Altered vitamin B12 status in recreational endurance athletes.

This study aimed to compare the vitamin B(12)and folate status of recreational endurance athletes and inactive controls by modern biomarkers. In 72 athletes (38 +/- 7 y) and 46 inactive controls (38 +/- 9 y) serum levels of vitamin B(2), methylmalonic acid (MMA), holotranscobalamin II (holoTC), folate, and homocysteine (Hcy) were measured. Vitamin B(12)and folate levels of both groups were comparable, but athletes had higher median (25.-75. percentile) MMA [242 (196 to 324) versus 175 (141 to 266) nmol/L] and holoTC concentrations [67 (52 to 93) versus 55 (45 to 70) pmol/L] than controls. Hcy was slightly lower in athletes [9.2 (7.2 to 12.6) versus 10.8 (8.9 to 12.9) nmol/L]. In controls, we found the following correlations: vitamin B(12)and MMA (r = -0.38), vitamin B(12)and holoTC (r = 0.51), MMA and holoTC (r = -0.36). In athletes, MMA did not correlate with vitamin B(12)and holoTC. Our data suggests an altered vitamin B(12)metabolism in recreational athletes that needs further investigation.