How to improve your bone health

For many, a reduction in bone health, strength, and density is an all too common part of the aging process. Fortunately, several healthy lifestyle habits can potentially slow or even reverse bone loss as you age.1 Because many variables are associated with bone health, it helps to know and understand how to maintain healthy bones as we age.


What is bone health and why is it so important?

Bone is a constantly changing living tissue, even though its hardened appearance may make you think otherwise. Bones are mostly made up of collagen – a protein which provides the soft framework – and calcium phosphate, which adds strength and hardens the framework.

Bones play many important functions in the body, such as providing structure and scaffolding for your body, allowing you to move, anchoring muscles, storing calcium, and protecting your organs (e.g., brain, heart) from injury.

In your late teens to late 20s, your bones reach their “peak bone mass,” meaning that most of the bone in your body has reached the highest density it will ever achieve during your life.2

Lifestyle habits — especially diet and exercise, and especially during the period of bone growth in childhood through young adulthood — can influence your peak bone mass by approximately 20 to 40%.3 Around midlife, you will likely start to lose bone as part of the aging process, though this loss can be blunted and sometimes prevented through adoption of important lifestyle habits. Since bone loss is “silent,” most people are unaware that they are losing bone.

Unfortunately, poor bone health later in life increases your risk of fracture and frailty, which can have a profound effect on your independence and quality of life. That is why it pays to prioritize bone health as you age.4


Measuring bone health

As bones start to slowly thin out with age, they can become less dense, more brittle, and more likely to break. As this process advances, it can result in osteopenia (low bone mass) or osteoporosis (severe bone loss). Osteoporosis afflicts approximately 200 million people worldwide.5 This condition leads to more than 8.9 million fractures every year, and an osteoporotic fracture occurs every 3 seconds around the world.6

How do you know if you have poor bone health? Bone health can be measured using a bone scan machine called DEXA, short for dual x-ray absorptiometry.7 This machine measures the density of your bones. If your density values are low compared to the appropriate reference population, you may be diagnosed as having osteopenia or osteoporosis.


Are you at risk for poor bone health?

We can divide the many factors associated with bone growth and bone loss into two main categories: nonmodifiable and modifiable.

Examples of the nonmodifiable risk factors — meaning you cannot change them — are age, sex, heredity, and ethnicity or race. Research shows that being female, having a genetic predisposition, and being Caucasian or Asian all increase your risk for accelerated, age-related bone loss.8 Although you cannot do anything to change these factors, you can focus on your modifiable variables to help keep your bones healthy.

Modifiable variables are ones you can change during your lifetime to help prevent or slow age-related bone loss. Most of these variables are associated with lifestyle, such as diet, exercise, smoking habits, and alcohol intake. Good nutrition — as well as staying active, not smoking, and avoiding heavy drinking — can help to keep your bones strong as you age.9

Even though a large amount of research has explored lifestyle factors, many questions remain. Let’s take a look at them, so you can start making informed choices about how to keep your bones healthy.


Will taking calcium and vitamin D supplements or eating foods rich in these nutrients protect your bones?

For many years, taking calcium and vitamin D supplements has been touted as one of the best ways to protect the bones. While many studies have suggested that this is a good way to reduce the risk of developing osteoporosis and having fractures, other studies have shown little to no benefit of these supplements in preventing bone loss and fractures in otherwise healthy people (i.e. people without osteoporosis).10

In 2018, the US Preventive Services Task Force (USPSTF) reviewed the research to date and concluded that the evidence clearly shows that low doses of calcium and vitamin D do not reduce fracture risk in healthy people. But the report admits that there wasn’t adequate evidence to determine whether the typical (higher) doses recommended by multiple medical societies reduce these risks.11

When it comes to the risks of calcium and vitamin D supplements, kidney stones from excessive calcium intake would be the main concern as reported by the USPSTF.12

While secondary analyses of randomized controlled trials had raised concern that calcium supplements might lead to increased cardiovascular events (e.g. heart attack and stroke), further review of the literature by multiple experts – as well as additional studies – have determined that the risk is most likely not increased.13

