Frank Horwill



  • These articles were first published many year's ago and whilst some are as relevant today as they were when new, many are now mostly of historical interest as modern research and coaching methods have superseded them.

Does Vitamin C supplementation improve physical performance?

by Frank Horwill

The answer to the question is - Yes and No. A Swiss researcher asked twelve distance runners of equal quality to run at 10 mph/16km on a treadmill until they could not longer maintain the speed. For the seven days before this test, six were given a placebo and the rest were given a 1000 mg vitamin C capsule daily. All the vitamin C group were able to maintain the required speed longer than the non vitamin group. A blood analysis revealed that the vitamin C group had produced extra hormonal levels which basically had the following effects:

  • Reduced blood pressure
  • Made them feel good
  • Pushed back the pain barrier

Unfortunately this bit of research, which was published in a running magazine in 1991, failed to give the name of the researcher and the exact location of the trial, it must therefore be treated with suspicion. But the bit about hormonal levels being altered in the way described has been substantiated since that report. In fact, vitamin C is a pretty powerful agent for altering the status quo in our bodies.

For instance females on the low oestrogen contraceptive pill who take over 500mg of vitamin C daily for a month will notice that they will experience the same effects as if on the high dose pill, thus possibly enhancing the adverse effects. Also, long term-use of vitamin C at 1000mg daily will reduce the availability of certain trace minerals, such as copper and zinc, as well as the amino acids lysine and cysteine.

The first will result in anaemia, among other things, and the second will undermine the immune system. A lack of lysine usually results in recurrent cold sores and herpes infections, while the degradation of cysteine will lead to further bronchial congestion with those already afflicted with chest infection. And, finally, the excretion of oxalic acid, as well as uric acid, common causes of kidney stones, is increased in certain individuals consuming high doses of the vitamin. A personal or family history of kidney stones is a warning that high doses should be limited to not more than a month at a time.

The great debunker of vitamin C as an aid to physical performance was M.H. Williams in 1984, who in ten valid studies that he reviewed decided that Vitamin C was not an ergogenic aid. That said, going into competition with reduced blood pressure, feeling good and a greater resistance to pain as described earlier after taking 1000 mg daily for seven days, is not a bad thing!

What is beyond dispute is that inadequate amounts of vitamin C daily will affect performance in sports people. While the RDA in most countries is fixed at 60mg a day, which is easily met by consuming a medium-sized orange or three medium sized potatoes. Is that enough for a person who, after a day’s work, does some strenuous training for one to three hours on five days a week?

To answer that question we have to look at another essential food constituent – Iron. According to the Colgan Institute of Sports Nutrition, a serious sports woman requires 41mg of iron daily, and the sportsman needs 36mg. Both figures are more than treble the RDA figures. Now, for one part of iron to be properly absorbed five parts of Vitamin C are required. That puts the vitamin C requirement for a sportswoman at 205mg daily, and for the sportsman at 180mg, and that’s just to ensure that iron is fully accommodated by the body. Now those figures are interesting, because Ludwig Prokiop, former nutritional adviser to the old East German Olympic teams, advises an intake of 200-240mg daily for all serious sports people. The East Germans didn’t believe in half measures, their athletes appear in the Top Ten World all time Lists in athletics from 100 – 800 metres, men and women, and in all the field-events, and they all passed frequent drug tests!

