INTRODUCTION
Vitamin C, or ascorbic acid, is a water-soluble vitamin. This means that it dissolves in water and is delivered to the body’s tissues but is not well stored, so it must be taken daily through food or supplements.
HISTORY
Until the end of the 18th century, many sailors who ventured on long ocean voyages, with little or no vitamin C intake, contracted or died from scurvy which was later found to be caused by vitamin C deficiency. During the mid-1700s, Sir James Lind, a British Navy surgeon, conducted experiments and determined that eating citrus fruits or juices could cure scurvy, although scientists did not prove that ascorbic acid was the active component until 1932.
ROLE OF VITAMIN C IN BODY
It is necessary for the growth, development and repair of all body tissues.
It is also involved in many body functions, including formation of collagen, absorption of iron, the proper functioning of the immune system, wound healing, and the maintenance of cartilage, bones, and teeth.
Vitamin C is one of many antioxidants that can protect against damage caused by harmful molecules called free radicals, as well as toxic chemicals and pollutants like cigarette smoke. Free radicals can build up and contribute to the development of health conditions such as cancer, heart disease, and arthritis.
RECOMMENDED DAILY ALLOWANCE
The Recommended Dietary Allowance(RDA) for adults 19 years and older is 90 mg daily for men and 75 mg for women. For pregnancy and lactation, the amount increases to 85 mg and 120 mg daily, respectively. Smoking can deplete vitamin C levels in the body, so an additional 35 mg beyond the RDA is suggested for smokers.
SOURCES OF VITAMIN C
- Fruits and vegetables are the best sources of this vitamin. They include,
- Citrus (oranges, kiwi, lemon, grapefruit)
- Bell peppers
- Strawberries
- Tomatoes
- Cruciferous vegetables (broccoli, brussel sprouts, cabbage, cauliflower)
- White potatoes
Vitamin C is also available as an oral supplement, typically in the form of capsules and chewable tablets.
GROUPS AT RISK OF VITAMIN C DEFICIENCY
- Smokers and passive smokers
- Infants fed with evaporated or boiled milk
- Individuals with limited food variety
- People with defect in absorption and certain chronic diseases
SIGNS OF DEFICIENCY
Vitamin C deficiency is rare in developed countries but may occur with a limited diet that provides less than 10 mg daily for one month or longer. In developed countries, situations at greatest risk for deficiency include eating a diet restricted in fruits and vegetables, smoking or long-term exposure to secondhand smoke, and drug and alcohol abuse. The following are the most common signs of a deficiency.
Scurvy, which is the hallmark disease of severe vitamin C deficiency, displays symptoms resulting from loss of collagen that weakens connective tissues: These include,
- Skin spots caused by bleeding and bruising from broken blood vessels
- Swelling or bleeding of gums, and eventual loss of teeth
- Hair loss
- Delayed healing of skin wounds
- Fatigue, malaise
- Anaemia due to decreased absorption of iron from diet
SAFETY AND SIDE EFFECTS
When taken at appropriate doses, oral vitamin C supplements are generally considered safe. Taking too much vitamin C can cause side effects, including:
- Nausea, vomiting and diarrhoea
- Heartburn
- Stomach cramps or bloating
- Fatigue and sleepiness, or sometimes insomnia
- Headache
- Skin flushing
In some people, oral vitamin C supplements can also cause kidney stones, especially when taken in high doses. Long-term use of oral vitamin C supplements over 2,000 milligrams a day increases the risk of significant side effects.
ADVICE TO GENERAL POPULATION
- You should be able to get all the vitamin C you need by eating a varied and balanced diet.
- If you take vitamin C supplements, do not take too much as this could be harmful.
- Taking less than 1,000mg of vitamin C supplements a day is unlikely to cause any harm.
Dr. Noel Menezes M.D
Associate Professor
Department of Biochemistry
Goa Medical College