Scurvy prevention

VITAMIN C ROLES AND REQUIREMENTS BEYOND SCURVY PREVENTION... 

Our word vitamin was coined m 1912 m the belief that the substances present m the diet that prevented scurvy pellagra beriberi rickets and other diseases were vital amines In many cases that belief was confirmed certain vitamins did prove to be amines In many other cases however vitamins were not amines Nevertheless the name vitamin entered our language and stands as a reminder that early chemists recognized the crucial place occupied by amines m biological processes... 

In addition to its role in preventing scurvy (see Human Biochemistry box Ascorbic Acid and Scurvy and also Chapter 6), ascorbic acid also plays important roles in the brain and nervous system. It also mobilizes iron in the body, prevents anemia, ameliorates allergic responses, and stimulates the immune system. 

Vitamin C occurs as L-ascorbic acid and dihydroascorbic acid in fruits, vegetables and potatoes, as well as in processed foods to which it has been added as an antioxidant. The only wholly undisputed function of vitamin C is the prevention of scurvy. Although this is the physiological rationale for the currently recommended intake levels, there is growing evidence that vitamin C may provide additional protective effects against other diseases including cancer, and the recommended dietary allowance (RDA) may be increased in the near future. Scurvy develops in adults whose habitual intake of vitamin C falls below 1 mg/d, and under experimental conditions 10 mg/d is sufficient to prevent or alleviate symptoms (Bartley et al., 1953). The RDA is 60 mg per day in the USA, but plasma levels of ascorbate do not achieve saturation until daily intakes reach around 100 mg (Bates et al., 1979). Most of the ascorbate in human diets is derived from natural sources, and consumers who eat five portions, or about 400-500 g, of fruits and vegetables per day could obtain as much as 200 mg of ascorbate. 

This of course goes a long way to explaining the association of scurvy with vitamin C deficiency, and the successful utilization by the British navy of lime juice as a means of prevention of the disease - hence the expression limey for British sailors. 

Vitamin C (ascorbic acid) is probably the most known vitamin in the world. Its legendary fame is based on the two events its exceptionally important role in the treatment of scurvy and Linus Pauling s proposal to use the huge doses of ascorbic acid for the prevention of common cold. The latter proposal, based obviously on the antioxidant properties of ascorbic acid, generated numerous studies and was frequently disputed, but many people (me including) successfully apply ascorbic acid for the treatment of starting stage of common cold. 

Ships that carried beer tended to be less affected than those that carried water and spirits. Presumably, the beer contained some vitamin C, possibly from the habit of dry hopping , i.e. adding a few hop cones to each barrel. Eventually, it was found that lemon or lime juice every day could prevent scurvy. The admiralty waited fifty years before they applied the discovery and then insisted that all British ships carried lime juice. 

While it was known that lime or lemon juice would prevent scurvy the active ingredient remained elusive. Experiments were conducted using dilute hydrochloric acid as a substitute. Predictably, they did not work. 

The structure of ascorbic acid was not known until the 1930s. The only knowledge of the appropriate dose came from the amount required to prevent scurvy. It remained unknown whether a higher dose was beneficial. 

June, 1912 Casimir Funk, a Polish biochemist working in London, England, wrote a review article in which he elaborated on the fact that diseases such as scurvy, beri-beri, rickets and pellagra had long been known to be associated with the dietary. Funk said that these diseases could be prevented or cured by adding certain organic substances to the diet, substances he called vitamines. 0 )... 

There is, without doubt, a wide spread between the amount of vitamin C needed to prevent frank scurvy and that required for the maintenance of best health. In young growing guinea pigs about 0.5 mg. ascorbic acid per day will protect against scurvy symptoms, but there are distinct gains in health when the intakes are up to 10 times this amount.46... 

The hypothesis that vitamin C will prevent scurvy is testable. Divide a population into two groups—one that has adequate vitamin C in the diet and one that has no vitamin C in the diet. Observe what happens over time. If the hypothesis is correct, the first group will be spared scurvy while the second will suffer from it. The hypothesis is falsifiable. If people have abundant vitamin C in their diet and stiU get scurvy, the hypothesis has been shown to be false. The hypothesis has predictive value if your diet lacks vitamin C, you will develop scurvy. 

In 1746, a Scottish naval surgeon named James Lind carried out a carefully controlled study of the effect of diet on scurvy and demonstrated, beyond reasonable doubt, that oranges and lemons would cure (or prevent) scurvy. However, it was not until 1795, about three hundred years since it was known that citrus fruit would cure scurvy and about 50 years after Lind s definitive work, that the British Royal Navy insisted that sailors receive a daily dose of a citrus fruit. Opinion and prejudice outweighed scientific evidence to the detriment of many for far too long. 

Ascorbic acid a coenzyme for prolyl hydroxylase the preventive and cure for scurvy also known as vitamin C. 

Prevention and treatment of scurvy. Parenteral administration is desirable in an acute deficiency or when absorption of oral ascorbic acid is uncertain. 

The nutritional need for accessory food factors was first stated explicitly in 1905-1906, although the influence of diet in preventing or curing some diseases such as scurvy had long been known. The name vitamine was proposed in 1912, but the terminal e was dropped when it was realized that not all these compounds are nitrogenous bases. The vitamins serve as coenzymes in various metabolic processes, and the necessary quantities are usually supplied by an adequate diet or by synthesis by the intestinal flora. Vitamin deficiency can arise from a failure to absorb the compound from the gut. The symptoms of deficiency vary in different animal species, and not all the substances found necessary in other species have been shown to be essential for human nutrition. Vitamins are used for the prevention or cure of deficiency diseases and for some other pathological conditions,... 

The antiscorbutic factor of fresh fruits, which prevents the development of the typical symptoms of scurvy in humans, is a carbohydrate derivative known as vitamin C or ascorbic acid. This substance is not a carboxylic acid, but a lactone, and owes its acidic properties (and ease of oxidation) to the presence of an enediol grouping. It belongs to the l series by the glyceraldehyde convention ... 

Vitamin C is well known for its role in the prevention of the deficiency disease scurvy (15,17-19). Its nonvitamin health promotion functions are still under investigation and remain controversial. They include the modulation of hypertension, ischemic heart disease, cancer, cataracts, immune responses, and the common cold (3,6,15,17,25-41). 

Aside from vitamins C and E many other compounds present in fruits and vegetables have been shown to have anti-oxidant properties. Among these compounds there are several classes of phenolic compounds. Aside from preventing scurvy these compounds have a positive influence on cardiovascular health. 

Vitamin C is important to all animals, including humans, and is vital in the production of collagen. Collagen is important in the formation of connective tissues that give our body shape and help to support vital organs. Vitamin C prevents the disease scurvy. 

Vitamin C [ascorbic acid) Men 90 mg/d Women 75 mg/d Cofactor for reactions requiring reduced copper or iron met-alloenzyme and as a protective antioxidant prevents scurvy Gastrointestinal disturbances, kidney stones, excess iron absorption... 

Scurvygrass is a powerful antiscorbutic, but, as scurvy, like other "deficiency" diseases, is now prevented and cured by purely dietetic methods, the herb is but rarely used. It is, however, given a place here both for its historic interest and for the striking way in which it exemplifies the curative potency of non-poisonous herbs. 

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