Nutrition
Nutrition and Bone Health
I've recently become fascinated by the connection between nutrition and bone health. I have my friend, Jessica Yeaton, DPT who is a fellow "bonehead" to thank for this recent obsession on all things bone health. I'm not sure I've met anyone more passionate about the skeletal system. She's been sending me bones and tendons podcasts for the past several months and I'm here for it.
Bones are incredible. It's also incredible how much bone health correlates with nutrition, or rather, adequate nutrition. The more we take care of our nutrition, the more we take care of our bones.
Approximately 10 million Americans over the age of 50 have osteoporosis and another 34 million have low bone mass. After the age of 50, a woman's risk of dying from a hip fracture is equal to her lifetime risk of dying from breast cancer.
Healthy nutritional habits combined with exercise are imperative for maintaining bone health.
Bones 101: Bone Function, Structure, and More
Before we dive into how to use nutrition to support your bone health, we need to talk about what bone is and how its function, structure, and more interacts with the rest of our body and systems.
Bone Structure
Bone is a living tissue. It's easy to overlook this fact and think of bone as somewhat inert. Maybe this is because bone is often depicted as a skeleton, which are often correlated with something that appears dead. However, bone is heavily vascularized, meaning it receives great blood and nutrient supply.
The most common types of bones include cortical/compact and trabecular/spongey bone. Cortical/compact bone is what forms the "shaft" and the exterior of long bones such as the femur and humerus. Trabecular/spongey bone is a rather porous type of bone that is composed of both hard and soft tissue components which can be found in the epiphyses (rounded portion at the ends of bones) and metaphyses (wide portion that contains the growth plate during childhood) of long bones and in the vertebral bodies. Figure 1 below provides a visual of general bone anatomy.
The main differences between the two bone types are their level of vascularization. Cortical bone is a dense, low-porosity and less metabolically active tissue. Trabecular bone is a honey-comb like network with a larger remodeling area and higher turnover rate.
Figure 1: General Bone Anatomy
And then there's bone marrow. Bone marrow is what's producing our white and red blood cells. The memory B cells and T cells part of our immune system actually reside in our bone marrow. If you're reinfected with a pathogen or virus you've previously had, your memory B cells and T cells that are sitting in your bone marrow can respond immediately and quickly upon reintroduction of the same antigen.
Hopefully, now you can see that bones are so much more than that static skeleton hanging in your high school science teacher's lab room!
Osteoblasts and Osteoclasts
Osteoblasts are the bone cells responsible for building bone. They accomplish this by producing a collagen bone matrix and mineralizing it.
Osteoclasts remove bone by reabsorbing calcified bone and the collagen matrix.
In summary, osteoblasts contribute to increasing our bone mineral density and osteoclasts do the opposite. This exists in an equilibrium. We are constantly remodeling bones, adding to and subtracting from our bones through calcium turnover.
Bones need to be both strong and flexible at the same time, which is why they're constantly engaging in remodeling. Bones that are strong but inflexible would be brittle and easily broken. Bones that are inflexible but not strong would not be able to support the weight of your body or stress from your muscles pulling on them. It's a fine (and oh so beautiful!) balance.
Bone Composition
Bone is made up of about 50 to 70 percent minerals (inorganic) and 20 to 40 percent an organic matrix of carbon, hydrogen, and oxygen. The remaining portion of bone is a bit of water and lipid (fat).
The mineral matrix component of bone is in the form of elongated platelet-like carbonated calcium phosphate particles whose elongated direction is aligned along the long axis of type 1 collagen fibrils. Those collagen fibrils compose the organic matrix of bone, together with different types of molecules, including proteoglycans and non-collagenous proteins.
At the micro level, calcium balance is happening quite frequently. Virtually all of the body's calcium is contained within bone and therefore bone plays a very important role in calcium homeostasis.
We tend to think of bones as structural entities, which of course that is their major role. However, they're also a very important reservoir for calcium, which is another very important ion/mineral in the activity of every cell in our body.
Osteopenia and Osteoporosis
Figure 2. Loss of bone mass in decline from healthy bone to osteoporosis
Osteopenia and osteoporosis exist on a continuum relative to healthy bone. As seen in Figure 2, healthy bone contains a more dense matrix of calcified mineral relative to bones experiencing osteopenia and osteoporosis.
When you go from healthy bones to osteopenia, that represents about a 10% reduction in bone mineral density relative to a young healthy adult. Osteoporosis is a further degradation of bone mineral density, where you hit about 25% reduction.
Bone mineral density can actually potentially improve up to about the age of 30 years old. It can stay quite consistent in both men and women until you're about 40 or 50, and then bone loss effectively starts to occur.
For women, bone loss can be much more pronounced. About seven to 10 years around the onset of menopause, bone loss can be three to 7% annually. By the time they reach 65, bone loss starts to slow down a bit, so it might look more like 0.5% to 2% per year.
In men over 65, it's actually a higher rate of bone loss, but they're starting at a much higher point than women because they don't suffer that precipitous loss the way women do after menopause due to the loss of estrogen. For men at age 65%, the bone loss is about 1% to 2% per year.
This is why it's SO IMPORTANT to optimize your nutrition and exercise throughout adolescence and your 20s to support your bone mineral density. Essentially, if you don't reach your full genetic potential for bone mineral density by the age of 20, you're missing an enormous opportunity later in life to have as strong of bones as possible.
If you're curious what your own bone mineral density is, a DEXA scan is a super low radiation scan that takes about 10 minutes. You lay flat on a table and a little scanner that uses low dose X-rays moves over your body. Prior to getting a DEXA scan, I would confirm they are giving you segmental bone analysis for the left hip, right hip, and lumbar spine and not just a whole body bone mineral density metric.
Role of Estrogen in Bone Health
The signaling process to deposit more bone tissue is highly regulated by the hormone estrogen. Estrogen modulates the signal of stress that comes from some external stimulus, such as lifting something heavy or climbing stairs. When your bone senses that they need to support a greater force, it remodels by depositing more and more bone tissue.
In the absence of estrogen, that signal gets reduced and that's effectively why menopause, which is a sudden withdrawal of estrogen, can be such an impactful thing for women who don't have their hormones replaced.
It's also why losing your menstrual cycle in the pre-menopause stage can be so harmful for your bone mineral density. Some athletes experiencing Relative Energy Deficiency in Sport or RED-S, may lose their cycle due to low energy availability, especially during intense training blocks. It's not a badge of honor to lose your menstrual cycle, it's actually a major signal from your body that something needs to be adjusted (training load, fueling, stress, etc.)
No, oral birth control, which contains synthetic estrogen, is not the answer either. I plan to do another blog post on this topic, as it's essential for female athletes to understand the importance of maintaining a regular menstrual cycle.
What about men? Does estrogen affect their bone health? Men are also losing estrogen as they age. Estrogen comes primarily from testosterone conversion. Testosterone is aromatized into estrogen. Therefore, a man with a testosterone level of 800 is going to have a higher estrogen level than a man with 300.
Men lose estrogen at a far more gradual rate than women, and that's why women experience this loss more significantly, placing them at a greater risk for osteopenia and osteoporosis.
