Vitamin C. Mmmm . . . maybe you think of a tall glass of Florida orange juice. Or maybe you grab it at the beginning of the cold season. But would you associate it with cardiovascular disease (CVD) or cancer? Maybe you should. According to an article published in October 2007, in the Journal of Nutrition, there is accumulating scientific evidence that very large (therapeutic) doses of vitamin C may be effective in treating both CVD and cancer. In addition, some scientists have hypothesized that the onset of these common degenerative diseases may actually be due to a vitamin C deficiency in the general population. Dr. Steven Hickey and Dr. Hilary Roberts with the Vitamin C Foundation and authors of the book ‘Ascorbate: the Science of Vitamin C’, have gone so far as to suggest that heart disease is actually a chronic form of the vitamin C deficiency disease called scurvy.

Vitamin C, found in a variety of fruits and vegetables, is essential not only for our good health, but our very survival. Without vitamin C, human beings will certainly die of scurvy, a disease characterized by bleeding gums, skin discolorations from small ruptured blood vessels, easy bruising, joint pain, loose and decaying teeth, and hyperkeratosis of hair follicles. But along the continuum of health, there is a difference between survival and optimal human health. The real question is how much vitamin C is required for optimal health?

Vitamin C has many essential roles in the body. It is required for the synthesis of collagen, which is a main structural protein in our bodies, giving support to our tissues, including strengthening our blood vessels, ligaments, tendons, bone, and teeth. It is also required for synthesis of hormones, neurotransmitters, and other important substances needed for metabolism. In addition to these functions, vitamin C is a powerful antioxidant. It neutralizes free radicals before they have a chance to damage our cells. Vitamin C is arguably one of the most important antioxidants in our human physiology for its versatility and wide ranging presence.

How Much?

The government’s Recommended Daily Allowance (RDA) is defined as the daily amount of a nutrient considered sufficient to meet the requirements of most healthy individuals. For Vitamin C, it is 75 mg/day for adult women and 90 mg/day for adult men (smokers are recommended to have an additional 35 mg/day). The current RDA is adequate to prevent death or serious health issues from acute deficiency of vitamin C (e.g., scurvy). The RDA is also adequate for required collagen and hormone synthesis (the RDA is mainly based on this). But to work effectively as an antioxidant, scientists are learning that vitamin C levels need to be significantly higher in our bodies. And the debate now is over how much is needed.

If we ate the recommended 5 servings of fruits and vegetables per day, we’d easily consume double the RDA for vitamin C and likely a lot more. According to Linus Pauling, a two time Nobel Prize winning chemist who is noted for his vitamin C research, our early human ancestors probably consumed 2,300 mg/day to 9,500 mg/day of vitamin C from their plant-based diet. This is 25 to 100 times more than today’s RDA for an adult man!

History

Scientists have determined that about 40,000 years ago humans lost their own ability, through a genetic mutation, to manufacture vitamin C. Our DNA no longer allowed our cells to make an enzyme which is required to produce vitamin C internally. Evolutionary biologists would argue that the mutation conferred a survival advantage. After all, humans could conserve energy by not manufacturing something that was already abundantly available in their diet.

Along the way, our dependence on fruits and vegetables became obvious. In the 1700’s, sailing ships started stocking limes or vegetables to prevent their crew members from dying of scurvy during long voyages. In 1928, Hungarian biochemist, Albert Szent-Györgyi, finally isolated the mysterious substance known as vitamin C. Since then, scientists have been working to understand exactly how vitamin C functions in our bodies.

Beyond Mere Survival

Today, scientific evidence is highlighting a discrepancy between the amount of vitamin C needed to avoid acute deficiency disease and the amount needed for effective antioxidant protection to ward off major degenerative diseases. This hypothesis is based on vitamin C’s function as a powerful, versatile and pervasive antioxidant in our bodies.

Free radicals are molecules with an unpaired electron that make them highly reactive. They “steal” an electron to make up a more stable pair, hence damaging the molecules around them that have had to relinquish an electron. Free radicals have shown to be a significant contributing factor in the development of cardiovascular disease (CVD) and cancer. They can trigger premature cell death and inflammation in our vascular system. They can reduce the availability of nitric oxide which helps maintain healthy artery dilation and blood flow. Free radicals can also oxidize LDL cholesterol. As we’re learning, it’s not so much the LDL cholesterol that’s implicated in the development of heart disease, it’s that the LDL cholesterol has been damaged, or “oxidized”, by free radicals. Free radicals can also cause DNA mutation and damage the supportive structure of our cells which can contribute to the development of cancer.

Many studies have shown that increased vitamin C intakes and increased plasma vitamin C concentrations are correlated with a decrease in degenerative diseases. Scientists have also determined and explained the specific mechanisms by which vitamin C scavenges and neutralizes these free radicals, thus providing powerful protection against free radical damage.

Conclusion

The current RDA may be sufficient to avoid acute deficiency disease but may not be enough to help protect us from free radical damage. A reduction of disease risk has been associated with 5 servings of fruits and vegetables per day, and this is likely due at least in part to their vitamin C content. But the vitamin C content in these servings is easily double the RDA. Scientists researching vitamin C have yet to agree upon how much is required for optimal human health. Their estimates vary and typically start at 400 mg/day and go higher.

Dr. Steve Hickey with the Vitamin C Foundation has published open letters to the Food and Nutrition Board and the National Institutes of Health, laying out the reasons why the current RDA is insufficient and why it should be reexamined and readjusted upward.

In the meantime, we can support our health and reduce our risk of degenerative diseases by making sure not to skimp on our 5 servings of fruits and vegetables per day. We may fortify ourselves with a good quality multi-vitamin supplement for the extra vitamin C it provides.

