RESUMO
Six groups of elderly subjects from central Guatemala were assessed for riboflavin status by using the erythrocyte glutathione reductase activity coefficient (EGRAC). The prevalence of riboflavin deficiency ranged from 50% to 76% among the free-living rural elderly subjects. Milk intake data that were collected from some of the subjects showed a significant correlation (P < 0.0001) between frequency of milk intake and riboflavin status. In a short-term riboflavin supplementation experiment in which nine riboflavin-deficient subjects were given 10 mg riboflavin/d for 3 d, all the subjects' EGRACs were normalized by the supplementation. However, they returned to a state of deficiency within 2 wk while consuming their usual diets without supplementation. It appears that the high prevalence of riboflavin deficiency in elderly Guatemalan people is caused by inadequate intake of riboflavin-rich foods such as dairy products, and that sufficient amounts of riboflavin need to be ingested regularly to maintain satisfactory riboflavin status.
Assuntos
Dieta , Leite , Deficiência de Riboflavina/epidemiologia , Idoso , Animais , Eritrócitos/enzimologia , Feminino , Glutationa Redutase/metabolismo , Guatemala/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Riboflavina/administração & dosagemRESUMO
The riboflavin requirements of two groups of riboflavin-deficient, but otherwise healthy, Guatemalan elderly persons over the age of 60 y were studied by varying the fat:carbohydrate ratio in two diets. The first group consumed a diet similar in macronutrient content to a Western-type diet with low carbohydrate and high fat; the second group consumed a typical Guatemalan diet with high carbohydrate and low fat. Energy and protein intakes of both groups were similar. Riboflavin status was monitored by weekly measurements of erythrocyte glutathione reductase activity coefficient (EGRAC) and urinary riboflavin excretion. Increasing increments of riboflavin were added to the subjects' diets until their status was normalized, as indicated by EGRAC of < 1.34 and a sharp increase in urinary riboflavin excretion. Using the EGRAC method, the mean value of riboflavin intake at which the subjects' EGRAC reached the limit of normality was 1.37 +/- 0.03 mg/d in the first phase and 1.29 +/- 0.03 mg/d in the second phase. The sharp increase in urinary excretion occurred at riboflavin intakes of 1.13 and 1.03 mg/d for Groups 1 and 2, respectively. Thus, the differences between the two groups suggest that diets with a lower fat:carbohydrate ratio can decrease the dietary need for riboflavin. The dietary requirement of riboflavin, as estimated by the more reliable urinary excretion method, was 1.1-1.3 mg/d for those consuming the Western-type diet, which is similar to values found over 40 y ago in young adults. We conclude that the dietary requirements of riboflavin in the elderly do not differ from those of young adults.