Nutrition and Supplements for Bone Health
There are several nutrients, micro and macro, that play a vital role in maintaining adequate bone health, including calcium, vitamin D, iron, magnesium, protein, and carbohydrates.
Bone is a living tissue, so it requires all essential nutrients for growth and maintenance. If you eat a balanced diet that contains a variety of fruits, vegetables, legumes, whole grains, nuts, seeds, and protein, you're likely getting enough of most of the nutrients needed to keep your bones healthy and functioning well. However, certain people, such as those over age 65, pregnant or lactating women, or endurance athletes, may need to be more strategic about certain nutrients in their diets.
Calcium
The Recommended Daily Allowance (RDA) for adults for calcium is 1000-12000 mg per day. The RDA is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals. Therefore, you should think of the RDA as the bare minimum recommended intake.
Some of my favorite dietary sources of calcium include Greek yogurt, dried figs, prunes, tofu, sesame seeds (tahini!), spinach, cheese, salmon, broccoli, almonds and almond butter, and white beans. There are a lot of different dietary sources of calcium beyond a glass of milk!
I don't usually recommend a calcium supplement, but calcium carbonate and calcium citrate are reasonable options. High or inappropriate doses of calcium supplements can lead to uncomfortable side effects, such as constipation. In addition, a meta-analysis including eleven randomized controlled trials showed calcium supplements have up to 30% increased risk for myocardial infarction.
The finding of an adverse trend in cardiovascular diseases with calcium supplementation is not necessarily surprising, as calcium supplements potentially contribute to elevated serum calcium levels and possibly accelerated cardiovascular calcification in the long run, which is predictive of cardiovascular event rates.
My Registered Dietitian opinion: take a food first approach when it comes to optimizing your calcium levels and work with a practitioner before supplementing with calcium. Whole foods, especially dairy, provide an entire package of nutrients structurally important to bones. Hydroxyapatite, the mineral complex providing bone structure, is very similar to the mineral composition of dairy products, including yogurt, cheese, and milk.
Vitamin D
The RDA for vitamin D is 800 to 1000 IU per day. Vitamin D is fairly difficult to obtain in adequate amounts from diet alone. The average adult American diet only contains about 150 to 300 IU of vitamin D per day. Not many foods are high in vitamin D, but those that are include salmon, mushrooms, eggs, beef liver, and fortified milk.
There are two forms of vitamin D: vitamin D2 and D3. Vitamin D3 is the active form, so when supplementing with vitamin D, always look for the D3 form. Something important to consider is that vitamin D increases the gut's absorption of calcium. Therefore, if you're vitamin D deficient, you're also going to have trouble absorbing calcium through the gut.
We can also get vitamin D from the sun, which is why it's often referred to as the "sunshine vitamin." When your skin is exposed to sunlight, it manufactures vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D.
The Endocrine society recommends 1500 - 2000 IU of daily vitamin D, and current research suggests that supplemental vitamin D is associated with decreases in mortality. Therefore, supplementation with 400 IU to 1000 IU of vitamin D per day is reasonable for the majority of healthy Americans. However, I recommend working with your doctor or Registered Dietitian to check your vitamin D levels annually to determine if you could benefit from higher doses of supplementation. In general, a vitamin D level that is greater than 60 ng/dL is favorable.
Magnesium
More than half of the body's store of magnesium is in the bone, and it plays an important role in organic matrix bone synthesis. Magnesium can also be lost through sweat, so if you're an active person who is sweating a lot, such as an endurance athlete, you may be at higher risk of experiencing magnesium deficiency.
The RDA for magnesium is 300 to 500 mg per day. Similar to vitamin D, magnesium is relatively difficult to eat in adequate amounts through food alone. Most people are magnesium deficient and may benefit from a daily supplement. Magnesium supplements exist in many different forms, and each of those forms serve a different purpose.
Magnesium glycinate is my favorite form and most widely used with all my clients. It's well absorbed in the body and supports muscle relaxation and sleep quality. If you struggle with constipation, magnesium citrate or oxide may be more appropriate for you, but they are not as well absorbed in the body. If you're looking for a form of magnesium to support anxiety and stress response, magnesium threonate may be the best choice for you.
Some of my favorite dietary sources of magnesium include pumpkin seeds, chia seeds, almonds, quinoa, dark chocolate, cacao nibs, dark leafy greens, avocado, and bananas.
Iron
Iron has an important role in vitamin D metabolism and collagen synthesis. Those with disorders of iron metabolism have been suggested to have lower bone mass and an increased risk of suffering an osteoporotic bone fracture.
Iron helps limit osteoclasts (bone breakdown) activity. Here's how this works:
Osteoclasts contain both HIF1a and estrogen.
HIF1a is a protein that responds to low oxygen concentrations.
As we discussed previously, estrogen plays an essential role to bone growth and development.
During iron deficiency, it's more difficult for the body to deliver oxygen to working muscles.
Under normal oxygen conditions (adequate iron) of the tissue, iron limits HIF1a (and therefore limits bone breakdown).
HIF1a accumulates when oxygen levels are insufficient (iron deficiency).
When estrogen is low, HIF1a stimulates osteoclast activity.
So, if you're iron deficient with or without anemia, it's safe to say you are at higher risk of a bone stress injury (especially as a female athlete) or that long term, bone density maybe be impacted under chronic conditions.
A very high intake of iron might also be bad for the bone, likely due to the increased oxidative stress and inflammatory response that can occur as a result of iron overload. This is a large reason why I'm not keen on blindly supplementing with iron without completing an iron blood serum panel.
I suggest working with your doctor to run a complete a CBC and iron panel, which would include serum iron, TIBC, UIBC, transferrin, and iron saturation. You may have to specifically ask for ferritin, which is a marker of your iron storage. It's important to consider that iron levels that may be within range for the general population may not be optimal for athletes, endurance athletes, female athletes, and athletes living at high altitude.
Some of my favorite dietary sources of iron include red meat, chicken thighs, legumes, nuts, whole grains, dried fruits, watermelon, and dark green leafy greens.
Protein
Protein is one of the main components of the organic matrix of bone for collagen structure. This important macronutrient has a role in the production of hormones and growth factors that modulate bone synthesis. Protein may have an indirect effect on bone health through its support for muscle mass and function, but also by increasing levels of IGF-1, which has an anabolic effect on bone. You can read more about protein and the differences between plant based and animal based protein in my blog post All About Protein.
Athletes are often recommended to consume more protein than is recommended for the general population, in order to support the additional demands of athletic training. The recommendations for athletes is to consume between 1.2 and 1.6 g/kg/day, although under certain circumstances this recommendation might increase to 2.2 to 2.5 g/kg/day, which is higher than the 0.8 g/kg/day recommended to the general population.
I can't talk about bones and protein without talking about collagen! Collagen accounts for about 30% of your body's total protein and is the most abundant protein in your body. As people age, the body’s ability to produce collagen decreases by around 1% to 1.5% per year. Collagen appears to support bone health, as collagen is an essential component to bone mass. Collagen has also been shown to help with with bone mineralization, which is the process that strengthens and hardens bones.
A 2018 study investigated the effects of specific collagen peptides on bone health in 131 postmenopausal people with reduced bone mineral density. The researchers measured the effects of taking 5 grams of collagen peptides daily for 12 months, compared with a placebo group. They looked at changes in bone mineral density in the femoral neck, which is the area where the thighbone joins the hip bone and the spine.
