Background: Thiamin deficiency in infancy is the underlying cause of beriberi, which can be fatal without rapid treatment. Reports of thiamin deficiency are common in Cambodia; however, population representative data are unavailable. Because B-complex vitamin deficiencies commonly occur in combination, riboflavin was also investigated.

Objective: We determined the biomarker status of thiamin and riboflavin in women of childbearing age in rural and urban Cambodia.

Methods: We measured thiamin (erythrocyte thiamin diphosphate; TDP) and riboflavin (erythrocyte glutathione reductase activity coefficient; EGRac) status in a representative sample of Cambodian women (aged 20–45 y) in urban Phnom Penh (n = 146) and rural Prey Veng (n = 156), Cambodia, and, for comparison purposes, in a convenience sample of women in urban Vancouver, British Columbia, Canada (n = 49).

Results: Thiamin insufficiency (TDP = 90 nmol/L) was common among both urban (39%) and rural (59%) Cambodian women (P < 0.001), whereas <20% of Vancouver women were thiamin insufficient (P < 0.001). The prevalence of suboptimal and deficient riboflavin status (EGRac = 1.3) was 89%, 92%, and 70% among women in Phnom Penh, Prey Veng, and Vancouver, respectively (P < 0.001).

Conclusions: Suboptimal status of both thiamin and riboflavin were common in Cambodian women, with substantially higher rates among women living in rural Prey Veng than in urban Phnom Penh. Strategies may be needed to improve the thiamin and riboflavin status of women in Cambodia. The unexpected finding of high riboflavin inadequacy status in Vancouver women warrants further investigation.