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Osteoporosis: Improving & Maintaining Bone Health
researched and written by the ProjectAWARE group, 2001
EXERCISE
The specific effects of physical activity on bone health have been
investigated in randomized clinical trials and observational studies.
There is strong evidence that physical activity early in life contributes
to higher peak bone mass. Some evidence indicates that resistance
and high impact exercise are likely the most beneficial.33
Exercise during the middle years of life has numerous health benefits,
but there are few studies on the effects of exercise on bone density.
Exercise during the later years, in the presence of adequate calcium
and vitamin D intake, probably has a modest effect on slowing the
decline in bone density.33
It is clear that exercise late in life, even beyond 90 years of
age, can increase muscle mass and strength twofold or more in frail
individuals. Unrelated to osteoporosis, there is convincing evidence
that exercise in elderly persons also improves function and delays
loss of independence and thus contributes to quality of life.33
LIFESTYLE
While race and ethnicity appear to play a role in risk for osteoporosis,
diet and lifestyle habits are equally important. Osteoporosis may
not cause specific symptoms until it is advanced, but there are
some warning signs that may signal bone loss is occurring. These
include a gradual loss of height, a stooping or rounding of the
shoulders, and generalized aches and pains.3
An active lifestyle involving exercise within tolerance and a healthy
diet have been shown to delay onset of osteoporosis and possibly
slow progression of bone loss. Smoking, regular alcohol consumption,
and stress tend to hasten bone loss. Long-term use of antacids,
blood thinners, diuretics, anti-seizure and ulcer medications also
promote osteoporosis. Use of cortisone interferes with the process
of bone renewal.
While adequate exercise is beneficial, excessive physical exercise
is not. Those who have fair skin, hypothyroidism, follow low-calorie
weight-loss diets, and drink only distilled water are thought to
be further at risk for osteoporosis.
It is believed by some that massage, hands-on energy treatments,
herbal poultices, isometric exercise, visualization, acupuncture,
sexual tension and release, and magnets stimulate weak electrical
charges believed to stimulate bone growth.
Beware of preventable falls, the biggest cause of broken bones.
Randomized clinical trials of exercise have been shown to reduce
the risk of falls by approximately 25 percent, but there is no experimental
evidence that exercise affects fracture rates. It also is possible
that regular exercisers might fall differently and thereby reduce
the risk of fracture due to falls, but this hypothesis requires
testing.33
Neuropsychiatric disorders may cause or be the result of osteoporosis.
Specific psychiatric disorders, including depression and anorexia
nervosa, are associated with osteoporosis or clinical fractures.
Medications used to treat psychiatric or neurologic disorders may
cause osteoporosis, and the diagnosis of osteoporosis may have psychological
implications. Research efforts into the relationship between neuropsychiatric
disorders and fracture risk should be strongly encouraged.33
NUTRITION
Because nutrition is a modifiable pathogenic
factor of osteoporosis, which has important practical and public
health implications, it is a topic that deserves special attention.27
Good nutrition is essential for normal growth. A balanced diet,
adequate calories, and appropriate nutrients are the foundation
for development of all tissues, including bone, but not everyone
follows a diet that is optimal for bone health. In particular, excessive
pursuit of thinness may affect adequate nutrition and bone health.