The results showed the collagen peptides increased bone mineral density and improved bone markers, indicating a reduction in bone loss and an increase in bone formation. In other words, collagen may help mitigate further bone loss.
You can get collagen from foods like bone broth, chicken skin, and organ meats. However, these foods are not often staples in most peoples diets, which is one of the reasons collagen supplements have become so popular and do have some merit to them.
Most collagen supplements are hydrolyzed, which means the collagen has been broken down to make it easier to absorb. These hydrolyzed formulas also dissolve nicely in beverages like coffee, making them easy to integrate into your daily routine. The types of collagen found in supplements vary — some contain one or two types, while others contain up to five. Type I collagen is the main type found in your skin, bones, tendons, and ligaments.
You can read more about collagen, its benefits, and the optimal dosage of collagen supplements in my blog post What You Need to Know About Collagen.
Carbohydrates
Carbohydrates don't often get thought of as an essential macronutrient for bone health. The relationship between carbohydrates and bone health is of particular importance to athletes and endurance athletes. While no studies have directly examined the effects of low carbohydrate availability on bone health in athletes, it has been shown that carbohydrate feeding can reduce bone turnover.
One study showed the provision of carbohydrate attenuated the bone resorption response to acute exercise in athletes involved in an 8-day overloaded endurance training trial. Sale et al. also showed a modest post-exercise reduction in bone resorption markers with carbohydrate feeding immediately before, during and immediately after a 120-min treadmill run in recreationally active individuals.
Bone stress injuries are common in athletes, resulting in time lost from training and competition. Diets that are low in energy availability have been associated with increased circulating bone resorption and reduced bone formation markers, particularly in response to prolonged exercise. However, studies have not separated the effects of low energy availability per se from an associated reduction in carbohydrate availability.
One study aimed to compare the effects of both low energy availability and low carbohydrate availability in elite endurance athletes. The study found that short‐term carbohydrate restriction resulted in reduced bone formation markers at rest and during exercise with further exercise‐related increases in a marker of bone resorption. Bone formation markers during exercise seemed to be maintained with low energy availability although resorption increased. In contrast, nutritional support with adequate energy and carbohydrate appeared to reduce unfavorable bone turnover responses to exercise in the the endurance athletes.
In summary, all these studies suggest that having adequate carbohydrate availability, particularly before, during, and after exercise, can help improve bone remineralization (which is a good thing!).
Major Takeaways
Quality nutrition is one of several important lifestyle choices to maintain good bone health. Quality nutrition also pertains to meeting your overall energy needs, especially if you're an athlete or endurance athlete.
There are key nutrients of concern related to bone health including protein, carbohydrates, iron, magnesium, calcium, and vitamin D.
The importance of quality nutrition can be difficult to appreciate because the effects are subtle over long periods of time. Small benefits daily over decades can make a big difference on having a higher risk of fracture or not.
Nutrition provides the raw materials for bone structure, but by itself, is not sufficient. Weight bearing exercise provides the stimulus and strain essential for bone remodeling. Check out Jessica Yeaton, DPT post on how to optimize bone health through strength training!
References:
Price CT, Langford JR, Liporace FA. Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet. Open Orthop J. 2012;6:143-149. doi:10.2174/1874325001206010143
Von Euw, S., Wang, Y., Laurent, G. et al. Bone mineral: new insights into its chemical composition. Sci Rep 9, 8456 (2019). https://doi.org/10.1038/s41598-019-44620-6
Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010;341:c3691.
Weaver CM. Nutrition and bone health. Oral Dis. 2017;23(4):412-415. doi:10.1111/odi.12515
Sale C, Elliott-Sale KJ. Nutrition and Athlete Bone Health. Sports Med. 2019;49(Suppl 2):139-151. doi:10.1007/s40279-019-01161-2
Bjarnason NH, Henriksen EE, Alexandersen P, Christgau S, Henriksen DB, Christiansen C. Mechanism of circadian variation in bone resorption. Bone. 2002;30(1):307-313. doi:10.1016/s8756-3282(01)00662-7
Sale C, Varley I, Jones TW, James RM, Tang JC, Fraser WD, et al. Effect of carbohydrate feeding on the bone metabolic response to running. J Appl Physiol. 2015;119(7):824–830.
Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52:376–384.
Fensham NC, Heikura IA, McKay AKA, Tee N, Ackerman KE, Burke LM. Short-Term Carbohydrate Restriction Impairs Bone Formation at Rest and During Prolonged Exercise to a Greater Degree than Low Energy Availability. J Bone Miner Res. 2022;37(10):1915-1925. doi:10.1002/jbmr.4658
May 13, 2024
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Nutrition
Nutrition and Bone Health
I've recently become fascinated by the connection between nutrition and bone health. I have my friend, Jessica Yeaton, DPT who is a fellow "bonehead" to thank for this recent obsession on all things bone health. I'm not sure I've met anyone more passionate about the skeletal system. She's been sending me bones and tendons podcasts for the past several months and I'm here for it.
Bones are incredible. It's also incredible how much bone health correlates with nutrition, or rather, adequate nutrition. The more we take care of our nutrition, the more we take care of our bones.
Approximately 10 million Americans over the age of 50 have osteoporosis and another 34 million have low bone mass. After the age of 50, a woman's risk of dying from a hip fracture is equal to her lifetime risk of dying from breast cancer.
Healthy nutritional habits combined with exercise are imperative for maintaining bone health.
Bones 101: Bone Function, Structure, and More
Before we dive into how to use nutrition to support your bone health, we need to talk about what bone is and how its function, structure, and more interacts with the rest of our body and systems.
Bone Structure
Bone is a living tissue. It's easy to overlook this fact and think of bone as somewhat inert. Maybe this is because bone is often depicted as a skeleton, which are often correlated with something that appears dead. However, bone is heavily vascularized, meaning it receives great blood and nutrient supply.
The most common types of bones include cortical/compact and trabecular/spongey bone. Cortical/compact bone is what forms the "shaft" and the exterior of long bones such as the femur and humerus. Trabecular/spongey bone is a rather porous type of bone that is composed of both hard and soft tissue components which can be found in the epiphyses (rounded portion at the ends of bones) and metaphyses (wide portion that contains the growth plate during childhood) of long bones and in the vertebral bodies. Figure 1 below provides a visual of general bone anatomy.
The main differences between the two bone types are their level of vascularization. Cortical bone is a dense, low-porosity and less metabolically active tissue. Trabecular bone is a honey-comb like network with a larger remodeling area and higher turnover rate.
Figure 1: General Bone Anatomy
And then there's bone marrow. Bone marrow is what's producing our white and red blood cells. The memory B cells and T cells part of our immune system actually reside in our bone marrow. If you're reinfected with a pathogen or virus you've previously had, your memory B cells and T cells that are sitting in your bone marrow can respond immediately and quickly upon reintroduction of the same antigen.
Hopefully, now you can see that bones are so much more than that static skeleton hanging in your high school science teacher's lab room!
Osteoblasts and Osteoclasts
Osteoblasts are the bone cells responsible for building bone. They accomplish this by producing a collagen bone matrix and mineralizing it.
