Facts About Antioxidants and Vitamins

Q. How much vitamin C should I take ?
Ans. I don't know. I don't think anyone knows, for sure. What I do know, however, is that although the present official recommended minimum daily allowance is probably enough to stop you from getting scurvy it isn't going to be much good for anything else. In certain circumstances it might not even prevent deficiency problems. The trouble is that the body's antioxidant needs are constantly changing. If your cells are especially under attack because of an infection or because you are on certain drugs or have inhaled a lot of car exhaust fumes or because you are a smoker, or even because you have accidentally taken some poisonous substance, then you will need a lot more than the basic amount whatever that is. The big trials under way should show what sort of dosage can cover most eventualities. I suspect that 1,000 mg a day should be considered a basic dose and that you should increase this temporarily to 2,000 mg or 3,000 mg if you think you are a special risk.

Q. What do you mean, 'at risk'?
Ans. if you get a slight sore throat or nay other indication of a cold, increase the daily dose. Similarly, if you feel unwell and suspect that you are 'sickening' for anything. Things like that. I suppose the time will come when we will up the intake for any early sign of indisposition or minor injury of any kind. Don't imagine, however, that an extra dose of vitamin C is any substitute for proper medical attention when this is obviously needed. Solid vitamin C tablets are also probably not a very good idea if you suffer from peptic ulcers or severe dyspepsia. In such cases, use a soluble preparation.

Q. What is the best preparation of vitamin C?
Ans. I recommend that you go for tablets which can be chewed or swallowed easily. Chewable tablets are also available in different flavors which camouflage the sour taste of vitamin C. it is almost impossible to eat plain ascorbic acid power.

Q. Some vitamin C tablets also contain flavonoids. Is this good?
Ans. Flavonoids are also antioxidant, but the presence of flavonoids might, theoretically, limit the safe dose of the vitamin C tablet. Unless you are taking very large doses, the presence of flavonoids shouldn’t matter.

Q. Is it true that some animals make their own Vitamin C?

A. Yes, In fact, only humans, other apes, primates, guinea pigs and some bats are unable to synthesize vitamin C. animals make it from glucose, but we lack the liver enzyme to carry out the last stage in the process. This suggests that earlier in evolution we were able to make the vitamin but that a mutation occurred in the common ancestor of the primates, may be around 25 million years ago, so that the gene for this enzyme was deleted.

Q. I understand the body stores vitamin C. Is this true?

Ans. Yes. Most people who are not taking supplementary vitamin C have a store of about 1,500 mg or more. If you take an additional daily dose, the store will reach about 2,500 mg and you will start to pass more vitamin C in the urine.

Q. Does a lot of vitamin C pass out in the urine ?

Ans. Yes. Vitamin C is rapidly lost from the body into the urine. In people saturated with vitamin C, the average half-life of the vitamin, after a 1 gram dose, is 3.37 hours. That means that after 3.37 hours after absorbing 1,000 mg, only an additional 500 mg will be left in the body. In 7 hours only about an additional 250 mg will be left and in 11 hours, only about an additional 125 mg will remain. Saturation means the presence in the body of a total of about 2.5 grams ( 2,500 mg) of vitamin C. Amounts above this level will be excreted as described. You don't need to take a lot of vitamin C to maintain saturation. Less than 250 mg per day will do it. The clinical evidence, however, implies that the best antioxidant effect requires levels above saturation.

Q. Doesn't this suggest that sustained release tablets of vitamin C are better? Is there any advantage in those?

Ans. Sustained release tablets may even out the levels above saturation, but we don't know whether this is beneficial. You will probably do just as well to take ordinary tablets twice or thrice a day.

Q. But don't these large fluctuations in body levels affect the efficiency of the antioxidant effect?

Ans. This is possible. But we don't really know. Many of the people in the successful trials are on once-a-day dosage. If you have reason to believe that free radicals are attacking, that is the time to take a supplementary dose so as to hit them hard.