Some aspects of health are visible on the outside. But below your skin, your hair, and your body fat percentage hide another, often-neglected part of your body that you can support (or destroy) with diet: your bones and joints. They don't show up in before-and-after photos, but as anyone with runner's knee or arthritis could tell you, the health of your skeleton has a huge impact on your quality of life.
The standard nutritional advice for “strong bones and teeth” goes something like this: drink lots of skim milk, eat lots of low-fat yogurt, and take a calcium supplement, and you’ll be golden. And mainstream nutrition has almost nothing at all to say about joint pain and joint disorders. But is this really good advice?
Not from a Paleo perspective. There’s a lot more to bone health than calcium, and diet actually is important for joint pain! So what really is important for good bone health, and how can you make sure your skeleton stays happy? When you look at all the evidence, Paleo isn’t perfect, but it sure beats the calcium overload.
Calcium and Bone Mineral Density
Let’s start with the one thing “everyone knows” about bones: to keep them strong, you need a lot of calcium. It’s true that a large percentage of your bones by weight is made up of minerals, calcium included. If those minerals are deficient in your diet, your body will make up the lack by leaching them out of your bones, and your bone mineral density (the amount of minerals present in your bones) will decrease.
Just judging from this, calcium seems like a no-brainer when it comes to avoiding bone density diseases (osteoporosis and osteopenia). More calcium equals denser, stronger bones, which reduces your risk of fracture…right?
Unfortunately, this theory really doesn’t hold water. First of all, calcium isn’t the only factor – or even the major factor – that accounts for increased bone mineral density. Take a look at these two studies:
- This study found that bone mineral density shows little variation with calcium intakes that range between 400 and 2000 mg per day (for reference the recommended daily value is 1000-1200mg). Going substantially over or under the official target had little noticeable effect.
- Calcium also has risks: In this study, for example, women who were randomized to calcium supplements (1000mg) or placebo; the women taking the supplements had a significantly increased risk of cardiovascular events.
The upshot: higher calcium intake does not necessarily correspond to better bone mineral density, and it may even have risks.
That doesn’t mean micronutrients are useless; it just means you need to be smart about them. For starters, calcium won’t actually do you any good without a little help from its friends:
- Vitamin D: allows your body to absorb the calcium so you can actually use what you eat. Study after study has shown that just taking calcium supplements without any Vitamin D has no effect whatsoever on preventing bone problems.
- Vitamin K2: makes sure that calcium gets to your bones (where you want it), and not your arteries (where you don’t).
Then there are all the other non-calcium-related micronutrients that your bones, joints, and skin need to stay in tip-top shape. These include Vitamins A, C, E, and K, magnesium, and potassium. But the good news is that there’s no evidence supporting the need to supplement with these nutrients. This review says it best: “supplementation…may not be required, except in those with chronic disease and the frail elderly.”
What you should do to get these valuable nutrients in your diet is to eat a wide variety of nutrient-dense foods: see the Food Recommendations section below.
Proteins for Strong Bones and Joints
Dethroning calcium from its cozy position as the king of bone mineral density is radical enough. But that’s just the tip of the iceberg. Even more counterintuitively, bone mineral density itself is very overrated as a predictor of fragility or real-life fracture risk So even if you could achieve incredible new heights of bone mineral density by increasing your calcium intake, it wouldn’t necessarily do you any good in the real world. Bones have a very complex structure that is made of more than just minerals, and all kinds of problems with the proteins involved can also lead to fragile bones.
This study explains some very convincing evidence that bone mineral density doesn’t explain the whole story about fragility and fracture risk:
- Most patients with fragile bones do not have osteoporosis or any problems with their bone minerals at all.
- Some treatments for osteoporosis increase bone mineral density, but decrease bone strength.
- Other treatments improve bone strength with almost no effect on bone mineral density.
- Strength training improves bone strength even when it only causes negligible increases in bone mineral density.
The lesson to draw from all of this is that the proteins in your bones are just as important as the minerals. Where minerals build strength, protein cross-linking builds durability, making your bones more resistant to shattering.
Proteins are also major components of your joints and cartilage: they help keep everything flexible enough to move without pain. For optimal bone and joint health, it’s important to get enough of these bone-building proteins in your diet, so your body can have them when it needs them:
- Collagen. Collagen is a protein found abundantly in human and animal skeletal systems (in its cooked form, derived from animal bones and skin, it’s also called gelatin). In this study, collagen hydrolysate improved joint pain significantly (52% of patients improved) compared to placebo (37% of patients improved) after 6 months of use.