Osteoclasts remove bone by reabsorbing calcified bone and the collagen matrix.
In summary, osteoblasts contribute to increasing our bone mineral density and osteoclasts do the opposite. This exists in an equilibrium. We are constantly remodeling bones, adding to and subtracting from our bones through calcium turnover.
Bones need to be both strong and flexible at the same time, which is why they're constantly engaging in remodeling. Bones that are strong but inflexible would be brittle and easily broken. Bones that are inflexible but not strong would not be able to support the weight of your body or stress from your muscles pulling on them. It's a fine (and oh so beautiful!) balance.
Bone Composition
Bone is made up of about 50 to 70 percent minerals (inorganic) and 20 to 40 percent an organic matrix of carbon, hydrogen, and oxygen. The remaining portion of bone is a bit of water and lipid (fat).
The mineral matrix component of bone is in the form of elongated platelet-like carbonated calcium phosphate particles whose elongated direction is aligned along the long axis of type 1 collagen fibrils. Those collagen fibrils compose the organic matrix of bone, together with different types of molecules, including proteoglycans and non-collagenous proteins.
At the micro level, calcium balance is happening quite frequently. Virtually all of the body's calcium is contained within bone and therefore bone plays a very important role in calcium homeostasis.
We tend to think of bones as structural entities, which of course that is their major role. However, they're also a very important reservoir for calcium, which is another very important ion/mineral in the activity of every cell in our body.
Osteopenia and Osteoporosis
Figure 2. Loss of bone mass in decline from healthy bone to osteoporosis
Osteopenia and osteoporosis exist on a continuum relative to healthy bone. As seen in Figure 2, healthy bone contains a more dense matrix of calcified mineral relative to bones experiencing osteopenia and osteoporosis.
When you go from healthy bones to osteopenia, that represents about a 10% reduction in bone mineral density relative to a young healthy adult. Osteoporosis is a further degradation of bone mineral density, where you hit about 25% reduction.
Bone mineral density can actually potentially improve up to about the age of 30 years old. It can stay quite consistent in both men and women until you're about 40 or 50, and then bone loss effectively starts to occur.
For women, bone loss can be much more pronounced. About seven to 10 years around the onset of menopause, bone loss can be three to 7% annually. By the time they reach 65, bone loss starts to slow down a bit, so it might look more like 0.5% to 2% per year.
In men over 65, it's actually a higher rate of bone loss, but they're starting at a much higher point than women because they don't suffer that precipitous loss the way women do after menopause due to the loss of estrogen. For men at age 65%, the bone loss is about 1% to 2% per year.
This is why it's SO IMPORTANT to optimize your nutrition and exercise throughout adolescence and your 20s to support your bone mineral density. Essentially, if you don't reach your full genetic potential for bone mineral density by the age of 20, you're missing an enormous opportunity later in life to have as strong of bones as possible.
If you're curious what your own bone mineral density is, a DEXA scan is a super low radiation scan that takes about 10 minutes. You lay flat on a table and a little scanner that uses low dose X-rays moves over your body. Prior to getting a DEXA scan, I would confirm they are giving you segmental bone analysis for the left hip, right hip, and lumbar spine and not just a whole body bone mineral density metric.
Role of Estrogen in Bone Health
The signaling process to deposit more bone tissue is highly regulated by the hormone estrogen. Estrogen modulates the signal of stress that comes from some external stimulus, such as lifting something heavy or climbing stairs. When your bone senses that they need to support a greater force, it remodels by depositing more and more bone tissue.
In the absence of estrogen, that signal gets reduced and that's effectively why menopause, which is a sudden withdrawal of estrogen, can be such an impactful thing for women who don't have their hormones replaced.
It's also why losing your menstrual cycle in the pre-menopause stage can be so harmful for your bone mineral density. Some athletes experiencing Relative Energy Deficiency in Sport or RED-S, may lose their cycle due to low energy availability, especially during intense training blocks. It's not a badge of honor to lose your menstrual cycle, it's actually a major signal from your body that something needs to be adjusted (training load, fueling, stress, etc.)
No, oral birth control, which contains synthetic estrogen, is not the answer either. I plan to do another blog post on this topic, as it's essential for female athletes to understand the importance of maintaining a regular menstrual cycle.
What about men? Does estrogen affect their bone health? Men are also losing estrogen as they age. Estrogen comes primarily from testosterone conversion. Testosterone is aromatized into estrogen. Therefore, a man with a testosterone level of 800 is going to have a higher estrogen level than a man with 300.
Men lose estrogen at a far more gradual rate than women, and that's why women experience this loss more significantly, placing them at a greater risk for osteopenia and osteoporosis.
Nutrition and Supplements for Bone Health
There are several nutrients, micro and macro, that play a vital role in maintaining adequate bone health, including calcium, vitamin D, iron, magnesium, protein, and carbohydrates.
Bone is a living tissue, so it requires all essential nutrients for growth and maintenance. If you eat a balanced diet that contains a variety of fruits, vegetables, legumes, whole grains, nuts, seeds, and protein, you're likely getting enough of most of the nutrients needed to keep your bones healthy and functioning well. However, certain people, such as those over age 65, pregnant or lactating women, or endurance athletes, may need to be more strategic about certain nutrients in their diets.
Calcium
The Recommended Daily Allowance (RDA) for adults for calcium is 1000-12000 mg per day. The RDA is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals. Therefore, you should think of the RDA as the bare minimum recommended intake.
Some of my favorite dietary sources of calcium include Greek yogurt, dried figs, prunes, tofu, sesame seeds (tahini!), spinach, cheese, salmon, broccoli, almonds and almond butter, and white beans. There are a lot of different dietary sources of calcium beyond a glass of milk!
I don't usually recommend a calcium supplement, but calcium carbonate and calcium citrate are reasonable options. High or inappropriate doses of calcium supplements can lead to uncomfortable side effects, such as constipation. In addition, a meta-analysis including eleven randomized controlled trials showed calcium supplements have up to 30% increased risk for myocardial infarction.
The finding of an adverse trend in cardiovascular diseases with calcium supplementation is not necessarily surprising, as calcium supplements potentially contribute to elevated serum calcium levels and possibly accelerated cardiovascular calcification in the long run, which is predictive of cardiovascular event rates.
My Registered Dietitian opinion: take a food first approach when it comes to optimizing your calcium levels and work with a practitioner before supplementing with calcium. Whole foods, especially dairy, provide an entire package of nutrients structurally important to bones. Hydroxyapatite, the mineral complex providing bone structure, is very similar to the mineral composition of dairy products, including yogurt, cheese, and milk.
Vitamin D
The RDA for vitamin D is 800 to 1000 IU per day. Vitamin D is fairly difficult to obtain in adequate amounts from diet alone. The average adult American diet only contains about 150 to 300 IU of vitamin D per day. Not many foods are high in vitamin D, but those that are include salmon, mushrooms, eggs, beef liver, and fortified milk.
There are two forms of vitamin D: vitamin D2 and D3. Vitamin D3 is the active form, so when supplementing with vitamin D, always look for the D3 form. Something important to consider is that vitamin D increases the gut's absorption of calcium. Therefore, if you're vitamin D deficient, you're also going to have trouble absorbing calcium through the gut.
