The Strange Case of Strontium
A Reason-Based Editorial
by Daniel Milosevich, CN, with Stephen Levine, Ph.D.
It is widely known that the new drug strontium ranelate offers a new option for drug treatment of osteoporosis. Now, various nutritional experts are recommending the trace mineral strontium as an essential nutrient for bone health, based on the research for the drug strontium ranelate. By ignoring the fundamental differences between drug activity (disease treatment) and nutritional support (benefiting the body’s structure and function), these writers have created two misconceptions: that strontium in high milligram doses is essential for bone health; and that nutritional strontium must be taken on an empty stomach. What is worse, everyone seems to have missed an obvious reason why ingesting a trace mineral in abnormally high amounts can increase bone mineral density – and what it is replacing. A reasoned look at strontium offers some surprises about how to safely use it nutritionally.
Osteoporosis is not caused by strontium deficiency, and good bone health does not rely on excessive strontium. The health of the bones is due to multiple interacting causes, and there is not a single drug or nutrient that is the key to the health (or disease) of the bones. Nutrients that support dense, strong bones are interdependent, and all are needed for optimal bone growth and strength. They include calcium, magnesium, vitamin D, vitamins K1 and especially K2, vitamin C, potassium, copper, manganese, zinc, silicon and boron.
Living Bones
The growth and development of the skeleton begins in early fetal life and continues for nearly two decades in a series of well-defined events. Minerals, particularly calcium, but also carbonate, magnesium, sodium, and fluoride, play vital structural and metabolic roles in bone growth and development. However, bone formation also is encouraged by hormones, such as estrogen, and by weight-bearing activity. Living bone is never metabolically at rest; its matrix and mineral stores are being remodeled constantly along the lines of mechanical stress. Home Care Provid. 1997 Apr;2(2):76- 81; quiz 82-3.
Real nutritional support for bones will account for as many of these factors as possible, rather than focusing on one magic ingredient. Healthy bones also depend on hormonal balance resulting from good endocrine system function, balance among macronutrients (protein, fatty acids, sugars), and appropriate exercise.
Drug developers, on the other hand, must look for one ingredient – or a way to utilize one ingredient – that can be shown to make a difference in a disease state. The novel compound strontium ranelate is composed of one part ranelic acid and two atoms of stable strontium. According to Dr. Reginster, a lead strontium ranelate researcher, it was chosen because it presented the most suitable physicochemical and pharmacokinetic characteristics, and was well tolerated and safe (although many other strontium salts also are well tolerated and safe). Undoubtedly, strontium ranelate was preferred over other known (and researched) strontium salts because, as a previously unknown form of strontium, it could be patented.
The confusion of strontium ranelate with the nutrient strontium partly stems from the fact that even Dr. Reginster admits that the strontium is the effective part of the compound, saying, “Certainly, the ranelic acid part of the strontium ranelate compound contributes nothing to the effects of strontium on your bones.” This implies that other forms of strontium could potentially have the same benefits, and nutritional writers were quick to extol the potential benefits of strontium without looking closely at what can really be logically extrapolated from the strontium ranelate research to the use of nutritional strontium.
A Closer Look at Strontium
Strontium is a trace mineral, typically ingested from food and water at 1-3 mg per day, although much less is absorbed. It may have some essential function as a trace mineral in the bones, although this is unverified. Trace amounts of strontium reside in the skeleton for years, replacing a small amount of calcium in the hydroxyapatite crystal lattice. This nutritional strontium is ingested with, and competes for absorption with, all the other elements that occur in food and water, yet the body has no problem making use of it at these levels.
In the research on strontium ranelate, the test subjects first normalized their vitamin D and calcium levels, and continued to take calcium and vitamin D during the time that strontium was taken. Because the absorption of strontium ranelate is reduced significantly by the presence of calcium or food, the drug was taken on an empty stomach. Strontium taken in this way can be adsorbed onto the surface of hydroxyapatite crystals, and this is probably where the increases in bone mineral density (BMD) occur. But because only a small quantity of calcium in the apatite is substituted by strontium at these pharmacological doses, once high-dose empty-stomach strontium treatment is withdrawn, bone strontium levels rapidly decrease. The drug researchers claim that the body targets the bones with strontium, but the body may simply be storing the excess there until it has an opportunity to get rid of it.