So, what exactly does vitamin C do? Well, contrary to what is frequently written, some vitamin C is stored in small amounts in the body, a storehouse has been located in the adrenal medulla (which secretes noradrenaline and adrenaline, required for all physical activity) and in the eyes. It is water soluble, and easily destroyed by heat and exposure to light. It has a number of important roles, some of which are of major concern to the serious sports person. They are:

  • Maintenance of healthy connective tissue and bones. It has an affinity for the cartilage of the knee. A chronic knee injury sufferer reported to an athletics magazine that he had received all the orthodox medical treatments for his knee trouble over the course of two years without avail. He visited a naturopath (one who treats most conditions by diet manipulation) who advised him to take 10,000mg of vitamin daily. Equivalent to consuming 142 oranges for a week. He was cured. The taking of such an enormous amount was described by the magazine’s medical officer in reply, as "lunacy". However, the athlete was cured and the curative powers of vitamin C have been greatly under estimated. In this particular case it would have been better if the massive dose had been intravenously injected, and in any case it would have been necessary for such an amount to be taken orally at the rate of 1000mg per hour and stopped as soon as "the trots" became apparent.
  • Vitamin C is required for the normal metabolism of cholesterol and the production of cortisol by the adrenal gland. Professor Linus Pauling claimed that an intake of 3,000mg in one dose dislodged cholesterol from partially blocked arterial walls. Linus Pauling was awarded the 1954 Nobel prize for chemistry and the 1962 Nobel prize for peace.
  • It is biochemically active in the production of collagen (found both in skin and bones). Without this "cement" between the injured tissue, not only will the injury take longer to mend, but when seemingly repaired the injury site will rupture again. All sports injuries should be internally treated with 1000mg of vitamin C daily for the first week with a reduction of 250mg per day for subsequent weeks to a level of 500mg per day. Gradjean reported in 1954 that pigs (which have a similar tissue to man) which had induced muscle tissue damage from pincers, under an anaesthetic, healed three times faster on a high vitamin C diet, compared to pigs on a normal diet.
  • It is active in the metabolism of various brain chemicals and hormones as mentioned, which has powerful effects upon pulse rate and blood pressure. It is a powerful anti-oxidant and detoxifies the harmful effects of heavy metal poisoning and alcohol.
  • Vitamin C encourages the formation of lymphocytes (white blood cells) which fight infections. The author has had spectacular results with athletes who have had severe colds and who were given 1000 mg of vitamin C every hour for 10 hours, resulting in a major reduction in the unpleasant aspects of the infection on the following day.

One of the criticisms of using megadoses of the vitamin is that the most of it is passed out in the urine, commonly summed up as "an expensive way to pass urine". However it is the writer’s view that the body quickly detects when it is had enough of the vitamin when urgent visits to the WC are made! But in the cases of the aforementioned athletes with severe colds this did not occur because the vitamin was being extensively burned up in its fight against the infection.

The Colgan Institute of Sports medicine in California has also reported that various individuals have a vitamin C idiosyncrasy. This was discovered when they routinely measured excretion of vitamin C and its metabolities in athlete’s urine. They found that some sports people could take 5000mg of the vitamin and show only a little increase in excretion, in other works, their bodies needed it. On the other hand some showed a large increase in excretion of vitamin C after taking only 1000mg – their bodies didn’t need it. They found the biochemical individuality in use of vitamin C is at least 10 fold.

There is an old coaching axiom in sport – keeping an athlete free of injury and sickness is the main challenge. For this, vitamin C should be used wisely and therapeutically. It is known that the vitamin boosts recovery after tough workouts. 24 young physical education students (16 males and 8 females) were randomly divided into three groups. For 21 days, one group ingested 400mg of vitamin C per day, while a second group ingested 400mg of vitamin E and a third group consumed a placebo. Taking extra C raised subject’s blood levels of the vitamin by about 50 per cent ; adding extra E increased blood E concentrations by 18 per cent. Both C and E are classified as "anti-oxidants" which may protect muscle integrity during exercise. After the duration of supplementation all subjects completed a soreness-producing bout of exercise which consisted of stepping up and down from a box for 60 minutes with a frequency of 24 steps per minute. In each case the box height was adjusted to the level of the subject’s kneecaps.

