Validation of three food frequency questionnaires and 24-hour recalls withserum carotenoid levels in a sample of African-American adults

The validity of self-reported fruit and vegetable intake in minority popula tions has not been adequately established. In this study, the authors exami ned the association of three food frequency questionnaires (FFQs) and 24-ho ur dietary recalls with serum carotenoid levels. Approximately 1,000 Africa n-American adults recruited from 15 churches in Atlanta, Georgia (1997-1998 ) completed three fruit and vegetable FFQs: a seven-item instrument assessi ng intake during the past month; a two-item measure assessing usual intake; and a 36-item measure adapted from the Health Habits and History Questionn aire. A total of 414 participants received a 24-hour recall by telephone, a nd 105 of them received two additional recalls. Serum levels of lycopene, l utein, cryptoxanthin, alpha -carotene, and beta -carotene were assessed in 813 participants and used as the validity criterion. The correlations of fr uit and vegetable servings with specific and total serum carotenoid levels were generally higher for the 36-item FFQ than for the two-item and seven-i tem instruments. The strongest correlation of fruit and vegetable servings with total carotenoid levels was observed for the three recalls (r = 0.42), with the 36-item FFQ and the single 24-hour recall yielding comparable cor relations (r = 0.35 and r = 0.37, respectively). The validity of the 36-ite m fruit and Vegetable FFQ was generally as strong as the validity of both 1 and 3 days of recalls. Given the lower cost and time needed for administra tion relative to recalls, it appears that the 36-item FFQ has merit for eva luating fruit and Vegetable health interventions.