0.48 mg · 4.2 MJ–1(1000 kcal–1), and 25% of them
have been found to be in a state of vitamin B 1
insufficiency as assessed by TPP method (blood
transketolase coefficient) (Chen et al. 1989). In
addition, systematic nutritional investigation
showed that there has been a trend towards a
decrease in vitamin B 1 intake because the con-
sumption of cereal, especially whole grains, has
decreased and the intake of animal foods has
increased. The RDA of vitamin B 1 for Chinese
athletes has been set at 3–6 mg · day–1, which is
about 1 mg · 4.2 MJ–1 (1000 kcal–1) (Table 21.1)
(Chen et al. 1989, 1992). The US National
Research Council reported that the increased
need of vitamin B 1 for athletes should be met by
the larger quantities of food consumed. There
has been no evidence for vitamin B 1 toxicity
through oral ingestion. Good food sources of
thiamin are identified in Chapter 20.
Riboflavin (vitamin B 2 )
Riboflavin functions as a coenzyme for a group
of flavoproteins concerned with cellular oxida-
tion: flavin adenine dinucleotide and flavin
mononucleotide are the most common, and these
act as hydrogen carriers in the mitochondrial
electron transport system, being a component of
oxidative enzymes, and are thus considered
important for aerobic endurance activities. These
coenzymes may also be important for the effi-
cient functioning of glycolytic enzymes, and may
have an effect on anaerobic type performance as
well. The RDA of vitamin B 2 for adults is 1.5–
1.7 mg · day–1for males and 1.2–1.3 mg · day–1for
females (US National Research Council 1989;
284 nutrition and exercise
Chinese Nutrition Society 1990). Since riboflavin
is a component of several respiratory enzymes,
the requirement is usually linked to energy
intake, and the level of riboflavin intake re-
commended by the WHO is 0.5 mg · 4.2 MJ–1
(1000 kcal–1). The RDA of vitamin B 2 for Chinese
athletes has been set at 2.5 mg · day–1(Chenet al.
1992). Exercise training may increase the need of
vitamin B 2. Using a RBC enzyme as an indicator
of riboflavin status, it was noted that at an intake
of 0.6 mg · 4.2 MJ–1(1000 kcal–1), young women
who started a jogging programme developed a
riboflavin deficiency (Belko et al. 1983), although
riboflavin supplements have not been shown to
have an effect on physical performance or
aerobic capacity (Belko 1987). Most athletes have
an adequate or greater than adequate intake of
vitamin B 2 (Guillandet al. 1989; Burke & Read
1993), although biochemical insufficiencies were
found for some athletes. The incidence of
vitamin B 2 insufficiency has been reported
to be relatively lower than that for thiamin
(Haralambie 1976; Chen et al. 1989, 1992). Over-
dose problems have not been reported, and there
is no evidence of toxicity. The possibility of
riboflavin deficiency should be a concern for the
vegetarian athlete if all dairy foods and other
animal protein sources are omitted. Good
sources include wheat germ, yeast, green leafy
vegetables, and enriched cereals (see Chapter
20).Niacin (nicotinamide, nicotinic acid)
Niacin is a component of two important co-
factors: nicotinamide adenine dinucleotide andTable 21.1Vitamin RDA for Chinese athletes. From Chen et al. (1992).
Vitamin A Vitamin B 1 Vitamin B 2 Niacin Vitamin C
Condition (RE)* (mg) (mg) (mg) (mg)
Training 1500 3–6 2.5 25 140
Special condition† 2400 5–10 2.5 25 200
- RE, retinol equivalent.
†Special condition refers to intensive vision for vitamin A, endurance training for vitamin B 1 , competition period
for vitamin C.