Vitamin C
Vitamin C was formally discovered in 1928 by accident. English sailors who went out to sea developed scurvy, an inflammation of the gums, loosening of teeth, dry skin, eyes and mouth and loss of hair. Scientists learned that a component in lemons and limes could reverse the disease. The sailors were nicknamed "limeys" and the antiscorbutic factor, hexuronic acid later named vitamin C was isolated.. Vitamin C's most renown role is collagen formation, the building block of new tissue, wound healing.
Vitamin C is essential to the process of iron absorption from vegetable sources. To use folic acid, vitamin C is needed for activation. Vitamin C assists in the conversion of tryptophan the amino acid into the neurotransmitter serotonin and the synthesis of carnitine from dietary amino acids. It enhances immunity and lessens the severity and duration of the common cold. Vitamin C also lessens the severity of allergies and asthma.
As an antioxidant, vitamin C has been studied in the prevention of cataracts and age related macular degeneration, one of the most common forms of blindness in the elderly. Cataracts are another malady that affects the eyes that vitamin C seems to help counteract.
Heart Disease and Vitamin C
It may raise levels of good cholesterol (HDL) and prevent oxidation of bad cholesterol (LDL). Oxidation is damage to the molecule that makes it more dangerous, increasing the risk of buildup inside the artery and increasing the risk of stroke and heart attack. Vitamin C helps in another way to keep your cholesterol levels low. It boosts the activity of an enzyme that stimulates the conversion of cholesterol to bile. This is the only way that cholesterol can be removed through the feces. High blood levels of C may also protect against gallstones, that develop from cholesterol that hangs around in the body instead of being converted to bile and excreted.
Gastrointestinal cancer e.g. stomach, colon, bladder, lung, esophagus and cervix have been correlated with low vitamin C levels and nitrosamines. Our bodies makes nitrosamines in response to cigarette smoke, water, polluted air and food. Vitamin C is thought to neutralize free radicals or block this formation and the tumors that nitrosamines can generate. High dose vitamin C inhibits H. pylori, the bacterium that cause most ulcers and may be responsible for an increased risk of stomach cancer.
Vitamin C other wise named ascorbic acid is widely found in citrus fruits, raw leafy vegetables and tomatoes, guava, strawberries, kiwi, cantaloupe, cabbage and green peppers. Potatoes are a good source as well. All fruits and veggies have some C. Storage and cooking methods can cause vitamin C losses. Refrigeration and freezing at the point of harvest maintains C. Food loses vitamin C during shipping, dry storage and time spent on supermarket shelves.
The daily value is 60mg/day. 500 -1000 mgs/day or 1500mg if you smoke seems more appropriate given all the attributes of vitamin C. For the antihistamine effect use 2 grams. For cataract prevention, 150-250mgs/day is the amount that saturates eye tissue
Bioflavanoids (often found in foods rich in vitamin C like grapefruit) also antioxidants protect against many cancers and heart disease
Vitamin like substances that include quercetin, anthocyanidins (Bilberry and blueberries) naringenin (grapefruit) epigalocatechin gallate ( green tea), isoflavones (soy) and oligmeric proanthocyanidins (grape seeds and skins , pine bark)
Vitamin C and the Bioflavanoids
Age related macular degeneration, glaucoma, diabetic neuropathy and night blindness, cataracts (vitamin C)
Collagen synthesis and skin integrity, protects capillaries from rupturing ( bruising)
Stroke prevention through antioxidant and blood thinning qualities.
Protection of cancer at any site particularly of the lung
Caution
High doses of C may cause stomach upset. Buffered may be better. If you have diarrhea cut back on C. If you are taking substantial doses of C and decide to stop do so gradually. There is a phenomena called "rebound scurvy", a form of vitamin C deficiency that occurs when you stop quickly. It consists of poor wound healing, loose teeth, loss of hair and dry itchy skin.
Another cautionary note
regarding vitamin C is that it promotes the absorption of iron. If you are at risk for iron overload disease (hematochromatosis) , do not take vitamin C supplements, or iron, or even a multivitamin that contains vitamin C and iron.
Supplement confusion- natural, esterfied, buffered, chewable, etc?
Unlike vitamin E, there is no difference between natural and synthetic vitamin C.
There is no difference in absorption, usage or excretion between esterfied C and the other varieties.
Buffered C is a good choice if vitamin C upsets your stomach or if you are taking larger doses.
Experts agree that splitting the dose- taking ½ in the morning and ½ in the evening for maximum efficacy.
Avoid chewable vitamin C to protect tooth enamel. If you must take the chewable if you must use this form wash it down immediately with water of juice.
Donna Tinnerello MS, RD, CD/N
Updated August 2000
Donna Tinnerello MS, RD, CD/N is registered dietitian with more than 10 years experience in HIV and nutrition. She works in lower Manhattan at Cabrini Medical Center, the community and in private practice. Her subspecialties are cardiovascular, renal, gastrointestinal disease, diabetes and weight loss. Donna is available for private consultation by referral only.