15 fascinating facts about vitamin C

The importance of vitamin C, also known as ascorbic acid, was first realised more than 250 years ago, when a shortage of it was discovered to be the cause of scurvy.

It is needed to form collagen, which is vital for the growth, health and repair of bones, tendons, cartilage and skin. Vitamin C also works as a potent antioxidant to prevent our bodies from cellular damage.

Plus, it increases the absorption of iron from food and helps to form enzymes that regulate a variety of processes in the body.

Some research shows that it may be able to improve cardiovascular health by lowering high blood pressure and levels of bad cholesterol. It also helps to keep blood vessels elastic.

The only mammals that can’t make vitamin C in their bodies are primates, guinea pigs, fruit bats and humans. Somehow, during evolution, we lost one of four vital enzymes needed to produce it.

This means we have to get vitamin C from elsewhere.

Mammals that make their own vitamin C can live eight to 10 times beyond their age of physical maturity. Those without this ability, such as humans, have a difficult time reaching three to four times beyond that age.

The best dietary sources of vitamin C are oranges, red and yellow capsicums, kale, Brussels sprouts, broccoli, kiwifruit, grapefruit, guava, strawberries and papaya.

Smoking causes the body to excrete more vitamin C than usual, so smokers need to up their intake.

Some experts, like Dr Levy, say that for optimal health, we need more vitamin C than we can get from food. They recommend supplements.

Vitamin C is generally regarded as safe. One of the most common side effects from taking large doses is diarrhoea.

However, people with kidney problems should not take high doses of vitamin C – it can predispose them to other problems.

Because it can affect blood sugar levels, diabetics or people taking drugs that affect those levels should keep a close eye on their blood sugar if they are taking extra vitamin C.

In high doses, vitamin C may also affect people taking blood-thinning medications, such as Warfarin.

Extremely high doses of vitamin C are used by some doctors as a part of cancer treatment. In these cases the vitamin C is given intravenously. This treatment is controversial – while some medics and patients swear by it, there are a number of doctors who say there is not enough evidence from trials to prove it is effective.

However, research carried out at the University of Otago into bowel cancer found that tumours containing higher levels of vitamin C were less aggressive and slower to grow than those with lower levels. It also found that patients who have higher levels of vitamin C in their body also live longer than those with lower levels.

The University of Otago team, led by Professor Margreet Vissers, is planning further clinical trials to look into the impact intravenous vitamin C can have on cancer.