Strontium's Secret
Millions of human beings have grown old with strong, healthy bones without loading up on strontium. Could it be that something else was low in the test population, something that excessive strontium can partially replace? Consider these points: 1. Magnesium is typically below optimum levels, or even deficient, in the population at large. 2. Osteoporosis can be considered a further risk marker for magnesium deficiency. 3. Giving extra calcium to already magnesium-low subjects will exacerbate any magnesium deficit. Since no attention was paid to magnesium status in any of the strontium ranelate studies, and all subjects had osteoporosis, and extra calcium was given, it’s almost certain that the general level of magnesium was sub-optimal at the least, and more likely, outright deficient in the population tested.
Strontium may possibly help stabilize mitochondrial structure, but magnesium is known to have critical importance for stabilizing mitochondrial structure. Strontium has some ability to enhance calcium deposition in bones, but magnesium already does this wonderfully. Strontium is said to be a “bone-seeking element that is closely related to calcium”, but magnesium is the other mineral “closely related to calcium”, and is not only bone-seeking, it is bone-residing: a healthy adult human skeleton contains 15-17 grams of magnesium. Magnesium is crucial for many body systems, but especially for bone formation and mineralization. In my opinion, high-dose strontium’s ‘secret’ is that it can partially ameliorate magnesium deficiency, filling in for magnesium’s superb ability to increase bone growth, bone density, and bone strength.
Is magnesium that important? Don't we all get enough magnesium?
Increased bone mineral density and bone mineral content in postmenopausal women have been positively correlated with intake of supplemental and/or dietary magnesium. Women with postmenopausal osteoporosis show significant reductions in bone mineral content and serum magnesium compared to age-matched controls. Insufficient magnesium stops bone growth, and leads to osteopenia and bone fragility. Magnesium makes bones and teeth dense, strong, resilient (not brittle), and hard.
Magnesium Crucial for Bones
There are hundreds of studies showing the crucial role that magnesium (Mg) plays in the health of the bones. For example, although severe Mg deficiency has long been known to be a risk factor, what happens with just a moderate Mg deficiency? Rats fed 0.04% of the nutrient requirement (NR) for Mg (severe Mg deficiency) get osteoporosis.
A more moderate dietary Mg restriction, 10% of NR, was then tested for six months. After just two months, bone Mg content was reduced 51%. Increased release of substance P and TNF-alpha were noted by the end of the study and bone loss. J Nutr. 2004 Jan;134(1):79-85.
Then 25% of NR was tested, and again decreased bone volume occurred. “These data demonstrate that Mg intake of 25% NR in the rat causes lower bone mass which may be related to increased release of substance P and TNFalpha.” Bone. 2005 Aug;37(2):211-9.
Recently a very moderate reduction of dietary magnesium (50% NR) was tested. As found in more severe Mg restriction, bone magnesium content was reduced at the 3- and 6-month time points, as was bone volume. Osteoporos Int. 2006;17(7):1022-32. Epub 2006 Apr 7. Other studies confirm a similar role for magnesium in humans.
Rats given half their needed magnesium suffered bone loss in 6 months. How many millions of human beings are subject to chronic, long-term 50% (or less) intake of optimal magnesium? Why are we surprised at the near-epidemic of osteoporosis?
More magnesium references & commentary here.
Research indicates dietary intake of magnesium has decreased in the United States, from 475-500 mg per day in 1900, to only 215-283 mg per day in 1990. Even those 1990 figures may be too high, since refining and cooking further reduce the magnesium content of foods. A high-fat diet, soft drinks, laxatives and many other common dietary practices all can seriously compromise magnesium absorption and retention. Other factors, such as high alcohol or sugar intake, elevated stress chemistry in the body, diuretics or high amounts of sodium or calcium can reduce re-absorption of magnesium in the kidneys. Additionally, acid rain washes magnesium out of the soil, fluoridation depletes it from drinking water, and the processing of grains and other foods lowers their magnesium content. A 1988 U.S. Government study concluded that the Standard American Diet (SAD) only provided 40% of the daily requirement of magnesium. Some experts believe this is a major root cause of the myriad chronic health conditions suffered in the modern world.
