By Barbara E. Amsler, MD
Vitamin “C” stands for “citrus” as it was first isolated from lemons in 1932. Also known as ascorbic acid, it is found in the liquid part of fresh fruits and vegetables and is often lost or reduced with cooking. Steaming vegetables is better as it preserves some of the vitamin. Ascorbic acid is sensitive to light, heat, air and alkali (like baking soda).
Vitamin C is easily and nearly completed absorbed by the small intestine (80-90%) when consumed in small doses (less than 100 mg). It is used quickly (within 2 hours) and out of the blood in 3-4 hours. Although a very small amount is stored in the body, the vast majority is excreted through the kidney.
Reduced blood vitamin C levels occur in illness, with antibiotic use (ampicillin, tetracycline, minocycline, and sulfa drugs), during stress and in those who use alcohol, cigarettes, birth control pills or estrogens. Anti-inflammatories like aspirin, Advil, Aleve and cortisone also reduce vitamin C levels. Exposure to environmental toxins like DDT, carbon monoxide, allergens and petroleum products as well as heavy metals like lead, copper, arsenic, mercury and cadmium reduce C because it is used to detoxify the body from these compounds.
Like the B vitamins, ascorbic acid functions as a coenzyme combining with larger compounds to make active enzymes. It is instrumental in a variety of chemical reactions involved in immune function, brain chemistry, production of cartilage and connective tissue (ligaments, spinal disks, joint coverings, vessel walls, bone, skin and teeth) and the healing of wounds.
Vitamin C also functions as an antioxidant. The addition of oxygen to certain molecules may damage them or make them very interactive with other chemicals. These “free radicals” can cause significant cellular damage. Antioxidants neutralize the “free radicals” there by protecting the cell. Vitamin C functions in this manner. Its antioxidant ability is greatly augmented by a group of over four thousand chemicals known as bioflavonoids. They are primarily found in the edible pulp of fruits and broccoli, green pepper and tomatoes.
Vitamin C levels can either be measured in the blood plasma or in white blood cells. Blood levels less than 0.2 mg/dl represent a deficiency state, called scurvy. Symptoms include decreased resistance to infections, weakness, fatigue, loss of appetite, slow wound healing, easy bruising, nosebleeds, anemia, mouth sores, shortness of breath and joint pain. In children, it may also be associated with impaired bone growth.
True toxicity is not generally an issue, even with higher doses. Some, most notably Linus Pauling, have advocated very large doses of vitamin C. Amounts over 10 grams daily may cause diarrhea, nausea, burning with urination and skin irritation. Ascorbic acid is converted to oxalate in the body which is excreted through the kidney. In the urine, oxalate may combine with calcium to form stones. There is a potential risk of increasing kidney stones with very high levels of vitamin C. However, research has not been conclusive regarding this potential risk.
Although we only need about 10-20 mg of vitamin C, daily, to prevent scurvy, the recommended daily allowance is between 75-90 mg daily. These values, however, are likely too low for our true needs. A more reasonable recommendation would be an intake of 500 -1000 mg daily.
The best sources of vitamin C are citrus fruits but peppers, cabbage, broccoli, Brussels sprouts, cauliflower, peas, spinach, radishes and tomatoes are also good.
Healthy Habits of Vitamin C Consumption:
1) For best results, vitamin C should be taken in smaller quantities every 4 hours, rather than one large dose.
2) Steaming vegetables or eating raw fruits and vegetables may improve the vitamin C content delivered to the blood stream.
3) People who are under emotional or physical stress/illness should take more vitamin C. There is a greater benefit in eating the whole fruit rather than drinking the juice or taking a supplement. The whole fruit contains bioflavonoids which super charge vitamin C.
4) Those who are on steroids or have received cortisone injections should take extra vitamin C to counteract the immune suppressing side effects of these drugs.
5) Those who regularly eat lunchmeats and sausages (especially bologna and hot dogs) should take extra C to block the cancer producing effects of nitrates used in preserving these foods.