Evaluation of vitamin B6 intake and status of 20- to 64-year-old Koreans

BACKGROUND/OBJECTIVES: Recent research regarding vitamin B6 status including biochemical index is limited. Thus, this study estimated intakes and major food sources of vitamin B6; determined plasma pyridoxal 5'-phosphate (PLP); and assessed vitamin B6 status of Korean adults. MATERIALS/METHODS: Three consecutive 24-h diet recalls and fasting blood samples were collected from healthy 20- to 64-year-old adults (n = 254) living in the Seoul metropolitan area, cities of Kwangju and Gumi, Korea. Vitamin B6 intake and plasma PLP were analyzed by gender and by vitamin B6 supplementation. Pearson's correlation coefficient was used to determine associations of vitamin B6 intake and plasma PLP. RESULTS: The mean dietary and total (dietary plus supplemental) vitamin B6 intake was 1.94 +/- 0.64 and 2.41 +/- 1.45 mg/day, respectively. Median (50th percentile) dietary intake of men and women was 2.062 and 1.706 mg/day. Foods from plant sources provided 70.61% of dietary vitamin B6 intake. Only 6.3% of subjects consumed total vitamin B6 less than Estimated Average Requirements. Plasma PLP concentration of all subjects was 40.03 +/- 23.71 nmol/L. The concentration of users of vitamin B6 supplements was significantly higher than that of nonusers (P < 0.001). Approximately 16% of Korean adults had PLP levels < 20 nmol/L, indicating a biochemical deficiency of vitamin B6, while 19.7% had marginal vitamin B6 status. Plasma PLP concentration showed positive correlation with total vitamin B6 intake (r = 0.40984, P < 0.0001). CONCLUSIONS: In this study, vitamin B6 intake of Korean adults was generally adequate. However, one-third of subjects had vitamin B6 deficiency or marginal status. Therefore, in some adults in Korea, consumption of vitamin B6-rich food sources should be encouraged.

Assessment of vitamin B6 status in Korean patients with newly diagnosed type 2 diabetes

The purpose of this study was to assess vitamin B6 intake and status in Korean patients with newly diagnosed type 2 diabetes. Sixty-four patients with newly diagnosed type 2 diabetes and 8-11% glycated hemoglobin (A1C), along with 28 age-matched non-diabetic subjects, participated. Dietary vitamin B6 intake was estimated by the 24 hour recall method and plasma pyridoxal 5'-phosphate (PLP) was measured. There was a significant difference in daily total calorie intake between the diabetic and non-diabetic groups (1,917 +/- 376 vs 2,093 +/- 311 kcal). There were no differences in intake of total vitamin B6 (2.51 +/- 0.91 vs 2.53 +/- 0.81 mg/d) or vitamin B6/1,000 kcal (1.31 +/- 0.42 vs 1.20 +/- 0.32 mg) between the diabetic and non-diabetic groups, andI intakes of total vitamin B6 were above the Korean RDA in both groups (180.0 +/- 57.9 vs 179.0 +/- 65.4). There was a higher percentage of diabetic subjects whose plasma PLP concentration was < 30 nmol/L compared to non-diabetic group. Plasma PLP levels tended to be lower in the diabetic subjects than in the non-diabetic subjects, although the difference was not statistically significant due to a large standard deviation (80.0 +/- 61.2 nmol/L vs 68.2 +/- 38.5 nmol/L). Nevertheless, plasma PLP levels should be monitored in pre-diabetic patients with diabetic risk factors as well as in newly diagnosed diabetic patients for long-term management of diabetes, even though this factor is not a major risk factor that contributes to the development of degenerative complications in certain patients.