It’s quite possible that a low-magnesium diet combined with high calcium intake will promote calcification of soft tissues and create an environment for osteoporosis to begin. Interestingly, the research also shows that increasing magnesium intake improves rather than interferes with calcium utilization. Magnesium regulates active calcium transport, crucial to bone metabolism. Plentiful magnesium is calcium-sparing, reducing the need for calcium.
Quality Bones
In a two-year study of postmenopausal women with osteoporosis, 170 mg of strontium per day reduced bone fracture risk more than the 680 mg dose used in the other studies, even though BMD did not increase as much at the lower dose. With the higher strontium dose, even as BMD increased, over time the fracture risk also started to increase again. Does either of these make sense if high quality bone were being formed?
It appears that bones deficient in magnesium and high in strontium, although very dense, are not as strong as bones with optimal magnesium content. The body is making do with what it can get, akin to soldiers armoring their vehicles with scrap metal. The vehicles are somewhat more bomb resistant (less prone to fracture), and certainly heavier (denser), but not as bomb resistant as those outfitted with high-grade armor (optimal magnesium). This makes sense, as the excess strontium is absorbed onto the surface, not the deep crystal lattice.
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What other functions do strontium & magnesium have?
Both magnesium and calcium, unlike strontium, are involved with hundreds of activities in human metabolism. Magnesium plays a role in the cardiovascular and GI systems, peripheral vascular function, energy production, and the heart, brain, kidney and liver. It is involved in the regulation of muscle and nerve activity through influencing cell membrane permeability, and functions as an electrolyte, helping maintain the charge balance in the body fluids. Magnesium governs the flow of sodium, potassium and calcium in and out of cells, and complements calcium. Strontium, on the other hand, is found exclusively in the bones and teeth in minute amounts, with no verified essential functions.
Do the large doses of strontium used in the studies pose any danger?
Strontium ranelate has been shown to increase BMD and reduce fracture risk in postmenopausal women, with pharmacological doses of 680 mg strontium per day, (but magnesium levels were not tested, or optimized, in either the test group or the controls). It is likely that these large doses of strontium are not dangerous, as long as calcium stores are maintained. Skoryna, an original researcher on calcium and strontium salts, wrote, “Supplementing a diet that provided the usual amount of calcium with stable strontium… demonstrated that there is a wide margin of safety in the amount of stable strontium intake in human subjects, since doses of up to 1750 mg/day of strontium ion did not produce any side effects.” However, he goes on to say that both high strontium/ low calcium diets, or massive doses of strontium (1.5% to 3% of the dietary intake) can lead to a pathological decrease of bone calcium originally described as “strontium rickets”. Excessive strontium intake has also been reported to produce insoluble phosphates, leading to phosphorus deficiency.
Those that advocate the use of large amounts of nutritional strontium on an empty stomach may not be considering these safety issues. For example, a senior citizen could start taking high-dose nutritional strontium twice a day, thinking this is what she needs for her osteoporosis, without understanding the need to keep her calcium and vitamin D stores up. Even if she is told to take calcium, she may forget, she may get confused, or there could be other reasons why she stops taking calcium. Such compliance issues are common. Over time, she could create serious problems for herself. The safety of nutritional strontium can only be assured when it is taken with calcium, magnesium, and other nutrients important for bone health.
Conclusion
For those who have no interest in optimizing their nutritional intake, and want to take one thing to cure their osteoporosis, the research suggests that the drug strontium ranelate may strengthen bones as well as, or possibly better than, any of the other drug treatments currently available, as long as they keep taking it, and take adequate calcium and vitamin D.
For those who wish to support the normal corrective processes that result when the body and bones are viewed as a complex system, attention would be paid to exercise, hormones, a balanced diet, and improved overall nutritional status. Emphasis would be placed on a daily intake of vitamin D, vitamins K1 and K2, vitamin C, lycopene, and a full array of minerals including calcium, magnesium, zinc, copper, manganese, strontium, silicon and boron. There is no need to trick the bones into absorbing physiologically abnormal amounts of strontium. There is also no requirement to take nutritional strontium on an empty stomach, and significant reasons not to do so. The strontium in such a program may support a speedier if temporary bulking of bones that are in dire need, while the body continues to build real bones with the macro nutrients calcium and magnesium. Strong, healthy bones do not need large amounts of nutritional strontium, but they will always require plenty of magnesium.
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