What’s the best form of vitamin C? Is natural better than synthetic? How much can you absorb anyway? So many myths exist. Firstly, vitamin C is ascorbic acid. This is exactly what plants and most animals produce primarily from glucose (sugar) or mannose in the case of plants. Primates, fruit-eating bats, guinea pigs and the red vented bulbul bird do not produce vitamin C because they lack the final enzyme L-gulonolactone oxidase, to make ascorbic acid. This enzyme ‘loss’ seems to have occurred approximately 60 million years ago in the case of primates and may be due to our distant ancestors living in a tropical fruit rich environment. If able to eat enough vitamin C the extra glucose could have given them more energy and thus an evolutionary advantage. Animals produce significant daily amounts – a goat my body weight equivalent makes about 16 grams a day. Twenty oranges is about 1 gram. Most primates in the wild consume around 1-3 grams a day.
Natural vz Synthetic
Natural and synthetic ascorbic acid are chemically identical. Studies that have compared the difference in blood levels between those given synthetic ascorbic acid and ascorbic acid from eg oranges, have found no difference.
Natural food sources of vitamin C, such as berries, are generally good sources of bioflavonoids, raising the possibility that these bioflavonoids might enhance vitamin C‘s bioavailability. Most studies have found little or no difference however one study, which included five men and three women, found that a 500-mg supplement of synthetic ascorbic acid, given in a natural citrus extract containing bioflavonoids, proteins, and carbohydrates, was more slowly absorbed and 35% more bioavailable than synthetic ascorbic acid alone.
Ascorbic acid vs Mineral Ascorbates
Vitamin C comes in two forms – ascorbic acid and ascorbate. Ascorbic acid is acidic and ascorbate is alkaline. (Acidity or alkalinity is measured as pH. A pH of 7 is neutral, with anything less being acidic and anything more is alkaline.)
Many people mistakenly think anything ‘acidic’ is bad. While it is true that a continuously increased acid level in the blood links to many disease states, the body controls the pH of blood very closely, protecting itself by being acidic. The skin is pH 5.5. The stomach, when not digesting, is pH 4 to 6. This acid level helps kills dangerous microbes. Ascorbic acid is pH 2 so, if taken with food will slightly raise the stomach’s pH level. Ascorbate forms of vitamin C, which average pH 7 to 8, in high dose are best taken away from or before meals so as not to dilute stomach acid.
I like ascorbates for three reasons. Firstly, it is a way to deliver an essential mineral together with vitamin C, wasting less space in a supplement. Secondly, the ascorbic acid helps the absorption of the mineral. Thirdly, the alkalinity, created by attaching vitamin C to alkaline minerals (usually calcium, sodium, potassium or magnesium)
‘buffers’ the acidity of pure ascorbic acid. However, something to be aware of if you are taking high daily doses of ascorbates is how much of the mineral you’re getting. Sodium ascorbate, in high doses, is not good if you have hypertension.
My general preference is to have half ascorbates and half ascorbic acid which is likely to reduce the pH to 5.5, about that of the stomach and skin.
How much vitamin C can you absorb?
Some say you can’t absorb high doses. Others that you just make expensive urine. You can’t have it both ways. If you make expensive urine you’ve absorbed it. Of course you excrete it, but in its ‘spent’ oxidised form, otherwise you’d be full of vitamin C. Same thing with water. It is true, however, that the more vitamin C you take in the less percentage is absorbed. Roughly 80 to 90% of the first 180mg is absorbed, compared to 50% of a 2 gram dose, 26% of a 6 gram dose and 16% of a 12 gram dose. However, people who are fighting an infection or cancer may absorb more if their body needs it. In high doses vitamin C acts as a pro-oxidant in cancer cells but not harming healthy cells – the hallmarks of an ideal chemotherapeutic agent - as predicted by twice Nobel Prize winner Linus Pauling back in the 70’s. it is also profoundly anti-viral.
Is too much vitamin C dangerous?
Most people experience mild loose bowels with high intake. For many this is a benefit. This is probably due to increased water retention or osmotic pressure, hence the loose bowels. This is how magnesium sulphate (Epsom salts) works as a laxative. Other symptoms include flatulence and mild discomfort. People vary in how much vitamin C they can tolerate. Some report that the ascorbate form of vitamin C, which is mildly alkaline, reduces these adverse effects. Good studies are lacking to confirm this.
Vitamin C doesn’t causer kidney stones. This was proven several years ago by research at the Kidney Stone Research Laboratory of the University of Cape Town, concluding that large doses of Vitamin C does not increase the risk of forming kidney stones.