We can also get vitamin D from the sun, which is why it's often referred to as the "sunshine vitamin." When your skin is exposed to sunlight, it manufactures vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D.
The Endocrine society recommends 1500 - 2000 IU of daily vitamin D, and current research suggests that supplemental vitamin D is associated with decreases in mortality. Therefore, supplementation with 400 IU to 1000 IU of vitamin D per day is reasonable for the majority of healthy Americans. However, I recommend working with your doctor or Registered Dietitian to check your vitamin D levels annually to determine if you could benefit from higher doses of supplementation. In general, a vitamin D level that is greater than 60 ng/dL is favorable.
Magnesium
More than half of the body's store of magnesium is in the bone, and it plays an important role in organic matrix bone synthesis. Magnesium can also be lost through sweat, so if you're an active person who is sweating a lot, such as an endurance athlete, you may be at higher risk of experiencing magnesium deficiency.
The RDA for magnesium is 300 to 500 mg per day. Similar to vitamin D, magnesium is relatively difficult to eat in adequate amounts through food alone. Most people are magnesium deficient and may benefit from a daily supplement. Magnesium supplements exist in many different forms, and each of those forms serve a different purpose.
Magnesium glycinate is my favorite form and most widely used with all my clients. It's well absorbed in the body and supports muscle relaxation and sleep quality. If you struggle with constipation, magnesium citrate or oxide may be more appropriate for you, but they are not as well absorbed in the body. If you're looking for a form of magnesium to support anxiety and stress response, magnesium threonate may be the best choice for you.
Some of my favorite dietary sources of magnesium include pumpkin seeds, chia seeds, almonds, quinoa, dark chocolate, cacao nibs, dark leafy greens, avocado, and bananas.
Iron
Iron has an important role in vitamin D metabolism and collagen synthesis. Those with disorders of iron metabolism have been suggested to have lower bone mass and an increased risk of suffering an osteoporotic bone fracture.
Iron helps limit osteoclasts (bone breakdown) activity. Here's how this works:
Osteoclasts contain both HIF1a and estrogen.
HIF1a is a protein that responds to low oxygen concentrations.
As we discussed previously, estrogen plays an essential role to bone growth and development.
During iron deficiency, it's more difficult for the body to deliver oxygen to working muscles.
Under normal oxygen conditions (adequate iron) of the tissue, iron limits HIF1a (and therefore limits bone breakdown).
HIF1a accumulates when oxygen levels are insufficient (iron deficiency).
When estrogen is low, HIF1a stimulates osteoclast activity.
So, if you're iron deficient with or without anemia, it's safe to say you are at higher risk of a bone stress injury (especially as a female athlete) or that long term, bone density maybe be impacted under chronic conditions.
A very high intake of iron might also be bad for the bone, likely due to the increased oxidative stress and inflammatory response that can occur as a result of iron overload. This is a large reason why I'm not keen on blindly supplementing with iron without completing an iron blood serum panel.
I suggest working with your doctor to run a complete a CBC and iron panel, which would include serum iron, TIBC, UIBC, transferrin, and iron saturation. You may have to specifically ask for ferritin, which is a marker of your iron storage. It's important to consider that iron levels that may be within range for the general population may not be optimal for athletes, endurance athletes, female athletes, and athletes living at high altitude.
Some of my favorite dietary sources of iron include red meat, chicken thighs, legumes, nuts, whole grains, dried fruits, watermelon, and dark green leafy greens.
Protein
Protein is one of the main components of the organic matrix of bone for collagen structure. This important macronutrient has a role in the production of hormones and growth factors that modulate bone synthesis. Protein may have an indirect effect on bone health through its support for muscle mass and function, but also by increasing levels of IGF-1, which has an anabolic effect on bone. You can read more about protein and the differences between plant based and animal based protein in my blog post All About Protein.
Athletes are often recommended to consume more protein than is recommended for the general population, in order to support the additional demands of athletic training. The recommendations for athletes is to consume between 1.2 and 1.6 g/kg/day, although under certain circumstances this recommendation might increase to 2.2 to 2.5 g/kg/day, which is higher than the 0.8 g/kg/day recommended to the general population.
I can't talk about bones and protein without talking about collagen! Collagen accounts for about 30% of your body's total protein and is the most abundant protein in your body. As people age, the body’s ability to produce collagen decreases by around 1% to 1.5% per year. Collagen appears to support bone health, as collagen is an essential component to bone mass. Collagen has also been shown to help with with bone mineralization, which is the process that strengthens and hardens bones.
A 2018 study investigated the effects of specific collagen peptides on bone health in 131 postmenopausal people with reduced bone mineral density. The researchers measured the effects of taking 5 grams of collagen peptides daily for 12 months, compared with a placebo group. They looked at changes in bone mineral density in the femoral neck, which is the area where the thighbone joins the hip bone and the spine.
The results showed the collagen peptides increased bone mineral density and improved bone markers, indicating a reduction in bone loss and an increase in bone formation. In other words, collagen may help mitigate further bone loss.
You can get collagen from foods like bone broth, chicken skin, and organ meats. However, these foods are not often staples in most peoples diets, which is one of the reasons collagen supplements have become so popular and do have some merit to them.
Most collagen supplements are hydrolyzed, which means the collagen has been broken down to make it easier to absorb. These hydrolyzed formulas also dissolve nicely in beverages like coffee, making them easy to integrate into your daily routine. The types of collagen found in supplements vary — some contain one or two types, while others contain up to five. Type I collagen is the main type found in your skin, bones, tendons, and ligaments.
You can read more about collagen, its benefits, and the optimal dosage of collagen supplements in my blog post What You Need to Know About Collagen.
Carbohydrates
Carbohydrates don't often get thought of as an essential macronutrient for bone health. The relationship between carbohydrates and bone health is of particular importance to athletes and endurance athletes. While no studies have directly examined the effects of low carbohydrate availability on bone health in athletes, it has been shown that carbohydrate feeding can reduce bone turnover.
One study showed the provision of carbohydrate attenuated the bone resorption response to acute exercise in athletes involved in an 8-day overloaded endurance training trial. Sale et al. also showed a modest post-exercise reduction in bone resorption markers with carbohydrate feeding immediately before, during and immediately after a 120-min treadmill run in recreationally active individuals.
Bone stress injuries are common in athletes, resulting in time lost from training and competition. Diets that are low in energy availability have been associated with increased circulating bone resorption and reduced bone formation markers, particularly in response to prolonged exercise. However, studies have not separated the effects of low energy availability per se from an associated reduction in carbohydrate availability.
One study aimed to compare the effects of both low energy availability and low carbohydrate availability in elite endurance athletes. The study found that short‐term carbohydrate restriction resulted in reduced bone formation markers at rest and during exercise with further exercise‐related increases in a marker of bone resorption. Bone formation markers during exercise seemed to be maintained with low energy availability although resorption increased. In contrast, nutritional support with adequate energy and carbohydrate appeared to reduce unfavorable bone turnover responses to exercise in the the endurance athletes.
In summary, all these studies suggest that having adequate carbohydrate availability, particularly before, during, and after exercise, can help improve bone remineralization (which is a good thing!).