So, where does this leave us in regard to calcium and vitamin D? Well, it is well-known that calcium and vitamin D are critical players in metabolic bone health. We also know that inadequate dietary intake of calcium and vitamin D is associated with fracture risk in observational studies. Further, when it comes to calcium, we know that absorption of dietary calcium is better than absorption of calcium pills.14

Even though the evidence for benefit is uncertain, the risks of worsening bone health as we age would appear to outweigh the risks of aiming to consume adequate calcium in the diet. Therefore, incorporating natural sources of calcium from foods — such as dairy products, fatty fish, and leafy green vegetables — should be a safe choice for healthy aging and bone health.

Taking a small dose of a calcium supplement if you don’t completely meet the recommended amount through diet is most likely not going to be dangerous.

As for vitamin D, many people find it difficult to get enough through diet and sun exposure, so taking a vitamin D supplement is often reasonable.

If you are currently taking or plan to start taking calcium and/or vitamin D supplements to help your bones, it is always best to consult with your physician.


What other nutrients may help keep your bones healthy?

Can other nutrients besides calcium and vitamin D help your bones? The answer is maybe.

It is important to understand that there are no definitive answers to whether a specific nutrient will improve bone health, mainly due to the limitations in nutrition research. However, a few other nutrients have been identified as potentially important for our bones and may help to prevent bone loss.

Protein

Let’s take a look at protein. Remember that collagen, which makes up the soft framework of your bones, is a protein.

Research suggests a possible association between higher protein intake and improved bone health. A high protein intake (greater than the current U.S. recommended daily allowance of 0.8 g/kg body weight/day) may be beneficial for the prevention of bone loss and hip fractures in older adults.15

Current research also suggests that higher levels of protein are needed as we age to prevent an age-related condition known as sarcopenia – the loss of muscle mass, strength, function and, ultimately, independence.16

The evidence for protein’s effect on bone and muscle health is very promising.

Vitamins and minerals

Other nutrients worthy of mention are vitamin K, potassium, magnesium, and vitamin C.

The current evidence for vitamin K suggests a beneficial role in bone health (with more evidence supporting K2), but findings from existing studies lack consistency. Nonetheless, there are a fair number of clinical trials that appear to show reduced fracture risk with various types of vitamin K supplementation.17

With respect to potassium, there are clinical trial and observational data suggesting that supplementing with potassium citrate or bicarbonate – or substantially increasing dietary potassium intake well above average levels – has the potential to improve bone health.

At these levels of intake, potassium can reduce urinary calcium losses and improve overall calcium balance in the body. On the other hand, not all trials have shown benefit, and the mechanism of how exactly potassium helps the bones is incompletely understood, raising more questions about the existence of a true benefit.18

When it comes to the relationship between magnesium and bone health, there are mechanistic data suggesting that it’s an important factor. However, clinical data in humans are mostly limited to observational studies, which have shown an association of lower magnesium intake with lower bone density and higher risk of fractures. Higher levels of magnesium intake, including via supplements, appear to be associated with higher bone density and lower risk of fracture.19

Similar to magnesium, there is good mechanistic evidence from animals and in vitro studies for why vitamin C is important for maintaining bone health. But most of the human data showing better bone density and lower fracture risk are from nutritional epidemiology studies and should be considered very weak evidence. The few intervention trials that exist had very different protocols, measured different variables, and showed mixed results, making it difficult to determine whether there is a role for vitamin C supplementation in preventing bone loss or treating osteoporosis.20

While it appears that vitamin K, potassium, magnesium, and vitamin C are important for maintaining bone health, it’s very difficult to link one specific nutrient to a specific outcome. A main reason for this is we eat foods containing a variety of nutrients that interact with each other, making it hard to separate out the specific effects of a single nutrient.

More recent studies have started to look at the impact of whole foods, food groups, and dietary patterns (vs single nutrients), with results being favorable for nutrient-rich green leafy vegetables and dairy intake.21

On the other hand, a Western-style diet — which includes energy-dense, nutrient-poor foods, such as refined carbohydrates and highly processed snack foods — may be associated with lower bone density and increased fracture risk.22

So, what’s the take-home message?