Vitamin C is a water-soluble vitamin, which means that it is not stored in the body and must be replaced by our diet every day. The Tolerable Upper Intake Level (UL) is the maximum continual intake of a nutrient that is unlikely to cause adverse health effects in almost all people, and for vitamin C the UL is 2 g/day (2,000 mg/day). The most common side effect of taking an amount larger than this is diarrhea. Therefore, healthy individuals have little concern of toxicity if consuming more vitamin C than specified by the RDA.

One word of caution - people who have a high risk of kidney disease, kidney stones, or disorders of iron metabolism should avoid large doses of vitamin C (>500mg). Consult your doctor or nutritionist prior to taking supplementation.

Virtually all fruits and vegetables contain some amount of vitamin C. According to the USDA nutrient database, fruits and vegetables that are among the highest in vitamin C content include: orange juice, grapefruit juice, peaches, peppers (sweet and hot), papayas, strawberries, broccoli, Brussels sprouts, kohlrabi, pineapple, and kiwi fruit. Other fruits noted for their high vitamin C content include: jujube, acerola, camu camu, guava, red and black currants, mango and persimmon.

About the author

Leigh Kirk is an investigative nutritionist currently pursuing her Master of Science in Human Nutrition at the University of Bridgeport. Special interests include disorders of metabolism, research on fats, antioxidants, trace minerals, and the ecology of nutrition. Email: investigativenutritionist@gmail.com

Flavonoids are highly beneficial anti-oxidant compounds found in many fruits and vegetables, as well as tea, red wine and even beer, and it’s now well established that a plentiful intake of anti-oxidants through foods, drinks and supplements is vital for optimal human health.

Anti-oxidants operate to neutralise the activity of so-called “free radicals”; compounds produced in the body as by-products of normal biochemical reactions, but which may nevertheless be highly damaging as they produce oxidative reactions damaging to cell structures. Ultimately this damage may contribute to the development of degenerative diseases characteristic of ageing, including cardiovascular disease, Parkinson’s Alzheimer’s and even some cancers.

The best known anti-oxidant nutrients are vitamins C and E, although these can only function properly when supported by adequate supplies of a wide variety of micro-nutrients, which include many of the flavonoids found in common fruits and vegetables. These compounds may therefore be regarded as important elements in the body’s anti-oxidant defences, but many of the more than 4,000 flavonoids identified have also been hailed for their beneficial effects on the immune system and anti-inflammatory properties.

From the point of view of incorporating flavonoids into a daily health regime, the good thing is the ease with which this can be achieved. Flavonoids are very widely found in fruits, vegetables, and even drinks normally regarded, for other reasons, as unhealthy. So even a diet ordinarily well provided with common fruits and vegetables may provide anything up to 800mg of various flavonoids.

Authoritative research has indicated that this level of flavonoid consumption may help protect against coronary heart disease and hardening of the arteries (atherosclerosis), an important precursor of both heart disease and stroke. These remain two of the major causes of premature mortality and disability in the Western world, and to this extent the UK government and health advisors’ frequent advice to consume five servings of fruit and vegetables each day is well founded.

The most potent of all the anti-oxidant flavonoids is believed to be a compound called quercetin, which is widely found in common or garden vegetables. The consumption of fruits with their skins on, such as apples, pears, grapes, bilberries, tomatoes etc will also provide a good supply. But perhaps the richest source is onions, a foodstuff also known since ancient times as a powerful anti-bacterial, anti-viral and anti-inflammatory agent.

There’s no doubt that a diet including plentiful supplies of fresh fruit and vegetables can only be beneficial to health. But the anti-oxidant properties of the flavonoids found in many common, even supposedly unhealthy, beverages should not be neglected.

For example, the anti-oxidant properties of the catechin polyphenols found in black and green tea and red wine are now well known and attested. But, as remarkable as it may sound, there is now evidence that even beer may contain unique anti-oxidants equal in potency to vitamin E. The flavonoid compounds, xanthohumol and isoxanthumol appear to be found only in beer and the hops that flavour it and although they have not been studied directly, there is speculation that they may be responsible for the remarkable and counter-intuitive finding that lager type beers may be more effective as anti-oxidants than red wine, grape juice or even green tea. Obviously there are other reasons, not least its high calorific value, why you wouldn’t want to depend on a high consumption of lager for your anti-oxidants, but in moderation it may indeed be beneficial.

In fact studies suggest that these particular flavonoid anti-oxidants may have a particular role in combatting the oxidation of low density lipids (LDLs), the so-called “bad cholesterol”, which is a known risk factor for the development of atherosclerosis and cardiovascular disease. The other main fat-soluble anti-oxidant which fights this process is vitamin E, and although there is evidence that the anti-oxidant potential of xanthohumol and isoxanthumol may be comparable with that of the vitamin, it is also clear that each of the three compounds functions best in the presence of each of the others.

Whilst orthodox medicine concedes, in fact insists, that further research is necessary, the implications of these findings are exciting; suggesting that there may be many more as yet undiscovered benefits of flavonoids. As always, however, the holistic functioning of the body means that maximum benefits will only be obtained by the consumption of the widest possible variety of all these compounds. As flavonoids are not yet widely available as supplements, this consumption is best achieved through the foodstuffs and beverages which combine them as nature intended. Such a flavonoid rich diet can only be of benefit to the action of the better known anti-oxidants, such as vitamins E and C, which are more readily obtainable in supplement form.

Flavonoids are highly beneficial anti-oxidant compounds found in many fruits and vegetables, as well as tea, red wine and even beer, and it’s now well established that a plentiful intake of anti-oxidants through foods, drinks and supplements is vital for optimal human health.
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