Vitamin C is one of the most important nutrients needed by the body. It is crucial for functioning of the immune system, and may be preventative for cardiovascular disease, as well as other conditions.

Researcher Mark Moyad, MD, of the University of Michigan says, “Vitamin C has received a great deal of attention, and with good reason. Higher blood levels of vitamin C may be the ideal nutrition marker for overall health.The more we study vitamin C, the better our understanding of how diverse it is in protecting our health, from cardiovascular, cancerstrokeeye health [and] immunity to living longer.”

Vitamin C, is a water-soluble vitamin naturally present in foods. Humans, unlike most animals, do not synthesize vitamin C naturally, so it is an essential dietary component [1].

Vitamin C is needed in the biosynthesis of collagen, and protein metabolism, and thus it plays a crucial role in connective tissue and wound healing. It is also used in the production of neurotransmitters.

Vitamin C is an important natural antioxidant [3] and it helps the body regenerate other antioxidants, like Vitamin E [4]. As such it may limit the damage done by free radicals in the body. This action might help to prevent or delay the development of cardiovascular disease, other diseases and possibly cancers.   Severe cases of Vitamin C deficiency,  lead to the development of scurvy, causing generalized fatigue , widespread connective tissue weakness, and blood vessel fragility [1,2,4,69].

3. Stroke. A study in the American Journal of Clinical Nutrition found that people with  higher concentrations of vitamin C in their blood had a 42% lower stroke risk than those with the low levels. As far as maintaining a healthy diet and good Vit C levels is concerned, researcher Phyo K Myint states,

“People who consume more fruit and vegetables will not only have higher [blood] levels of vitamin C, but higher intake of other nutrients potentially beneficial to health, such as fiber and other vitamins and minerals.”

Skin Aging. Vitamin C  antioxidant properties can help the appearance of aging through its benefit to the skin. The American Journal of Clinical Nutrition published a study of skin aging in greater than 4,0000 women between the 40 and 74 years of age. Higher vitamin C intake was associated with an appearance of less wrinkling. They also said that  topical treatments containing  Vitamin C were helpful.

In the body higher levels of vitamin C are found in the highest concentrations  in leukocytes (white blood cells), the eyes, adrenal glands, pituitary gland, and the brain.

Sources of Vitamin C

  • Fruits and vegetables are the best sources of vitamin C (see Table ) [12]. Citrus fruits, tomatoes and, and potatoes are major sources in the typical American’s diet [8].  Vitamin C is not naturally present in grains, but it is added to fortified  cereals. Vit C is lost in cooking , but thankfully the commonest sources like fruits are commonly eaten raw. Steaming or microwaving lessens their loss in cooking. The standard dietary advice to consume five servings of fruits and vegetables per day provides more than 200 mg of vitamin C, more than the minimum daily need.
    FoodMilligrams (mg) per serving
    Red pepper, sweet, raw, ½ cup95
    Orange juice, ¾ cup93
    Orange, 1 medium70
    Grapefruit juice, ¾ cup70
    Kiwifruit, 1 medium64
    Green pepper, sweet, raw, ½ cup60
    Broccoli, cooked, ½ cup51
    Strawberries, fresh, sliced, ½ cup49
    Brussels sprouts, cooked, ½ cup48
    Grapefruit, ½ medium39
    Broccoli, raw, ½ cup39
    Tomato juice, ¾ cup33
    Cantaloupe, ½ cup29
    Cabbage, cooked, ½ cup28
    Cauliflower, raw, ½ cup26
    Potato, baked, 1 medium17
    Tomato, raw, 1 medium17
    Spinach, cooked, ½ cup9
    Green peas, frozen, cooked, ½ cup8
    Vitamin C is widely available in nutritional supplements in tablets, capsules or in powder form. Powder may provide the best bioavailability especially for those with gastrointestinal conditions who may have poor absorptive capabilities.

