According to a new study, consuming more than the recommended intake of vitamin D can actually reduce bone density – meaning that consuming more than 600 IU (international units) of vitamin D daily is not recommended.
It is known that vitamin D is essential for building strong healthy bones, but only to a certain amount.
In the new study, 303 people between the ages of 55 and 70 consumed 400, 4000, or 10,000 IU of vitamin D supplementation once daily for 3 years. At 6, 12, 24 and 36 months, the strength and density of bones in their joints were measured, as well as vitamin D and calcium levels.
During those three years, bone mineral density (BMD) decreased by 1.4% in the group consuming 400 IU daily, 2.6% in those consuming 4000 IU daily and 3.6% in those with 10,000 IU daily. It should be noted that a decrease in BMD also occurs during aging.
The reason for this is probably due to the fact that high doses of vitamin D are associated with an increase in the blood marker for bone fragility and suppression of parathyroid hormone (PHT).
PHT keeps blood calcium at a normal level and stimulates normal bone maintenance – removing the old bone and stimulating new bone formation. The combination of increased bone fragility and less PHT stimulation results in bone loss.