Dietary diversity within food groups: an indicator of specific nutrient adequacy in Tehranian women.

OBJECTIVE: To determine the relationship between dietary diversity within food groups and dietary diversity score and the probability of nutrient adequacy in Tehranian women.

DESIGN: Cross-sectional study assessing food intake by two 24-hour recalls questionnaires on two different occasions. Dietary diversity was defined according to diet quality index revised. The mean probability of adequacy across 14 nutrients was calculated using the Dietary Reference Intakes.

SETTING: District 13 of Tehran, Iran.

SUBJECTS: 286 females aged 18-80 years.

RESULTS: Whole grain diversity score mostly correlated with protein and vitamin B2 (r = 0.35, p < 0.05). Fruit diversity score was correlated with vitamin C (r = 0.44, p < 0.05). Dairy diversity score was correlated with calcium intake (r = 0.54, p < 0.05). Meat diversity score was correlated with protein intake (r = 0.34, p < 0.05). Most subjects failed to meet vitamin B6, zinc, magnesium, calcium, copper, and vitamin B12 adequacy. Energy intake was a strong predictor of the mean probability of adequacy in models controlled for age, BMI, education level and job status (model R2 = 0.53). Adding the number of servings from each of the food group to the models significantly improved the model fit (model R(2) = 0.59). Adding the dietary diversity score improved the model fit significantly (model R2 = 0.64). Dairy diversity score had the strongest association with improved nutrient adequacy.

CONCLUSION: Dietary diversity score is a useful indicator of specific nutrient adequacy in Tehranian women. However, to determine the adequacy of a specific nutrient, the diversity scores of specific food groups might be taken into account.