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:: September 2007 Volume 6/Number 7
Research Review:
Maintaining Bone Density
By Felicia M. Tomasko
Our bones are alive and
constantly changing within their matrix of protein (collagen) and mineral
(calcium phosphate). This malleability is necessary to keep the structure of
our skeleton, our very support, healthy. Bone that is not being reformed can become brittle
and break more easily. There is a balance between the osteoblasts, the cells
that manufacture new components of the skeletal matrix in a process known as
formation, and the osteoclasts, the cells that break down bone mineral so it
can be reformed in resorption. To maintain bone density and bone health, we
need to build bone as much as or more than we are breaking it down.
Peak Bone
Our peak bone mass is reached
at around the age of 30. For this reason, our nutritional status as well as how
we use our bodies throughout childhood and young adulthood are both extremely
important for setting the stage for the health of our bones in the rest of our
life.
[1]
On the other hand, since bone is always being remade, we have the opportunity
to strengthen bone density and maintain bone health at any point in life.
Osteoporosis and Osteopenia
Osteoporosis and osteopenia,
the precursor to osteoporosis, are conditions in which there is a net loss of
bone formation. This is either because resorption is happening too quickly or
formation too slowly. According to statistics from the National Osteoporosis
Foundation, women are four times as likely as men to develop osteoporosis, yet
men can still suffer from bone loss.[2]
Visible symptoms of bone loss may not appear, and people can break or fracture
bones without knowing it has even happened. Bone loss is expensive from a
healthcare perspective; the costs related to broken bones and osteoporosis
represent $14 billion annually from 1.5 million fractures.[3]
Risk Factors
Bone loss is caused by a
combination of genetic and environmental factors.
[4]
,
[5]
Some risk factors include: being
a woman, being of smaller size, heredity, low levels of estrogen or
testosterone, high alcohol consumption, being sedentary, low levels of Vitamin
D, medication use such as long-term glucocorticoid use and physiological
acid/base imbalances. Depression, higher cortisol levels and chronic diseases
such as HIV are also associated with lower bone density.
[6]
,
[7]
,
[8]
,
[9]
Consuming nutrients important
for bone health is necessary throughout life, particularly when younger,
beginning in early childhood. Regular,
long-term intake of minerals is vital.[10]
A number of minerals are all necessary, including: calcium, magnesium,
manganese, Vitamin D and zinc.
Calcium
Calcium is one of the most
abundant minerals in the body; in the body 99% of the calcium is stored within
the bone, providing the mineral structure. The rest of the body's calcium
supply circulates throughout the bloodstream. Calcium is necessary for proper
functioning of the nervous and musculoskeletal systems; release of calcium
within a muscle cell initiates contraction, so the mineral is an intimate
component of each heartbeat. For this reason, the body will take calcium from
the storage sites in the bone to
ensure there is adequate circulating calcium, and blood tests will not reveal
whether calcium levels in the body are adequate for maintaining bone density.
When choosing calcium
supplements, select ones without iron (calcium and iron are not well-absorbed
together). Test the supplement's absorbability by dissolving a small amount in
water; if it does not dissolve, it does not absorb. Calcium is best absorbed in
an with acid in the digestive system, so choosing calcium citrate, having
calcium with meals when stomach acids are high or drinking citrus juice
increase calcium absorption.[11]
Good vegan sources of dietary calcium include sesame seeds, almonds, kale, broccoli,
collard greens and turnip greens.
Vitamin D
Produced in the deeper layers
of our skin when exposed to sunlight, Vitamin D is necessary for calcium
absorption, assimilation and the mineral's uptake into bone, a good reason to
include daily walks in the fresh air as part of a regular routine. A study
completed with people at high fall risk found that those who took Vitamin D
supplements (800 IU daily) had a reduced rate of falls.[12]
Acidity and pH
Nutritional factors are more
than dietary intake of recommended daily allowances of minerals. Work done at
the Osteoporosis Education Project investigates internal pH (distinct from
digestive pH). Among other physiological processes, it is observed that
acid-alkaline balance affects bone mineralization. Our body is naturally
slightly alkaline, and needs to maintain that balance; if it becomes too
acidic, buffering minerals are drawn from the bone. Increased acidity is
related to consumption of phosphoric acid, coffee and caffeine, processed
sugar, processed foods and excessive fat and animal protein.
[13]
Phosphoric Acid
A common ingredient in cola
drinks and other beverages, phosphoric acid is thought to interfere with
mineral absorption and bone mineralization. Women who are regular cola drinkers
have lower measured bone density, even with adequate calcium intake.[14]
Cola drinks (containing phosphoric acid), but not other carbonated drinks, are
implicated.[15] These
results are taken from the long-term (begun in 1971) Framingham Osteoporosis
Study.
