NUTRITION IN SPORT

Water-soluble vitamins and

functional capacity

Thiamin

chemistry and
biochemical functions

Thiamin or vitamin B 1 , the former being the

268 nutrition and exercise

accepted chemical name, consists of a pyrimi-

dine ring joined to a thiazole ring (Halsted 1993).

The principal, if not sole, cofactor form of

thiamin (vitamin B 1 ) is thiaminpyrophosphate

(TPP) (McCormick 1986). TPP is needed as a

cofactor in muscle metabolism and in the central

nervous system. Body stores are small, about

30 mg, almost half of which is stored in the

muscles (Johnson Gubler 1984).

Marginal Adequate Excess

Max.

Min.

Functional output

Minimal requirement

of maximal output

Vitamin supply

Fig. 20.1The association between vitamin

supply and functional output.

Toxic supply Functional

changes

Excess supply

Increase in tissue

levels, enzyme

activity, etc.

Adequate

supply

Normal

function

Marginal supply

Lowering of tissue

levels, metabolites

and enzyme activity

Subclinical

depletion

Functional

changes

Clinical

depletion

Severe

functional

changes

Fig. 20.2Dietary micronutrient intake and

stages of nutritional status. Adapted from

Solomons and Allen (1983), Piertzik (1986)

and Brubacher (1989).