High serum folate level is positively associated with pulmonary function in elderly Korean men, but not in women

A limited number of studies have been conducted on the relationship between serum vitamin levels and pulmonary function, particularly in the elderly population. This study attempted to confirm the association between serum vitamin levels (folate, vitamin A, and vitamin E) and pulmonary function in the elderly population of Korea. A total of 1166 subjects (528 men and 637 women) participated in the Korean National Health and Nutrition Examination Survey from 2016 to 2018. Serum levels of folate, vitamin A, and vitamin E were measured in the subjects. The subjects’ pulmonary function measurement items were as follows: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory volume in one second/forced vital capacity (FEV1/FVC), forced expiratory flow at 25% and 75% of the pulmonary volume (FEF25–75%), forced expiratory volume in 6 s (FEV6), and peak expiratory velocity (PEV). We performed regression analysis considering FEV1, PEV, FVC, FEF25–75%, and FEV1/FVC and FEV6 as dependent variables. Serum vitamin A levels were not associated with pulmonary function. In elderly men, serum vitamin E levels were negatively correlated with FVC [B =  − 0.012, 95% confidence interval (CI) − 0.022 to − 0.003, p = 0.012] and FEV1 (B =  − 0.010, 95% CI − 0.115 to − 0.007, p = 0.028). We confirmed a positive correlation of the serum folate level with FEV1 (B = 0.017, 95% CI 0.004–0.030, p = 0.009), FEV1/FVC (B = 0.003, 95% CI 0.001–0.005, p = 0.007), and FEF25–75% (B = 0.031, 95% CI 0.010–0.053, p = 0.005) in elderly men. This study confirmed that high serum folate levels were positively associated with pulmonary function in elderly men in Korea. Further studies are needed to understand the longitudinal effect of folate and its biological mechanism in pulmonary function.

Nutrient intakes from supplement and factors associated with supplement use among breast cancer survivors: A cross-sectional study

OBJECTIVE

We investigated the contribution of supplement use to total nutrient intake, the prevalence of inadequate nutrient intake and the factors associated with supplement use among breast cancer survivors.

METHODS

A total of 701 Korean breast cancer survivors were included. We calculated the contribution of dietary supplements to total nutrient intake and the proportion of the population below the estimated average requirements (EARs) or exceeding the tolerable upper intake levels (ULs). Stepwise logistic regression was used to identify factors associated with dietary supplement use.

RESULTS

A total of 66.5% of the survivors used dietary supplements, with multivitamins and minerals being the most commonly consumed ones. The per cent contribution of supplement to the total intake was the highest for vitamin C. 28.2%-55.4% of the non-users consumed below the EAR of riboflavin, folate and calcium; 6.1%, 4.9% and 6.5% of the supplement users consumed above the UL of vitamins A and C, and iron, respectively. Supplement users had higher education levels or longer survival time.

CONCLUSION

66.5% of Korean breast cancer survivors used dietary supplements. A higher education level or prolonged survival time was associated with higher use of dietary supplements.

High Serum Folate Concentration Is Associated with Better Lung Function in Male Chronic Obstructive Pulmonary Disease Patients Who Are Current Smokers: Analysis of Nationwide Population-Based Survey

Folate, folic acid, has a role in mitigating inflammatory reactions in the human body. This study aimed to evaluate the association of serum folate levels with lung function in chronic obstructive pulmonary disease (COPD) patients. Of the 8149 participants of the 2016 Korean National Health and Nutrition Examination Survey (KNHANES), 311 subjects (192 males and 119 females) having COPD defined by the lower fifth percentile of the reference population were selected. Pearson's correlation coefficient was used to investigate the relationship between serum folate level and lung function measurements. The association between the serum folate level and lung function in patients with COPD was evaluated using multivariable linear regression analysis after adjustment for age, sex, height, high sensitivity C-reactive protein, total calorie intake, residence, smoking status and smoking pack-years, education, and household income. The serum folate level showed a positive correlation with the predicted percentage of forced expiratory volume in one second (FEV₁%). In males, a trend for a positive correlation with serum folate level was observed in predicted FEV₁%, FEV₁ value, predicted percentage of forced vital capacity (FVC%), FVC value, and peak expiratory flow (PEF). No significant correlation between the serum folate level and lung function in females was observed. In the multivariable linear regression model, the serum folate level was associated with an increase in predicted FEV1%, FEV₁ value, predicted FVC%, FVC value, and PEF; however, the significance was only observed in males, especially among current smokers. High serum folate level was positively associated with lung function measurements in male COPD patients who were current smokers. Further longitudinal studies are needed to elucidate the underlying mechanisms.

