Urinary excretion of thiobarbituric acid reactive substances of healthy subjects supplemented with a high dose of d-alpha-tocopherol.

The level of urinary thiobarbituric acid reactive substances (TBARS) consisting of bound forms of malonaldehyde and, to a lesser extent, other aldehydes is one of the indices of lipid peroxidation status. Levels of urinary TBARS in healthy subjects before and after supplementation with a high dose of d-alpha-tocopherol were measured using high performance liquid chromatography. Four healthy Japanese were given a supplement of 300 mg d-alpha-tocopherol/d, about 40-fold higher than the normal intake recommended, for a period of 50 d. Levels of urinary TBARS (nmol/kg body weight.h) within-day, before and after supplementation with d-alpha-tocopherol, exhibited similar behavior and levels of daily urinary TBARS (nmol/kg body weight.d) were unchanged by d-alpha-tocopherol supplementation. These results indicate that supplementation with a high dose of d-alpha-tocopherol does not affect the level of urinary TBARS.