We tend to think of our skeletal system as a structure that just holds up all the important parts
like muscles, skin and internal organs. Because it is out of sight it tends to be out of mind. But
our skeletal structure is just as alive as the other tissues in our body and contains nerves and
blood vessels, minerals and proteins.
The strong outer layer of bone, called cortical bone, surrounds a spongelike inner layer of trabecular bone. The cortical bone makes up about 80% of the bone mass in an adult and provides skeletal support, protects organs and is active in storing and releasing calcium and phosphorus, helping the body to maintain a healthy pH balance. Trabecular bone comprises the remaining 20% and contains bone marrow which produces our red blood cells.
Bone even acts like an endocrine organ, secreting several hormones control controlling various physiological pathways. Osteocalcin, secreted by osteoblasts, has a minor effect on bone density. Instead, it is involved with glucose balance, exercise capacity and muscle development, brain development, male fertility and more.
Like other tissues in our bodies, bone is always remodeling. About 20% of bone is replaced annually by the remodeling process. Five stages make up the bone remodeling process and the entire process can take anywhere from 4 to 8 months. The stages of remodeling consist of activation, resorption, reversal, formation and quiescence.
-In activation, pre-osteoclasts are attracted to the site of old and brittle bone. The pre-osteoclasts adhere to the bone and form osteoclasts.
-In resorption, osteoclasts dig out a pit in spongy bone called a resorption pit or burrow a tunnel in compact bone. The calcium mobilized in this process is released for various physiological functions. At the end of the resorption phase, the osteoclasts disappear.
-In the reversal phase, mesenchymal stem cells which are precursors to osteoblasts appear along the burrow or pit where they multiply and transform into pre-osteoblasts.
-In the formation stage, the pre-osteoblasts mature into osteoblasts along the borough or pit and release osteoid at the site which forms a soft new non-mineralized matrix.This new matrix is then mineralized by calcium and phosphorus.
-In quiescence, the new bone tissue remains quiet until the next cycle of remodeling.
For most people, bone development reaches a peak in the late teen years and begins decreasing after age 35. It’s important that we maximize are bone density in early years. In middle age many of us will lose bone faster than we build bone. It becomes much more difficult to build bone as we grow older. But even those of us who weren’t able to optimize bone density in our early years can still ensure good bone health for life.
Diane Schneider, MD, author of the book ‘The Complete Book of Bone Health’ states bone health is like a 401(k) from which we must take mandatory withdrawals in adulthood. The key is to limit those withdrawals – and maybe even do a little building! With bone-healthy lifestyle and nutrition, we can help ensure our bone density retirement account stays robust.
It is important to identify and address health concerns that may impact bone density. Conditions such as type 1 diabetes, thyroid disorders, liver disease and eating disorders along with certain medications can impact bone health and should not be ignored.
Nutrition plays a critical role in bone health. Remember the role of osteoclasts in breaking down bone and releasing that calcium? If our system is too acidic, osteoclasts become more active in an effort to maintain a proper pH balance. Eating a diet full of processed foods, sugar, dairy, alcohol and meats tends to push our pH into the acidic range. The bones will release calcium to buffer the acid, increasing bone thinning over time. By decreasing acid producing foods, we can prevent bone loss due to pH imbalance. Strips can be purchased to measure urine pH and track progress over time.
Dairy has long been promoted as a good source of calcium, but it is a double edged sword. Dairy does contain calcium, but tends to promote acidity. And as mentioned, acidity is the enemy of bone density. Full fat yogurt is less acid producing than milk and cheese due to the fermentation process. Goat milk products tend to be less acidifying than cow’s milk.
Perhaps a more sound approach is to maximize intake of foods that have an alkalinizing effect, some of which also contain calcium. Examples are leafy greens, broccoli, kale, lemons and limes, kelp and parsley. These foods also provide polyphenols and other nutrients that help quench bone damaging inflammation and free radicals. Of course, your nutrition is only as good as what your body is able to digest and absorb, so assuring good gut health is an important piece of the puzzle.
Most folks are now aware that an adequate vitamin D level is essential for absorbing calcium from our foods and supplements. Just as important is where that calcium goes once we absorb it. Vitamin K2 takes the calcium and deposits it in our bones and teeth, keeping the calcium away from the lining of the arteries and the kidneys. In nature, we get vitamin D from exposure to ultraviolet rays. The process from the sun’s rays hitting the skin to the active form of vitamin D is a complex process with multiple organs and enzymes involved. Some people can easily move to the active form of vitamin D but for many this is difficult. Because of this, each person is unique in their need for supplementation. Testing, dosing and retesting can help customize the vitamin D dose for each individual.
The B vitamins play a role in bone health. Deficiencies of vitamins B2, B12 and folate increase resorptive activity of osteoclasts. Some genotypes such as MTHFR C677TT have exceptional needs for certain B vitamins. Again, micronutrient testing can help reveal gaps in these nutrient defenses.
Antioxidants such as vitamin C, vitamin E, vitamin A and others help control free radical activity and resulting inflammation, protecting bone health. As with the other nutrients discussed, we can measure the body’s stores of these nutrients to assure adequate protection.
Adequate protein is also essential for bone health. Protein makes up 20-30% of bone mass and can influence growth hormone and other growth factors, indirectly affecting bone health.
Hormones either build up bone and muscles or break them down. Estrogen and testosterone tend to build bone and muscle, where cortisol breaks down. This is why both with menopause and andropause women and men tend to experience bone loss with age. Pair this with a high stress level, causing higher cortisol, and you have a recipe for bone thinning. Where appropriate, bioidentical hormone therapy can help moderate this process, along with addressing the stress response to decrease cortisol.
Hypothyroidism and hyperthyroidism both can contribute to accelerating bone loss. Hyperthyroidism poses the greater risk, as too much thyroid hormone speeds up bone loss.
No discussion of bone health is complete without considering the role of exercise. Putting a ‘load’ on bone tells it to get stronger. External bone loading is the compressive force of body weight or gravity. This is what the astronauts are missing in zero gravity, resulting in rapid bone loss. Walking, running and certain yoga postures provide external bone loading. Internal bone loading is the force placed on bone from contracting a muscle. This is greatest where the muscle’s tendon attaches to the bone. All forms of exercise help with internal bone loading but strength training is the best way to achieve this. Postural and balance training help maintain strength of muscles in the upper back for spinal health and fall prevention.
Even if we are well past our peak bone building years, there is much we can do to minimize bone loss. Assuring a balanced diet with plenty of alkalinizing vegetables and avoiding acidifying foods such as sugar, excessive red meat and processed foods is a great start.
Understanding bone physiology and treating health conditions that contribute to bone loss is critical. As many micronutrients are cofactors in bone health, testing to assure adequate levels can go a long way to minimizing bone loss. Targeted exercise on a daily basis can help build bone. And, as proper hormone balance can help build bone, working with bioidentical hormone therapy where appropriate can augment our protocol for bone health. Turning down bone thinning cortisol with life modifications and stress management, meditation, conscious relaxation and more can not only add to quality of life but protect bone density as well.
With conscious effort, there is no need to resign ourselves to frailty later in life.