Introduction
Many factors are known or suspected to accelerate the rate of bone loss. These
factors include smoking, alcohol, low calcium intake, lack of exercise, various
medications, and several illnesses. Excessive consumption of vitamin A may also
increase the risk of osteoporosis, and rapid weight loss may
increase the risk in postmenopausal women. Raw-food vegetarians are also likely to
have significant bone thinning.
In general, women are far more prone to osteoporosis than men. For this reason,
the following discussion focuses almost entirely on women.
Hormone
replacement therapy prevents or reverses osteoporosis in
women. However, long-term use of hormone replacement therapy has been found to be
unsafe, so conventional medical treatment for osteoporosis in women centers mainly
on drugs in the bisphosphonate family, including Fosamax (taken with calcium and
vitamin D).
Exercise, especially weight-bearing exercise, almost certainly helps strengthen
bone (although the evidence for this is weaker than one might expect). Minimal
evidence suggests that the Chinese exercise Tai Chi may
also provide some benefit.
Principal Proposed Natural Treatments
There is good evidence that people with osteoporosis, or who are at risk for it,
should take calcium and vitamin D supplements regardless of what other treatments
they may be using. Substances called isoflavones found in soy and other plants may
be helpful for osteoporosis (and for general menopausal symptoms). Vitamin K and a
newer supplement called strontium ranelate have also shown promise. A
semisynthetic isoflavone called ipriflavone has shown considerable promise for
osteoporosis, but safety concerns have decreased its popularity.
Calcium and vitamin D. Calcium is necessary to build and maintain
bone. Humans need vitamin D too, as the body cannot absorb calcium without it.
Many people do not get enough calcium in their daily diet. Although the body can
manufacture vitamin D when exposed to the sun, supplemental vitamin D may be
necessary because of the common use of sunscreen.
According to most studies, calcium supplements (especially as
calcium citrate, and taken with vitamin D) appear to be modestly
helpful in slowing bone loss in postmenopausal women. Contrary to some reports,
milk does appear to be a useful source of calcium for this purpose. Any
improvements in bone density rapidly disappear once the supplements are stopped.
People who ensure that they continue calcium use may do better than those who
forget from time to time. Vitamin D without calcium, however, does not appear to
offer more than minimal bone-protective benefits for the elderly.
The effect of calcium and vitamin D supplementation in any form is relatively minor and may not be strong enough to reduce the rate of osteoporotic fractures. A large study of more than three thousand postmenopausal women age sixty-five to seventy-one years found that three years of daily supplementation with calcium and vitamin D was not associated with a significant reduction in the incidence of fractures. The use of calcium supplements early in life might prevent problems later, especially when children also engage in physical exercise; however, study results are somewhat contradictory.
One study found benefits for elderly men using a calcium- and vitamin D-fortified milk product. However, there are some concerns that excessive calcium intake could raise the risk of prostate cancer in men.
Vitamin D and calcium taken together may also have a modestly protective effect against the severe bone loss caused by corticosteroid drugs such as prednisone. Certain other supplements may enhance the effects of calcium and vitamin D. One study found that adding various trace minerals (zinc at 15 milligrams [mg], copper at 2.5 mg, and manganese at 5 mg) produced further improvement. However, copper by itself may not be helpful.
There is some evidence that essential fatty acids may also enhance the effectiveness of calcium. In one study, sixty-five postmenopausal women were given calcium with either placebo or a combination of omega-6 fatty acids (from evening primrose oil) and omega-3 fatty acids (from fish oil) for eighteen months. At the end of the study period, the group receiving essential fatty acids had higher bone density and fewer fractures than the placebo group. In contrast to this, however, a similar twelve-month double-blind trial of forty-two postmenopausal women found no benefit from essential fatty acids. The explanation for the discrepancy may lie in the differences among the women studied. The first study involved women living in nursing homes, while the second studied healthier women living on their own. The second group of women may have been better nourished and already receiving sufficient essential fatty acids in their diet. Vitamin K may also enhance the effect of calcium.
