Vitamin C

Facts about Vitamin C

Vitamin C was the first vitamin to be isolated in the laboratory by Albert Szent-Györgyi who later also discovered flavonoids. It took a further five years to determine its correct structure and in 1933 it was finally named ascorbic acid (Latin a, "not"; scorbutus, "scurvy"). Scurvy is a Vitamin C deficiency that can be fatal if left untreated.

Vitamin C refers to both ascorbic acid and dehydroascorbic acid (DHA). DHA is converted into ascorbic acid inside our cells. Unlike most animals, our body is unable to make its own Vitamin C. It must be supplied in our diet. Interestingly, it is a common misconception that fruit, especially citrus, is the best source, in fact, vegetables provide us with more. Just be aware, that it can easily be destroyed by heat or prolonged storage. Vitamin C is water soluble.

Vitamin C is widely known as a powerful antioxidant, supplying electrons to free radicals. Although oxygen is essential to life, it is also damaging: oxygen is the reason why metal rusts and our body ages. A nice example is the browning of apples when cut and left standing. We can delay this process if we sprinkle lemon juice onto it and that is why ascorbic acid is often added to food as a preservative.

Vitamin C works better in combination with other nutrients. For example, it recycles Vitamin E and other antioxidants after they have spent their electrons. However, there may be possible interactions with polyphenols (grape seed extract) and Vitamin B12. Large doses should therefore not be taken at the same time.

Vitamin C activates white blood cells to fight bacteria and viruses. It is essential in the formation of collagen and elastin, therefore providing our body with structure, strength, and elasticity. It is also essential for the metabolism of fat, folic acid, histamine and more. It is even involved in our body's stress response. However, it has not been established to be a coenzyme.

Benefits of Vitamin C

Vitamin C regulates our cholesterol levels: it lowers elevated low-density lipoprotein (LDL) cholesterol ('bad' cholesterol) and increases high-density lipoprotein (HDL) cholesterol ('good' cholesterol). Furthermore, it blocks hyaluronidase, an enzyme that breaks down hyaluronic acid. Hyaluronic acid is an important part of our connective tissue and joints that functions to lubricate and cushion. Hyaluronic acid has lately also been linked to as a possible "Anti-Aging Remedy".

Two times Nobel laureate Ph.D. Linus Pauling recommended high doses of Vitamin C for the common cold in 1970. He also founded the Linus Pauling Institute where his work and research still continues today. Although we might not be able to prevent the common cold and flu, we can reduce the symptoms in length and severity.

Vitamin C is beneficial when dealing with many aches, pains, and diseases, including:

High-dose of Vitamin C may also help to reduce the often extreme pain of cancer patients. However, cancer patients should work with a physician instead of treating themselves, because Vitamin C interacts with medications, Chemotherapy, and radiation.

Although Vitamin C is the most widely known vitamin, decades of research have still not provided clear evidence of all its benefits. The difficulty of studying a single vitamin in isolation, without its network of interactions, tends to be based on too many questionable assumptions.

Vitamin C Deficiency

Our body cannot produce its own Vitamin C. It needs to be obtained through our diet, though a wide variety of food should supply us with enough to avoid deficiency symptoms. But be aware that stressors like strong emotions, illnesses, and numerous medications can deplete or interfere with our Vitamin C levels. For this reason it is often added to medications, not as a well meant added benefit but rather for damage reduction. Women taking the Pill should also increase their Vitamin C intake.

Without any Vitamin C in our diet, it takes no more than two months for our small body stores to be used up and for deficiency symptoms to appear. If left untreated, a deficiency can be fatal. Nowadays, severe deficiencies are rare in developed countries but unrecognized deficiencies are still common. Possible signs of deficiency include:

Vitamin C Toxicity

The Food and Nutrition Board (FNB) could not establish data supporting a toxic dose for Vitamin C. Thus, the upper intake level has been rated a "No-Observed-Adverse-Effect-Level" (NOAEL). Absorption also reduces to less than 50% for doses above 1g a day and excess levels get excreted in the urine.

Adverse effects are mainly caused by too much unabsorbed ascorbic acid and should quickly improve when the intake is reduced. Symptoms include:

• abdominal cramps
• bloating
• burning sensation during urination
• diarrhoea
• flatulence
• nausea
• skin rash
• upset stomach

The Food and Nutrition Board 2000 also discredited a potential harm through pro-oxidant effects (when a "good" antioxidant turns "bad" and increases free radical attacks). However, a potential risk of increased iron absorption resulting in iron overload might still be a concern. Excessive intake might also reduce our Vitamin B12 and copper status.

Foods high in Vitamin C

Interestingly, we still believe that fruit, especially citrus, is the best source of Vitamin C. In fact, vegetables do provide us with more. In Australia, some 40% of Vitamin C comes from vegetables, 19% from fruits, and a further 27% from fruit and vegetable juices (ABS 1998).

The value of Vitamin C content depends much on growing conditions, ripeness, and season. It is easily destroyed by heat or prolonged storage. Rich sources include:

The absorption of Vitamin C can be improved with Vitamin B2, B3, B9, B12, and bioflavonoids. Intake should be spread over the day to further increase absorption. Vitamin C also supports iron absorption, thus drinking a glass of orange juice with dinner can enhance iron levels. So far, there is no evidence that natural Vitamin C will be better absorbed than synthetic Vitamin C which is usually derived from corn sugar.

The current Dietary Reference Intake (DRI) for Vitamin C established by the Food and Nutrition Board (FNB) at the Institute of Medicine of The National Academies currently states 90 mg for adult men and 75 mg for adult women. Smokers require about 35 mg more than non-smokers. Australia and New Zealand only state 45 mg as their Nutrient Reference Value (NRV) for adult men and women, based on an Estimated Average Requirement (EAR) of 30 mg. The EAR is still considered adequate and represents a value half-way between tissue saturation and the appearance of clinical signs of scurvy.

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