Because vitamin B1 (thiamin) facilitates energy utilization, requirements are tied to energy intake, which can be very much dependent on activity levels. The recommendations are based on an average caloric intake.

 

In 1993, the European Scientific Committee for Food set population reference intakes (PRI) for vitamin B1 (thiamin) in milligrams (mg) per day (14):

 

Age	Males: mg/day	Females: mg/day
6–12 months	0.3	0.3
1–3 years	0.5	0.5
4–6 years	0.7	0.7
7–10 years	0.8	0.8
11–14 years	1.0	0.9
15–17 years	1.2	0.9
18 years and older	1.1	0.9
Pregnant	-	1.0
Breast-feeding	-	1.1

In 1998, the U.S. Food and Nutrition Board set a recommended dietary allowance (RDA) for vitamin B1 (thiamin), based on the prevention of deficiency in generally healthy individuals (15):

 

Life Stage	Age	Males: mg/day	Females: mg/day
Infants	0–6 months	0.2 (AI)	0.2 (AI)
Infants	7–12 months	0.3 (AI)	0.3 (AI)
Children	1–3 years	0.5	0.5
Children	4–8 years	0.6	0.6
Children	9–13 years	0.9	0.9
Adolescents	14–18 years	1.2	1.0
Adults	19 years and older*	1.2	1.1
Pregnancy	all ages	-	1.4
Breastfeeding	all ages	-	1.4

 

* For adults, the RDA is 0.5 mg per 1,000 kcal, which amounts to a range of 1.0–1.1 mg per day for women and 1.2–1.5 mg for men, based on an average caloric intake.

As some studies have found inadequate dietary intake and thiamin insufficiency to be more common in elderly populations (16), at least 1.5 mg/day thiamin can be recommended for older adults.

 

For a detailed overview of recommended daily intakes (PRIs/RDAs) of vitamins and minerals for adults derived from different countries and organizations see PDF.