Vitamin C

Deficiency symptoms include capillary fragility (due to its role in collagen formation) which often manifests clinically as bleeding gums, easy bruising, tender joints, muscle weakness and poor wound healing.

Subclinical deficiency can also result in lowered immunity, anemia (due to vitamin C’s ability to enhance iron absorption), and fatigue (due to its role in the synthesis of carnitine and certain hormones).

Dietary sources rich in vitamin C include the following:

- Broccoli,

- Brussel Sprouts,

- Cantaloupe,

- Cauliflower,

- Citrus Fruits,

- Guava,

- Kiwi,

- Papaya,

- Parsley,

- Peas,

- Potatoes,

- Red and Green Peppers,

- Rose hip,

- Strawberries,

- and Tomatoes.

The government DRI (Dietary Reference Intake) for vitamin C is listed below, published in 2000, although intakes of 200 -1000mg have been commonly used for therapeutic benefit.

Adult men: 90 mg per day

Pregnant women:  85 mg per day

Adult women: 75 mg per day

Lactating women: 120 mg per day

Mega-doses of vitamin C (several grams) have been used for specific conditions such as viral infections and cancer, although the therapeutic benefit to mega-doses is thought to occur due to a pro-oxidant effect of vitamin C on viral or cancer cells. Since excess vitamin C can actually increase free radical production, it is important to balance it with other antioxidants in order to not induce a pro-oxidant effect. Large doses may result in diarrhea.

The Tolerable Upper Intake Level has been established at 2000 mg per day. Although vitamin C is easily absorbed in the small intestine, mineral ascorbates are the preferred supplement form (versus ascorbic acid) to maximize absorption. It is recommended to ingest therapeutic doses at various intervals throughout the day since the body readily excretes excess vitamin C shortly after ingestion.

Physical or emotional stress will increase the body’s requirement for vitamin C. In some patients, excess vitamin C can produces high amounts of oxalic acid, which are linked to kidney stones so patients with kidney disease or a history of kidney stones should exercise caution in taking mega-doses of vitamin C.

Vitamin C is required for several metabolic functions in the body. One of its major roles is in the synthesis of collagen and elastin, the main structural proteins of skin, cartilage and blood vessels.

It is also necessary in the production of several stress response hormones including adrenalin, noradrenalin, cortisol and histamine, and it is required in the synthesis of carnitine, an amino acid that facilitates the conversion of fatty acids into energy within the mitochondria.