Study on the Associations of Dietary Variety and Nutrition Intake Level by the Number of Survey Days

Lee, Ji Eun; Ahn, Younjhin; Kimm, Kuchan; Park, Chan

Abstract

Due to the common dietary practice of preparing foods in various ways using the same food item, in addition to rather a large number of food items that average Koreans consume, it is difficult to accurately assess the nutritional adequacy. In an effort to identify a reliable means of assessing the nutritional adequacy of Korean adults, we analyzed the association between the scores of dietary diversity (DDS) and dietary variety (DVS), and the quality of nutrient intake as assessed by Nutrient Adequacy Ratio (NAR) and Mean Adequacy Ratio (MAR). A three day-dietary record was obtained from each of 324 inhabitants, aged 40 to 69 years (mean +/- SD, 52.4 +/- 8.7), of a rural area (Ansung) and a mid-sized city(Ansan) of Korea. These individuals were randomly selected among the participants of the Korean Health and Genome Study. The number of consumed foods and food groups were assesses by DDS (scored 1 to 5) and DVS (ranked 30 < or = , 31 - 40, 41 - 50, 51 - 60, and 60 <) over three-day period, respectively. As DDS/DVS increased, mean daily food intakes tended to increase, and NAR/MAR was improved. Thus, DDS and DVS were significantly correlated with the quality of nutrient intake. Over 95% of the subjects scored less than 2 in DDS for the first one-day period, whilst over 62% recorded 4 during the full three-day period (p < .0001). The mean number of consumed food items increased from 24.9 to 44.4 as a function of days of the record period (p < .0001). We also analyzed the association of DDS and DVS with MAR, using regression analysis, controlling age and sex as covariates. For DDS, the adjusted coefficient determination (adj R2) values were 8.7%, 15.8%, 23.3% of MAR, also increasing as a function of the record duration, whereas they were 27.3%, 33.3%, 37.6% for DVS, respectively, demonstrating that NAR/MAR has a better correlation with DVS than DDS. Our data show that DDS, and DVS in particular, are useful parameters for evaluating nutrient intake in the Korean population. Our data also support that one day-dietary records are by no means adequate for accurately describing a wide variety of food choices offered for average Koreans, and that dietary assessment at least for 3 days or longer should be obtained for a reliable evaluation of dietary quality using DDS or DVS.