Yes, we know. Calcium is an essential part of a bone health diet. Kudos to the dairy industry for making the two synonymous. And while it’s not necessarily a bad thing to think of calcium – or even dairy – when we think bone, calcium certainly isn’t the end of the story. Indeed, if we stop there, we’re in big trouble.
A rich body of research shows that calcium is just one small piece of the bone health puzzle. And, guess what? We can even get that calcium from non-dairy sources. So, in today’s article, let’s explore all the factors associated with a bone health diet.
The Life Cycle of Bone
While it may seem like bones are more static than the other tissues in our bodies, they’re simply not. Bones experience a high rate of turnover, just like our skin cells, muscle cells, and more. To this end, bones are continually breaking down and building up. And this is necessary for bone repair and for safeguarding blood mineral levels.
Until about the age of 20 we have the opportunity to build our bone “retirement fund”. Small deposits can be made when we have the appropriate food/nutrients coming in. The right amounts of stress – think exercise – can also make a huge difference over time.
However, starting around the age of 40, bone withdrawals start to exceed bone deposits. If bone deposits early in life were sparse (e.g., poor nutrition and no exercise), the bone bank account runs dry rather quickly, leading to weakness and pathology.
After the age of 50, 1 in 2 women (and 1 in 4 men) will experience a fracture related to weak bones. And that’s a shame because many of these are preventable with the right intake of food and drink – and appropriate exercise. To this end, let’s discuss the critical nutritional factors related to strong bones.
Dietary Minerals and Bone Health
If there isn’t enough calcium coming into the body, bone is broken down to restore levels in the blood. This helps to maintain whole body calcium homeostasis, making bone an important storage site for mobilizable calcium.
Unfortunately, consuming a lot of dietary calcium doesn’t automatically lead to stronger bones. What really matters is how much of that calcium gets absorbed.
In the United States and Canada, calcium requirements are 1,200 mg/day for adults. And this recommendation is a result of the standard American diet’s effect on calcium absorption and retention – it tends to reduce both. Individuals requirement for calcium, of course, can vary greatly with some data indicating as little as 415 mg per day and some indicating as much as 1,740 mg/day, depending on the overall diet.
Here’s an interesting fact. In many other countries where average daily calcium intake is lower (e.g., Japan, India, Peru), the incidence of bone fractures is also quite low. How can this be? Well, because a high intake of dietary calcium might not be all that important for bone health. Especially calcium in supplemental form.
Sure, there’s some research to suggest calcium is important. But for every study that says it is, another says it isn’t. One reason the data may be mixed – with supplementation in particular – is that in those who are deficient, calcium supplements may reduce bone turnover and fracture. However, if someone’s dietary intake is adequate, the supplements will have no impact on bone health.
But there is some bad news for those supplementing excessively. Too much dietary calcium can decrease phosphorus, iron and zinc absorption, and lead to calcium plaques on blood vessels, triggering cardiovascular problems.
Magnesium is another important mineral that contributes to the bone matrix. And potassium promotes calcium retention. Plus, both minerals support an alkaline environment in the body, essential for good bone health. When potassium and magnesium intake are low, and sodium intake is high – as is common in the standard American diet – bone development can be impaired as excessive dietary sodium can increase urinary calcium losses.
Another mineral important here is phosphorus. Balancing phosphorus with calcium intake is necessary for bone mineralization (more information on this below).
Dietary Vitamins and a Bone Health Diet
One of the most important vitamins related to a bone health diet is vitamin D. Without enough active vitamin D in the body, dietary calcium cannot be absorbed and bone renewal is halted. Since there’s very little vitamin D in our food supply, it’s important to get vitamin D in supplemental form, or from the sun. For more information on vitamin D, click here.
In addition, the following vitamins play an important role in a bone health diet:
- Vitamin A deficiency or excess can cause bone abnormalities.
- An adequate intake of B vitamins can help offset elevated levels of homocysteine in the blood, helping to preserve bone.
- Vitamin B12, vitamin C and vitamin E can stimulate bone building cells, inhibit bone breakdown, and reduce oxidative stress.
- Vitamin K may help to slow age related bone loss and works in collaboration with vitamin D.