    Studies have been done to test bioavailability differences  among various forms of vitamin C. Calcium ascorbate is a form of Vitamin C available in  Ester-C which, was shown to produce a higher concentration in a person’s white blood cells measured 24 hours after its ingestion [18]. Vitamin C status is typically assessed by measuring plasma vitamin C levels [4,14].

  • Vitamin C Deficiency
  • Hundreds of years ago sailors who ventured on long ocean voyages, with little or no vitamin C intake, died from scurvy, a disease of severe Vitamin C deficiency. In the mid-1700s, a British Navy surgeon Sir James Lind, determined that eating citrus fruits or fruit juices could cure scurvy. He was right and this scourge causing the death of sailors was conquered. It was not until 1932 that scientists proved that ascorbic acid (Vitamin C) was the active component in those fruits which  provided the protective effect. [2426].Today scurvy is rare in developed countries [8]. Where it does occur it will lead to a host of symptoms such as fatigue,  malaise, inflammation of the gums [4,11]. As the condition worsens bruising,  joint pain, and poor wound healing occur. Other signs would be swollen, bleeding gums and loosening and  loss of teeth [6,8,9]. If  untreated, scurvy will be fatal [6,9]. Scurvy  appears within 1 month of little or no vitamin C intake [6,7,22,23].
  • Smokers and passive smokers

    Studies consistently show that smokers and those exposed to secondhand smoke have lower plasma and leukocyte vitamin C levels than nonsmokers. [8].

    Feeding Infants

    In developed countries infant formulas or breast milk are advised as the best way to nurture infants, because cow’s milk has very little Vit C and evaporated milk is therefore not recommended.[6,12].

    People with malabsorption and certain chronic diseases

  •  People who have intestinal malabsorption are at high risk vitamin C deficiency.

Vitamin C and Health

Due to its many and varied functions vitamin C intake has been felt to be helpful in preventing or treating a number of health conditions.

Cancer prevention
  • Epidemiologic studies have provided evidence that higher intakes of fruits and vegetables may lower risk of many  types of cancer[1,2]. Vitamin C inhibits the formation of certain carcinogens, and helps a person’s immune system [2,4]. Also, Vitamin C’ antioxidant function, may inhibit oxidative damage in the body which might lead to cancer [1].Many studies have provided evidence that low Vitamin C levels contribute to the development of cancers of the breast,  lung, stomach, colon, oral cavity,  and the esophagus [2,4].

    Some studies have shown that less cancer is found in individuals whose Vitamin C intake is greater than 100mg/day.

     Cardiovascular disease

    Many epidemiological studies have shown that higher intake of fruits and vegetables reduce risk of cardiovascular disease [1,55,56].

    The Nurses’ Health Study, lasted 16-years with over 85,000 subjects. It showed that in these nurses higher vitamin C intakes lowered coronary heart disease risk [58].

    Another study of over 20,000 British had similar findings.Health Risks from Excessive Vitamin C

  • Are there any health risks of taking too much Vitamin C ?
  • Vitamin C  is not believed to cause and serious adverse effects [8]. People do commonly experience diarrhea, nausea, or abdominal cramps, if ingesting high levels of vitamin C supplements. These symptoms do resolve, however, by lowering the amount taken. Vitamin C helps to absorb iron, and there had been a concern that high vitamin C intakes might cause excess iron in the body. This appears not actually to be a problem. However, in individuals with hereditary hemochromatosis characterized by high iron levels, Vit C supplementation should be avoided [4,8].

    Vitamin C and Healthful Diets

     Dietary Guidelines for Americansexternal link disclaimer and the USDA’s MyPlate.external link disclaimer are good sources of information which in summary advise the following :

    A healthy dietary would be one that contains these sources of Vitamin C.

      • Citrus fruits, fruit juices, and many vegetables are excellent sources . Breakfast cereals may be fortified with vitamin C.
    • Protein foods such as lean meats, poultry, eggs and seafood
    • Beans, peas, and lentils, nuts and seeds.
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