Use of published analyses of food items to determine dietary trans octadecenoic acid.

To estimate the dietary levels of trans octadecenoic acid (18:1t) in the diets of eight healthy white adolescent girls, diet records were obtained for a 7-day period. Published trans fatty acid values in foods were used to calculate the trans octadecenoic acid present in the diets. The usefulness of this method was tested by comparing the estimated values with values obtained by chemical analysis of diets collected by the duplicate portion technique from the same subjects over the same period of time. There was no significant difference in the values for the trans octadecenoic acid content of the 54 diets used in this study whether the values were calculated from the diet records or determined by chemical analysis. Dietary trans octadecenoic acid averaged 5.3% of total fatty acids by both methods. The mean trans octadecenoic acid in the daily diet was 2.8 gm as calculated from the diet records and 2.6 gm according to actual analysis. Those values were not significantly different. The present study demonstrated that the trans octadecenoic acid content of the diets of a group of adolescent girls can be estimated from diet records using previously published values for individual food items.