By Richard P. Huemer, MD
One treatment that can be considered both hormonal and nutritional is vitamin D. In its active, hormonal form, vitamin D enhances absorption of calcium from the small intestine. Its deficiency results in inadequate skeletal mineralization (rickets in children) or mineral depletion (osteomalacia in adults). When vitamin D is lacking, the parathyroid gland’s output increases to compensate for low calcium in the body, and the unfortunate result is more bone resorption—the hallmark of osteoporosis. Although 400-600 IU is the recommended daily dose of vitamin D for adults over the age of 50, the National Osteoporosis Found-ation recommends 800 IU for those at risk of deficiency. The safe upper dose is at least 2000 IU per day.28
Along with vitamin D, doctors routinely prescribe calcium for their osteoporotic patients and others at risk. One standard reference suggests a baseline preventive dietary intake of at least 1000 mg of calcium a day, unless osteoporosis risk factors or the disease itself is present, in which case the recommendation is 1000-1500 mg from calcium supplements.2 Because a daily dietary intake of 600 mg a day of calcium is about par for most Americans,3 calcium supplements clearly need to be used for preventing osteoporosis as well as treating it.
Although everyone with osteoporosis can probably benefit from calcium, it is especially important for those on bisphosphonate drugs to receive adequate daily calcium and vitamin D. In fact, low blood calcium is a contraindication to the drugs.29
Many forms of supplemental calcium are available on the market. In one study, calcium in the form of its citrate and malate salts (calcium citrate malate) was absorbed better than milk calcium and calcium carbonate.30 In another study, calcium citrate malate was most absorbable, followed by milk calcium, calcium carbonate, and calcium phosphate.31 Calcium citrate decreases biochemical bone resorption markers unaffected by calcium carbonate.32 As for much-touted coral calcium, it outperformed only calcium carbonate in the sole comparison contained in the peer-reviewed literature.33
Calcium has many health benefits beyond maintaining bone strength. It helps regulate the heartbeat, transmits nerve impulses, assists blood clotting, activates enzymes, and stimulates hormone output. Calcium even protects against colon polyps, especially the kind most likely to turn cancerous.34
The Bone-Building Team
Calcium may excel at building bone, but it cannot work alone.35 Calcium’s bone-building team has many players. The most important are the mineral elements magnesium, manganese, boron, silicon, zinc, and copper, as well as vitamin D3, the natural form of vitamin D. Vitamins C and K also play key roles.
The teamwork effect is nicely illustrated in a study by Strause and colleagues,36 who gave calcium citrate malate—either with or without the trace minerals zinc, manganese, and copper—to healthy postmenopausal women over a two-year period. The researchers evaluated spinal bone loss. The most loss occurred in women receiving placebo (with no calcium). At the end of the study, the group that had received both calcium citrate malate and the trace minerals was clearly better off than the placebo group, whereas other between-group comparisons were not significant.
Magnesium is an important team player, with a role in regulating active calcium transport. Some studies have associated its dietary intake with increased bone mineral density. A two-year study of postmenopausal women supplemented with magnesium showed significant protection from osteoporosis and greater bone mineral density.37 Many doctors favor maintaining a magnesium intake that is approximately half your calcium intake as measured in milligrams.
Herbalists have long used a silicon-rich plant called horsetail to heal bones. In animals, silicon deficiency causes bone defects. Dietary silicon is absorbed as orthosilicic acid, which has recently been shown to stimulate the synthesis of collagen type 1 (the kind found in bone matrix) and to induce characteristic osteoblast enzymes in osteoblast-like cells.38 In a small retrospective study, women who received silica had significantly increased bone mineral density in the femur.39
Boron may mimic the action of estrogen, a hormone that protects bone health. In one report, postmenopausal women lost calcium and magnesium from their bodies when they were made boron deficient, and retained those minerals on a boron-supplemented diet; they also manufactured more estrogen and testosterone when on boron supplementation. In another study, vitamin D status improved in boron-deficient women after they received boron.40
Vitamin D acts as the “gatekeeper” of calcium by facilitating its absorption in the intestine. Natural vitamin D3 comes from sunshine and animal sources. A plant-derived form, vitamin D2 or ergocalciferol, is a common additive to dairy products. Vitamin D3, whether ingested or created naturally by the action of sunlight on the skin, is carried to internal organs that convert it into a potent, hormonal form. Only a few minutes of full sun exposure will create thousands of units of vitamin D3.41,42
If vitamin D is calcium’s gatekeeper in the body, vitamin K is its shepherd. Vitamin K ensures that calcium goes into the bones where it belongs, and stays out of parts of the body such as the arteries where it does not belong. It accomplishes this by helping an enzyme that activates special Gla-proteins that control calcium deposition.43 Using vitamin K does not require a physician’s supervision; however, because vitamin K is involved in blood clotting and may interact with certain medications, it should not be used by those taking anti-coagulant drugs like Coumadin®.
Finally, vitamin C helps to create the collagen-rich bone matrix. One component of collagen (connective tissue) is hydroxyproline, an amino acid formed when proline becomes hydroxylated, a step that requires vitamin C. That is why bones break so easily and tissues are so weak in people with scurvy, which is the overt form of vitamin C deficiency. Although scurvy is rare, scientists like Linus Pauling and Irwin Stone long ago pointed out that most of us exist in a state of chronic subclinical scurvy due to near-universal insufficiency of vitamin C in our diet.44
Osteoporosis Prevention Guidelines
The National Osteoporosis Foundation, which provides educational material to the public and health professionals, has posted on its website (www.nof.org) the following guidelines for preventing osteoporosis:
To these well-conceived rules, the Life Extension Foundation adds four more:
While a certain amount of bone loss may occur with aging, developing osteoporosis is certainly not inevitable. Regardless of genetic risks, most of us can maintain strong, fracture-resistant bones throughout our lifetimes by avoiding dietary and lifestyle habits that lead to bone loss, exercising regularly, receiving preventive health check-ups, and nourishing our bone-building cells with bioavailable calcium and other supportive nutrients.
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