Life Extension Magazine

Life Extension Magazine August 2011

Book-Excerpt

Your Bones

By Lara Pizzorno, MA, LMT, and Jonathan V. Wright, MD

What else increases my risk for Osteoporosis?

Despite widespread misconception, low bone mass or osteoporosis poses a significant threat to the health and well-being of maturing women and men. A compromised skeletal system not only boosts your risk of life-altering injury; its adverse effects are now known to manifest across multiple systems of the body. Increasingly, cutting-edge researchers are discovering just how critical a role bone health plays in the prevention (or onset) of many killer diseases of aging, from heart disease to diabetes. In this enlightening excerpt from Your Bones, experts Lara Pizzorno, MA, LMT, and Jonathan V. Wright, MD, shed light on the overlooked dangers to healthy bones posed by commonly prescribed pharmaceuticals, surgery, and alcohol.

Gastric Bypass: Free Pass? Not for Your Bones

Gastric bypass (or small-bowel resection) reduces the amount of absorptive surface area in the intestines, and by doing so lessens the body’s ability to absorb not just fat and calories, but also all the nutrients needed to maintain and form healthy bone.

The gastric bypass is the leading surgery to treat morbid obesity performed in the United States. Since this operation causes the primary sites where calcium absorption occurs to be bypassed, patients become deficient in calcium and vitamin D. In response to these deficiencies, the body up-regulates the secretion and activity of parathyroid hormone. Parathyroid hormone has two bone-related effects: it causes an increase in the production of the most active form of vitamin D (1,25-dihydroxyvitamin D), which helps us absorb more calcium from food, but it also causes increased bone resorption (bone breakdown) to liberate more calcium for calcium’s many other uses in the body.1,2

Calcium wears a lot of “hats” in the body, playing vital roles in a number of critical physiological processes not related to its use in bone. These include helping blood to clot, so we don’t bleed to death when cut; helping nerves to send impulses and muscles to contract (in the case of the heart muscle, contraction = heartbeat); and regulating our cell membranes, so our cells can allow entry of what they need and send out what they don’t.

Gastric Bypass: Free Pass? Not for Your Bones

Because these activities are essential to life, the body tightly controls the amount of calcium in the blood to ensure that sufficient calcium is available for them. Our bones, where approximately 99% of the calcium in our bodies is stashed, serve as a calcium “bank” from which withdrawals can be made to maintain normal blood concentrations whenever the need arises—which it surely will after gastric bypass (or if we fail to consume calcium-rich foods and/ or supplemental calcium sufficient to meet our body’s needs).

Gastric banding, another surgical procedure for morbid obesity, is a safer, potentially reversible, and effective alternative to the Roux-enY gastric bypass that has not been shown to produce as much bone loss as the Roux-en-Y procedure. In gastric banding, an inflatable silicone device is placed around the top portion of the stomach to create a small pouch at the top of the stomach that holds about 3.5 to 6.5 ounces of food. When a person eats, the pouch quickly fills with food, and the band slows its passage from the pouch to the lower part of the stomach. As soon as the upper part of the stomach registers as full, the brain is sent a message that the entire stomach is full, which helps the person eat smaller portions, eat less often, and lose weight over time. Within six to eight years, weight loss from gastric banding is comparable to that achieved by gastric bypass; however, many physicians and patients choose gastric bypass because it results in faster weight loss and resolution of diabetes.3 The fact that some of the weight lost comes from the patient’s bones is somehow overlooked.

What Does This Mean for YOU?

Either of these surgeries will lessen your body’s ability to absorb calcium and the other nutrients necessary for bone health. If you have had or are considering either of these surgical interventions for morbid obesity, please discuss the potential adverse effects on your bones with your physician. Medical journal articles alerting physicians to these concerns are just beginning to appear, and many doctors remain unaware of these issues.4

Although increasing calcium or vitamin D intake does not suppress parathyroid hormone or prevent the acceleration in bone resorption caused by gastric bypass, it is possible that highly absorbable supplements may help lessen the damage.5 Anyone who has had either of these surgeries should be using calcium supplements.

The Liver–Kidney Connection to Bone

You’ve probably heard about how important vitamin D is for bone health. Here’s why: vitamin D stimulates the absorption of calcium from the intestines and also calcium’s resorption from the kidneys, greatly improving the likelihood that adequate calcium will be present in the bloodstream for all the body’s calcium needs.

The Liver–Kidney Connection to Bone

However, these effects of vitamin D do not occur until after vitamin D has been converted into its most active form in the body. This conversion occurs in two stages, the first of which takes place in the liver, and the second in the kidneys. For this reason, dysfunction in either the liver or the kidneys can compromise vitamin D activation, calcium absorption, and bone health.

Approximately 23% of patients with chronic liver disease have osteoporosis. You may be thinking that this couldn’t possibly concern you, that liver disease is uncommon and caused only by alcoholism or hepatitis. You’d be wrong.

Today, the most rapidly increasing liver disease is nonalcoholic fatty liver disease or NAFLD, and it is caused by insulin resistance and type 2 diabetes. Following menopause, risk for NAFLD goes up significantly. In a surprising 55% of women over age 60, liver function is compromised by NAFLD.6-9 High blood pressure and diabetes also increase risk for chronic kidney disease, which is estimated to affect 11.5% of adults aged 20 or older in the US.10

What Does This Mean for YOU?

NAFLD and other liver diseases often produce no noticeable symptoms and may therefore go undiagnosed. Particularly if you have been diagnosed with metabolic syndrome or type 2 diabetes, be sure your annual physical includes the standard lab tests that check liver function.11

Symptoms of worsening kidney function are also unspecific and may go unnoticed. Symptoms include feeling generally unwell and loss of appetite. Check to be sure that the lab tests run for your annual physical include creatinine. Higher levels of creatinine indicate a decrease in kidney function and the ability to excrete waste products.

Anyone suffering from chronic liver or kidney disease is at significantly increased risk for vitamin D deficiency and osteoporosis. Supplemental vitamin D has been found to help lessen bone loss associated with liver and/or kidney disease.12-16