Vitamin D may offer another benefit for osteoporosis in the elderly: Most, though not all, studies have found that vitamin D supplementation improves balance in the elderly (especially women) and reduces the risk of falling. Because the most common adverse consequence of osteoporosis is a fracture caused by a fall, this could offer a meaningful benefit. Also, there is weak, preliminary evidence that calcium supplementation in healthy, postmenopausal women may slightly increase the risk of cardiovascular events, such as myocardial infarction.
Genistein and other isoflavones. Soy contains substances called
isoflavones that produce effects in the body somewhat
similar to the effects of estrogen. (For this reason, they are called
phytoestrogens.) Although study results are not entirely
consistent, growing evidence suggests that genistein and
other isoflavones can (like estrogen) help prevent bone loss.
For example, in a one-year, double-blind, placebo-controlled study, ninety women age forty-seven to fifty-seven were given genistein at a dose of 54 mg per day or standard hormone replacement therapy (HRT) or placebo. The results showed that genistein prevented bone loss in the back and hip to approximately the same extent as HRT. No adverse effects on the uterus or breast were seen. A subsequent two-year double-blind study of 389 postmenopausal women with mild bone loss found that 54 mg of genistein plus calcium and vitamin D improved bone density to a greater extent than did calcium and vitamin D alone. However, a fairly high percentage of participants given genistein experienced substantial digestive distress.
In a one-year, double-blind, placebo-controlled study of 203 postmenopausal Chinese women, the use of soy isoflavones at a dose of 80 mg daily had mildly positive protective effects on bone mass in the hip. This supplement contained 46.4 percent daidzein, 38.8 percent glycetein, and 14.7 percent genistein.
Another study evaluated an isoflavone supplement made from red clover (containing 6 mg biochanin A, 16 mg formononetin, 1 mg genistein, and 0.5 mg daidzein daily). In this one-year, double-blind, placebo-controlled study of 205 people, the use of red clover isoflavones significantly reduced loss of bone in the lumbar spine. Benefits were also seen in a one-year, double-blind, placebo-controlled study using an extract made from the soy product tofu.
However, it is not clear that the consumption of foods rich in isoflavones offers the same benefits. For example, in placebo-controlled study involving 237 healthy women in the early stages of menopause, the consumption of isoflavone-enriched foods (providing an average of 110 mg isoflavone daily) for one year had no effect on bone density or metabolism.
The effect of isoflavones on bone may be more complex than that of
estrogen. Bone is always undergoing two opposite processes
at once: bone breakdown and bone formation. Estrogen acts on the first of these
processes by inhibiting bone breakdown. Isoflavones may affect both sides of the
equation at once: inhibiting bone breakdown, while at the same time enhancing new
bone formation.
In about one of three people, intestinal bacteria convert some soy isoflavones into a substance called equol. Isoflavones may have a greater bone-protecting effect in such equol producers.
Strontium. Growing evidence indicates that the mineral
strontium (as strontium ranelate) is effective as an aid in
the treatment of osteoporosis. The best and largest study on strontium was a
double-blind, placebo-controlled study of 1,649 postmenopausal women with
osteoporosis. In this three-year study, a dose of strontium ranelate at 2 grams
(g) daily significantly increased bone density in the spine and hip and
significantly decreased the rate of vertebral fractures.
While some treatments for osteoporosis act to increase bone formation and others act to decrease bone breakdown, some evidence suggests that strontium ranelate has a dual effect, providing both these benefits at once. There is one major caveat, however. All major controlled clinical trials of strontium ranelate have involved some of the same researchers. Entirely independent confirmation is needed. It is not clear to what extent the “ranelate” portion of strontium ranelate is necessary for this benefit, or whether other strontium salts would work too. (The strontium used in these studies is not the same as the radioactive strontium that was such a concern during the decades of above-ground atomic testing in the mid-twentieth century.)
Vitamin K. Increasing, but inconsistent, evidence indicates that
vitamin
K may help prevent osteoporosis. It may work by reducing bone
breakdown, rather than by enhancing bone formation.
