Development of a new instrument for evaluating individuals' dietary intakes

With the aim of developing a new dietary instrument for assessing an individual's usual intakes, we evaluated a hand-held personal digital assistant with camera and mobile telephone card, called Wellnavi (Matsushita Electric Works, Ltd, Osaka, Japan).

Twenty-eight college students majoring in food and nutrition in Okayama University of Japan voluntarily participated in this study.

Applying a cross-sectional study design, participants were asked to keep 1-day weighed food records. Digital images of all recorded foods were obtained simultaneously and sent to registered dietitians by a mobile telephone card. The following day, a 24-hour recall was obtained. These procedures were repeated after 6 months. Participants' opinions about the three methods were determined using a questionnaire.

Differences in estimated median nutrient intake among the three methods were compared by Wilcoxon matched-pairs signed rank test. Relationships among the nutrient estimates by each method were evaluated using Spearman rank correlation coefficients.

We found no significant differences between the Wellnavi method when compared with food records for most nutrients, except zinc, manganese, vitamin E, saturated fatty acid, polyunsaturated fatty acid, and dietary fiber. The median correlation coefficients for the nutrient estimates were 0.66 between the Wellnavi method and the food records. The survey showed that 57.1% of subjects considered the Wellnavi method the least burdensome of the three methods and the least time consuming (16 minutes) to record daily diet. About half of participants indicated that they would be willing to use the Wellnavi for 1 month to record their diet.

This study suggests that a hand-held digital assistant may be a valid and convenient instrument for evaluating dietary intake.