Nutrient Profile—Vitamin C

Definition
Vitamin C is a water-soluble vitamin found in many plant sources. It is a powerful antioxidant that is necessary for tissue growth, adrenal function, and oral health.

Clinical applications
As an antioxidant, vitamin C promotes resistance to oxidative stress, which releases a flood of free radicals—rogue molecules that destroy healthy cells. Free radicals are implicated in cancer, atherosclerosis (hardening of the arteries from plaque build-up), high blood pressure, cataracts, arthritis, and Alzheimer’s disease.

Vitamin C has a number of clinical uses, ranging from fighting the common cold to preventing heart disease and cancer. Below are just a few of its most popular uses.

Immune system boost. Vitamin C has been touted for ages as an immune-system booster, demonstrated by the fact that most of us pop a vitamin C tablet or drink an extra glass of orange juice when we feel a cold coming on. But does it actually help to prevent illness? One recent study looked at the effects of vitamin C intake on the immune cells of 12 healthy individuals. The researchers found that, after two weeks of taking 1 gram per day, the participants had increased immune activity. In fact, in some of those participants, the immune cells were stronger as little as five hours after taking the vitamin.

Vitamin C and cancer. Research indicates that a diet rich in fruits and vegetables may protect against certain types of cancer. In two such European studies, vitamin C from these sources appeared to provide some protection against breast cancer and cancers of the digestive tract. And an Indian study found that vitamin C levels, along with levels of vitamin A and zinc, were lower in people with laryngeal cancer than in the general population.

Cardiovascular disease. Vitamin C supports the cardiovascular system in a number of ways. It can lower total cholesterol and raise high-density lipoprotein (HDL)—the “good” cholesterol. In addition, it can prevent lipid oxidation in LDL, which can lead to heart disease. Circulation seems to be affected by vitamin C intake. A recent study on the effects of intravenous vitamin C therapy found that it significantly improved myocardial blood flow.Vitamin C’s ability to improve circulation points to possible use as a stroke preventative. In fact, one study found that stroke patients have significantly lower plasma levels of vitamin C than the general population.

Diabetes support. Vitamin C reduces insulin resistance, contributes to eye health, and helps prevent cataracts—a common complication of diabetes. In addition, vitamin C contributes to improved circulation, is a powerful antioxidant, and helps fight infections, which frequently occur in diabetics.

Sources & dosage
Vitamin C is found in many food sources, including peppers, broccoli, Brussels sprouts, cauliflower, red cabbage, strawberries, papayas, spinach, oranges, grapefruit, mangoes, asparagus, cantaloupe, and green onions (listed in order of highest concentration, with peppers containing most).

The recommended daily allowance for vitamin C is 60 mg for adolescents and adults. However, many natural medicine practitioners recommend doses of 500 to 1,000 mg per day. Side effects are rare, but some people experience diarrhea while consuming high doses (over 1,000 mg per day).

Final thoughts
Vitamin C is an important part of any diet. The best way to increase your intake is to focus on foods that are rich in vitamin C, instead of relying on supplements. Foods containing vitamin C also are rich in flavonoids and carotenes, which enhance the effects of vitamin C and are very valuable nutrients on their own.