Aim to eat a healthy and nutrient-rich diet that includes plenty of dairy products and protein, as well as plant-based foods rich in vitamin K, potassium, magnesium, and vitamin C. This includes leafy greens, avocados, and berries — all part of a low-carb lifestyle, as we discuss later in this guide.


What type of exercise is best for bone health?

An active life is beneficial for both mental and physical health. Exercise has numerous benefits, and its effects on bone health are well documented for both preventing bone loss as well as treating conditions associated with poor bone health.

The evidence to date suggests that impact exercises combined with progressive strength-training – which places increasing amounts of mechanical load on the bones – is associated with small but statistically significant gains in bone density.23

While walking does not appear to have much impact on increasing bone density, regular walking over long periods of time may help preserve bone density at the hip.24

Taken as a whole, these findings suggest that you should combine regular physical activity, such as walking, with a strength-training program to maximize bone health.

It is important to note that when starting a new exercise program, you should consult with your doctor and a trained fitness professional if possible, especially if you have osteopenia or osteoporosis.


What are the effects of a low-carb or keto diet on bone health?

This is a question asked by many low-carb followers. To date, only a few studies have looked at the association between low-carb diets and bone health. In these studies, bone density was either preserved or went down but was no different than in the control group.25

One small clinical trial suggested that a ketogenic diet may be detrimental to bone. However, the study had several weaknesses in methodology, making the findings questionable.26

Future studies will hopefully shed more light on the association between low-carb diets and long-term bone health.

Protein

Let’s revisit the issue of protein as it relates to a low-carb diet. It has been suggested that moderate to higher amounts of protein intake on a low-carb or keto diet may have an adverse effect on bone due to the potential increased acidity from protein-rich foods.

This “acid-alkaline” myth suggests that higher protein levels can lead to high acid levels in the body, thereby increasing calcium loss from the bone to “buffer” the high acidity. However, the mechanistic data upon which this hypothesis is based have been questioned and – to a large extent – refuted.27 And the majority of clinical data suggest higher protein intake is beneficial, not harmful, to bone health.28

Conclusion

Although research about the effects of a low-carb diet on bone health is limited, the evidence we have suggests that carbohydrate restriction does not lead to bone loss. Importantly, we must also consider that well-formulated low-carb diets emphasize the consumption of protein and nutrient-rich vegetables, which evidence suggests are important for bone health as well as overall health.

  1. The Cochrane Database of Systemic Reviews 2011: Exercise for preventing and treating osteoporosis in postmenopausal women [systematic review of randomized controlled trials type; strong evidence]

    Nutrients 2019: Nutritional Support and Physical Modalities for People with Osteoporosis: Current Opinion[overview article; ungraded]

  2. Osteoporosis International 2000: Peak bone mass [overview article; ungraded]

  3. Osteoporosis International 2016: The National Osteoporosis Foundation’s position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations [review of RCTs and observational studies; weak evidence]

  4. Clin Orthop Relat Res. 2004. Osteoporosis: a review [review; ungraded]

  5. Clinical Orthopedics and Related Research 2004: Osteoporosis: a review [review; ungraded]

  6. Osteoporosis International 2006: An estimate of the worldwide prevalence and disability associated with osteoporotic fractures [observational prevalence study; weak evidence]

  7. Annals of the New York Academy of Sciences 2000: Assessing body composition and changes in body composition. Another look at dual-energy X-ray absorptiometry [overview; ungraded]

  8. Journal of Cellular Physiology 2015: Determinants of muscle and bone aging [overview article; ungraded]

  9. Current Osteoporosis Reports 2015: Lifestyle and osteoporosis [review; ungraded]

  10. Lancet 2007: Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis [meta-analysis of randomized controlled trials; strong evidence]

    Journal of the American Medical Association 2017: Association between calcium or vitamin D supplementation and fracture incidence in community-dwelling older adults: A systematic review and meta-analysis [systematic review and meta-analysis of randomized controlled trials; strong evidence]

    British Medical Journal 2015: Calcium intake and risk of fracture: systematic review [systematic review of RCTs and cohort studies; moderate evidence]

