Re: Question for THORN

Smokers. Smoking interferes with absorption of a number of vitamins, importantly vitamin C. In fact, in one study nearly 25% of female smokers and 31% of male smokers were deficient in vitamin C. Folic acid supplements may be important for all smokers. Taking high doses of antioxidant vitamins, however, may actually be harmful in smokers, especially beta carotene. Instead of taking supplements, most smokers should be sure their diets are rich in fresh fruits and vegetables and whole grains.

Alcoholics. Alcoholics often suffer from multiple vitamin deficiencies. The most dangerous deficiencies are from vitamins B1 (thiamin), folic acid, B6 (pyridoxine), B2 (riboflavin), and vitamin C.

Dieters and Vegetarians. People on weight-reduction diets with less than 1,000 calories a day should probably take a multivitamin and should also check regularly with a physician.



Vitamin C (Ascorbic Acid)
Benefits
Vitamin C is a water-soluble vitamin. Acts as an antioxidant (reduces harm from damaging chemical processes in the body). Essential for the production of collagen, the basic protein in bones, cartilage, tendons, and ligaments. May help boost the immune system.

Recommended daily allowance (RDA) or dietary reference intake (DRI)

(mcg = micrograms, mg = milligrams, IU = international units)
DRI is 75 mg (women) and 90 mg (men). (Smokers need an additional 35 mg.)


Foods containing the vitamin
Citrus fruits and juices, papayas, hot chili peppers, bell peppers, broccoli, potatoes, kale, red cabbage, cauliflower, cantaloupe, sweet potatoes, and Brussels sprouts. Note: Orange juice is the most important source of vitamin C in the US, with frozen juice being the best source of the vitamin.

Effects of deficiencies
Scurvy is the primary deficiency disease. Affects most body tissues, particularly bones, teeth, and blood vessels. Early symptoms include tiredness, weakness, irritability, weight loss, and vague muscle aches. Later symptoms are bleeding gums, wounds that wont heal, rough skin, and wasting away of the muscles. Deficiencies may contribute to periodontal disease and gallstones. Low dietary intake of vitamin C has been associated with impaired lung function in children. Low intake may also increase lead levels in the blood.

People at risk for deficiencies
Deficiency has been uncommon in the US, usually occurring in the elderly, alcoholics, cancer patients, and some food faddists. Surprisingly, however, studies now suggest that as many as 16% of middle-aged Americans, with the highest risk in smokers and middle aged men, are deficient in vitamin C. High doses of aspirin taken over a long period of time can interfere with vitamin C.

Toxicities
Tolerable upper limit is 2000 mg/day. High doses may cause headaches and diarrhea. Long-term high doses may increase risk for kidney stones. Ascorbic acid increases iron absorption so people with blood disorders, such as hemochromatosis, thalassemia, or sideroblastic anemia, should avoid high doses. Large doses may also thin blood and interfere with anticoagulant medications, blood tests used in diabetes, and stool tests. Rebound scurvy can occur after abrupt withdrawal from long-term large doses. This may affect infants or pregnant women who withdraw suddenly from high doses.