Eating Patterns and a Bone Health Diet
While we often spend most of our time discussing individual nutrients, when looking at the research, overall eating patterns actually predict bone health far better than individual nutrients. That’s why consuming whole foods – and enjoying the rich bounty of vitamins and minerals present within – is a better strategy than loading up on supplements.
Of course, fruits and vegetables are rich in nutrients and compounds that protect bone. So diets emphasizing them seem to be bone building. On the other hand, diets emphasizing processed foods, sugars and animal proteins (which can displace plant foods if we’re not careful) seem to be less protective of bones.
It’s important to note here that we’re not suggesting supplements are useless in helping with bone health. Rather, we’re suggesting that you look to whole foods first. Then, if deficiencies persist, a supplement might be warranted. For more on vitamin and mineral supplements, click here.
Dairy Intake and a Bone Health Diet
The Dairy Council has convinced millions that consuming additional dairy is essential for bone health. However, the research paints a different picture. Diets emphasizing dairy don’t necessarily optimize bone health. In many parts of the world dairy is a negligible part of the diet, and yet bone problems associated with lack of calcium are rare. So other factors are at play.
This quote sums up the research quite well:
Scant evidence supports nutrition guidelines focused specifically on increasing milk or other dairy product intake for promoting child and adolescent bone mineralization. (Lanou 2006)
Again, we’re not suggesting dairy is bad. Instead, we’re just pointing out that the food most promoted for bone health isn’t necessary the strongest choice. Indeed, with less dairy in the diet, there’s more room for bone building vegetables and fruits, especially calcium-rich choices like dark leafy greens, beans, nuts, and seeds.
Here’s a list of the top plant-based, non-dairy sources of calcium:
- Tofu 350 mg per ½ cup
- Tapioca 300 mg per ½ cup
- Chia seeds 300 mg per 1.5 ounces
- Fortified non-dairy milk 300 mg per 1 cup
- Collard greens 210 mg per ½ cup
- Kale 205 mg per ½ cup
- Bok Choy 190 mg per ½ cup
- Figs 135 mg per 5 figs
- White Beans 120 mg per ½ cup
- Turnip Greens 104 mg per ½ cup
- Spinach 99 mg per ½ cup
- Almonds 93 mg per ¼ cup
- Sesame Seeds 51 mg per 1 tablespoon
In the end, the research is clear. The foods most correlated with a bone health diet are plant-based foods; namely calcium-rich veggies and fruits. Dairy falls lower down the list. For more about dairy and milk, click here.
Protein Intake and Bone Health
In the past, there was some debate as to whether a higher intake of protein could negatively impact bone health. But this idea has been thoroughly debunked. Indeed, consuming up to 1.6 g/kg of protein per day (2x the current recommendation) can help:
- Increase calcium absorption
- Increase IGF-1 (a compound that stimulates bone deposition)
- Decrease parathyroid hormone (low protein intake can lead to secondary hyperparathyroidism)
All three of these lead to stronger bones. That’s why a higher protein diet is likely best for bone health. But keep in mind that consuming mostly animal protein in the diet can lead to higher calcium losses. That’s why a key to balancing out higher animal protein intakes is to make sure that plenty of whole vegetables and fruits are included in the diet. Again, these are rich in bone building and alkalizing nutrients.
A quick note on soy: soy-based foods are a dense source of protein and tend to have a positive impact on bone. This might be due to the impact of soy isoflavones on estrogen receptors. However, because of the potentially negative impact of soy on the other systems of the body, we recommend it only make up a very small percentage of the diet. For more about soy, click here.
Dietary Alkalinity and a Bone Health Diet
The overall acidity (or alkalinity) of the diet can play a large role in bone health as well. Interestingly, grains – as well as foods high in protein and phosphorus – present themselves as acidic once digested and absorbed. On the other hand, foods high in potassium, calcium and magnesium present themselves as alkaline once digested and absorbed.
If the diet is out of balance, and too many acidic foods (think meat, fish, most grains and cheeses) dominate at the expense of alkaline foods (think vegetables and fruits), low-grade acidosis can develop in the body. And this metabolic situation can cause calcium to be leached from bones to help neutralize the pH of body fluids. Fortunately, this situation is easily corrected by increasing the intake of alkaline food and drink, with vegetables and fruits being the best options.
