had EGRAC values lower than 1.25 on a mean baseline riboflavin intake of 1.8 ± 0.1 (standard error) mg/day, and urinary excretion values in both groups were substantially above levels indicating possible risk of deficiency.

In elderly Guatemalans, normalization of EGRAC to less than 1.34 was achieved with approximately 1.3 mg/day of riboflavin (0.7 mg/ day from the diet plus 0.6 mg/day from a supplement), and a sharp increase in urinary riboflavin occurred at intakes above 1.0 to 1.1 mg/day. Requirements of the elderly did not differ from those of young adults (Boisvert et al., 1993).

Although there is a decrease in energy expenditure with aging and the EAR for older adults would be expected to decrease, the study by Boisvert and colleagues (1993) supports the use of the same EAR for the elderly as for younger adults.

The RDA for riboflavin is set by assuming a coefficient of variation (CV) of 10 percent (see Chapter 1) because information is not available on the standard deviation of the requirement for riboflavin; the RDA is defined as equal to the EAR plus twice the CV to cover the needs of 97 to 98 percent of the individuals in the group (therefore, for riboflavin the RDA is 120 percent of the EAR).

Few studies provide information about the riboflavin requirements of pregnant women. Bamji (1976) reported that infants born to women with high erythrocyte glutathione reductase (EGR) activity may also have a high EGRAC but to a lesser degree than their mothers. Bates and colleagues (1981) reported that a sample of 59 pregnant women in the United Kingdom had a mean riboflavin intake of 2.2 mg/day and a mean EGRAC of 1.19 ± 0.08 (standard deviation). Maternal riboflavin intake (estimated from a crosscheck