 1913 discovered a substance in cod liver oil which later was called "vitamin A". British doctor Edward Mellanby noticed dogs that were fed cod liver oil did not develop rickets and concluded vitamin A or a closely associated factor, could prevent the disease. In 1921, Elmer McCollum tested modified cod liver oil in which the vitamin A had been destroyed. The modified oil cured the sick dogs, so McCollum concluded the factor in cod liver oil which cured rickets was distinct from vitamin A. He called it vitamin D because it was the fourth vitamin to be named. It was not initially realized that unlike other vitamins, vitamin D can be synthesised by humans through exposure to UV light.
In 1923, it was established that when 7-dehydrocholesterol is irradiated with light, a form of a fat-soluble vitamin is produced (now known as D3). Alfred Fabian Hess showed "light equals vitamin D." Adolf Windaus, at the University of Göttingen in Germany, received the Nobel Prize in Chemistry in 1928, for his work on the constitution of sterols and their connection with vitamins. In 1929 a group at NIMR in Hampstead, London, were working on the structure of vitamin D, which was still unknown, as well as the structure of steroids. A meeting took place with J.B.S. Haldane, J.D. Bernal and Dorothy Crowfoot to discuss possible structures, which contributed to bringing a team together. X-ray crystallography demonstrated that sterol molecules were flat, not as proposed by Windaus. In 1932 Otto Rosenheim and Harold King published a paper putting forward structures for sterols and bile acids which found immediate acceptance. The loose association between the team members Bourdillon, Rosenheim, King and Callow was very productive and led to the isolation and characterization of vitamin D. At this time the policy of the MRC was not to patent discoveries, believing that results of medical research should be open to everybody. In the 1930s Windaus clarified further the chemical structure of vitamin D.

Sunday, July 22, 2012

Vitamin C

The discovery of Vitamin C
The need for vitamin C was known well before the vitamin was discovered. Many people died of scurvy, which is a severe lack of vitamin C and numerous scientists and doctors worked to provide cures for the disease. James Lind is credited with being the first to understand that a particular aspect of citrus fruits could stop incidences of scurvy. He did not know that it was vitamin C but he carried out research in 1747 to show that citrus fruits did stop the scurvy from developing. It was Lind’s work that was the basis for many of the other scientific investigations that led to the discovery of vitamin C. In 1907 Axel Holst and Theodor Frølich, two Norwegian physicians conducted research that showed the anti scorbutic factor. Albert Szent-Györgyi was the first to discover and isolated the chemical hexuronic acid. He along with other research scientists proved that it was the deprivation of this acid that was the cause of scurvy. In 1948 Albert Szent-Györgyi was awarded the Nobel Prize for Medicine (for his discoveries in connection with the biological combustion processes, with special reference to vitamin C and the catalysis of fumaric acid).

What is vitamin C?
Because of its widespread use as a dietary supplement, vitamin C may be more familiar to the general public than any other nutrient. Studies indicate that more than 40% of older individuals in the U.S. take vitamin C supplements and in some regions of the country, almost 25% of all adults, regardless of age, take vitamin C. Outside of a multivitamin, vitamin C is also the most popular supplement among some groups of registered dietitians and 80% of the dietitians who take vitamin C take more than 250 milligrams.

Why is this nutrient so popular?
Vitamin C, also called ascorbic acid is a water-soluble nutrient that is easily excreted from the body when not needed. It's so critical to living creatures that almost all mammals can use their own cells to make it. Humans, gorillas, chimps, bats, guinea pigs and birds are some of the few animals that cannot make vitamin C inside of their own bodies. Humans vary greatly in their vitamin C requirement. It's natural for one person to need 10 times as much vitamin C as another person; and a person's age and health status can dramatically change his or her need for vitamin C. The amount of vitamin C

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:

Thursday, July 19, 2012

Vitamin A

Discovery of vitamin A:
The discovery of vitamin A may have stemmed from research dating back to 1906, indicating that factors other than carbohydrates, proteins and fats were necessary to keep cattle healthy. By 1917 one of these substances was independently discovered by Elmer Me collum at the University of wisconcin-Madision and Lafayette Mendel and Thomas Burr Osborne at Yale University. Since water soluble factor B(vitamin-B) had recently been discovered, the researchers chose the name "fat-soluble factor A" (vitamin A). In 1919, Steenbock (University of Wisconsin) proposed a relationship between yellow plant pigments (beta-carotene) and vitamin A. Vitamin A was first synthesized in 1947 by two Dutch chemists, David Adriaan van Dorp and Jozef Ferdinand Arens.

Vitamin A (or Vitamin A Retinol, retinal, and four carotenoids including beta carotene) is a vitamin that is needed by the retina of the eye in the form of s specific metabolite, the light absorbing molecule retinal, that is necessary for both low high (scotopic vision) and color vision. Vitamin A also functions in a very different role as an irreversibly oxidized form of retinol known as retinoic acid, which is an important hormone-like growth factor for epithelial and other cells.

In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to the retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. The associated acid (retinoic acid), a metabolite that can be irreversibly synthesized from vitamin A, has only partial vitamin A activity, and does not function in the retina for the visual cycle.

Wednesday, July 18, 2012

About drinks

 Everybody should know about drinks. You know you should drink water (the standard recommendation is eight 8-ounce glasses a day, and more as needed after exertion and in hot or dry weather), but did you also know that drinking water can help you lose fat? It may have no calories, but having water between meals helps keep your stomach full.
 We have built-in sensors in our stomachs, so we get fuller sooner with liquid, which is also why soup is more filling than solid foods. So add a slice of lemon with some ice to your water for a pleasant variety once in a while. There is some evidence, also, that when some people’s bodies are craving water, it is read by their brains as a signal for sweets. Talk about crossed wires, right? If you seek that sweet thing in your mouth, choose sugar-free drinks that use Splenda (the safest, best tasting sweetener) as the sweetener agent. Go with natural diet sodas, diet drinks, sugar-free lemonades

Wednesday, July 11, 2012


For decades, the belief that the more fat you ate, the more body fat you stockpiled was shared by many nutritionists. We became “fat obsessed,” and one trip down the supermarket aisle shows that we still are, with the preponderance of “fat-free” and “low-fat” items. Yet we are fatter than ever because these products may be low in fat, but they often are extremely high in sugar (to make them taste better) and thus calories, usually more than the full-fat versions that they are replacing.

Many followers of the low-carbohydrate, high-fat regimen have gone the way of the successful low-fat, higher-carbohydrate dieters: weight loss in the short term (due mostly to fewer calories), then dissatisfaction with the diet coupled with diminishing returns leading to millions of dropouts.

As a result, going in the opposite direction and eating more fat than normal to lose weight doesn’t work, either. One, fats are twice as calorically dense as carbohydrates or protein, so in general you want to limit your overall consumption. Two, fats are also downright dangerous, as excess fat consumption has been shown to increase degenerative diseases (heart and arthritis), cancer, vascular disease (kidney and liver failure as well as stroke), heart attack risk, and even acne. In particular, recent research implicates certain fats in the development of certain diseases. Saturated fats and