Thiamin requirement of the adult human

Although recommended thiamin allowances are related to calorie intake, the relationship is not adequately known. In a 6 period study ranging from 11 to 21 days per period, 2 groups of 3 and 4 young men were fed diets of 2800 or 3600 calories, the higher level attained with increased carbohydrates, with varying intakes of thiamin. Thiamin intake per day with both calorie intakes was 0.38 mg, 0.56 mg in periods 2 to 4, 0.84 mg for the 2800 calorie diet and 1.08 mg for the 3600 calorie diet in period 5, and more than 2 mg for both groups in period 5. Urinary excretion measured by microbiological assay and creatinine levels and erythrocyte transketolase measurements all showed a relationship between increased carbohydrate calorie intake and utilization and an increased need for thiamin. To reach the apparent minimum requirement of 0.30 mg per 1000 kcal, the higher calorie group had to consume 1.08 mg of thiamin per day as compared with 0.84 mg for the lower calorie group.