Total antioxidant capacity of the Korean diet

Abstract

Background/objectives: The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet.

Materials/methods: Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC).

Results: Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 µmol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each.

Conclusions: The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables.

Keywords: Korean diet; dietary antioxidants; total dietary antioxidant capacity; total phenolics intake.

Fig. 1

Comparison of total phenol content and mean antioxidant capacity (mean of DPPH, ORAC and TEAC values) of plant foods based on the dry matter edible part in the Korean diet.

Fig. 2

Correlation of total phenolic content and antioxidant capacities obtained from DPPH, ORAC and TEAC assays.

Fig. 3

Correlation of antioxidant capacities obtained from TEAC assay and those obtained from ORAC or DPPH assay.

Fig. 4

Contribution of total antioxidant capacities (mean of DPPH, ORAC and TEAC) from all plant foods as a percentage of total dietary antioxidant capacities (TDAC) from per capita daily intake in the Korean diet. The TDAC values were obtained by multiplying the total antioxidant capacity of each food group and the intake of each food.