Supplementation of calcium and vitamin D may be indicated. However,
study is needed to understand the influence of nutrition on micronutrients
and non-patentable medical interventions.33
Mineral and trace element insufficiency states are actually more
likely to occur than are vitamin insufficiency states. Those at
risk include the elderly, pregnant women, vegetarians, people who
eat low-calorie diets, people on certain drugs (such as diuretics),
and those living where the soil is deficient in minerals. Suboptimal
intake can be due to factors other than soil depletion and are as
diverse as the effects of acid rain and the over-refining, over-processing
of foods.15
Studies have shown a positive association between high dietary
intake of fruit and vegetables and bone health in premenopausal,
perimenopausal, and elderly postmenopausal women as well as elderly
men. The mechanisms behind the effect may lie in the beneficial
effect of the alkaline environment induced by a diet rich in fruit
and vegetables, which contain good quantities of potassium, magnesium,
beta-carotene, fiber, and vitamin D.27
The findings of these studies with respect to a positive link between
fruit and vegetable consumption and bone health are further strengthened
by the results of the DASH trial (Dietary Approaches to Stopping
Hypertension) published by Appel and coworkers in 1997. The study
consisted of a 3-week control diet and then 8 weeks of either a
fruit and vegetable diet, a combination diet of fruit, vegetables
and low-fat dairy products, or a control diet. Increasing the fruit
and vegetable intake from 3.6 to 9.5 daily servings resulted in
a reduction of urinary calcium excretion from 157 mg/day to 110
mg/day. No measurements of bone metabolism markers were available
in this trial, but there are definite implications with respect
to bone health, and further studies are warranted.27
Boron
Studies have shown that 3 milligrams (mg) of boron daily reduces
urinary excretion of calcium and magnesium, especially when dietary
magnesium is low. Boron supplementation elevates the serum concentrations
of 17 beta estradiol and testosterone, again when dietary magnesium
is low. The findings suggest that supplementation of a low-boron
diet with an amount of boron commonly found in diets high in fruits
and vegetables induces changes in postmenopausal women consistent
with the prevention of calcium loss and bone demineralization.4,
31, 32
Cabbage ranks highest in boron content among leafy vegetables,
with 145 parts per million (ppm) on a dry-weight basis. Dandelion
shoots run a close second with 125 ppm. Dandelion also has more
than 20,000 ppm of calcium, meaning that just under 7 tablespoons
of dried dandelion shoots could provide more than 1 mg of boron
and 200 mg of calcium.7
Calcium: Supplementation
There has been considerable debate over the past two decades as
to the effectiveness of calcium supplements in reducing peri/postmenopausal
bone loss and much inconsistency in the findings of published studies.
These discrepancies may have resulted from the failure of many of
these studies to identify the special circumstances created by estrogen
withdrawal in the years following menopause.27
The major mechanism whereby calcium affects bone is probably through
inhibition of PTH secretion. Many people would like to believe that
they could prevent osteoporosis by increasing their calcium intake.
Calcium excess does not necessarily result in bone gain or even
in prevention of bone loss, but calcium deficiency certainly will
make bone loss worse.6
The division of women into early (< 5 years) and late (>
5 years) postmenopause has significantly contributed to our understanding
of the role of calcium on bone loss. Intervention trials suggest
that calcium supplementation is effective in reducing bone loss
in women who are more than 5 years postmenopause and in such women
who have low habitual calcium intakes (< 400 mg/day). Results
of trials in the early postmenopausal stage are inconclusive.27
The North American Menopause Society (NAMS), a nonprofit scientific organization
dedicated to promoting the understanding of menopause, has published a
formal consensus opinion regarding the role of calcium in peri/postmenopausal
women. "Adequate calcium intake (in the presence of adequate levels of
vitamin D) certainly plays a major role in reducing the incidence of osteoporosis
(a bone-thinning disease) and resultant fractures, and it is considered
an essential component of any prescription drug therapy regimen for osteoporosis
prevention and treatment". The NAMS consensus opinion is published in
the March-April 2001 issue of the Society's journal, Menopause,
which can be found in its entirety on the NAMS Web site http://www.menopause.org/
The NAMS consensus recommends supplementation with at least 1,200
mg/day of calcium. Levels greater than 2,500 mg/day are not recommended.
To ensure adequate calcium absorption, a daily intake of 400-600
IU of vitamin D is recommended, either through sun exposure or through
diet or supplementation. Since no accurate test to determine calcium
deficiency exists, clinicians should focus instead on ensuring that
a woman consumes enough calcium to meet the recommended levels.24
Absorbability of calcium supplements varies considerably,15
but it is thought by some that the most absorbable type of calcium
is hydroxyapatite; the second most absorbable is calcium citrate,
which is not made from animal bones.2
Some early studies show that microcrystalline hydroxyapatite compound
(MCHC) has prevented bone loss and the progression of osteoporosis.
