This vitamin is probably better known and more widely used than any other nutritional supplement. But even if you think you're familiar with vitamin C, read on. You may be surprised to discover exactly how versatile and health-enhancing this nutrient truly is.
What it is?
As early as 1742, lemon juice was known to prevent scurvy, a debilitating disease that often plagued long-distance sailors. But not until 1928 was the healthful component in lemon juice identified as vitamin C. Its antiscurvy, or antiscorbutic, effect is the root of this vitamin's scientific name: ascorbic acid. Today, interest in vitamin C is based less on its ability to cure scurvy than on its potential to protect cells. As the body's primary water-soluble antioxidant, vitamin C helps to fight damage caused by unstable oxygen molecules called free radicals – especially in those areas that are mostly water, such as the interior of cells.
What it does?
Vitamin C is active throughout the body. It helps to strengthen the capillaries (the tiniest blood vessels) and cell walls and is crucial for the formation of collagen (a protein found in connective tissues). In these ways, vitamin C prevents bruising, promotes healing, and keep ligaments (which connect muscle to bone), tendons (which connect bone to bone) and gums strong and healthy. It also helps to produce haemoglobin in red blood cells and helps the body to absorb iron from foods.
As an antioxidant, vitamin C offers protection against cancer and heart disease, several studies have shown that low levels of this vitamin are linked to heart attacks. In addition, vitamin C may actually lengthen life. In one study, men who consumed more than 300 mg of vitamin C a day (from food and supplements) lived longer than men who consumed less than 50 mg a day.
Another study found that over the long term, vitamin C supplements protect against cataracts, a clouding of the lens of the eye that interferes with vision. Women who took vitamin C for 10 years or more had a 77% lower rate of early 'lens opacities', the first stage of cataracts, than women who didn't use supplements.
Does vitamin C prevent colds? Probably not, but it can help to lessen symptoms and may shorten the duration of this illness. In a 1995 analysis of studies exploring the connection between vitamin C and colds, the researchers concluded that taking 1000 – 6000 mg a day at the onset of cold symptoms reduces the cold's duration by 21% - about one day. Other studies have shown that vitamin C helps elderly people to fight severe respiratory infections. Vitamin C also appears to be a natural antihistamine. High doses of the vitamin can block the effect of inflammatory substances produced by the body in response to pollen, per dander or other allergens.
The vitamin is an effective asthma remedy as well. Numerous studies have found that vitamin C supplements helped to prevent or improve asthmatic symptoms. For people with type 1 diabetes, which interferes with the transport of vitamin C into cells, supplementation with 1000 – 3000 mg a day may prevent some complications of the disease, such as eye problems and high cholesterol levels.
- Enhances immunity.
- Minimizes cold symptoms; shortens duration of illness.
- Speeds wound healing.
- Promotes healthy gums.
- Treats asthma.
- Helps to prevent cataracts.
- Protects against some forms of cancer and heart disease.
- Don't take more than 500 mg a day if you have kidney stones, kidney disease or haemochromatosis, a genetic tendency to store excess iron (vitamin C enhances iron absorption).
- Vitamin C can distort the accuracy of medical tests for diabetes, colon cancer and haemoglobin levels. Let your doctor know if you're taking it.
- Reminder: If you have a medical condition, talk to your doctor before taking supplements.
How much you need?
The daily RDI for vitamin C is 40 mg for men and 30 mg for women (but for smokers, it's at least 80 mg). However, even conservative experts think that an optimal intake is at least 200 mg a day, and they recommend higher doses for the treatment of specific diseases.
If you get too little:
You'd have to consume less than 10 mg a day to get scurvy, but receiving less than 50 mg a day has been linked with an increased risk of heart attack, cataracts and a shorter life expectancy.
If you get too much:
Large doses of vitamin C – more than 2000 mg a day – can cause diarrhoea and flatulence; these can be corrected by reducing your daily dose. At this level, the vitamin may interfere with the absorption of copper and selenium if taken together, so make sure you consume enough of these minerals in foods or supplements.
How to take it?
For general Health: Get 500 mg of vitamin C a day from foods and supplements.
For the treatment of varicose veins: Depending on the condition, 1000 – 6000 mg a day may be appropriate.
Guidelines for use:
Large amounts are best absorbed in 1000 mg doses, taken with meals. The vitamin works very well when combined with other antioxidants, such as vitamin E.
Citrus fruits and juices, broccoli, red capsicums, dark green vegetables, strawberries, and kiwi fruit are all good sources.
- The jury is still out on specialized vitamin C products (such as esterified C). There's no evidence that they are more efficiently absorbed than plain odd ascorbic acid, but some nutritionists think that they may be better utilized.
- Vitamin C may help to prevent reblockage (restenosis) of arteries after angioplasty (an alternative to bypass surgery). A study of 119 angioplasty patients found that restnosis occurred in just 24% of those who took 500 mg of vitamin a day for four months, compared with 43% of those who did not take the vitamin.
- In addition to being an antioxidant, vitamin C helps the body to recycle other antioxidants. In one study, vitamin E concentrations were 18% higher in people who got more than 220 mg of vitamin C a day than in those who got 120 mg or less.
- Vitamin C recently came under attack when a small test-tube study found that it cause genetic damage, potentially increasing the risk of cancer. But scientists have since identified serious flaws in the study. Many better studies show that vitamin C provides numerous benefits, including helping to prevent certain cancers.
Did you know?
A 250 ml glass of freshly squeezed orange juice supplies 125 mg of vitamin C, which is more than three times the RDI for this vitamin.