    British Medical Journal 2015: Calcium intake and bone mineral density: systematic review and meta-analysis [systematic review and meta-analysis of randomized controlled trials; strong evidence]

  11. Journal of the American Medical Association 2018: US Preventive Services Task Force: Vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling Adults: US Preventive Services Task Force recommendation statement [systematic review and meta-analysis; strong evidence]

  12. Journal of the American Medical Association 2018: US Preventive Services Task Force: Vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling Adults: US Preventive Services Task Force recommendation statement [systematic review and meta-analysis; strong evidence]

  13. Current Osteoporosis Reports 2014: Calcium supplementation: is protecting against osteoporosis counter to protecting against cardiovascular disease? [overview article; ungraded]

    Journal of Bone and Mineral Research 2014: The effects of 3 years of calcium supplementation on common carotid artery intimal medial thickness and carotid atherosclerosis in older women: an ancillary study of the CAIFOS randomized controlled trial[randomized trial; moderate evidence]

    Journal of Bone and Mineral Research 2015: The effects of calcium supplementation on verified coronary heart disease hospitalization and death in postmenopausal women: a collaborative meta-analysis of randomized controlled trials [systematic review and meta-analysis; strong evidence]

  14. Clinical Nutrition Research 2015: The role of calcium in human aging. [overview article; ungraded]

    Clinical Journal of the American Society of Nephrology 2008: Vitamin D in health and disease [overview; ungraded]

  15. Computational and Structural Biotechnology Journal 2019: High versus low dietary protein intake and bone health in older adults: a systematic review and meta-analysis [meta-analysis of observational studies and one RCT, very weak evidence]

    One randomized trial and a large observational study report better bone health in those who ate more protein.

    Journal of Bone and Mineral Research 2011: A real and volumetric bone mineral density and geometry at two levels of protein intake during caloric restriction: a randomized, controlled trial
    [ moderate evidence]

    Journal of Bone and Mineral Research 2000:
    Effect of dietary protein on bone loss in elderly men and women: the Framingham Osteoporosis Study
    [nutritional epidemiology study with HR<2; very weak evidence]

  16. The following reviews summarize the evidence for this nicely.

    Nutrients 2016: Protein consumption and the elderly: What is the optimal level of intake? [overview article; ungraded]

    American Journal of Clinical Nutrition 2015: Protein and healthy aging [overview article; ungraded]

    The following observational study reports a high association between eating more protein and having less disability with aging.

    Journal of the American Geriatrics Society 2019: Protein intake and disability trajectories in very old adults: The Newcastle 85 Study [observational study with HR over 2, weak evidence]

    Higher protein intake, especially when eating animal foods, is associated with greater muscle mass and the lowest functional decline risk.

    Journal of Gerontology Biological Science and Medical Science 2017: High-protein foods and physical activity protect against age-related muscle loss and functional decline [nutritional epidemiology study; very weak evidence]

    Subjects ages 70 to 79 eating more protein lost 40% less muscle mass compared to those who ate less:

    American Journal of Clinical Nutrition 2008: Dietary protein intake is associated with lean mass change in older, community-dwelling adults: the Health, Aging, and Body Composition (Health ABC) Study
    [nutritional epidemiology study with HR<2; very weak evidence]

  17. Nutrients 2020: Vitamin K and Osteoporosis[overview article; ungraded]

    Metabolism 2017: Vitamin K and osteoporosis: Myth or reality? [systematic review of randomized and nonrandomized trials; weak evidence]

  18. Advances in Nutrition 2013: Potassium and health[overview article; ungraded]

    Nutrients 2018: Potassium Citrate Supplementation Decreases the Biochemical Markers of Bone Loss in a Group of Osteopenic Women: The Results of a Randomized, Double-Blind, Placebo-Controlled Pilot Study[randomized trial; moderate evidence]

    Nutrition Research and Practice 2020: The association of potassium intake with bone mineral density and the prevalence of osteoporosis among older Korean adults[retrospective cross-sectional study; very weak evidence]