Reduction in bone mineral content was halted, trabecular bone volume
increased, back pain decreased, and gain in cortical bone thickness
has been observed in these studies.42, 35, 8 This form
of calcium, derived from ground cow or ox bone, is beneficial because
it is identical to the calcium found in our bones, is the most easily
absorbable form, and can be said to prevent osteoporosis.2
Calcium hydroxyapatite is now available in vitamin and health food
stores and does not require a prescription.
Of the sources available on the market, bone meal contains absorbable
forms of calcium, but it may be contaminated with lead. Calcium
chloride is irritating to the gastrointestinal tract. Both calcium
carbonate and magnesium carbonate are found in dolomite, a popular
food supplement. However, the magnesium carbonate in dolomite is
not a very "available" form of magnesium. Those taking calcium carbonate
should consume it with meals, as this form of calcium needs a lot
of acid (hydrochloric acid produced by the stomach or as a supplement)
for absorption, and it is important to remember that we produce
less acid as we age. Calcium gluconate, calcium lactate and calcium
citrate are more soluble forms of calcium but are less concentrated
in calcium.15
There is now some good data to show bone turnover has a strong
diurnal variation, with the highest bone resorption occurring during
the night and reaching a peak at 7 a.m. It is therefore appropriate
for a large proportion of calcium supplements to be taken at night.27
Side effects from a 1,000 mg daily dose of calcium) are very few.
Those persons who have already had a kidney stone and who have absorptive
hypercalciuria should not take excess calcium.6 And those
taking the drug Digoxin, also known as Lanoxin, should avoid high
doses of calcium ascorbate.2
Calcium: Nutritional
While supplementing the diet with calcium appears to be sound medical
advice, osteoporosis is much more than a lack of dietary calcium.
Deficiency of calcium in the bone results in osteomalacia, or softening
of the bone, whereas osteoporosis indicates a lack of both calcium
and other minerals, as well as a decrease in the non-mineral framework
(organic matrix composed of collagen and other proteins) of bone.23
Normal bone metabolism is dependent on nutritional and hormonal
factors, with the liver and kidneys having a regulatory effect.
Stomach acid, calcium, vitamin D, and hormonal factors such as secretion
of parathyroid hormone by the parathyroid glands, a decrease in
calcitonin by the thyroid and parathyroids, and estrogen deficiency
all play an important role in the metabolism of calcium.23
Sufficient data exist to recommend specific dietary calcium intakes
at various stages of life. The National Institutes of Health Concensus
recommends calcium intake be maintained at 1,000 to 1,500 mg/day
for older adults, yet only about 50 to 60 percent of this population
meets this recommendation.33
Treatment of osteopenia (a bone density that is somewhat low) depends
on age and the presence of other risk factors for fractures. For
women between 50 and 70, the best prevention is estrogen with calcium
and exercise.6
When we have a low dietary intake of calcium, or in conditions
of increased need, such as growth and pregnancy, the rate of absorption
increases. Calcium absorption is also increased by the parathyroid
hormone, lactose, vitamin A, vitamin D, and the amino acids lysine
and arginine. Taking a calcium supplement with vitamin C can significantly
increase calcium absorption. Magnesium, phosphorus, boron, selenium,
iron, manganese and vitamin E are also important for calcium metabolism.
Other dietary practices that affect calcium metabolism, such as
high animal protein diet and salt and sugar intake cause the body
to excrete increased amounts of calcium. The body is forced to "steal"
calcium from the bones to meet its requirements. Too much magnesium
or phosphorus and many drugs inhibit calcium absorption in the bone
and bone marrow.3 Wheat bran, raw spinach, fructose (as
in high-fructose corn syrup in soft drinks), caffeine, alcohol,
and tobacco can all interfere with calcium absorption.46
Some insist that calcium makes them constipated, although in blinded
trials this complication is no more frequent than with placebo.