- Glucosamine. Glucosamine is a protein found in cartilage and connective tissue, as well as the exoskeletons of shellfish (like shrimp and crayfish). This makes it promising for bone and joint health, as a “building block” of healthy tissue. This study and this one examined the available evidence for glucosamine as a treatment for osteoarthritis. In several clinical trials, glucosamine reduced pain and improved joint function in arthritis patients. The evidence is (as always) conflicting and some trials show no significant improvement, but on the other hand, there aren’t any reported serious side effects.
These proteins are found largely in the “odd bits,” animal products much scarcer in the American diet today than they used to be. So it’s no surprise that even the dairy-heavy, calcium-rich American diet leads to all kinds of bone and joint pain: it completely ignores an essential class of nutrients for maintaining our skeleton in peak condition. By contrast, the Paleo model of nose-to-tail eating provides much more of these important proteins.
Metabolic Syndrome and Bone Health
Another topic that you’ll rarely hear about in the standard literature about bone health is carbohydrates. But maintaining a healthy and normal ability to metabolize carbohydrates is crucial for avoiding fractures. People with diabetes have much higher fracture rates (despite having higher than usual bone mineral density – more proof that the minerals alone don’t tell the whole story). In this study, for example, women with Type 2 diabetes had higher bone mineral density at the neck, but “weaker skeletal geometry:” in real-life situations, their bones didn’t hold up as well to stress.
Some studies have suggested that this effect might be caused by advanced glycation end-products, harmful free radicals formed in people with very high blood sugar, especially when they eat a lot of PUFA or fructose.
Whatever its cause, the diabetes-bone health connection is another reason to pick a Paleo diet over calcium supplements when it comes to avoiding osteoporosis: Paleo is low in fructose and PUFA, and helps many people control their blood sugar and manage the metabolic effects of diabetes by finding a carb level that’s right for them.
Other Nutrients to Consider
Two other nutrients are worth a mention for their potential to help your bones and joints stay strong and pain-free:
- Chondroitin. Chondroitin is a type of carbohydrate found in both human and animal bones. It’s usually given along with glucosamine when taken as a supplement. This study found that glucosamine plus chondroitin was effective for joint pain.
- Omega-3 fats, especially when they’re not oxidized. This study found that an antioxidant-rich lemon extract plus fish oil improved joint pain and stiffness. And this study confirmed that, showing the benefits of Omega-3 fats for juvenile arthritis.
In case the pattern isn’t pretty clear by now, these are both much more prevalent in a Paleo diet than in the standard American diet. Again, eating the foods your body actually needs turns out to be a much better strategy than overloading it with just one nutrient (calcium) to make up for a bad diet.
Exercise for Bone Health
Another important but underappreciated aspect of preventing (or managing) chronic bone and joint problems is actually a lifestyle fix: getting the right kind of exercise.
Resistance training improves bone strength.
One of the best things you can do for your bones is to do some kind of strength training on a regular basis. Strength training helps decrease fracture risk and improve bone health even though it doesn’t always improve bone mineral density. This is true for the typical “weightlifter” type (15-35 and healthy), but it’s never too late to start. For example, this Cochrane review found that resistance training in postmenopausal women had a small, but potentially significant benefit.
On the topic of weight training, one myth deserves to be mentioned and debunked: the total nonsense that “squatting is bad for your knees.” Attempting to keep their joints healthy and strong, many people avoid squatting, or only do half squats, because they believe that squatting to parallel will put too much stress on their knees and cause pain later.
This is simply not true. Squatting with bad form is, of course, bad for all kinds of things (your knees and back among them). But a correctly performed deep squat actually puts less pressure on your knees than a half squat. Take a look at this study. A relevant quotation:
Concerns about degenerative changes of the tendofemoral complex and the apparent higher risk for chondromalacia, osteoarthritis, and osteochondritis in deep squats are unfounded. With the same load configuration as in the deep squat, half and quarter squat training with comparatively supra-maximal loads will favour degenerative changes in the knee joints and spinal joints in the long term.
Translation: half squatting is bad for your knees. Deep squatting makes them stronger. The full range of motion in a squat below parallel makes squatting one of the most effective exercises for building strength, bone health, muscle power, balance, coordination, flexibility, and joint strength. There’s absolutely no reason to be afraid of it.
