Note: You can see the summary from this article at the bottom of the post.
As a basketball player and high jumper, I racked up 10 stress fractures over the course of 8 years. Upon hearing this, acquaintances often ask, “oh, did you not get enough calcium?” Actually, I did. Doctors checked my blood, my calcium levels were normal. So were my vitamin D levels. I always came back slowly from these injuries as well – they never seemed to heal in the 4-6 week timetable my doctors would allot, even in college with the help of athletic trainers and physical therapists. I would always ask the doctors, what am I doing wrong? They could never answer. So I eventually did my own research, and, as it turns out, I was doing quite a bit wrong. This will be a four part series focusing on the role that diet has on bone strength and development:
Part I: The Milk Myth
Part II: What Matters Most – How Calcium is Absorbed
Part III: Where to get the required minerals to maximize calcium absorbtion (listed in Part II) – Foods, Herbs & Supplements
Part IV: The Bone Builder’s Cookbook – Several Easy Recipes
Part I: The Milk (and Supplement) Myth
Drink enough milk, they say. It’ll give you strong bones, they say. Lower rates of milk drinking are often cited as a reason behind the current epidemic of osteoporotic injuries (injuries from weak/brittle bones) in America. The International Osteoporosis Foundation estimates that “around 40% of US white women and 13% of US white men aged 50 years will experience at least one clinically apparent fragility fracture in their lifetime.” Some doctors believe that this problem is because of a lack of calcium in the diet. But is this true?
If we were to look at the countries with the highest per capita dairy consumption, we’d also see the strongest bones, with all the calcium that dairy consumption provides, right? Wrong. Scandinavia is leading the way in dairy consumption, and guess who has the highest rates of osteoporosis in the world? I’m not quick to say that dairy consumption causes bones to weaken (although that’s a possibility: cheese contains high amounts of phosphoric acid, the same substance that is believed to be why colas (not all sodas) have been scientifically proven to cause bone loss). The lack of sun must also be involved in the Scandinavian epidemic, as vitamin D “turns on” calcium absorption.
If dairy doesn’t work, what about supplements? If just getting enough calcium doesn’t work, vitamin D will help, right?
The US Preventative Services Task Force actually recommends not taking calcium and vitamin D supplements, since the evidence does not clearly show that they have any effect on fractures in women. There are actually concerns about the safety of calcium supplements, as some studies have shown an increased risk of heart disease for those taking the supplements. Sunlight and a healthy diet are highly correlated with regular vitamin D levels, which are highly correlated with strong and healthy bones, and supplements of vitamin D have been shown to effectively raise levels in the blood in many cases. However, in my case, and in the cases of at least three fellow stress fracture-plagued athletes I met through my career, our vitamin D and calcium levels were tested and came back normal, and we still kept breaking bones. Is it possible that we had normal calcium and vitamin D in our blood and they were still not doing the jobs that they were supposed to do?
Part II: What Matters Most – How Calcium is Absorbed
Magnesium & Vitamin D
WebMD.com says that “magnesium is a mineral that is present in relatively large amounts in the body. Researchers estimate that the average person’s body contains about 25 grams of magnesium, and about half of that is in the bones. Magnesium is important in more than 300 chemical reactions that keep the body working properly.” More than 300 reactions, including those in which vitamin D is involved. Actually, magnesium turns out to be a cofactor in every interaction requiring vitamin D. Carolyn Dean, MD says that “When you take high doses of Vitamin D and if you are already low in magnesium, the increased amount of metabolic work drains magnesium from its muscle storage sites. That’s probably why muscles are the first to suffer magnesium deficiency symptoms — twitching, leg cramps, restless legs and charlie horses. Angina and even heart attacks affecting the heart muscle are all magnesium deficiency symptoms.” This is very important for athletes that play sports outside – if you use magnesium to metabolize vitamin D, and you get a lot of vitamin D (from the sun) then you must make sure that you are getting enough magnesium. One reason for the lack of attention that magnesium gets by the average doctor may be because it is very difficult to test for.
Calcium, Magnesium & Calcitonin
Magnesium stimulates the release of the hormone calcitonin. Calcitonin is produced by the thyroid, and is a regulator of calcium and phosphorous levels in the blood. It actually prevents the release of calcium into the bloodstream. When the message reaches the thyroid that there is a large amount of calcium in the blood, the thyroid releases calcitonin, which both enhances the uptake of calcium and phosphorous by the bone AND slows the activity of osteoclasts (cells that recycle bone). If you want stronger bones, you want less osteoclast activity, as the osteoclasts break down bone to release their mineral content (osteoblasts, on the other hand, are the cells that build bones).
Lastly, studies have shown that even a small amount of missing magnesium from the body can interfere with the quality of your sleep – and sleep is required to rebuild the bones and all of the tissues of the body. Another interesting fact is that magnesium is required for serotonin production. Low serotonin can cause migraine headaches and is associated with depression, anxiety and other mood disorders.
-Getting enough calcium is important, but it isn’t everything. Ever been told drinking milk will build strong bones? Countries that eat the most dairy products, per capita, have the weakest bones. What matters is how much calcium actually gets absorbed by your bones.
-Phosphoric acid (in colas) has been proven to weaken bones. Sorry, no more Pepsi/Coca Cola if you’re going to be a
n athlete person.
-Vitamin D is crucial for calcium absorption, but cannot be absorbed if it there is not an adequate amount of magnesium in the body. Due to the Standard American Diet (processed foods lose much, if not all, of their mineral content), magnesium is often a missing link for American athletes.
-If you play sports outdoors or consume a lot of vitamin D in food or supplement form, you must be sure that you are getting enough magnesium. Your body’s demand for it is greater.
-Magnesium also is involved in the release of the hormone calcitonin, which is required to keep calcium in the bones (where you want it) instead of the bloodstream and soft tissues (which can lead to calcification of the arteries and arthritis, among other things).
-Magnesium deficiency is hard to test BUT some signs that you may not be getting enough are leg cramps and charlie horses.
-Further, magnesium can help to improve your mood, relax your muscles and your mind (as serotonin production is dependent on magnesium), as well as helping you to sleep better by relaxing the central nervous system.
Next Monday we will look at both the sources of bone building substances in the food world and also common inhibitors of those substances. In addition, we will look at some popular (and lesser known) herbs and supplements, their function in building super-strong bones, and some of their pros and cons.
UPDATE: Further research has shown that the alkalinity/acidity of the blood (highly influenced by diet) also has a huge impact on the health of bones and soft tissues. Later this October a specific post will summarize this rather complex topic.