Food intake and dietary patterns that affect urinary sodium excretion in young women

We aimed to clarify food intake and dietary patterns that affect urinary sodium excretion (urinary salt excretion) among young women. We used 2012 to 2018 data from the health and nutrition testing on admission, which is a part of ongoing epidemiological studies, for students enrolling in the Faculty of Nutrition Science, Nakamura Gakuen University. Fasting urine samples were collected from the participants, and their estimated daily salt excretion was calculated using the Tanaka equation. The dietary assessment used was the semi-quantitative food frequency questionnaire, and we confirmed its validity. The participants included 2218 women aged 18 to 20 years who were classified into four groups according to urinary salt excretion (g/d) from their spot urine: Q(1), <5.56; Q(2), 5.56 <=, <6.79; Q(3), 6.79 <=, <8.12; and Q(4), 8.12<. The high urinary salt group had a significantly higher consumption of oil and fat, fish, meat, eggs, soybean, green and yellow vegetables, white vegetables, seaweeds, and pickled vegetables compared with the low urinary salt groups. When we compared the differences of the quartiles for urinary sodium excretion and the factor loadings for three dietary patterns by factor analysis with varimax rotation, the high urinary salt group showed a higher tendency for Japanese dietary patterns of factor 1 compared with the low urinary salt group. In conclusion, the various foods, including foods containing proteins and vegetables and Japanese dietary pattern centering on fish, vegetables, soybeans, and seaweed, affected the urinary sodium excretion in young women.