In fact, not only is strength training good for preventing bone and joint injuries in the first place, it’s actually beneficial for reducing knee pain in runners. That doesn’t mean that squatting are a magical therapy for injury – if you’re hurt, see a doctor before you try to self-medicate with a barbell. But it does demolish the idea that lifting heavy weights is in any way dangerous for your joints.
Aerobic exercise isn’t as good.
For improving bone strength, the ideal exercise is something that puts a heavy load on the bones, and cardio, unfortunately, doesn’t fit the bill. That’s not to say that it’s bad. It might help you reach other goals, or it might just be enjoyable to participate in, but it won’t do a whole lot if your goal is avoiding fracture risk.
Shock sports are a risk for overuse injuries.
It’s not all good on the exercise front, though. So-called “shock sports” are activities that require a lot of repetitive running, jumping, or pounding – think jogging on the sidewalk or playing basketball on a concrete court. As you might expect, this type of activity is a risk for overuse injuries: according to this recent review, up to 70% of recreational runners sustain injuries every year, the vast majority of those are overuse injuries, and fully half of them occur at the knee.
Overtraining in endurance sports can also have negative effects on bone quality even when it doesn’t lead to injury. This study found that endurance athletes had lower BMD scores than strength athletes – and, more alarmingly, sometimes they even had lower BMD scores than sedentary controls. BMD doesn’t tell the whole story, but it’s still telling that something supposedly “healthy” could actually make things worse.
Female athletes in particular should beware of the “Female Athlete Triad” (calorie restriction, osteoporosis, and amenorrhea). This is a problem affecting women who train too much and eat too little: if you’ve lost your period from intense exercise, chances are good that your bones are suffering too.
The lesson: more is not better. Again, the Paleo recommendation to get a moderate amount of exercise beats the standard “run on the treadmill as far as you can” line. A reasonable amount of strength training is just what the doctor ordered for maintaining good bone and joint health into old age, but be smart about activities that are tough on your body, and make sure you aren’t overtraining in anything.
So, how does all this science-talk actually help you improve your diet? Not sure where to get your chondroitin? Or concerned about how you can get your calcium without any dairy foods? Take a look at the top four Paleo foods for healthy bones:
- Bone-in Fish. With a big helping of anti-inflammatory Omega-3s, Vitamin D, and calcium all in one delicious package, bone-in sardines or salmon are a convenient triple dose of bone health.
- Green vegetables cooked in grass-fed butter. Grass-fed (but not grain-fed) butter is a rich source of Vitamin K2, and most green vegetables are quite high in calcium. This gives you the perfect combination: calcium to help your bones grow strong, and Vitamin K2 to make sure it gets there.
- Chuck roast. Chuck roast is full of collagen from all the connective tissue in the meat: that’s why it’s tough when it’s cooked wrong, but fall-apart tender and smooth when it’s done right. And if you braise it or slow-cook it in broth, keep the liquid: it’s full of good stuff and makes a delicious base for soups and stews.
- Bone broth. The old adage to “eat what ails you” comes true in this case: the best source of gelatin (the cooked form of collagen), glucosamine, and all the other important proteins in bones is…bones! The most nourishing bone broth is made with plenty of “odd bits: knuckle bones, chicken feet, gristle, skin – anything weird or lumpy can go straight into the pot. Simmer it for 24-48 hours, and enjoy.
Paleo flies in the face of the standard “bone health” recommendations. But if you actually take a look at the evidence, you’ll see that this is a good thing! The calcium-heavy model focused on bone mineral density to the exclusion of all else just isn’t working: rates of osteoporosis in the United States are shockingly high even though most people do get enough calcium in their diet. And on the joint front, arthritis now affects 23% of US adults – how many of those people could get at least some relief from eating a diet rich in traditional broths and stocks, and nourishing their joints with the nutrients they need?
Instead of zeroing in on calcium as the one-size-fits-all solution to these problems, a better strategy is to maximize the micronutrient content of your entire diet, and learn to cook with bones and “odd bits” that contain the nutrients your bones and joints really need to be healthy. And lifestyle changes can help too: weight-bearing exercise is excellent for your bones and joints, not to mention every other part of you. Unfortunately for everyone still stuck in the mainstream model, the evidence is pretty clear: Paleo beats calcium chews hands down, and if you’re on the hunt for a bone-health superfood, broth will get you a lot further than fat-free yogurt.