Caffeine and Coffee
Caffeine and coffee interfere
with bone mineralization. Caffeine reduces the reabsorption of calcium and
magnesium in the kidney;
[16]
,
[17]
it is particularly difficult for older women to compensate for the calcium loss
due to caffeine.
[18]
High coffee
intake is associated with an increased risk of lower bone density w.
[19]
,
[20]
,
[21]
,
[22]
Bone loss associated with caffeine consumption is especially pronounced in
women who do not consume adequate calcium.
[23]
Exercise and Yoga
Placing stress or resistance
from a load or weight on the bone stimulates mineralization. The increase in
internal strain initiates osteogensis, or bone formation.
[24]
For this reason, not all exercise is created equally when maintaining bone
density. Bone density is demonstrably higher in athletes who engage in impact
loading activities such as walking, running or gymnastics, than
non-weight-bearing activities such as swimming.
[25]
Use of heavier weights and fewer repetitions of the weights in resistance
exercise lead to greater gain in bone density.
[26]
Women especially need to be cautious of overtraining, since amenorrhea, the
loss of menstrual cycle, can inhibit osteogensis.
[27]
Yoga is often suggested as a
method for increasing or building bone density and research studies are currently
investigating yoga practice and bone density. Yoga postures have been shown to
increase bone density in the spine.[28]
Dynamic loads, holding weight or using resistance while moving, particularly in
unusual positions, stimulate osteogensis.[29]
Regular yoga practice helps older women with kyphosis, a rounded spine, stand
straighter and reduce the excessive curvature.[30]
If someone does have
osteoporosis, there are a number of important cautions in implementing a yoga
practice. When bone loss had already occurred, it is possible for a bone to
break without realizing that it has been broken. Suza Francina, in The New
Yoga for Healthy Aging, outlines some
guidelines for yoga practice in the case of osteoporosis: avoid high-impact
activities and sudden, jerking movements, avoid activities in which a person is
hunched over or collapsed, avoid hyperextending the neck and avoid poses that
bear weight.[31]
Conclusion
Bone strength is much more
complicated than an actual measurement of bone density, and bone health is
representative of health throughout the entire body. From an Ayurvedic
perspective, asthi, or bone is the
fifth of the seven dhatus, or
tissue layers. This means that the nutrients we take in must feed four other components
of our physiology (plasma or fluid, blood, muscle and fat) before we even begin
to build bone. Adequate nutrition, maintaining overall balance and engaging in
fun, daily movement are all important for our overall health, as well as the
structure that provides our support.
Selected Resources
Suza Francina, The New
Yoga for Healthy Aging
Dr. Susan Love, Dr. Susan
Love's Hormone Book
Dr. Susan Brown, Better
Bones, Better Body
References
The author would like to thank Suza Francina and Millie
Sweesy for their assistance.
[1] Eastell, R.,
Lambert, H. 2002. Strategies for
skeletal health in the elderly. Proceedings of the Nutrition Society. 61(2):173-80.
[2] National
Institute of Arthritis and Musculoskeletal and Skin Diseases. 2006. Osteoporosis Overview.
[3] National
Institute of Arthritis and Musculoskeletal and Skin Diseases. 2006. Osteoporosis
Overview
[4]
Ongphiphadhanakul, B. 2007. Osteoporosis: the role of genetics and the
environment. Forum of Nutrition. 60:158-67.
[5] Williams,
F.M., Spector, T.D. 2006. Recent advances in the genetics of osteoporosis. Journal
of Musculoskeletal and neuronal interactions. 6(1):
27-35.
[6] National
Institute of Arthritis and Musculoskeletal and Skin Diseases. 2006. Osteoporosis
Overview.
[7] Brown, S.E.
and Jaffe, R. 2000. Acid-Alkaline imbalance and its effect on bone health. International
Journal of Investigative Medicine. 2(6).
[8] Altindag,
A., Altindag, O., Asoglu, M., Deveci, Z., Gunes, M., and Soran, N. 2007.
Relation of cortisol levels and bone mineral density among premenopausal women
with major depression. International Journal of Clinical Practice. 61(3):416-420.
[9] Grinspoon,
S. 2006. Longitudinal analysis of bone density in human immunodeficiency
virus-infected women. The Journal of Clinical Endocriniology and Metabolism.
91:2938-2945.
[10] New, S.A.,
Bolton-Smith, C. Grubb, D.A. and Reid, D.M. 1997. Nutritional Influences on
bone mineral density: a cross-sectional study in premenopausal women. American
Journal of Clinical Nutrition. 65(6):
1831-9.
