This study was to assess the effect of a fixed dietary intake on biomarkers of red blood cell (RBC) biosynthesis and degradation. Over a two-year period, eight collegiate rhythmic gymnasts participated in this study. During the first year, they ate self-selected diets. During the second year, a fixed dietary intake involving consumption of common Japanese foods containing 15 mg iron and 1500 kcal energy was maintained for 4 wk at the beginning of the program. Fixed dietary intakes resulted in significantly increased intakes of protein, minerals and vitamins, and significantly decreased fat intake, but total energy and carbohydrate intakes were unchanged. Mean values of RBC, Hb, Ht, or TIBC were not affected by the intervention. A fixed dietary intervention appeared to enhance RBC turnover by increasing the capacity for erythrocyte biosynthesis and degradation, although the prevalence of iron-deficiency anemia remained unchanged.
Sakuko Ishizaki and Jun Yamakawa are with Japan Women’s College of Physical Education, Tokyo 157-8565, Japan. Takako Koshimizu is with Japan Institute of Sports Sciences, Nishigaoka, Tokyo 115-0056, Japan. Kae Yanagisawa is with the Department of Human Nutrition, Faculty of Humanities, Seitoku University, Matsudo-city, Tiba Prefecture 271-8555, Japan. Yoshiko Akiyama, Yuko Mekada, Nobuhiro Shiozawa, and Yukari Kawano are with the Department of Nutritional Science, Tokyo University of Agriculture, Tokyo 156-8502, Japan. Noriko Takahashi is with the Department of Health Care Science, Showagakuin Junior College, Ichikawa-city, Chiba 272-0823, Japan.