For a week after their pain-producing exertion, the students continued their supplementation while the Birmingham University, England, scientists evaluated their leg muscle strength and fatigue. Intake of extra vitamin C produced two beneficial effects:

  • Post exercise recovery of muscle strength was much greater in the C Group. Twenty four hours after the gruelling box stepping. C group members recovered 85 per cent of their original muscle strength, while the E and placebo group subjects regained only 75 per cent.
  • Muscle fatigue was lower for C takers during the 24 hours after exercise. It was thought that vitamin C de-activates "free radicals", chemicals which can harm muscle membranes and internal structures after hard work outs. The vitamin may also stabilise an athlete’s intrinsic stores of vitamin E, further protecting muscle fibres against stress.

Sources of Vitamin C

The hoary question of natural versus synthetic vitamin C is one that requires taking in a lot of often overlooked facts. Prokop claims to have proved that vitamin C in the natural form (for example, in fruit juices) is clearly superior to synthetic ascorbic acid. Using standardised stresses his tests showed a decrease in oxygen debt and lowering of pulse and blood pressure.

The reason for this increased effectiveness of natural vitamin C in fruit juices was because of the presence of vitamin P which stabilised the vitamin C. Vitamin P-complex (rutin, cirtin, hesperidin), is used in relatively large amounts by the body and has a certain direct influence on performance because of its productive effect of vitamin C – as well as possible other water soluble vitamins. It is often referred to as one of the bioflavonoids and protects both vitamin C and adrenaline.

When assessing the vitamin C content of vegetables it is wise to remember that if they are placed in cold water in a saucepan and then brought to boil, about two thirds of the vitamin’s strength will be destroyed. If placed in boiling water from the outset and the water is later used for soup, about two-thirds of the strength will be maintained. The contents of the following vegetables is in milligrams:

  • Brussels sprouts 135 (1 cup)
  • Cabbage 48 (1 cup)
  • Potatoes 22 (1 medium sized boiled)
  • Lettuce 18 (4 inch diameter)
  • Carrot/Onions 9 (1 cup)
  • Broccoli 162 (1 stalk)

The vitamin C content of other foods is:

  • Blackcurrants 1 cup (270)
  • Tomatoes – 3 inch diameter (42)
  • Oranges – 3 inch diameter (60)
  • Apples (3)
  • Pears (7)
  • Bananas (12)
  • Grapefruit – 4 inch diameter (44)
  • Grapefruit juice – 1 cup (92)
  • Pineapple – cup diced (24)

It will be seen that a glass of one of the pure fruit juices before each meal and immediately after a work-out will account for around 500mg of vitamin C daily, while vitamin C from other sources may well bring the total to 600mg.

The Colgan Institute of Sports Nutrition state. "There are no natural vitamins". By that they mean many supplement makers use the word "natural" in their advertising and product labels. They assert that all vitamins on sale today are predominantly synthetic. That is, they are pure chemicals created out of a food base. Most vitamin C, for example, is made from corn. First, the corn is chemically concerted to sugar (d-glucose) and crystallised then it is chemically converted to pure, synthetic L-ascorbic acid. There is not an atom of the natural corn left.

Another ruse by manufacturers is because rose hips in their natural state contain huge amounts of vitamin C, it is put on the label. But look carefully. If it isn’t a come-on, it will state "with rose hips" or "with acerola vitamin C". The top rose hip powder contains only a few milligrams of vitamin C per ounce. A 1,000mg rose hip vitamin C tablet has to be 99 per cent synthetic ascorbic acid, because a 1,000mg pill made of pure rose hip vitamin C would be the size of a cricket ball. The same argument applies to the use of acerola powder.

The Colgan Institue of Sports Nutrition are pro-supplements of the right kind because of the "tampering" involved in its preparation from growth on non organic fields, sprayed with numerous chemicals and devoid of much of its true nutritional value.

It took 400 years to realise that scurvy in sailors was a vitamin C deficiency caused by lack of fruit on long sea voyages. We are entering the age of optimal nutrition in sport and those who advocated twenty-five years ago that a sports person just needed to eat the RDA for all foods for success have been shown to be lacking in foresight.