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
found in food varies as dramatically as our human requirement. In general, an unripe food is much lower in vitamin C than a ripe one but provided that the food is ripe, the vitamin C content is higher when the food is younger at the time of harvest.

What foods provide vitamin C?
Excellent food sources of vitamin C include broccoli, bell peppers, parsley, Brussels sprouts, cauliflower, lemon juice, strawberries, mustard greens, kiwifruit, papaya, kale, cabbage, romaine lettuce, turnip greens, oranges, cantaloupe, summer squash, grapefruit, pineapple, chard, tomatoes, collard greens, raspberries, spinach, green beans, fennel, cranberries, asparagus, watermelon and winter squash. The Kakadu plum and the camu camu fruit contain the highest concentration of the vitamin. It is also present in some cuts of meat, especially liver. Vitamin C is present in mother's milk but not present in raw cow's milk all excess vitamin C is disposed of through the urinary system. Vitamin C is the most widely taken nutritional supplement and is available in a variety of forms, including tablets, drink mixes, crystals in capsules or naked crystals.
Food sources: Orange, Grapefruit, Strawberries, Tomato, Sweet red pepper, Broccol, Potato.

Deficiency of vitamin C:
When there is a shortage of Vitamin C, various problems can arise, although scurvy is the only disease clinically treated with vitamin C. However, a shortage of vitamin C may result in "pinpoint" hemorrhages under the skin and a tendency to bruise easily, poor wound healing, soft and spongy bleeding gums and loose teeth. Edema (water retention) also happens with a shortage of vitamin C and weakness, a lack of energy, poor digestion, painful joints and bronchial infection and colds are also indicative of an under-supply. 
Intake of vitamin C:

0-6 months: 40 milligrams
7-12 months: 50 milligrams
1-3 years: 15 milligrams
4-8 years: 25 milligrams
Males 9-13 years: 45 milligrams
Males 14-18 years: 75 milligrams
Males 19 years and older: 90 milligrams
Females 9-13 years: 45 milligrams
Females 14-18 years: 65 milligrams
Females 19 years and older: 75 milligrams
Pregnant females 18 years: 80 milligrams
Pregnant females 19 years and older: 85 milligrams
Lactating females 18 years: 115 milligrams
Lactating females 19 years and older: 120 milligrams
Breast-feeding 19 years and older: 120 milligrams 

Deficiency symptoms for vitamin C:
 Full-blown symptoms of the vitamin C deficiency disease called scurvy - including bleeding gums and skin discoloration due to ruptured blood vessels - are rare in the U.S. Poor wound healing, however, is not rare and can be a symptom of vitamin C deficiency. Weak immune function, including susceptibility to colds and other infections, can also be a telltale sign of vitamin C deficiency. Since the lining of our respiratory tract also depend heavily on vitamin C for protection, respiratory infection and other lung-related conditions can also be symptomatic of vitamin C deficiency.

Vitamin C chemically decomposes under certain conditions, many of which may occur during the cooking of food. Vitamin C concentrations in various food substances decrease with time in proportion to the temperature they are stored at and cooking can reduce the Vitamin C content of vegetables by around 60% possibly partly due to increased enzymatic destruction as it may be more significant at sub-boiling temperatures. Longer cooking times also add to this effect, as will copper food vessels, which catalyse the decomposition.

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