Major Takeaways
Quality nutrition is one of several important lifestyle choices to maintain good bone health. Quality nutrition also pertains to meeting your overall energy needs, especially if you're an athlete or endurance athlete.
There are key nutrients of concern related to bone health including protein, carbohydrates, iron, magnesium, calcium, and vitamin D.
The importance of quality nutrition can be difficult to appreciate because the effects are subtle over long periods of time. Small benefits daily over decades can make a big difference on having a higher risk of fracture or not.
Nutrition provides the raw materials for bone structure, but by itself, is not sufficient. Weight bearing exercise provides the stimulus and strain essential for bone remodeling. Check out Jessica Yeaton, DPT post on how to optimize bone health through strength training!
References:
Price CT, Langford JR, Liporace FA. Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet. Open Orthop J. 2012;6:143-149. doi:10.2174/1874325001206010143
Von Euw, S., Wang, Y., Laurent, G. et al. Bone mineral: new insights into its chemical composition. Sci Rep 9, 8456 (2019). https://doi.org/10.1038/s41598-019-44620-6
Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010;341:c3691.
Weaver CM. Nutrition and bone health. Oral Dis. 2017;23(4):412-415. doi:10.1111/odi.12515
Sale C, Elliott-Sale KJ. Nutrition and Athlete Bone Health. Sports Med. 2019;49(Suppl 2):139-151. doi:10.1007/s40279-019-01161-2
Bjarnason NH, Henriksen EE, Alexandersen P, Christgau S, Henriksen DB, Christiansen C. Mechanism of circadian variation in bone resorption. Bone. 2002;30(1):307-313. doi:10.1016/s8756-3282(01)00662-7
Sale C, Varley I, Jones TW, James RM, Tang JC, Fraser WD, et al. Effect of carbohydrate feeding on the bone metabolic response to running. J Appl Physiol. 2015;119(7):824–830.
Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52:376–384.
Fensham NC, Heikura IA, McKay AKA, Tee N, Ackerman KE, Burke LM. Short-Term Carbohydrate Restriction Impairs Bone Formation at Rest and During Prolonged Exercise to a Greater Degree than Low Energy Availability. J Bone Miner Res. 2022;37(10):1915-1925. doi:10.1002/jbmr.4658
May 13, 2024
Food is Medicine —
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Nutrition
Nutrition and Bone Health
I've recently become fascinated by the connection between nutrition and bone health. I have my friend, Jessica Yeaton, DPT who is a fellow "bonehead" to thank for this recent obsession on all things bone health. I'm not sure I've met anyone more passionate about the skeletal system. She's been sending me bones and tendons podcasts for the past several months and I'm here for it.
Bones are incredible. It's also incredible how much bone health correlates with nutrition, or rather, adequate nutrition. The more we take care of our nutrition, the more we take care of our bones.
Approximately 10 million Americans over the age of 50 have osteoporosis and another 34 million have low bone mass. After the age of 50, a woman's risk of dying from a hip fracture is equal to her lifetime risk of dying from breast cancer.
Healthy nutritional habits combined with exercise are imperative for maintaining bone health.
Bones 101: Bone Function, Structure, and More
Before we dive into how to use nutrition to support your bone health, we need to talk about what bone is and how its function, structure, and more interacts with the rest of our body and systems.
Bone Structure
Bone is a living tissue. It's easy to overlook this fact and think of bone as somewhat inert. Maybe this is because bone is often depicted as a skeleton, which are often correlated with something that appears dead. However, bone is heavily vascularized, meaning it receives great blood and nutrient supply.
The most common types of bones include cortical/compact and trabecular/spongey bone. Cortical/compact bone is what forms the "shaft" and the exterior of long bones such as the femur and humerus. Trabecular/spongey bone is a rather porous type of bone that is composed of both hard and soft tissue components which can be found in the epiphyses (rounded portion at the ends of bones) and metaphyses (wide portion that contains the growth plate during childhood) of long bones and in the vertebral bodies. Figure 1 below provides a visual of general bone anatomy.
The main differences between the two bone types are their level of vascularization. Cortical bone is a dense, low-porosity and less metabolically active tissue. Trabecular bone is a honey-comb like network with a larger remodeling area and higher turnover rate.
Figure 1: General Bone Anatomy
And then there's bone marrow. Bone marrow is what's producing our white and red blood cells. The memory B cells and T cells part of our immune system actually reside in our bone marrow. If you're reinfected with a pathogen or virus you've previously had, your memory B cells and T cells that are sitting in your bone marrow can respond immediately and quickly upon reintroduction of the same antigen.
Hopefully, now you can see that bones are so much more than that static skeleton hanging in your high school science teacher's lab room!
Osteoblasts and Osteoclasts
Osteoblasts are the bone cells responsible for building bone. They accomplish this by producing a collagen bone matrix and mineralizing it.
Osteoclasts remove bone by reabsorbing calcified bone and the collagen matrix.
In summary, osteoblasts contribute to increasing our bone mineral density and osteoclasts do the opposite. This exists in an equilibrium. We are constantly remodeling bones, adding to and subtracting from our bones through calcium turnover.
Bones need to be both strong and flexible at the same time, which is why they're constantly engaging in remodeling. Bones that are strong but inflexible would be brittle and easily broken. Bones that are inflexible but not strong would not be able to support the weight of your body or stress from your muscles pulling on them. It's a fine (and oh so beautiful!) balance.
Bone Composition
Bone is made up of about 50 to 70 percent minerals (inorganic) and 20 to 40 percent an organic matrix of carbon, hydrogen, and oxygen. The remaining portion of bone is a bit of water and lipid (fat).
The mineral matrix component of bone is in the form of elongated platelet-like carbonated calcium phosphate particles whose elongated direction is aligned along the long axis of type 1 collagen fibrils. Those collagen fibrils compose the organic matrix of bone, together with different types of molecules, including proteoglycans and non-collagenous proteins.
At the micro level, calcium balance is happening quite frequently. Virtually all of the body's calcium is contained within bone and therefore bone plays a very important role in calcium homeostasis.
We tend to think of bones as structural entities, which of course that is their major role. However, they're also a very important reservoir for calcium, which is another very important ion/mineral in the activity of every cell in our body.
Osteopenia and Osteoporosis
Figure 2. Loss of bone mass in decline from healthy bone to osteoporosis
Osteopenia and osteoporosis exist on a continuum relative to healthy bone. As seen in Figure 2, healthy bone contains a more dense matrix of calcified mineral relative to bones experiencing osteopenia and osteoporosis.
When you go from healthy bones to osteopenia, that represents about a 10% reduction in bone mineral density relative to a young healthy adult. Osteoporosis is a further degradation of bone mineral density, where you hit about 25% reduction.
Bone mineral density can actually potentially improve up to about the age of 30 years old. It can stay quite consistent in both men and women until you're about 40 or 50, and then bone loss effectively starts to occur.
For women, bone loss can be much more pronounced. About seven to 10 years around the onset of menopause, bone loss can be three to 7% annually. By the time they reach 65, bone loss starts to slow down a bit, so it might look more like 0.5% to 2% per year.
