Cheese positively affects serum osteocalcin levels, bone turnover markers and bone mineral density in cross-country skiers: a dose-response study

Background: Vitamin K2-rich Jarlsberg Cheese is demonstrated to increase Osteocalcin and bone turnover markers in fertile women. The impact on endurance-trained young cross-country skiers (XCS) with elevated bone turnover remains unclear. Purpose of study was to estimate the optimal daily efficacy dose of Jarlsberg cheese to increase serum Osteocalcin level in young female and male XCS and estimate the Jarlsberg effect on bone turnover markers (BTMs) and bone mineral density (BMD). Methods: In a parallel group study consisting of three design levels, 10 female and 10 male XCS were included, using Response Surface Pathway design. Blood samples were taken at each level for measurements of Osteocalcin, vitamin K2, BTMs and other biochemical parameters. Resting metabolic rate (RMR), BMD, VO2max and muscle strength were measured at start and at the end of the study. Results: The Osteocalcin development with increasing dose of Jarlsberg cheese was almost parallel in both sexes. These variables were reduced significantly from baseline during the first two design levels but increased above baseline by the end of the study. BTMs decreased significantly during the first and second level but increased during the third level. Total and L1-L4 BMD, s-phosphate, s-urea, RMR, muscle strength and Peak VO2 increased significantly while s-calcium and s-magnesium decreased. Conclusions: Estimated OED of Jarlsberg cheese was 73 and 84 g/day for females and male athletes, respectively. The development in OC, BTMs and BMD suggest an antiresorptive and perhaps anabolic effect of Jarlsberg Cheese on bone tissue. VO2 max, RMR and muscular strength development indicated an anabolic situation.