  19. As with all nutritional epidemiology studies, the strength of evidence should be considered very weak.

    Osteoporosis International 2016: Dietary magnesium intake, bone mineral density and risk of fracture: a systematic review and meta-analysis [systematic review and meta-analysis of observational studies; very weak evidence]

    British Journal of Nutrition 2017: Dietary magnesium intake and fracture risk: data from a large prospective study [nutritional epidemiology study; very weak evidence]

    Nutrients 2021: Magnesium in Aging, Health and Diseases[overview article; ungraded]

  20. Nutrients 2020: Role of Vitamin C in Osteoporosis Development and Treatment-A Literature Review [overview; ungraded]

    Journal of Bone and Mineral Research 2015: The roles and mechanisms of actions of vitamin C in bone: New developments [overview; ungraded]

  21. Bone Reports 2020: The effects of vitamin K-rich green leafy vegetables on bone metabolism: A 4-week randomised controlled trial in middle-aged and older individuals [moderate evidence]

    This next paper used RCTs for the outcome of bone mineral density, which constitutes strong evidence. For fracture risk, which takes greater numbers of people and longer time periods to measure, they used prospective cohort studies, considered very weak evidence. Overall, therefore, we grade this as weak evidence.

    Nutrition Research Reviews 2018: Dairy products and bone health: how strong is the scientific evidence? [systematic review of randomized and observational trials; weak evidence]

  22. Nutrients 2017: Fat, sugar, and bone health: A complex relationship [overview; ungraded]

  23. Menopause 2017: A systematic review of the exercise effect on bone health: the importance of assessing mechanical loading in perimenopausal and postmenopausal women [systematic review of randomized controlled trials type; strong evidence]

    The Cochrane Database of Systemic Reviews 2011: Exercise for preventing and treating osteoporosis in postmenopausal women [systematic review of randomized controlled trials type; strong evidence]

  24. Menopause 2013: Effects of walking on the preservation of bone mineral density in perimenopausal and postmenopausal women: a systematic review and meta-analysis [systematic review and meta-analysis of randomized controlled trials; strong evidence]

  25. Nutrition 2016: Long-term effects of a very-low-carbohydrate weight-loss diet and an isocaloric low-fat diet on bone health in obese adults [randomized trial; moderate evidence]

    Annals of Internal Medicine 2010: Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial [randomized trial; moderate evidence]

    The Journal of Pediatrics 2010: Efficacy and safety of a high protein, low carbohydrate diet for weight loss in severely obese adolescents [randomized trial; moderate evidence]

  26. The trial involved just 30 subjects for only three and a half weeks. In addition, the study population was athletes, so findings may not be applicable to the general population.

    Perhaps most importantly, they measured bone turnover markers (as opposed to bone mineral density) as a surrogate for bone health. Bone turnover markers are a dynamic measure and don’t always correlate well with bone density changes or fracture risk, so it’s hard to know how these findings should be interpreted.

    Frontiers in Endocrinology (Lausanne) 2020: A short-term ketogenic diet impairs markers of bone health in response to exercise [randomized trial; moderate evidence]

    To further explain how bone turnover markers don’t always equate with clinically meaningful outcomes, consider the following study that demonstrates the importance of measuring the right variables. Even though ghrelin had been shown to be associated with bone turnover, there was no association of ghrelin with changes in bone mineral density.

    Journal of Bone and Mineral Research 2006: Ghrelin and bone: is there an association in older adults? The Rancho Bernardo study. [nonrandomized trial; weak evidence]

  27. Current Osteoporosis Reports 2017: High dietary protein intake and protein-related acid load on bone health [overview article; ungraded]

    British Journal of Nutrition 2013: Nutritional disturbance in acid-base balance and osteoporosis: a hypothesis that disregards the essential homeostatic role of the kidney[overview article; ungraded]

  28. Nutrition Today 2019: Optimizing dietary protein for lifelong bone health [overview article; ungraded]

    International Journal of Vitamin and Nutrition research 2011: Protein intake and bone health
    [overview article; ungraded]

    American Journal of Clinical Nutrition 2008: Amount and type of protein influences bone health
    [overview article; ungraded]