Our Greatest Wealth Is Health

Andrew Siegel MD  11/9/19

Bones comprise the scaffold and foundation that supports the body.  If one’s bony infrastructure is compromised, organs and tissues that depend on intact support can be negatively impacted. In addition to providing the body’s framework, bones protect vital organs (e.g., the brain within the skull and the spinal cord within the vertebral column), allow for movement and mobility, and contain marrow that is responsible for production of the cellular elements of the blood.  Additionally, bones are the reservoir for storage of minerals, particularly calcium and phosphate.  Our bones are truly amazing, multi-tasking structures.  Today’s entry is a prelude to next week’s discussion of bone health in prostate cancer patients.

Attribution of image above: © Nevit Dilmen [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)%5D

Bone mineralization

Bone consists of widely separated cells surrounded by a matrix of inorganic salts and collagen fiber.  Bone mineralization—the process by which minerals are integrated into the matrix of bones—is a dynamic process as bones are not fixed in composition, but are continually being remodeled, restructured and refashioned.  This process occurs in accordance with the availability of building materials in an adaptive response to bio-mechanical forces including gravity and muscular and skeletal stresses. “Osteoblasts” are the specialized cells that promote bone formation and “osteoclasts” are the cells that induce bone resorption.

Bone development

The bone formative process begins during childhood and continues through adolescence, when the body builds its greatest share of bone mass.  Bone mass peaks in our early 20s. Like so many physical attributes, bone strength and integrity have a strong hereditary basis, although environmental factors are also important.

Environmental factors that contribute strongly to healthy bone development are diet, sun exposure, physical activity and weight. Because calcium is a vital component of bone mass and vitamin D facilitates absorption of calcium, ample consumption of calcium and vitamin D are essential to develop and maintain healthy bones.

Calcium

A nutritionally-sound diet rich in calcium-containing foods includes dairy sources such as milk, yogurt and cheese.  Non-dairy sources of calcium include vegetables such as Chinese cabbage, kale, broccoli and spinach. Seafood sources include salmon and sardines. Many food items are calcium-fortified, including breakfast cereals, tofu and fruit juices.

Vitamin D

Vitamin D, a fat-soluble vitamin that is stored in the liver and fatty tissues, is necessary to absorb and utilize dietary calcium. A brief amount of daily sunlight exposure is generally sufficient to ensure adequate levels of vitamin D, which the body manufactures in response to exposure to ultraviolet-B waves.  Many people do not get sufficient sun exposure in winter months to make adequate levels of vitamin D since the sun is lower in the winter sky and exposure time is limited because of the cold weather and the need to bundle up in clothing.  Vitamin D synthesis tends to diminish with age.

Exercise

Bones require physical activity to maintain their proper state of mineralization.  Generally, the more active one is, the greater the bone mineral density (BMD) and the less risk for fracture. Most exercises promote bone health, but certain ones are better at achieving this than others. Just as our bodies require a variety of different and variable nutrients, so our bones demand a variety of different exercises, movements and stresses to maintain their health.

When our bodies are kept in a sedentary state—e.g., when one’s arm is in a cast because of a fracture, or when one is immobilized by a severe injury and is at bed rest—there is rapid demineralization and thinning of the bones.  Spinal cord injured patients who are paralyzed undergo a very rapid bone demineralization. A rapid demineralization also occurs when our bodies are not exposed to the force of gravity. Astronauts who spend time in zero gravity experience a remarkably fast demineralization and run the risk not only of thinning bones—as does anyone with rapid demineralization—but also of developing kidney stones that result from the calcium mobilized from the bones.

Bone mineralization is stimulated by varying stresses placed upon the bones, as opposed to repetitive, monotonous movements. BMD is greater in sprinters, ball sport athletes and gymnasts than in endurance sports athletes, including walkers, runners, swimmers and cyclists.  Aerobic ball sport activities that provide variable stresses on bones that work against gravity and provide periods of rest include tennis, squash, football, soccer, basketball, hockey, field hockey, lacrosse, dancing and gymnastics.  Additionally, weight training and any activity that uses resistance equipment can effectively promote bone mineralization.  Physical activities that involve straining, versatile movements, and high-peak forces more beneficially mineralize bone than training with many low-force repetitions.

Repetitive, unvarying stresses can demineralize bone and are an ineffective means of increasing bone strength. For this reason, runners and swimmers have the lowest BMD among athletes. Some studies have shown that endurance and non-weight-bearing sports participants may actually have bones that are weaker and at a greater risk of fracture than sedentary and inactive people.  Endurance athletes may burn so many calories that there is insufficient energy remaining to fuel the process of bone health maintenance, with the possible consequence of stress fractures due to repeated strains on weight-bearing bones. To optimize bone health when running, swimming and cycling, it is best to do interval training at variable speeds, intensities and durations and not maintain monotonous motion. Of equal importance is sufficient calorie intake to fuel the bone mineralization process.

Body weight

Those with low body weight or who have recently experienced weight loss tend to experience more bone demineralization than those who are heavy.

One of the few advantages of being overweight is that it requires extra effort to carry around the added pounds, and it is this exertion against the force of gravity that helps to mineralize and fortify bones.

Aging bones

There is a gradual loss of bone mass that occurs with aging, which correlates with the likelihood for “osteopenia,” the medical term for bone loss. “Osteoporosis” is the medical term applied to severe bone loss, which incurs a greater risk of fractures.

Although osteopenia and osteoporosis occur in both genders, women are at much higher risk than men. The male and female sex hormones, testosterone and estrogen, respectively, promote bone health and mineralization. After menopause, with the sudden drop in estrogen there is typically an acceleration of bone loss. Men usually experience a gradual drop in testosterone levels with aging, with lower testosterone levels correlating with more bone loss.  In general, men tend to experience bone loss at a slower rate than women since they weigh more and keep their bones better mineralized by supporting the extra weight; additionally, the testosterone decline with aging is much less than the accelerated decline in estrogen at menopause.

Next week’s entry: Bone Health and Prostate Cancer

Wishing you the best of health,

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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  He is an Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area, Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community. He is a urologist at New Jersey Urology, the largest urology practice in the United States.  Dr. Siegel is the author of Prostate Cancer 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families.  The first section of the book provides abundant information on the prostate and prostate cancer, while the second and third sections address male urinary and sexual concerns, respectively.

Video trailer for Prostate Cancer 20/20

Preview of Prostate Cancer 20/20

Andrew Siegel MD Amazon author page

Prostate Cancer 20/20 on Apple iBooks

PROSTATE CANCER 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families is now on sale at Audible, iTunes and Amazon as an audiobook read by the author (just over 6 hours). 

Dr. Siegel’s other books:

FINDING YOUR OWN FOUNTAIN OF YOUTH: The Essential Guide to Maximizing Health, Wellness, Fitness and Longevity

PROMISCUOUS EATING— Understanding and Ending Our Self-Destructive Relationship with Food

MALE PELVIC FITNESS: Optimizing Sexual and Urinary Health

THE KEGEL FIX: Recharging Female Pelvic, Sexual, and Urinary Health

Tags: aging bones, Andrew Siegel MD, bone health, bone mineralization, calcium, exercise, osteopenia, osteoporosis, vitamin D

This entry was posted on November 9, 2019 at 6:27 AM and is filed under health and wellness. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.