These Old Bones Aren’t as Old as You Think!

            Dolly Parton sings “These old bones will tell your story, these old bones will never lie”. But your bones only tell part of your story because every 10 years, you have a completely new skeleton. This is a little known “factoid” that I love relaying to my patients in the UAB Osteoporosis Prevention and Treatment Clinic because it’s really kind of cool.

                We think of our bones as being with us throughout our lives but your bones are in a constant state of flux. Cells called “osteoclasts” break down old bone and make way for cells called “osteoblasts” to come along and build new bone in its place. The rate of this “bone remodeling” ends up replacing much of our adult bones from the previous ten years! So if you’re 45, your skeleton is not really made up of any of the same bone you had at 35.

                This bone remodeling also paves the way for bone loss and possibly osteoporosis later in life because as we get older the osteoclasts speed up and the osteoblasts slow down. In other words, we are losing more bone than we can replace. For women, this is a particular problem as our estrogen levels drop with menopause. Estrogen slows down the osteoclasts (the cells that break down old bone) so when we lose estrogen we lose bone much more quickly. Getting older also speeds up bone loss in both men and women.

For more information about osteoporosis visit our virtual clinic at www.uab.edu/toneyourbones

Beth Kitchin, PhD, RDN
Assistant Professor, Nutrition Sciences
Patient Educator, UAB Osteoporosis Prevention & Treatment Center
University of Alabama at Birmingham