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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:
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:
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:
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:
The vitamin C content of
other foods is:
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. Frank Horwill
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