Effects of a calcium supplement on bone mineral density in male cyclists.

The purpose of this study was to maintain or improve bone density in male road cyclists through provision of calcium and vitamin D3 supplementation ingested before cycling.Participants were male cyclists (N=17), with a mean (±SD) age of 42.7 (9.4) years. Measurements of lumbar spine and hip areal bone mineral density (aBMD) were performed at the start and end of a cycling season. Cyclists were randomized into the calcium supplement (CAL) or the control group (CON) group based on lumbar spine T-scores. The CAL group was instructed to consume 1600 mg calcium and 1000 IU vitamin D3 prior to cycling for the 5-month period.Femoral trochanter aBMD significantly decreased during the 5 month cycling season. There was no difference in aBMD between CAL and CON groups.Negative effects of competitive cycling on aBMD in hip structures can be observed within 5 months. Calcium and vitamin D3 ingested prior to cycling does not ameliorate this effect. This proof of concept paper provides evidence that more work is needed to find mechanisms to protect cyclists from destructive bone loss in hip structures.