Association of Coffee or Green Tea with Ferritin or Hemoglobin in Premenopausal Women

Background: This study aimed to examine the association between coffee or green tea consumption and ferritin or hemoglobin levels in premenopausal women. Methods: We used the fifth Korea National Health and Nutrition Examination Survey (2010-2012), and a total of 4,322 individuals were surveyed. In women of reproductive age, average ferritin and hemoglobin levels were calcu-lated according to coffee or green tea consumption. Covariates included in the analysis were demographic vari-ables, such as age, body mass index, education, drinking, smoking, history of hypertension, history of diabetes di-agnosis, physical activity, total energy intake, and daily iron intake. Results: In 4,322 participants, the average hemoglobin level was 12.90 +/- 0.02 g/dL, and the average level of ferritin was 31.95 +/- 0.67 ng/mL. As a result of testing, correlation between ferritin and coffee intake and difference in ferritin levels according to coffee consumption was significant (P<0.05). In this study, a post hoc test indicated that ferritin level significantly differed between one and two cups, two and three cups, and three and one cup groups (overall P<0.001). Additionally, there was a negative correlation between ferritin level and coffee intake; ferritin level de-creased by 2.09 ng/mL with a one-cup increase in daily coffee consumption. Conclusion: In premenopausal women, coffee intake is associated with low serum ferritin levels. Our results indi-cate that drinking >2 cups of coffee significantly affect ferritin levels in Korean premenopausal women.