Perhaps the best evidence for a beneficial effect comes from a three-year, double-blind, placebo-controlled trial of 181 women. Participants, all postmenopausal women between the ages of fifty and sixty years, were divided into three groups: placebo, calcium plus vitamin D plus magnesium, or calcium plus vitamin D plus magnesium plus vitamin K (at a dose of 1 g daily). Researchers monitored bone loss by using a standard dual-energy X-ray absorptiometry bone density scan. The results showed that the study participants using vitamin K with the other nutrients did not lose as much bone as those in the other two groups. However, another placebo-controlled trial involving 452 older men and women with normal levels of calcium and vitamin D failed to demonstrate any beneficial effects of 500 micrograms per day of vitamin K supplementation on bone health over a three-year period.
Ipriflavone. Ipriflavone is a semisynthetic
variation of soy isoflavones. Ipriflavone appears to help prevent osteoporosis by
interfering with bone breakdown. Estrogen works in much the same way, but
ipriflavonedoes not appear to produce estrogenic effects anywhere else in the body
other than in bone. For this reason, it probably does not increase the risk of
breast or uterine cancer. However, it also does not reduce the hot flashes, night
sweats, mood changes, or vaginal dryness of menopause. In addition, it may cause
health risks of its own.
Numerous double-blind, placebo-controlled studies involving more than seventeen hundred participants have examined the effects of ipriflavone on various forms of osteoporosis. Overall, it appears that ipriflavone can stop the progression of osteoporosis and perhaps reverse it to some extent. For example, a two-year double-blind study followed 198 postmenopausal women who had evidence of bone loss. At the end of the study, there was a gain in bone density of 1 percent in the ipriflavone group compared to a loss of 0.7 percent in the placebo group.
Conversely, the largest and longest study of ipriflavone found no benefit. In this three-year trial of 474 postmenopausal women, no differences in extent of osteoporosis were seen between ipriflavone and placebo groups. However, for reasons that are not clear, the researchers in this study gave women only 500 mg of calcium daily. All other major studies of ipriflavone gave participants 1,000 mg of calcium daily. It is possible that ipriflavone requires the higher dose of calcium to work properly.
Ipriflavone may also be helpful for preventing osteoporosis in women who are
taking Lupron or corticosteroids, medications that accelerate bone loss.
(However, the combined use of ipriflavone and drugs that suppress the immune
system, such as corticosteroids, presents risks.)
There is some evidence that combining ipriflavone with estrogen may improve benefits against osteoporosis. However, it is not known whether such combinations increase or decrease the other benefits and adverse effects of estrogen-replacement therapy. Finally, for reasons that are not clear, ipriflavone appears to be able to reduce pain in osteoporosis-related fractures.
Other Proposed Natural Treatments
It is often said that magnesium supplements are helpful for strong bones, but there is only minimal evidence to support this claim. It has been suggested (though with little meaningful supporting evidence) that the typical American diet causes the body to become acidic, and that this in turn leads to bone loss. One study tested potassium citrate as a treatment for bone loss, in the belief that this supplement would counteract this hypothesized diet-related acidity. The results in this one-year study of 161 postmenopausal women indicated that potassium citrate reduced bone loss to a greater extent than did the placebo (potassium chloride). This study had numerous problems in design, analysis, and reporting, so it does not necessarily show anything about dietary “acidity.” It may, however, indicate that the citrate part of potassium citrate has some bone-protective effects. If this is true, it could in turn explain why calcium citrate has, in some studies, proven more effective for treating or preventing osteoporosis than other forms of calcium.
Observational studies hint that higher levels of homocysteine might increase the
risk of osteoporosis. Vitamins B12, B6, and folate are known
to reduce homocysteine levels. On this basis, supplementation with these vitamins
has been proposed for preventing or mitigating the effects of osteoporosis. One
double-blind study found weak evidence that supplemental folate and
vitamin B12 (known to reduce homocysteine) might reduce risk of
osteoporotic fractures in people who had had a stroke. However, two other studies
failed to find that the use of mixed B-vitamins had any positive effect on bone
density or chemical markers of bone turnover.
Some evidence suggests that the hormone dehydroepiandrosterone (DHEA) may be helpful for preventing or treating osteoporosis, especially in postmenopausal women older than age seventy years. Also, one study found weak evidence that DHEA might be helpful for preventing the osteoporosis that sometimes develops in women with anorexia nervosa.
