A Popular Science View of Osteocalcin in Aging
In recent years, researchers have shown that osteocalcin levels decline with age. Restoring osteocalcin in mice has been shown to reverse age-related loss of memory via increased BDNF. In fact, BDNF shows up as a common mechanism of action for many interventions shown to improve cognitive function, such as restoring a more youthful gut microbiome. Among other things, increased BDNF means increased neurogenesis, the process by which new neurons are generated and integrated into neural circuits. This is certainly essential to memory function, but also to maintenance and function of the brain more generally.
As we age, all of us inevitably lose bone. Research shows that humans reach peak bone mass in their 20s; from then onwards, it is a slow decline that can eventually lead to frailty and diseases such as osteoporosis in old age. Over the past decade, new findings have suggested that this reduction in bone mass may also be linked to the weakening of muscles - referred to in medical terms as sarcopenia - as well as the memory and cognitive problems that many of us experience as we grow older. This appears to be connected to the levels of osteocalcin in the blood, through its role as a master regulator, influencing many other hormonal processes in the body.
"Osteocalcin acts in muscle to increase the ability to produce ATP, the fuel that allows us to exercise. In the brain, it regulates the secretion of most neurotransmitters that are needed to have memory. The circulating levels of osteocalcin declines in humans around mid-life, which is roughly the time when these physiological functions, such as memory and the ability to exercise, begin to decline."
Researchers have conducted a series of experiments in which he has shown that by increasing the levels of osteocalcin in older mice through injections, you can actually reverse many of these age-related ailments. "Osteocalcin seems to be able to reverse manifestations of ageing in the brain and in muscle. What is remarkable is that if you give osteocalcin to old mice, you restore memory and you restore the ability to exercise to the levels seen in a young mouse. That makes it potentially extremely attractive from a medical point of view." Scientists have also found that for humans, one way of naturally maintaining the levels of this hormone in the blood, even as we age, is through exercise, something that makes intuitive sense, as physical activity has long been known to have anti-ageing properties.