Calcium: Fact and Fiction


There is no question that calcium is a crucial mediator of numerous body processes, necessary as a metabolic signal, mediator of heart muscle contraction, nerve conduction, as well as a component of bone structure. If blood levels of calcium are too high (hypercalcemia) or too low (hypocalcemia), it can be fatal. Calcium blood levels are therefore maintained tightly within a healthy range under the control of parathyroid hormone (PTH), vitamin D, dietary calcium, phosphate and other factors. It is a somewhat complicated situation. Perhaps this is why much conventional information surrounding calcium reads more like an episode from Brothers Grimm Fairy Tales than real science.

Among the common fictions that strangely persist in everyday healthcare and doctors’ advice despite evidence to the contrary:

  • You must take calcium supplements to ensure adequate intake of calcium and prevent osteoporotic fractures.
  • Calcium supplementation is safe and benign.
  • Eat a balanced diet that includes whole grains to obtain nutrients like calcium.
  • You must consume dairy to obtain sufficient calcium.

Here are some facts and observations to consider:

  • Calcium supplementation of 500-1200 mg per day or more increases bone density slightly, approximately 1% over the first year of supplementation with little to no additional improvement over a longer time period (according to randomized controlled trials, not epidemiological studies). As the average postmenopausal woman loses 1% of bone density every year (without efforts to stop or slow the process), calcium has a minimal effect over time. For these reasons, the International Osteoporosis Foundation has adopted a policy that states “supplementation with calcium alone for fracture reduction is not supported by the literature,” and the United States Preventive Services Task Force does not recommend that people without osteoporosis take calcium to prevent it.
  • Including wheat and grains in the diet means that phytates will bind calcium in the gut that you then pass out into the toilet. In other words, consumption of grains virtually ensures inadequate absorption of calcium.
  • Grain phytates also bind magnesium, also passed into the toilet. Magnesium is crucial for maintaining bone density, with bone density-increasing effects that are at least on a par with calcium, if not greater.
  • Phytate binding of iron, zinc, and magnesium mean that these minerals are unavailable to block cadmium absorption that, in turn, contributes to a reduction in bone density.
  • The gliadin protein of wheat and related grains causes calciuria, loss of calcium in the urine. (This also increases urinary calcium to form calcium oxalate kidney stones.)
  • Restoring vitamin D to a healthy level (that I would define as 60-70 ng/ml, the level at which parathyroid hormone, PTH, is suppressed, minimizing mobilization of calcium from bones) increases small intestinal absorption of calcium by 40%.
  • Calcium supplementation adds little to no bone calcium, but increases risk for “ectopic” calcium deposition, i.e., accumulation of calcium in places it doesn’t belong, such as calcium oxalate kidney stones and coronary artery, carotid, and aortic calcification, especially when intake (dietary + supplementation) exceeds 1400 mg per day.
  • There is continued debate over whether increased intakes of calcium in “bolus” form, i.e., a large dose all at once as happens with a calcium supplement, increases risk for heart attack and cardiovascular death.
  • The anthropological record reveals a marked reduction in bone density occurred with the conversion of hunter-gatherer lifestyles to agriculture-based lifestyles. While the reduction in bone density has been attributed to a reduction in physical activity of agriculture compared to hunting and foraging (which I think is debatable), I believe we must also factor in the presence of calcium- and magnesium-binding phytates from grain consumption.
  • The loss of the intestinal microbial species L. reuteri by approximately 96% of the American public means that they have lost a species responsible for causing oxytocin release from the hypothalamus/pituitary, a hormone that is crucial for maintaining bone density.
  • The increasing burden of dysbiosis and small intestinal bacterial overgrowth, SIBO, among Americans means that calcium absorption is impaired.
  • The failure to include prebiotic fibers in the diet, especially galactooligosaccharides (GOS), means greater intestinal calcium and magnesium loss. Accordingly, increased intake of GOS fibers increase calcium and magnesium absorption.
  • Even vitamin C supplementation has been shown to yield greater effects on bone density than calcium.
  • Seeds (120 mg/tbsp), legumes, nuts, collard greens, spinach, kale, broccoli, and sardines are among the non-dairy sources of calcium.

Let me restate the first item re: calcium supplementation. Calcium supplementation of 500-1200 mg per day or more increases bone density slightly in populations who consume calcium- and magnesium-binding phytates, experience calciuria, hyperabsorb cadmium, have lost L. reuteri and have lower levels of oxytocin, have dysbiosis/SIBO, and typically fail to include plentiful prebiotic fibers in their diet.

Perhaps you are beginning to see the power in not consuming phytates or gliadin, supplementing magnesium (that should come from drinking water but no longer), restoring L. reuteri, and managing your intestinal microbiome. You’ve got to wonder if it means that our calcium needs are less than people who don’t take these measures. I hope you also appreciate the huge oversimplification represented by the advice to “take calcium for bone health.” You may also notice that nearly every strategy I have articulated that improves bone density is a natural strategy: not consuming grain phytates is how humans ate for the first 99.6% of our time on this planet, obtaining magnesium from drinking water and plant matter, running around in loincloth in a tropical or sub-tropical sun exposed the skin to sunlight that activated vitamin D in the skin, we did not take antibiotics, synthetic sweeteners like aspartame, or emulsifying agents like polysorbate 80 that disrupted the intestinal microbiome.

In other words, the conventional practice of focusing almost exclusively on calcium while ignoring many other factors (for the sake of brevity, I did not include all factors that influence bone density, such as estrogen, boron, vitamin K2 and others) means that many natural, safe, and effective methods to increase bone density are neglected, a practice that paves the way in modern healthcare to prescription agents.