Vitamin C is a nutrient needed for normal growth and development. Among other functions, it helps repair wounds and is vital to maintaining healthy bones, cartilage, gums and teeth. In recent years, there has been a lot of speculation about the role of vitamin C in prevention of the common cold. Many studies have been conducted, with mixed results.

Some studies appear to show that taking anywhere from 1,000 to 6,000 milligrams of vitamin C a day can reduce the length of a cold by a day, and may slightly relieve symptoms such as runny nose and sore throat. However, this amount is more than 100 times the recommended dietary allowance (RDA). The body can absorb a limited amount of vitamin C at one time and excess amounts have the potential to lead to health problems.

Meanwhile, other studies have not found any link between vitamin C consumption and reduced cold symptoms. Experts generally agree that conclusive evidence has yet to emerge about the potential role of vitamin C in preventing colds or reducing the symptoms of these illnesses.

For now, people are urged to take only the recommended daily dose of vitamin C. Although the evidence is inconclusive about whether or not vitamin C protects against colds, drinking beverages rich in vitamin C, such as orange juice and grapefruit juice, does provide fluids and extra energy necessary to restore a patient’s health.

All fruits and vegetables contain vitamin C, although the amount varies from food to food. It is best to eat fresh fruit and vegetables that are raw as cooking destroys some of the vitamin’s beneficial properties. It is recommended that individuals try to receive vitamin C from dietary sources rather than from supplements.

Vitamin C is a water-soluble nutrient that people need for normal growth and development. This vitamin helps repair tissues and forms collagen, a protein used to make blood vessels, ligaments, scar tissue, skin and tendons. Vitamin C helps repair wounds and is vital to maintaining healthy bones, cartilage, gums and teeth. Vitamin C also helps the body to absorb iron.

In recent years, there has been a lot of speculation about the role of vitamin C in common cold prevention. Many studies have been conducted, with mixed results. Some studies appear to show that taking anywhere from 1,000 to 6,000 milligrams (mg) of vitamin C daily can reduce the length of a cold by a day, and may slightly relieve symptoms such as runny nose and sore throat.

However, this amount is more than 100 times the recommended dietary allowance (RDA) established by the Food and Nutrition Board of the National Academy of Sciences. This has the potential to lead to health problems. Taking supplemental doses of vitamin C as low as 500 mg daily has been shown to cause diarrhea in some people. Small children and the elderly are particularly at risk for health problems associated with such diarrhea. In addition, other studies have shown that excessive vitamin C consumption has no influence on the number or severity of colds.

Other studies have found that vitamin C supplementation can significantly reduce the number of colds a person catches. Still, experts generally agree that conclusive evidence has yet to emerge about the potential role of vitamin C in preventing colds or reducing the symptoms of these illnesses. The results of some studies even suggest that there may be no link between taking vitamin C and reduced cold symptoms.

For now, people are urged to take only the recommended daily dose of vitamin C. The body is capable of absorbing about 200 mg of vitamin C at one time. Any excess of the vitamin is excreted in urine. Although it is unclear whether or not vitamin C protects against colds, drinking vitamin C-rich beverages, such as orange juice and grapefruit juice, does provide fluids and extra energy necessary to return a patient to good health. Fruits and vegetables contain vitamin C and other important nutrients such as fiber.

Vitamin C does play a role in the immune system. Immune system cells appear to take in high amounts of the vitamin. There has been at least anecdotal evidence of vitamin C helping to fight many different forms of infection, not just the common cold. For example, some studies suggest that vitamin C may help to fight the bacteria that cause stomach ulcers.

The Food and Nutrition Board of the National Academy of Sciences has issued the following RDAs for vitamin C. The figures are expressed in milligrams:

All fruits and vegetables contain vitamin C, although the amount varies from food to food. It is best to eat fresh fruit and vegetables that are raw. Cooking destroys some of the vitamin’s beneficial properties. Foods with high vitamin C content include:

• Broccoli
• Cantaloupe
• Citrus fruits and juices
• Green peppers
• Leafy green vegetables
• Strawberries
• Sweet and white potatoes
• Tomatoes

Other foods that are good sources of vitamin C include:

• Blueberries
• Brussels sprouts
• Cabbage
• Cauliflower
• Cranberries
• Mango
• Papaya
• Pineapple
• Raspberries
• Red peppers
• Watermelon
• Winter squash

Proper amounts of vitamin C are required for the body to function. Having too little or too much of the vitamin stresses tissues and, in extreme cases, can lead to death. It is important to consume vitamin C every day because it is not fat-soluble and therefore cannot be stored in the body.

Because it is water-soluble, excess vitamin C is usually excreted with the urine and overdoses are rare. When they do occur, symptoms include nausea, abdominal cramps and diarrhea. Kidney stones may also result from overdoses of vitamin C, though this is most likely to occur in patients with kidney disease or gout.

Excessive vitamin C, either from substances or natural sources (e.g., grapefruit), may also interact with medical treatments or conditions. Examples of these interactions include:

• Diabetes tests. May cause false positives and false negatives.
  
  
• Anti-clotting medications. Reduces the effectiveness of these medicines used to prevent recurring strokes and blood clots.
  
  
• Iron excess. Increases absorption of iron and may worsen the symptoms of patients who already have too much iron in their bodies.

A deficiency of vitamin C affects the entire body and many of the symptoms reflect the body’s inability to synthesize collagen. Tissues may begin to break down, frequently starting with the capillaries (small blood vessels). This causes the earliest signs of a vitamin C deficiency – inflammation and bleeding gums (gingivitis) and small red spots under the skin (pinpoint hemorrhages). Over time, symptoms become more severe and affect the patient’s ability to function. Other signs of vitamin C deficiency include:

• Anemia (low levels of red blood cells)
• Difficulty fighting off infections
• Dry, scaly skin
• Nosebleeds
• Painful, swollen joints
• Slow healing of wounds
• Tendency to bruise easily
• Weakened tooth enamel
• Weight gain

Advanced vitamin C deficiency is called scurvy. Since its cause was discovered, it rarely occurs in the United States and other industrialized nations. Cases are often associated with general malnourishment due to restrictive diets or alcoholism. Possible signs and symptoms of scurvy include:

• Bleeding at hair follicles
• Skin becomes rough, brown, scaly and dry
• New wounds do not heal and old ones reopen
• Bone pain and increased risk of fracture
• Teeth become loose
• Weakness and fatigue
• Increased incidence of infections
• Hysteria
• Depression

Under a physician’s care, scurvy can be cured by correcting the vitamin C deficiency. For adults, supplements of 100 milligrams of vitamin C are given daily for one to two weeks. Treatment for infants and children varies with age, but usually includes vitamin C supplements or adding dietary sources (e.g., orange juice) of the vitamin.

Preparing questions in advance can help patients have more meaningful discussions with their physician regarding their conditions and treatments. Patients may wish to ask their doctor the following questions about vitamin C:

1. How will I know if I’m getting enough vitamin C in my diet?
   
   
2. What foods should I eat to ensure I get enough vitamin C?
   
   
3. Should I consult with a dietitian to make sure I get enough vitamin C?
   
   
4. What are your recommendations about increasing vitamin C intake to fight colds?
   
   
5. Should I take vitamin C supplements when I have a cold?
   
   
6. Do I have a disorder or disease that precludes me from taking such supplements?
   
   
7. Should I drink extra orange juice or grapefruit juice when I have a cold?
   
   
8. How will I know if I’m exceeding my limits of vitamin C?
   
   
9. What should I do if I start experiencing diarrhea due to my vitamin C intake?
   
   
10. Should I take a multivitamin that contains vitamin C?