Introduction
This blog post will be the first of a series of three where we will talk about bone health throughout stages of life. Today’s post will provide a brief overview of bone composition, purpose, and what happens to our skeleton during growth and development, primarily in childhood and adolescence. We will also look at ways to optimize bone health at the stage in life where we can have the biggest impact on overall health- childhood!
Bone Physiology
There are two main types of bone:
1) cortical bone, the hard, outer layer which is strong and dense and
2) trabecular bone, the inner portion, which is spongy and less dense.
Bones are made up of a protein called collagen as well as minerals such as calcium phosphate. Inside our bones contains bone marrow, blood vessels, nerves, and connective tissue vital for the health of our whole body. There are three main cells that work to produce, regulate, and maintain our bone health: osteoblasts, osteoclasts, and osteocytes [1].
1. Osteoblasts: B = build
This blog post will be the first of a series of three where we will talk about bone health throughout stages of life. Today’s post will provide a brief overview of bone composition, purpose, and what happens to our skeleton during growth and development, primarily in childhood and adolescence. We will also look at ways to optimize bone health at the stage in life where we can have the biggest impact on overall health- childhood!
Bone Physiology
There are two main types of bone:
1) cortical bone, the hard, outer layer which is strong and dense and
2) trabecular bone, the inner portion, which is spongy and less dense.
Bones are made up of a protein called collagen as well as minerals such as calcium phosphate. Inside our bones contains bone marrow, blood vessels, nerves, and connective tissue vital for the health of our whole body. There are three main cells that work to produce, regulate, and maintain our bone health: osteoblasts, osteoclasts, and osteocytes [1].
1. Osteoblasts: B = build
- Purpose: depositing materials to create new bone (such as during growth, in response to stimuli such as exercise, or after a fracture)
- Purpose: bone reabsorption; these cells help break down damaged bone
- The most abundant cells in our bones. These cells make up most of our bones and also regulate the work of osteoblasts and clasts!
 |  |
Functions of the Skeleton
Our bones (along with articular structures and ligaments) make up our skeleton which is vital for purposes such as support, protection (of organs), mineral storage, blood cell production, and, of course, movement! Our bones act as levers for muscles to exert force on, which leads to movement. Our joints (synovial, particularly) act as a fulcrum for our bodies to move about [1].
Bone Mineral Density (BMD)
Simply put, bone mineral density is a measure of the concentration of minerals we have in our bones. The more minerals we have in our bones, the denser they are (increasing the mass). The denser our bones are, the stronger and healthier they are. This reduces risk of developing osteopenia, osteoporosis, fractures, vitamin and mineral deficiencies, and even chronic pain [2].
Optimizing Bone Mineral Density
Growth and Development
Peak bone mass is defined as the amount of bony tissue at the end of skeletal maturity (this is when bones are done growing, typically around age 18).
Bone mass attained early in life is one of the most important determinants of lifelong skeletal health. Bone mineral content increases exponentially during childhood. In fact, 40%-60% of the total adult bone mass is accrued during puberty.
It is proven that those who obtain a higher peak bone mass in youth will be better protected against osteoporosis and fractures later in life [3].
Our bones (along with articular structures and ligaments) make up our skeleton which is vital for purposes such as support, protection (of organs), mineral storage, blood cell production, and, of course, movement! Our bones act as levers for muscles to exert force on, which leads to movement. Our joints (synovial, particularly) act as a fulcrum for our bodies to move about [1].
Bone Mineral Density (BMD)
Simply put, bone mineral density is a measure of the concentration of minerals we have in our bones. The more minerals we have in our bones, the denser they are (increasing the mass). The denser our bones are, the stronger and healthier they are. This reduces risk of developing osteopenia, osteoporosis, fractures, vitamin and mineral deficiencies, and even chronic pain [2].
Optimizing Bone Mineral Density
Growth and Development
Peak bone mass is defined as the amount of bony tissue at the end of skeletal maturity (this is when bones are done growing, typically around age 18).
Bone mass attained early in life is one of the most important determinants of lifelong skeletal health. Bone mineral content increases exponentially during childhood. In fact, 40%-60% of the total adult bone mass is accrued during puberty.
It is proven that those who obtain a higher peak bone mass in youth will be better protected against osteoporosis and fractures later in life [3].
What Can We Do About This?
From this point on, we will focus on modifiable factors relating to bone health. In particular, we will focus on diet and exercise. See below for all factors that contribute to bone health.
From this point on, we will focus on modifiable factors relating to bone health. In particular, we will focus on diet and exercise. See below for all factors that contribute to bone health.
Nutrition and Bone Health
When discussing bone health, the effects of a healthy diet (and lack thereof) are extremely significant. In fact, children with vitamin D deficiency are 6 times more likely to have a higher severity fracture than those with normal vitamin D levels [4].
As explained earlier, bone has collagen and mineral components that help make up its strength.
Ingredients for healthy bones include calcium, vitamin D, vitamin C, vitamin K, silicon, boron, and magnesium.
Physical Activity and Bone Health
As nutrition is extremely important in our developing years, the affects of increasing BMD are much much greater in children who participate in physical activity. One study found that physical activity 1-2 times per week increased BMD in children. Physical activity was also shown to increase cortical bone thickness [4]. Another study found a much more prominent increase in BMD when physical activity was paired with the consumption of calcium at ≥1100 mg/day [3]. As mentioned, strength training alone can increase cortical thickness, which in turn increases bone strength, but to get benefits to bone mineral density as well, most studies demonstrate exercise + nutrition to have the best effects.
