The Body Vitamin B₁ Levels of Rats Fed a Diet Containing the Minimum Requirement of Vitamin B₁ Is Reduced by Exercise

抄録

It is thought that increasing energy expenditure increases consumption of vitamin B₁, leading to an increase in the requirement of vitamin B₁. However, evidence supporting this hypothesis is lacking. To examine the hypothesis, initially, we determined the minimum requirement of vitamin B₁ for weaning rats. We found that the minimum requirement of vitamin B₁ for optimum growth of weaning rats was around 0.786 mg thiamin/kg diet. Next, rats fed a diet containing the minimum requirement of vitamin B₁ were forced to swim until exhaustion. Concentrations of vitamin B₁ in the blood and liver as well as urinary excretion of swimming rats decreased significantly compared with those of non-swimming rats (p<0.05), while in rats fed the diet containing a sufficient amount of vitamin B₁ (4.720 mg thiamin/kg diet), vitamin B₁ amounts in the blood, liver and urine were not affected by swimming. We clearly and firstly showed the reduction of body vitamin B₁ following increases in energy expenditure.