Loss of citrate may result in thinning bones, osteoporosis

While bones need vitamin D and calcium to avoid becoming brittle or developing osteoporosis, scientists at the U.S. Department of Energy's Ames Laboratory have announced that the compound citrate may contribute to bone strength, too.

Research published in the journals Proceedings of the National Academy of Sciences and Chemistry of Materials announced that a specific balance between citrate and carbonated apatite, a mineral found in bones, may be what gives the skeleton its strength and resilience.

The last study to examine citrate's effect on skeletal health was published more than 35 years ago, the team said, adding that uncovering the substance's contribution to bone structure was an accident.

According to the accounts published in the studies, researchers at the Ames Lab were using nuclear magnetic resonance spectroscopy (NMRS) to determine the size of apatite crystals found in bone matrix.

The University of South Florida's College of Arts and Sciences states that apatite crystals give bones their hardness, while the collagen that surrounds them lends the skeleton a resilience to breaking.

However, researchers were largely unaware that citrate played a part in maintaining this structure. When their materials supplier used citrate to dissolve the collagen provided for the study, the group realized that this was the compound that their NMRS scans indicated was present on the surface of apatite crystals.

After analyzing bones from humans, cattle and fish, researchers concluded that the balance between citrate and apatite helps keep bones strong.

A decline in citrate levels could lead to brittleness and, ultimately, to osteoporosis, the study's authors concluded.

Until health authorities determine how citrate levels can be measured and monitored, it is up to individuals at risk for osteoporosis to maintain healthy levels of vitamin D and calcium.