[11] National
Institute of Arthritis and Musculoskeletal and Skin Diseases. 2005. Calcium
Supplements: What to Look for.
[12] Broe, K.E.,
Chen, T.C., Weinberg, J., Bischoff-Ferrari, H.A., Holick, M.F. and Kiel, D.P.
2007. A higher does of Vitamin D reduces the risk of falls in nursing home
residents: a randomized, multiple-dose study. Journal of the American
Geriatric Society. 55(2):234-9.
[13] Brown, S.E.
and Jaffe, R. 2000. Acid-Alkaline imbalance and its effect on bone health. International
Journal of Investigative Medicine. 2(6).
[14] Tucker, K.
2003. Regular cola consumption linked to lower bone density in women. Results Presented at the 25th Annual
Meeting of the American Society for Bone and Mineral Research.
[15] Tucker,
K.L. 2006. American Journal of Clinical Nutrition. 84: 936-42.
[16] Bergman, E.A., Massey,
L.K., Wise, K.J. and Sherrard, D.J. 1990. Effects of dietary caffeine on renal
handling of minerals in adult women. Life Sciences. 47(6):557-64.
[17] Kynast-Gales, S.A. and
Massey, L.K. 1994. Effect of caffeine on circadian excretion of urinary calcium
and magnesium. Journal of the American College of Nutrition. 13(5):467-72.
[18] Massey, L.K. and Whiting,
S.J. 1993. Caffeine, urinary calcium, calcium metabolism and bone. Journal
of Nutrition. 123(9):1611-4.
[19] Korpelainen, R., Korpelainen, J., Heikkinen, J.,
Vaananen, K. and Keinanen-Kiukaanniemi, S. 2003. Lifestyle factors are
associated with osteoporosis in lean women but not in normal and overweight
women: a population-based cohort study of 1222 women. Osteoporosis
International. 14(1):34-43.
[20] Barrett-Connor, E., Chang,
J.C. and Edelstein, S.L. 1994. Coffee-associated osteoporosis offset by
daily milk consumption. The Rancho Bernardo Study. JAMA. 271(4). 280-3.
[21] Hernandez-Avila, M.,
Stampferm M,J,, Ravnikar, V.A., Willett, W.C., Schiff, I., Francis, M.,
Longcope, C. and McKinlay, S.M. 1993. Caffeine and other predictors of bone
density among pre- and perimenopausal women. Epidemiology. 4(2):128-34.
[22] Rapuri, P.B., Gallagher,
J.C., Kinyamu, H.K. and Ryschon, K.L. 2001. Caffeine intake increases the rate of bone loss in elderly
women and interacts with vitamin D receptor genotypes. American Journal
of Clinical Nutrition. 74(5):694-700.
[23] Harris, S.S. and
Dawson-Hughes, B. 1994. Caffeine and bone loss in healthy postmenopausal women.
American Journal of Clinical Nutrition.
60(4):573-8.
[24] Lanyon,
L.E. and Rubin, C.T. 1984. Static versus dynamic loads as an influence on bone
remodeling. Journal of Biomechanics. 17:897-905.
[25] Fehling,
P.C., Alekel, L., Clasey, J., Rector, A., Stillman, R.J. 1995. A comparison of
bone mineral densities among female athletes in impact loading and active
loading sports. Bone. 17(3):205-10.
[26] Kerr, D.,
Morton, A., Dick, I. Price, R. 1996. Exercise effects on bone mass in
postmenopausal women are site-specific and load-dependent. Journal of Bone
and Mineral Research. 11(2): 218-25..
[27] Gibson,
J.H., Harries, M., Mitchell, A., Godfrey, R., Lunt, M. and Reeve, J. 2000.
Determinants of bone density and prevalence of osteopenia among female runners
in their second to seventh decades of age. Bone. 26(6):591-8.
[28] Cited in
Francina, S. 2007. The New Yoga for Healthy Aging. Health Communications, Inc: Deerfield Beach, FL. Page
130.
[29] Lanyon,
L.E. 1992. The success and failure of the adaptive response to functional
load-bearing in averting bone fracture. Bone. 13 Suppl 2:S17-21.
[30] Greendale,
G.A., McDivit, A.M., Carpenter, A., Seeger, L. and Huang, M-H. 2002. Yoga for
women with hyperkyphosis: results of a pilot study. American Journal of
Public Health. 92(10):1611-1614.
[31] Francina,
S. 2007. The New Yoga for Healthy Aging. Health
Communications, Inc: Deerfield Beach, FL. Pages 124-9..
All Rights Reserved.
Copyright © 2002-2006
LA Yoga Ayurveda & Health Magazine
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