Vitamin B 12 Status and Optimal Range for Hemoglobin Formation in Elite Athletes.

Background: Athletes and coaches believe in the ergogenic effect of vitamin B-12 (which results from enhanced erythropoiesis) and they often insist on its unjustified supplementation. Therefore, our study aimed to assess the vitamin B-12 status in Polish elite athletes and its influence on red blood cell parameters. Methods: In total, 1131 blood samples were collected during six years from 243 track and field athletes divided into strength and endurance groups, as well as according to the declared use of vitamin B-12 injections. Results: An average vitamin B-12 concentration in all subjects was 739 +/- 13 pg/mL, with no cases of deficiency. A weak but significant relationship was found between vitamin B-12 and hemoglobin concentrations. A significant increase in hemoglobin appeared from very low vitamin B-12 concentration and up to approx. 400 pg/mL, while hemoglobin did not significantly change from 700 pg/mL and onwards. Vitamin B-12 injections were used by 34% of athletes, significantly more often by endurance than by strength athletes. In athletes who declared no use of injections, a higher concentration of vitamin B-12 was observed in the endurance group. Conclusion: The main finding of the present study is the determination of the range of vitamin B-12 concentration which may favor better hemoglobin synthesis in athletes. They should regularly monitor vitamin B-12 concentration and maintain the range of 400-700 pg/mL as it may improve red blood cell parameters. We might suggest application of a supplementation if necessary. Special attention is required in athletes with a vitamin B-12 concentration below 400 pg/mL.