processes. It is an essential component in the for-
mation and function of red blood cells. Because
of this role, it is sometimes thought by athletes
and their coaches that vitamin B 12 supplement
should enhance the oxygen-carrying capacity of
the blood and improve performance in those
events where oxidative metabolism is important.
In practice, however, vitamin B 12 supplementa-
tion will only help in cases of pernicious anaemia
or macrocytic anaemia, and will not show bene-
fits for the athlete with iron deficiency anaemia
or for athletes whose iron stores are replete. In
spite of this, vitamin B 12 injection is a common
practice in sport, and it has been noted that some
athletes have been receiving 1000 mg about 1 h
before competition (Ryan 1977). The RDA for
vitamin B 12 for the general adult population is
2 mg · day–1, and the average diet contains about
5–15mg · day–1, so deficiency is rare. As for the
general population, deficiency in athletes is rare,
except for those who are complete vegetarians.
This group may be susceptible to vitamin B 12
deficiency as the vitamin is found only in animal
protein including meat, poultry, fish, egg, milk
and milk products, and some fermented soybean
products (see Chapter 20). Most vegetarians,
however, are well aware of the need to ensure an
adequate intake.
Pantothenic acid
Pantothenic acid is a part of CoA, thus mak-
ing it important in metabolism involving the
Krebs cycle. The RDA for pantothenic acid is 4–
7 mg · day–1(Williams 1985). Inadequate intakes
of pantothenic acid are rare for the individual
who has a normal diet, because it is widely dis-
tributed in foods including animal and plant
foods such as eggs, yeast, whole grains, etc. It is
not known if exercise increases the requirement
for pantothenic acid. Results of studies on the
effect of pantothenic acid supplementation on
performance are equivocal (Nice et al. 1984; Litoff
et al. 1985; Clarkson 1991). Nice et al. reported
that supplementation with 1 g pantothenic acid ·
day–1(10 000% RDA) for 2 weeks had no effect on
a treadmill run to exhaustion, pulse rate, blood
286 nutrition and exercise
glucose levels, or several other blood measures
in highly trained distance runners; it was con-
cluded that pantothenic acid in pharmacological
dosages has no significant effect on human exer-
cise capacity (Nice et al. 1984).Folic acid (folate)
Folic acid acts as an coenzyme functioning in
DNA synthesis for red blood cell formation, and
is also important for nucleotide and amino acid
metabolism. A deficiency state may cause
anaemia, and at least in theory, a deficiency may
affect aerobic endurance performance. The RDA
has been set at 400mg · day–1for non-trained adult
males (US National Research Council 1989). The
RDA set by the FAO/WHO is 200mg · day–1. No
study is known to have been performed on the
effects of folic acid supplements on physical per-
formance. Since folate is present in large
amounts in vegetables, fruits, and animal foods,
a balanced diet would appear to provide ade-
quate amounts of this vitamin (see Chapter 20).Vitamin B complex
Because of the close association of the vitamins in
the B complex, the effects of deprivation of or
supplementation with various combinations of
the B vitamins have been studied. Results of
some of the early studies showed that a defi-
ciency of the B complex vitamins over a period of
time, a few weeks at the most, could create a defi-
nite decrease in endurance capacity (Berryman
et al. 1947). It is extremely unlikely that athletes
on a well-balanced diet will encounter this level
of deficiency. However, the effects of vitamin B
complex supplements remain contradictory and
further study is needed to determine the useful-
ness of vitamin B complex supplemention for
athletes (Read & McGuffin 1983; Clarkson 1991).Ascorbic acid (vitamin C)
Vitamin C functions in the biosynthesis of colla-
gen, catecholamines, serotonin and carnitine. It is
also a powerful antioxidant which may aid intra-