Folate content of Korean vegetable dishes prepared outside the home: Comparison between analyzed and calculated values

The study objectives were to measure folate content in commonly consumed Korean vegetable dishes prepared outside the home (VDOHs) and to compare the analyzed values with the values calculated using the recipes of a nutrient analysis program. A total of 56 VDOHs were collected from restaurants and catering companies between 2013 and 2016. Folate content was measured by microbiological assay after trienzyme extraction and calculated using the Computer-Aided Nutritional Analysis Program developed by the Korean Nutrition Society. Folate content ranged from 3.1 μg/serving (seasoned bracken, pickled cucumber) to 84.8 μg/serving (curled mallow soybean paste soup) by analysis and from 0.2 μg/serving (pickled cucumber) to 164.3 μg/serving (spinach soybean paste soup) by calculation. The calculated folate values per serving as well as per 100 g were significantly higher than the analyzed values, and the Bland-Altman plots showed poor agreement between the calculated and analyzed values. Our results indicate that folate intake from VDOHs or cooked vegetables could be overestimated by calculation. Therefore, a folate database should be constructed to reflect the weight changes and folate retention of food employing various cooking methods to accurately estimate folate intake in the South Korean population.