In men over 65, it's actually a higher rate of bone loss, but they're starting at a much higher point than women because they don't suffer that precipitous loss the way women do after menopause due to the loss of estrogen. For men at age 65%, the bone loss is about 1% to 2% per year.
This is why it's SO IMPORTANT to optimize your nutrition and exercise throughout adolescence and your 20s to support your bone mineral density. Essentially, if you don't reach your full genetic potential for bone mineral density by the age of 20, you're missing an enormous opportunity later in life to have as strong of bones as possible.
If you're curious what your own bone mineral density is, a DEXA scan is a super low radiation scan that takes about 10 minutes. You lay flat on a table and a little scanner that uses low dose X-rays moves over your body. Prior to getting a DEXA scan, I would confirm they are giving you segmental bone analysis for the left hip, right hip, and lumbar spine and not just a whole body bone mineral density metric.
Role of Estrogen in Bone Health
The signaling process to deposit more bone tissue is highly regulated by the hormone estrogen. Estrogen modulates the signal of stress that comes from some external stimulus, such as lifting something heavy or climbing stairs. When your bone senses that they need to support a greater force, it remodels by depositing more and more bone tissue.
In the absence of estrogen, that signal gets reduced and that's effectively why menopause, which is a sudden withdrawal of estrogen, can be such an impactful thing for women who don't have their hormones replaced.
It's also why losing your menstrual cycle in the pre-menopause stage can be so harmful for your bone mineral density. Some athletes experiencing Relative Energy Deficiency in Sport or RED-S, may lose their cycle due to low energy availability, especially during intense training blocks. It's not a badge of honor to lose your menstrual cycle, it's actually a major signal from your body that something needs to be adjusted (training load, fueling, stress, etc.)
No, oral birth control, which contains synthetic estrogen, is not the answer either. I plan to do another blog post on this topic, as it's essential for female athletes to understand the importance of maintaining a regular menstrual cycle.
What about men? Does estrogen affect their bone health? Men are also losing estrogen as they age. Estrogen comes primarily from testosterone conversion. Testosterone is aromatized into estrogen. Therefore, a man with a testosterone level of 800 is going to have a higher estrogen level than a man with 300.
Men lose estrogen at a far more gradual rate than women, and that's why women experience this loss more significantly, placing them at a greater risk for osteopenia and osteoporosis.
Nutrition and Supplements for Bone Health
There are several nutrients, micro and macro, that play a vital role in maintaining adequate bone health, including calcium, vitamin D, iron, magnesium, protein, and carbohydrates.
Bone is a living tissue, so it requires all essential nutrients for growth and maintenance. If you eat a balanced diet that contains a variety of fruits, vegetables, legumes, whole grains, nuts, seeds, and protein, you're likely getting enough of most of the nutrients needed to keep your bones healthy and functioning well. However, certain people, such as those over age 65, pregnant or lactating women, or endurance athletes, may need to be more strategic about certain nutrients in their diets.
Calcium
The Recommended Daily Allowance (RDA) for adults for calcium is 1000-12000 mg per day. The RDA is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals. Therefore, you should think of the RDA as the bare minimum recommended intake.
Some of my favorite dietary sources of calcium include Greek yogurt, dried figs, prunes, tofu, sesame seeds (tahini!), spinach, cheese, salmon, broccoli, almonds and almond butter, and white beans. There are a lot of different dietary sources of calcium beyond a glass of milk!
I don't usually recommend a calcium supplement, but calcium carbonate and calcium citrate are reasonable options. High or inappropriate doses of calcium supplements can lead to uncomfortable side effects, such as constipation. In addition, a meta-analysis including eleven randomized controlled trials showed calcium supplements have up to 30% increased risk for myocardial infarction.
The finding of an adverse trend in cardiovascular diseases with calcium supplementation is not necessarily surprising, as calcium supplements potentially contribute to elevated serum calcium levels and possibly accelerated cardiovascular calcification in the long run, which is predictive of cardiovascular event rates.
My Registered Dietitian opinion: take a food first approach when it comes to optimizing your calcium levels and work with a practitioner before supplementing with calcium. Whole foods, especially dairy, provide an entire package of nutrients structurally important to bones. Hydroxyapatite, the mineral complex providing bone structure, is very similar to the mineral composition of dairy products, including yogurt, cheese, and milk.
Vitamin D
The RDA for vitamin D is 800 to 1000 IU per day. Vitamin D is fairly difficult to obtain in adequate amounts from diet alone. The average adult American diet only contains about 150 to 300 IU of vitamin D per day. Not many foods are high in vitamin D, but those that are include salmon, mushrooms, eggs, beef liver, and fortified milk.
There are two forms of vitamin D: vitamin D2 and D3. Vitamin D3 is the active form, so when supplementing with vitamin D, always look for the D3 form. Something important to consider is that vitamin D increases the gut's absorption of calcium. Therefore, if you're vitamin D deficient, you're also going to have trouble absorbing calcium through the gut.
We can also get vitamin D from the sun, which is why it's often referred to as the "sunshine vitamin." When your skin is exposed to sunlight, it manufactures vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D.
The Endocrine society recommends 1500 - 2000 IU of daily vitamin D, and current research suggests that supplemental vitamin D is associated with decreases in mortality. Therefore, supplementation with 400 IU to 1000 IU of vitamin D per day is reasonable for the majority of healthy Americans. However, I recommend working with your doctor or Registered Dietitian to check your vitamin D levels annually to determine if you could benefit from higher doses of supplementation. In general, a vitamin D level that is greater than 60 ng/dL is favorable.
Magnesium
More than half of the body's store of magnesium is in the bone, and it plays an important role in organic matrix bone synthesis. Magnesium can also be lost through sweat, so if you're an active person who is sweating a lot, such as an endurance athlete, you may be at higher risk of experiencing magnesium deficiency.
The RDA for magnesium is 300 to 500 mg per day. Similar to vitamin D, magnesium is relatively difficult to eat in adequate amounts through food alone. Most people are magnesium deficient and may benefit from a daily supplement. Magnesium supplements exist in many different forms, and each of those forms serve a different purpose.
Magnesium glycinate is my favorite form and most widely used with all my clients. It's well absorbed in the body and supports muscle relaxation and sleep quality. If you struggle with constipation, magnesium citrate or oxide may be more appropriate for you, but they are not as well absorbed in the body. If you're looking for a form of magnesium to support anxiety and stress response, magnesium threonate may be the best choice for you.
Some of my favorite dietary sources of magnesium include pumpkin seeds, chia seeds, almonds, quinoa, dark chocolate, cacao nibs, dark leafy greens, avocado, and bananas.
Iron
Iron has an important role in vitamin D metabolism and collagen synthesis. Those with disorders of iron metabolism have been suggested to have lower bone mass and an increased risk of suffering an osteoporotic bone fracture.
Iron helps limit osteoclasts (bone breakdown) activity. Here's how this works:
Osteoclasts contain both HIF1a and estrogen.
HIF1a is a protein that responds to low oxygen concentrations.
As we discussed previously, estrogen plays an essential role to bone growth and development.
During iron deficiency, it's more difficult for the body to deliver oxygen to working muscles.
Under normal oxygen conditions (adequate iron) of the tissue, iron limits HIF1a (and therefore limits bone breakdown).