Folate food source, usual intake, and folate status in Korean adults

BACKGROUND/OBJECTIVES

The purposes of the study were to investigate folate intakes and plasma folate concentrations as well as estimate folate status in Korean healthy adults.

SUBJECTS/METHODS

A total of 254 healthy 19- to 64-year-old adults (68 men and 186 women) living in Seoul metropolitan area, Gumi, and Kwangju, Korea participated. Three consecutive 24-hour dietary recalls, information on folate supplementation, and fasting blood samples were collected from the subjects.

RESULTS

The mean dietary folate intakes were 587.4 and 499.2 µg dietary folate equivalent (DFE)/day for men and women, respectively. The median dietary intakes of men and women were 566.6 and 474.6 µg DFE/day, respectively. Forty subjects (16.7% of total) less total folate than the estimated average requirement (EAR). Folate intakes of 23.3% of men and 34.8% of women aged 19-29 years did not meet the EAR for folate. Major food sources consumed for dietary folate were baechukimchi (Chinese cabbage kimchi), rice, spinach, eggs, and laver, which provided 44% of dietary folate intake for the subjects. Plasma folate concentrations were 23.4 nmol/L for men and 28.3 nmol/L for women, and this level was significantly lower in men than in women. Approximately 13% of men and 3% of women were folate-deficient, and the percentages of subjects showing folate concentrations lower than 10 nmol/L were 27.9% of men and 6.4% of women.

CONCLUSIONS

Folate intakes of Korean adults in this study were generally adequate. However, one-third of young adults had inadequate folate intakes.

Dietary supplement use among cancer survivors and the general population: a nation-wide cross-sectional study

BACKGROUND

Use of dietary supplements among cancer survivors is common and controversial, but information on the amount of nutrients from supplements among cancer survivors is limited. We examined the amount of nutrients and their contribution to total nutrient intake from supplements and compared these data between cancer survivors and cancer-free individuals. We also identified factors associated with supplement use among cancer survivors.

METHODS

We identified 400 cancer survivors and 10,387 cancer-free individuals, aged ≥ 19 years, from the fifth Korea National Health and Nutrition Examination Survey (KNHANES) V-1, 2 (2010, 2011). We calculated the amount of nutrients consumed from foods and supplements, the percent contributions of supplement nutrients to total nutrient intakes and cancer survivors' nutrient intakes relative to the Estimated Average Requirements (EARs) and the Tolerable Upper Intake Levels (ULs). We examined factors associated with supplement use among cancer survivors.

RESULTS

We found that 33.3% of cancer survivors and 22.1% of cancer-free individuals reported the use of dietary supplements. Compared to cancer-free individuals, cancer survivors had higher intakes of riboflavin, folate, and iron from foods (p < 0.05 for each), and higher intakes of calcium (p = 0.05) and vitamin C (p = 0.01) from foods and supplements. The similar pattern was observed for the percent contributions to total nutrient intake. Cancer survivors had higher proportion of participants below EARs than cancer-free individuals for thiamin and niacin (p < 0.05 for each). The proportions of cancer survivors below the EARs were 61.2% for calcium, 49.1% for riboflavin, and 43.5% for folate and the proportions of cancer survivors above the ULs were 3.3% for iron, and 2.3% for vitamin A. For female cancer survivors, education above an elementary school level, moderate physical activity, low vegetable intake, and high circulating vitamin D levels were associated with supplement use. For male cancer survivors, living in an urban area, no consumption of alcohol, and lower energy intake, were associated with supplement use.

CONCLUSIONS

Korean cancer survivors have higher rate of dietary supplement use and higher contribution from supplements to total nutrient intake than cancer-free individuals. Demographic and lifestyle factors were associated with supplement use among cancer survivors.