Physical Activity - Pubertal Years
During puberty, the difference between males and females’ bone mass presents itself (see the chart above). This difference appears to be essentially due to a more prolonged bone maturation period in males than in females, with a larger increase in bone size and cortical bone thickness [4].
The American Academy of Pediatrics’ states that resistance training is an important and safe component of sport and exercise training for adolescents [5]. A key component of this type of training in the younger years is to focus on proper form and technique rather than just weight and resistance. The goal is to engage children and adolescents in strength training to promote a culture of activity and avoid the decrease in physical activity participation that often occurs during pubertal years. This is a key factor in encouraging youth to build a healthy relationship with movement that can last a lifetime!
When discussing bone health, the effects of a healthy diet (and lack thereof) are extremely significant. In fact, children with vitamin D deficiency are 6 times more likely to have a higher severity fracture than those with normal vitamin D levels [4].
As explained earlier, bone has collagen and mineral components that help make up its strength.
Ingredients for healthy bones include calcium, vitamin D, vitamin C, vitamin K, silicon, boron, and magnesium.
- Vitamin D: needed for the body to be able to absorb calcium.
- Boron: extends the half-life of vitamin D and estrogen.
- Estrogen: regulates the function of osteoclasts (we will talk more about the indications of estrogen and bone health in Part 2 and 3).
- Estrogen: regulates the function of osteoclasts (we will talk more about the indications of estrogen and bone health in Part 2 and 3).
- Vitamin K: helps enable calcium binding.
- Silicon: attracts calcium.
- Magnesium: supports calcium absorption and also assists in forming bone.
- Vitamin C: helps form collagen and impacts osteoblasts’ ability to build bone [4].
Physical Activity and Bone Health
As nutrition is extremely important in our developing years, the affects of increasing BMD are much much greater in children who participate in physical activity. One study found that physical activity 1-2 times per week increased BMD in children. Physical activity was also shown to increase cortical bone thickness [4]. Another study found a much more prominent increase in BMD when physical activity was paired with the consumption of calcium at ≥1100 mg/day [3]. As mentioned, strength training alone can increase cortical thickness, which in turn increases bone strength, but to get benefits to bone mineral density as well, most studies demonstrate exercise + nutrition to have the best effects.
Physical Activity - Pubertal Years
During puberty, the difference between males and females’ bone mass presents itself (see the chart above). This difference appears to be essentially due to a more prolonged bone maturation period in males than in females, with a larger increase in bone size and cortical bone thickness [4].
The American Academy of Pediatrics’ states that resistance training is an important and safe component of sport and exercise training for adolescents [5]. A key component of this type of training in the younger years is to focus on proper form and technique rather than just weight and resistance. The goal is to engage children and adolescents in strength training to promote a culture of activity and avoid the decrease in physical activity participation that often occurs during pubertal years. This is a key factor in encouraging youth to build a healthy relationship with movement that can last a lifetime!
How Does Exercise Actually Help?
Wolff’s Law
This principle states that bone adapts to the loads placed upon it, becoming stronger and denser with increased stress (like exercise) and weaker with decreased stress (like inactivity) [4]. Basically, when we stand, walk, run, jump, and so on, we are placing stress on our skeleton. Our body responds to this stress by getting stronger, so it is better able to tolerate the load. This occurs through a continuous process of remodeling, where new bone tissue is formed (remember, osteoblasts) to meet demand and old bone is reabsorbed (remember osteoclasts) [4]. There are various types of stress to put on bones. One example is hopping places a compressive force on our leg bones. Our leg bones in turn get stronger and become better at resisting compressive forces. In other words, use it or lose it!
Wolff’s Law
This principle states that bone adapts to the loads placed upon it, becoming stronger and denser with increased stress (like exercise) and weaker with decreased stress (like inactivity) [4]. Basically, when we stand, walk, run, jump, and so on, we are placing stress on our skeleton. Our body responds to this stress by getting stronger, so it is better able to tolerate the load. This occurs through a continuous process of remodeling, where new bone tissue is formed (remember, osteoblasts) to meet demand and old bone is reabsorbed (remember osteoclasts) [4]. There are various types of stress to put on bones. One example is hopping places a compressive force on our leg bones. Our leg bones in turn get stronger and become better at resisting compressive forces. In other words, use it or lose it!
Summary
In conclusion, bone health is extremely important and has indications on various aspects of life. During childhood and adolescence is the time where our bones grow the fastest and have the best ability to increase our bone mineral density. Bone mineral density is a vital component in reducing fracture risk. Bone health is influenced by many factors including both healthy diet and exercise. Preventing fractures and osteoporosis in adult stages of life begins during childhood!
In conclusion, bone health is extremely important and has indications on various aspects of life. During childhood and adolescence is the time where our bones grow the fastest and have the best ability to increase our bone mineral density. Bone mineral density is a vital component in reducing fracture risk. Bone health is influenced by many factors including both healthy diet and exercise. Preventing fractures and osteoporosis in adult stages of life begins during childhood!
Resources
- https://www.niams.nih.gov/health-topics/what-bone
- https://www.niams.nih.gov/health-topics/bone-mineral-density-tests-what-numbers-mean#:~:text=What%20is%20a%20bone%20mineral,the%20effectiveness%20of%20osteoporosis%20treatment.
- https://doi.org/10.1016/j.jposna.2024.100031
- https://www.ncbi.nlm.nih.gov/books/NBK499863/
- https://publications.aap.org/pediatrics/article/145/6/e20201011/76942/Resistance-Training-for-Children-and-Adolescents?autologincheck=redirected
- https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables/reference-values-elements.html
RSS Feed