Chinese studies suggest that the herb Epimedium brevicornum has phytoestrogenic effects and, on this basis, may be helpful for preventing bone loss. (E. brevicornum is related, but not identical, to E. sagittatum, otherwise known as horny goat weed.)
Preliminary evidence suggests that black tea may help protect against
osteoporosis. Similarly weak evidence hints that the herb black cohosh
might help prevent osteoporosis. Although it has long been stated that high
phosphorus intake from the consumption of soft drinks might lead to osteoporosis,
there is no solid evidence for this claim. Elevated intake of phosphorus may help
prevent osteoporosis. The reason is that bone contains both calcium and
phosphate.
According to one preliminary study, but not another, boron may be helpful for
preventing osteoporosis. However, there are some concerns that boron
supplements may raise levels of the body’s own estrogen, especially in women on
estrogen-replacement therapy, and therefore might present an increased risk of
cancer. To increase boron intake, one should eat more fruits and vegetables.
One study widely advertised as showing that silicon is helpful for osteoporosis actually failed to show much of anything. Extremely weak evidence hints at possible benefit for osteoporosis through the use of royal jelly.
Although it has long been believed that consuming too much protein (especially animal-based protein) increases the risk of osteoporosis, the balance of available evidence suggests the reverse: If anything, high intake of protein appears to help strengthen bone. One study found that calcium supplements may do a better job of strengthening bones in people with relatively high protein intake than in those with lower intake.
It has been suggested both that water fluoridation helps prevent osteoporosis
and also that it causes the condition; on balance, however, the evidence suggests
that it does neither. Another study failed to find arginine supplements helpful
for enhancing bone density.
Progesterone. Many books promote the idea that natural
progesterone prevents or even reduces osteoporosis. In this
case, the term “natural” means the same progesterone found in the body. It is
still made synthetically, but it is called natural progesterone to distinguish it
from its chemical cousins known as progestins. Generally, prescription
“progesterone” is actually a progestin.
The progesterone-osteoporosis story began with test-tube and other preliminary studies suggesting that progesterone or progestins can stimulate the activity of cells that build bone. Subsequently, a poorly designed and uncontrolled study (actually, a series of case histories from one physician’s practice) purportedly demonstrated that progesterone cream can slow or even reverse osteoporosis.
However, a one-year double-blind trial of 102 women using either progesterone cream (providing 20 mg progesterone daily) or placebo cream, along with calcium and multivitamins, found no evidence of any improvements in bone density attributable to progesterone. Furthermore, in a three-year study of 875 women, combination treatment with estrogen and oral progesterone was no more effective for osteoporosis than estrogen alone.
Estriol. Some alternative medicine practitioners have popularized
the use of a special form of estrogen called estriol,
claiming that, unlike standard estrogen, it does not increase the risk of cancer.
However, this claim is unfounded.
Controlled trials performed in Japan have found that estriol helps prevent bone loss in menopausal women, although one small study found no benefit. However, like other forms of estrogen, oral estriol stimulates the growth of uterine tissue. This leads to a risk of uterine cancer.
In a placebo-controlled study of 1,110 women, greater uterine tissue stimulation was seen among women given estriol orally (1 to 2 mg daily) than among those given placebo. Another large study found that oral estriol increased the risk of uterine cancer. In another study of 48 women given estriol at a dose of 1 mg twice daily, uterine tissue stimulation was seen in the majority of cases.
In contrast, a twelve-month double-blind trial of oral estriol (2 mg daily) in sixty-eight Japanese women found no effect on the uterus. It may be that the high levels of soy in the Japanese diet altered the results. Additionally, test-tube studies suggest that estriol is just as likely to cause breast cancer as any other form of estrogen. Women who use estriol should consider it like any other form of estrogen.
Herbs and Supplements to Use with Caution
While the evidence is not yet strong, some research suggests that excessive intake of vitamin A may increase the risk of osteoporosis. Also, herbs and supplements may interact adversely with drugs used to treat osteoporosis, so persons should be cautious when considering the use of herbs and supplements.
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