Videotape dietary assessment: validity, reliability, and comparison of results with 24-hour dietary recalls from elderly women in a retirement home.

The validity and reliability of a videotape method for quantifying food intake were tested, and results of the method were compared with results obtained from 24-hour dietary recalls. Participants were 37 elderly Catholic nuns (aged 81.8 +/- 4.1 years) who were ambulatory and living in a retirement home. The videotape method of dietary assessment consisted of videotaping food trays of each participant for three meals during 1 day and the subsequent identification of food types and amounts from the videotapes. Estimates of food amounts obtained were used in the calculation of energy and nutrient intake. Correlation coefficients between values for energy and 14 nutrients obtained by direct measurement of food and estimates from the videotape method were high (r = 0.86 to 1.0). Compared with measured food amounts, the videotape method underestimated food quantities by an average of 6%. The reliability test indicated that mean nutrient values obtained from the videotape method by two research assistants differed by an average of 3.7% and were highly correlated (r = 0.84 to 0.98). Comparison of the videotape method with 24-hour dietary recalls revealed differences between mean values that were greater than 10% for energy and 6 of the 14 nutrients and correlations that ranged from 0.09 to 0.82. These results suggest that use of 24-hour dietary recalls among the elderly may result in a high percentage of error.