Also remember, while our ability to buffer a net acid load with calcium from bone is frowned upon for longevity and health, during times of starvation and/or high meat intake at the exclusion of plant foods, this ability gave us a survival advantage. For more about dietary acid and alkaline balance, click here.
Beverage Consumption and a Bone Health Diet
We often hear that soft drinks – even diet soft drinks – are bad for a bone health diet. This is because they often contain phosphoric acid. Especially cola. Lots of phosphorus coming in the body can bind calcium (leaving less for bones), stimulate parathyroid hormone, and diminish active vitamin D formation.
And speaking of beverages, alcoholism is associated with poor bone health (for the exact reasons you are probably thinking of). High alcohol intake can displace nutrient rich food intake, interfere with nutrient absorption, increase parathyroid hormone, and can skew reproductive hormones in the body.
Conversely, moderate alcohol consumption might be bone protective. Why? Well, beer and wine contain silicone, a compound that can help bone. And since moderate alcohol intake may slightly increase estrogen levels in the body, this can help to preserve bone as well. For more about alcohol intake, click here.
Recommendations for a Bone Health Diet
In the end, as you’ve probably considered so far, eating to improve bone health also promotes general health. According to the research, the best practices include:
- Focus on overall dietary quality more than any one single food or beverage.
- Eat nutrient rich whole foods, including plenty of vegetables and fruits – at least 5 servings per day. One serving is about the size of your fist.
- Eat plenty of foods rich in calcium, magnesium, potassium, and B vitamins.
- Consider getting blood levels of vitamin D tested and using a supplement if needed.
- Eat enough protein to assist in bone building, which happens to be the same dose required muscle building – for men this means about 2 palm-sized portions per meal and for women this means about 1 palm-sized portion per meal.
- Consider a vitamin B12 supplement if needs aren’t being met from the diet.
- If one’s diet is built around animal proteins, grains and/or processed foods, consider a calcium supplement as well.
For Extra Credit
Looking for more interesting facts about how diet and lifestyle impact bone health? Check these out:
- Performing regular physical activity with impact is the soundest method of preserving bone health. Still, masters level athletes experience bone loss, so other factors are at play.
- The hormone estrogen tends to increase bone formation.
- Smoking damages bones.
- Visceral fat (around your organs) seems to have a more negative influence on bone, whereas subcutaneous fat (just under your skin) seems to have a protective effect.
- The supplement creatine may increase bone formation via increases in osteoblast activity and decreases in osteoclast activity.
- While all fruits and vegetables appear to improve bone health, prunes appear to have a bonus effect. Eating 10 prunes per day has been shown to inhibit bone breakdown.
- The hormone leptin tends to have a positive influence on bone.
- Per calorie, kale has more calcium than milk. And it might be absorbed better as well.
- Bone contains 99% of the body’s calcium.
- Bone contains 60% of the body’s magnesium.
- The recommended calcium intake per day in Japan for adults is 600 mg/day.
About The Authors
Dr. John Berardi received his PhD in exercise physiology and nutrient biochemistry at the University of Western Ontario, Canada. He’s currently an Adjunct Professor at Eastern Michigan University and the University of Texas. For the last 4 years, Dr. Berardi has acted as the director of the world’s largest body transformation project, a one-of-a- kind lifestyle-coaching program that’s produced more weight loss than all seasons of The Biggest Loser combined. Dr. Berardi is currently the Chief Science Officer of Precision Nutrition, offering life-changing, research-driven nutrition coaching for everyone.
Ryan D. Andrews is a registered dietitian and strength and conditioning specialist who completed his education in exercise and nutrition at the University of Northern Colorado, Kent State University, and Johns Hopkins Medicine. He’s written dozens of research articles on nutrition, exercise, and health, authored Drop The Fat Act & Live Lean, and coauthored The Essentials of Sport and Exercise Nutrition Certification Manual. Ryan is currently a coach with Precision Nutrition, offering life-changing, research-driven nutrition coaching for everyone.
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For more information, check out my Osteoporosis Guidelines.