Calcium citrate may help in these situations, as may increasing
intake of fruit juices. Others complain of gastritis, which might
be caused by taking calcium carbonate between meals, thus stimulating
rebound acid production.6
The American Family Physician (Mar 2001) summarizes: Prevention
is the most important step, and women of all ages should be encouraged
to take 1,000 to 1,500 mg of supplemental calcium daily, participate
in regular weight-bearing exercise, avoid tobacco and excessive
alcohol intake, avoid medications known to compromise bone density,
and institute hormone replacement therapy at menopause unless contraindicated.41
Vitamin A
Vitamin A is essential for metabolism of calcium. Recommended dosage
for adults is 5,000-10,000 IU/day, and for seniors is 10,000-15,000/day.2
Those with chronic kidney failure may develop bone disease from
increased bone resorption, leading to high levels of calcium in
the blood (hypercalcemia).15 Vitamin A toxicity is rare,
and a toxic dose is considered to be in excess of 100,000 IU daily
for 6-15 months. However, when the vitamin is stopped, signs of
toxicity disappear quickly. Beta carotene, because of its lower
conversion rate to vitamin A, is not considered toxic, and a daily
dose of 25,000 IU is considered normal. Pregnant women should not
take more than 8,000 IU daily, as birth deformities have occurred
at doses of 25,000 IU daily.2
A study from Sweden found that Vitamin A has been shown to increase
bone resorption, and high levels are associated with osteoporosis.
This study involved 247 women with hip fracture who were compared
with 873 matched controls. Every 1mg/day increase in vitamin A (retinol)
intake increased the risk of hip fracture by 68%.22
Vitamin B12
There is some evidence in the literature to suggest that vitamin
B12 suppresses osteoblastic activity. At the World Congress on Osteoporosis
2000, Beynon and coworkers (UK) presented work on the potential
important role that vitamin B12 may play in osteoporosis.
A total of 263 osteoporotic patients were studied (244 women, 19
men). Of the 44 subjects with low vitamin B12, 22 had
suffered a fracture. Further research in this area is required,
but vitamin B12 may be implicated in osteoporosis and
is clearly a measurement that should be performed in osteoporosis
clinics.27
Vitamin B12 is involved in the formation of red blood
cells, cell longevity, healthy nervous system, metabolism and mental
function. Current recommended dosage for adults is 100-1,000 mcg/day,
and for seniors is 100-2,000 mcg/day. A sublingual form is much
more absorbable than an oral form. Higher levels may be required
to treat specific health conditions. Vegetarians can suffer from
vitamin B12 depletion.2
Vitamin D
Vitamin D (in combination with PTH) plays a crucial role in the
regulation of calcium and phosphorus metabolism and promotes calcium
absorption from the gut and kidney tubules. Supplementation trials
have shown vitamin D to improve calcium absorption, lower PTH levels,
and reduce wintertime bone loss in postmenopausal women.27
Randomized clinical trials have demonstrated that adequate calcium
intake from diet or supplements increases spinal bone density and
reduces vertebral and nonvertebral fractures. When consumption of
dairy products decreases, vitamin D intake is less likely to be
adequate, and this may adversely affect calcium absorption. A recommended
vitamin D intake of 400 to 600 IU/day has been established for adults.33
The elderly population is especially at risk for either insufficiency
or deficiency of vitamin D. Vitamin D and calcium supplemention
trials have been shown to significantly reduce fracture rates in
the institutionalized and free-living elderly populations, but vitamin
D given as a supplement alone does not appear to be as effective.
