A Functional Approach to Osteoporosis

"When you change the way you look at things, things you look at change."

- William Dyer

As an orthopedic trauma surgeon, I have experienced the social, psychological, and physical impacts of fragility fractures associated with osteoporosis. Reduced bone mineral density is estimated to affect 54 million Americans, and 10.2 million are estimated to have osteoporosis. Bone mineral density testing is most often performed by dual-energy X-ray absorptiometry (DEXA) scanning. This test directs a quantified dose of X-ray radiation at specific bones, at risk for fragility fracture, and measures the amount of radiation absorbed at the receiver. The less radiation absorbed by the receiver indicates greater refraction from the bone and increased bone mineral density. Conversely, the more radiation that is absorbed by the receiver represents less refraction and decreased bone mineral density. These data are compared to population statistics of "normal" controls. A T-score is given at each anatomical site measured and represents the standard deviation from the mean bone mineral density of a given control population.

By mass, bone tissue is composed of 50-70% inorganic material and the other 30-50% is an organic, type 1 collagen matrix. The inorganic component mostly consists of calcium hydroxyapatite but also has significant amounts of other minerals, including magnesium, potassium, and sodium. Calcium supplementation, through the conventional model, has been advocated as a strategy to help slow the process of bone mineral depletion and reduce fracture risk. Research on calcium supplementation, however, has been mixed, showing modest to no reduction in fracture risk (here, here, here, here, and here). Additionally, they have been shown to increase the risk of gastrointestinal complications and kidney stones and may increase the risk of cardiovascular complications (here, here here, here, here, and here). One study, over a 5-year period, showed significant improvements in calcium-treated patients in quantitative ultrasound attenuation of the calcaneus and bone stiffness, but not speed of sound or reduction in fragility fracture. Changes in the former metrics are likely a result of unorganized calcium deposition disease rather than the normal, coordinated physiologic deposition.

Instead of calcium supplementation, there are five other supplements I recommend to slow the rate of bone demineralization over time: magnesium, silica, vitamin D, vitamin K2, and collagen. As I wrote about in “The Necessary Role of Stomach Acid,” proton pump inhibitors (omeprazole, pantoprazole, etc.) can inhibit the absorption of protein (collagen) and vitamin D. It is important to make patients aware of this and possibly find alternative solutions to their acid reflux symptoms. Calcium is important to building and maintaining strong bones, but this mineral should be obtained from dietary sources, not supplementation. The recommended dietary allowance (RDA) for calcium is 1,000-1,200mg/day. It is hypothesized that dietary calcium absorption occurs much slower than supplementation and this is a possible reason why high dietary calcium intake rarely causes the problems that supplements do.

Magnesium

It is estimated that 48% of US adults have an insufficient dietary intake of magnesium, but likely higher as the RDAs they used in this analysis are lower than more contemporary recommendations. Magnesium is a cofactor in over 300 enzymatic reactions; it is involved in energy production, nucleic acid and protein synthesis, ion transport, and cell signaling. Severe deficiency has also been shown to impede vitamin D and calcium homeostasis. Reduced serum concentrations have been associated with cardiovascular disease, osteoporosis, metabolic syndrome, hypertension, and type 2 diabetes. The RDA for magnesium can be found here in Table 1. Nuts and seeds are a rich dietary source of magnesium, but their bioavailability is poor due to the presence of phytic acid.

Silica

Silica, or silicon dioxide, is one of the most abundant, complex, naturally-occurring molecules composed of several minerals in crystalline form. While silica, the most common component of sand, has been used for several industrial purposes, primarily in the production of concrete, it has been found to have significant health benefits. This compound plays a major role in bone formation and maintenance. Many silica-rich foods do not provide a high content of silica and some of the foods on the list lack nutrient density, such as beer, lentils, and cereal. In addition to the lack of nutrient density, lentils and oat cereals also have high levels of environmental toxins such as glyphosate and chlormequat. Phytic acid in oats and other plant-based products also binds to essential minerals, blocking their absorption. There is no current RDA for silica, but the best estimates are between 20-50mg/day (here), with the upper tolerable limit at 350mg/day. Because silicon dioxide is found in such nutrient-empty foods, I recommend supplementation of silica, 20-30mg/day. This study showed no difference in absorption and excretion rates between different formulations of silica supplements.

Vitamin D3

Vitamin D3 plays a significant role in calcium and phosphorous homeostasis in the body. In addition to the benefits of bone health, it is also involved in the proper functioning of the immune, endocrine, and cardiovascular systems. Sunlight is the main source of vitamin D that comes from photoreceptors in the skin that are activated by sunlight. People living in the northern or southern hemispheres, further away from the equator, do not produce sufficient amounts for normal physiological functioning. It is believed that vitamin D acts by binding to a vitamin D receptor in the cell and directly initiates DNA transcription of specific genes involved in bringing calcium and phosphorus into the body from the kidney and intestines and inhibits bone degradation. The RDA recommendations can be seen here, but these recommendations are arbitrary and highly individualized. It is best to obtain vitamin D levels 3-4 times per year and ensure normal physiological levels that adequately suppress parathyroid hormone.

Vitamin K2

There are two naturally occurring forms of vitamin K, phylloquinone (vitamin K1) and menaquinone (vitamin K2). Vitamin K1 is the form often referred to when discussing vitamin K (“K” is derived from the Danish word “koagulation”). This form is involved in the production of coagulation factors in the liver and patients on warfarin (Coumadin) know to avoid vitamin K-rich foods, such as leafy vegetables (“phyllo-“ is a prefix for “leaf”). Menaquinones, conversely, are found in cheeses, animal products, and some fermented foods. The proposed mechanism for vitamin K2 action in bone formation is gamma-carboxylation of several bone-related proteins, most importantly osteocalcin, to increase the capacity of these proteins to bind to calcium accelerating the formation of calcium hydroxyapatite. Vitamin D is necessary to stimulate cells within the bone (osteoblasts) to produce osteocalcin and other bone-forming proteins. Natto, fermented soybeans, are a rich source of vitamin K2 (MK-7 form) and the consumption of natto showed to reduce bone loss in postmenopausal women. Many more studies (here, here, here, here, and here) have demonstrated the utility of vitamin K2 to maintain or slow the progression of declining bone mineral density. RDA for vitamin K2 is 120mcg/day for adults and children. Here is a resource for vitamin k2-rich foods.

Collagen

Collagen is the most abundant protein in the human body and contributes significantly to normal bony architecture, comprising of 90% type 1 collagen and 10% non-collagen proteins. Dietary supplementation with collagen peptides has been shown to increase bone mineral density in postmenopausal women. This study shows that aging has a reduced pepsin output that initiates protein digestion in the stomach. This effect may be improved if these test subjects received acid-stable proteases (protein-digesting enzymes). Read more about collagen here.

While the pharmaceutical industry has developed reasonably good options for increasing or slowing the progression of bone loss associated with aging, there are also non-pharmacological options that can help as well. Bone turnover is a complex process and diet has a significant influence on bone mineral density. It is important to evaluate patients for reduced stomach acid and avoid acid-suppressing drugs to help absorb appropriate nutrients. Proton pump inhibitor use has been associated with increased fracture risk in both children and adults (here, here, here, here, here, and here). Improving the health of our patients is imperative and it should start with nutrition and lifestyle modification first. If we optimize the patient to the degree to which they are willing to engage, then, at that point, pharmaceuticals can be entertained. 

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