HIF1a accumulates when oxygen levels are insufficient (iron deficiency).
When estrogen is low, HIF1a stimulates osteoclast activity.
So, if you're iron deficient with or without anemia, it's safe to say you are at higher risk of a bone stress injury (especially as a female athlete) or that long term, bone density maybe be impacted under chronic conditions.
A very high intake of iron might also be bad for the bone, likely due to the increased oxidative stress and inflammatory response that can occur as a result of iron overload. This is a large reason why I'm not keen on blindly supplementing with iron without completing an iron blood serum panel.
I suggest working with your doctor to run a complete a CBC and iron panel, which would include serum iron, TIBC, UIBC, transferrin, and iron saturation. You may have to specifically ask for ferritin, which is a marker of your iron storage. It's important to consider that iron levels that may be within range for the general population may not be optimal for athletes, endurance athletes, female athletes, and athletes living at high altitude.
Some of my favorite dietary sources of iron include red meat, chicken thighs, legumes, nuts, whole grains, dried fruits, watermelon, and dark green leafy greens.
Protein
Protein is one of the main components of the organic matrix of bone for collagen structure. This important macronutrient has a role in the production of hormones and growth factors that modulate bone synthesis. Protein may have an indirect effect on bone health through its support for muscle mass and function, but also by increasing levels of IGF-1, which has an anabolic effect on bone. You can read more about protein and the differences between plant based and animal based protein in my blog post All About Protein.
Athletes are often recommended to consume more protein than is recommended for the general population, in order to support the additional demands of athletic training. The recommendations for athletes is to consume between 1.2 and 1.6 g/kg/day, although under certain circumstances this recommendation might increase to 2.2 to 2.5 g/kg/day, which is higher than the 0.8 g/kg/day recommended to the general population.
I can't talk about bones and protein without talking about collagen! Collagen accounts for about 30% of your body's total protein and is the most abundant protein in your body. As people age, the body’s ability to produce collagen decreases by around 1% to 1.5% per year. Collagen appears to support bone health, as collagen is an essential component to bone mass. Collagen has also been shown to help with with bone mineralization, which is the process that strengthens and hardens bones.
A 2018 study investigated the effects of specific collagen peptides on bone health in 131 postmenopausal people with reduced bone mineral density. The researchers measured the effects of taking 5 grams of collagen peptides daily for 12 months, compared with a placebo group. They looked at changes in bone mineral density in the femoral neck, which is the area where the thighbone joins the hip bone and the spine.
The results showed the collagen peptides increased bone mineral density and improved bone markers, indicating a reduction in bone loss and an increase in bone formation. In other words, collagen may help mitigate further bone loss.
You can get collagen from foods like bone broth, chicken skin, and organ meats. However, these foods are not often staples in most peoples diets, which is one of the reasons collagen supplements have become so popular and do have some merit to them.
Most collagen supplements are hydrolyzed, which means the collagen has been broken down to make it easier to absorb. These hydrolyzed formulas also dissolve nicely in beverages like coffee, making them easy to integrate into your daily routine. The types of collagen found in supplements vary — some contain one or two types, while others contain up to five. Type I collagen is the main type found in your skin, bones, tendons, and ligaments.
You can read more about collagen, its benefits, and the optimal dosage of collagen supplements in my blog post What You Need to Know About Collagen.
Carbohydrates
Carbohydrates don't often get thought of as an essential macronutrient for bone health. The relationship between carbohydrates and bone health is of particular importance to athletes and endurance athletes. While no studies have directly examined the effects of low carbohydrate availability on bone health in athletes, it has been shown that carbohydrate feeding can reduce bone turnover.
One study showed the provision of carbohydrate attenuated the bone resorption response to acute exercise in athletes involved in an 8-day overloaded endurance training trial. Sale et al. also showed a modest post-exercise reduction in bone resorption markers with carbohydrate feeding immediately before, during and immediately after a 120-min treadmill run in recreationally active individuals.
Bone stress injuries are common in athletes, resulting in time lost from training and competition. Diets that are low in energy availability have been associated with increased circulating bone resorption and reduced bone formation markers, particularly in response to prolonged exercise. However, studies have not separated the effects of low energy availability per se from an associated reduction in carbohydrate availability.
One study aimed to compare the effects of both low energy availability and low carbohydrate availability in elite endurance athletes. The study found that short‐term carbohydrate restriction resulted in reduced bone formation markers at rest and during exercise with further exercise‐related increases in a marker of bone resorption. Bone formation markers during exercise seemed to be maintained with low energy availability although resorption increased. In contrast, nutritional support with adequate energy and carbohydrate appeared to reduce unfavorable bone turnover responses to exercise in the the endurance athletes.
In summary, all these studies suggest that having adequate carbohydrate availability, particularly before, during, and after exercise, can help improve bone remineralization (which is a good thing!).
Major Takeaways
Quality nutrition is one of several important lifestyle choices to maintain good bone health. Quality nutrition also pertains to meeting your overall energy needs, especially if you're an athlete or endurance athlete.
There are key nutrients of concern related to bone health including protein, carbohydrates, iron, magnesium, calcium, and vitamin D.
The importance of quality nutrition can be difficult to appreciate because the effects are subtle over long periods of time. Small benefits daily over decades can make a big difference on having a higher risk of fracture or not.
Nutrition provides the raw materials for bone structure, but by itself, is not sufficient. Weight bearing exercise provides the stimulus and strain essential for bone remodeling. Check out Jessica Yeaton, DPT post on how to optimize bone health through strength training!
References:
Price CT, Langford JR, Liporace FA. Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet. Open Orthop J. 2012;6:143-149. doi:10.2174/1874325001206010143
Von Euw, S., Wang, Y., Laurent, G. et al. Bone mineral: new insights into its chemical composition. Sci Rep 9, 8456 (2019). https://doi.org/10.1038/s41598-019-44620-6
Bolland MJ, Avenell A, Baron JA, et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010;341:c3691.
Weaver CM. Nutrition and bone health. Oral Dis. 2017;23(4):412-415. doi:10.1111/odi.12515
Sale C, Elliott-Sale KJ. Nutrition and Athlete Bone Health. Sports Med. 2019;49(Suppl 2):139-151. doi:10.1007/s40279-019-01161-2
Bjarnason NH, Henriksen EE, Alexandersen P, Christgau S, Henriksen DB, Christiansen C. Mechanism of circadian variation in bone resorption. Bone. 2002;30(1):307-313. doi:10.1016/s8756-3282(01)00662-7
Sale C, Varley I, Jones TW, James RM, Tang JC, Fraser WD, et al. Effect of carbohydrate feeding on the bone metabolic response to running. J Appl Physiol. 2015;119(7):824–830.
Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52:376–384.
Fensham NC, Heikura IA, McKay AKA, Tee N, Ackerman KE, Burke LM. Short-Term Carbohydrate Restriction Impairs Bone Formation at Rest and During Prolonged Exercise to a Greater Degree than Low Energy Availability. J Bone Miner Res. 2022;37(10):1915-1925. doi:10.1002/jbmr.4658
May 13, 2024
Food is Medicine —
Stay in the loop
Join the Rooted Nutrition Community for updates on all things from Sky's Rooted Nutrition.
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