Our knowledge is limited by the small number of supplementation
trials published, and there is an urgent need for further research
in this area.27
Vitamin D deficiency is seen in patients with inadequate sunlight
exposure who also ingest inadequate amounts of vitamin D. Particular
examples are nursing home patients and breast-fed babies who don't
get outside. Patients with malabsorption also may have vitamin D
deficiency.6
Active metabolites of vitamin D have been advocated for treatment
of osteoporosis; however, a common misunderstanding is that calcitriol
(D3) has a dose-dependent effect on bone mass. Studies
have found that those with vitamin D deficiency or poor calcium
nutrition show improvement in bone mass, but this is not true for
women who are well nourished. In the U.S. three studies of calcitriol
all showed no significant increase in bone mass compared to baseline.
Researchers from New Zealand concluded that calcitriol treatment
reduced the rate of vertebral fractures; however, this unblinded
study had a 30% drop-out rate which might have biased the results,
and bone mass was not measured.6
Vitamin K
Vitamin K may have a role to play in bone health, as bone proteins
are dependent on vitamin K for their synthesis. There is now good
evidence of significant circulating levels of menaquinone (vitamin
K2) in healthy elderly women and following osteoporotic fractures
of the spine and hip. However, there are considerable technical
problems with the assay used to measure osteocalcin. In addition,
osteocalcin is dependent on the synthesis of vitamin D, which may
indicate that undercarboxylation can be normalized with vitamin
D alone. Further work is required.27
In addition to producing blood-clotting factors and having a role
in the prevention and treatment of postmenopausal osteoporosis,
vitamin K has unusual anti-tumor properties. Suggested dosage range
for adults is 300-500 mcg/day, and for seniors is 300-500 mcg/day.
Supplementation is not usually necessary as foods usually supply
enough vitamin K. However, anticoagulants such as Coumadin, Dicumarol
and Panwarfin, as well as caffeine and medicines containing caffeine,
laxatives and lubricants such as castor oil and mineral oil can
cause vitamin K deficiency. Systemic sulfonamides and topical steroids,
tetracyclines and other medications such as Chloramphenicol and
Cholestyramine, Clofibrate, Kanamycin and Propantheline also cause
deficiency.2
Acid-alkaline Balance and Potassium
Acid-base homeostasis (acid-alkaline balance) disruptions in adults
have been suggested as a reason behind the progressive decline in
bone mass with aging. Recent population-based studies have suggested
a positive association between high intakes of fruit and vegetables
(and hence high intakes of potassium, magnesium, beta-carotene,
fiber, and vitamin D) in the diet and bone mass and bone metabolism
in premenopausal, perimenopausal, postmenopausal women and elderly
men.28, 29, 30, 44 The mechanisms behind the effect may
lie in the beneficial effect of the alkaline environment thus created.27
Bone loss may be attributable to life-long mobilization of skeletal
salts that balance endogenous acid generated from acid-producing
foods. Potassium reduces urinary calcium, improving calcium balance.
Deprivation of potassium stimulates bone resorption, causing a more
negative calcium balance. Supplementation of potassium bicarbonate
in postmenopausal women has been shown to improve calcium and potassium
balance, reduce bone resorption, and increase the rate of bone formation.27
Recently, a study in the USA reported that the protein-to-potassium
ratios in the diet predicts net acid excretion via the urine, and
that, in turn, net acid excretion via this route predicts calcium
excretion.39
New and colleagues (UK) have presented data showing further analysis
of nutrition and bone mass datasets published in 1997 and 2000.
Results indicated that those women who had the most acidic diets
had the poorest bone density (both in axial and peripheral skeleton)
and the highest level of bone resorption. Furthermore, analysis
of NEAP (nonendogenous acid production) intakes were found to be
significantly higher among women who stated that they had experienced
fractures. This is the first study to report a difference in indices
of bone health with NEAP intakes, and further analysis of other
datasets is warranted.27
Essential Fatty Acids
Most women are very concerned with menopausal weight gain and may
diet extensively to control their weight. A study by Salamone et
al in 1999 demonstrated that this could have damaging effects on
bone mineral density (BMD). The study involved a non-dieting control
group and an intervention group of perimenopausal women who modified
their lifestyle to lose weight by lowering fat intake and increasing
physical activity. There was a two-fold greater rate of loss in
hip BMD in the intervention group. The loss of BMD with dieting
may be induced by alterations in the total body content of the essential
fatty acids, such as by membrane depletion or preferential utilization
and excretion.18
Dietary supplementation with fish oil, flaxseeds, and flaxseed
oil in animals and healthy humans significantly reduces cytokine
production while concomitantly increasing calcium absorption, bone
calcium, and bone density. In 2001 the Alternative Medicine Review
reported that possibilities may exist for the therapeutic use of
the omega-3 fatty acids, as supplements or in the diet, to blunt
the increase of the inflammatory bone resorbing cytokines produced
in the early postmenopausal years in order to slow the rapid rate
of postmenopausal bone loss. Evidence also points to the possible
benefit of gamma-linolenic acid (GLA) in preserving bone density.18
Although there are no studies that can definitively conclude that
increasing the level of omega-3 fatty acids or manipulating the
ratio of GLA:EPA in the diet will slow the rapid loss of bone at
menopause, there are interesting associations that deserve further
attention. It has been found that incorporating higher amounts of
omega-3 fatty acids, thereby altering the ratio of omega-6 to omega-3,
while concurrently increasing vitamin E to inhibit lipid peroxidation,
may have a positive effect on calcium absorption and bone density.
There is need for additional study to further understand the relationship
between fatty acids, calcium and vitamin D in pre- and postmenopausal
women.18
Phytoestrogens
There is a great deal of public interest in natural estrogens,
particularly plant-derived phytoestrogens. These compounds have
weak estrogen-like effects, and although some animal studies are
promising, no effects on fracture reduction in humans have been
shown.33
Protein
Insufficient intakes of dietary protein have been implicated in
the pathogenesis of osteoporosis, and supplementation of protein
has been shown to improve the clinical outcomes of hip fractures.27
However, high protein diets leach calcium from bone. Some nutrition
experts suggest that people at risk for osteoporosis limit protein
intake to no more than one gram of protein per kilogram of body
weight, which translates into around two to three ounces of protein
(equivalent to one chicken breast) daily for the average woman.7
Sodium
High sodium levels are closely related to increased calcium excretion.
This is a concern, considering that adequate calcium intake plays
a major role in reducing the incidence of osteoporosis.24
Of note, however, is that there is very little data available on
the effect of high sodium intakes on bone health, with most studies
showing little or no association. This may simply be due to the
lack of term follow-up of subjects, and further research in this
area is warranted.27
At the World Congress on Osteoporosis 2000, Dr. Cappuccio and coworkers
(UK) presented data looking at the relationship between blood pressure,
urinary sodium excretion, and ethnic origin with daily and fasting
urinary calcium excretion. A total of 743 subjects were studied,
407 of them women. Urinary calcium (24-hr collection) was found
to be significantly associated with ethnic origin, blood pressure,
and urinary sodium. It was found that higher levels of sodium predicted
higher calcium loss through the urine.27
In a second double-blind, randomized study presented by this group,
reducing sodium intake was found to reduce urinary calcium losses
in the elderly. A total of 47 subjects aged 60-78 years took part
in a 2-month controlled trial of modest salt restriction. Reduced
urinary calcium was found in the salt-restricted group. The authors
speculate that these changes may be equivalent to a loss of bone
mass of about 1.5% per year, which has a substantial impact on bone
mass maintenance in the elderly.27
This interesting observation is not new. There is good evidence
in the literature to support a positive relationship between urinary
sodium and calcium excretion in young and adult free-living individuals
who consume a normal diet. It is also known that reduction in renal
sodium reabsorption leads to a reduction in calcium absorption and
increased calcium urinary losses.27
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Herbs & Supplements at a Glance 
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