People with osteoporosis have brittle bones, which increases the risk of bone fracture, particularly in the hip, spine, and wrist. Although the risk of becoming osteoporotic is tied to many dietary and lifestyle issues, the true cause of this condition remains somewhat unclear. Osteoporosis is most common in postmenopausal Oriental and white women. Pre-menopausal women are partially protected against bone loss by the hormone estrogen. Black women often have slightly greater bone mass in early adulthood compared with other women, which helps protect against bone fractures even though postmenopausal black women lose bone mass just as other women do. In men, testosterone partially protects against bone loss even after middle age. Beyond issues of race, age, and gender, incidence varies widely from society to society, suggesting that osteoporosis is largely preventable.

If, as suggested by some of the above research, animal protein is associated with increased osteoporosis risk, then vegetarians should have reduced risk. The bone strength of vegetarians, measured as bone mineral density (BMD), has been compared to that of non-vegetarians in several studies. Early research suggested that vegetarians may have higher BMD.^{7 8 9} However, more recent studies have found that the BMD of vegetarians is similar to that of omnivores.^{10 11 12 13} The issue is further complicated by a recent study of elderly Chinese women that found vegetarians to have consistently lower BMD at the hip, the main site of osteoporotic fractures.¹⁴ The authors of this study also found a higher sodium intake among the vegetarians, which may have contributed to bone loss by increasing the loss of calcium in the urine. Many doctors recommend a move toward vegetarian diets for people wishing to avoid osteoporosis or for those already diagnosed with it. However, until the contribution of other dietary factors to osteoporosis is better understood, broad dietary changes (e.g., a change to vegetarianism) cannot be recommended without qualification.

Bone formation requires protein, so if people eat too little protein, risks associated with osteoporosis may increase. In one trial of older women (average age 82) who had suffered an osteoporotic fracture, those given a 20 gram per day protein supplement had fewer complications, were less likely to die, and had much shorter hospital stays compared with women not assigned to receive extra protein.¹⁵ Similarly, in a three-year study of American women aged 50 to 69 funded by the National Dairy Council, those eating more animal protein had a lower risk of osteoporotic hip fracture compared with those eating less.¹⁶ A related double-blind trial in older women who had recently suffered an osteoporotic hip fracture found that a 20 gram per day protein supplement reduced bone loss compared with those not receiving protein.¹⁷

Pending further research, these conflicting reports show that drawing the line between too much protein and too little remains elusive. Nonetheless, most studies currently suggest that life-long high intake of animal protein correlates with an increased risk of osteoporosis; however, protein supplementation following a fracture in elderly people appears to result in better bone and overall health compared with no protein supplementation.

Short-term increases in dietary salt result in increased urinary calcium loss, which suggests that over time, salt intake may cause significant bone loss.¹⁸ Researchers have shown that increasing dietary salt increases markers of bone loss in post- (though not pre-) menopausal women.^{19 20 21} Although a definitive link between salt intake and osteoporosis has yet to be proven, most doctors often recommend that people wishing to protect themselves against bone loss use less salt and less highly salted processed and restaurant foods.

Caffeine has also been linked to fracture of the hip in a large study following American women for six years.²² Like salt, caffeine increases urinary loss of calcium.²³ In one trial caffeine was linked with lower bone mass but only in women who consumed relatively little calcium.²⁴ The authors of this report concluded that two to three cups of coffee per day might speed bone loss in women with calcium intakes of less than 800 mg per day. Many doctors recommend decreasing caffeine intake from caffeinated coffee, black tea, and cola drinks as a way to improve bone mass.

The relationship between soft drinks and bone mass is controversial. In some reports, young cola drinkers have an increased incidence of bone fractures,²⁵ though short-term consumption of carbonated beverages has not affected markers of bone health.²⁶ The problem, if one exists, may be linked to phosphoric acid, a substance found in many soft drinks. In one trial, children consuming at least six glasses of soft drinks containing phosphoric acid had more than five times the risk of developing low blood levels of calcium compared with other children.²⁷ Avoidance of phosphoric acid–containing soft drinks has also reduced kidney stone recurrence, again incriminating soda pop as a cause of abnormal calcium metabolism.²⁸ Although a few studies have not linked soft drinks to bone loss,²⁹ the preponderance of evidence now suggests that a problem may exist, and there is certainly no harm in decreasing drinks filled with sugar and chemicals, a dietary change that may reduce urinary loss of calcium.

Soy foods such as tofu, soy milk, roasted soy beans and soy extract powders may be beneficial in preventing osteoporosis. Isoflavones from soy protect animals from bone loss.³⁰ Taking 40 grams of soy protein powder per day (containing 90 mg isoflavones per day) increased bone mineral density of the spine in a double-blind trial.³¹ However, lower intakes (providing 56 mg isoflavones per day) did not improve bone density in this report. A synthetic isoflavone, ipriflavone, has reduced the incidence of osteoporotic bone fractures in several reports.³² Although the use of soy in the prevention of osteoporosis looks hopeful, no long-term human studies have yet examined the effects of soy or isoflavones on bone density or fracture risk. A number of studies are currently underway and should soon provide greater insight into this issue.³³

Preliminary evidence suggests that progesterone might play a role in bone metabolism that, in theory, could reduce the risk of osteoporosis.³⁴ An uncontrolled preliminary study using topically applied natural progesterone cream in combination with diet, exercise, vitamin and calcium supplementation, and estrogen therapy, reported consistent gains in bone density over a three-year period in postmenopausal women, but no comparison was made to the same protocol without progesterone.³⁵ However, at least one trial has found that adding natural progesterone to estrogen therapy does not improve the bone-sparing effects of estrogen when taken alone³⁶ and another trial reported that progesterone applied topically every day for one-year period did not reduce bone loss.³⁷ Thus, no consistent support for the use of topical progesterone in the treatment or prevention of osteoporosis has appeared in published research.

Exercise is known to help protect against bone loss.³⁹ The more weight-bearing exercise done by men and postmenopausal women, the greater their bone mass and the lower the risk of osteoporosis. Walking is sometimes considered the perfect weight-bearing exercise. For pre-menopausal women, exercise is also important, but taken to extreme, it can be overdone. Exercise so excessive that it leads to cessation of the menstrual cycle actually contributes to osteoporosis.⁴⁰

Excess body mass helps protect against osteoporosis. As a result, researchers have been able to show that people who successfully lose weight have greater loss of bone compared with those who do not lose weight.⁴¹ Therefore, people who lose weight need to be more vigilant about preventing osteoporotic fractures.

In several studies calcium intake has not correlated with protection—for example, in men⁴³ or in women shortly after becoming menopausal.⁴⁴ Moreover, even most positive studies focusing on the effects of isolated calcium supplementation on bone mass show only minor effects. Nonetheless, a review of the research shows that calcium supplementation plus hormone replacement therapy is much more effective than hormone replacement therapy without calcium.⁴⁵ Double-blind research has found that increasing calcium intakes results in greater bone mass in girls.⁴⁶ A meta-analysis of many studies investigating the effects of calcium supplementation in pre-menopausal women has also shown a significant positive effect.⁴⁷ Most doctors recommend calcium supplementation as a way to partially reduce the risk of osteoporosis and to help people already diagnosed with the condition. In order to achieve the 1,500 mg per day calcium intake many researchers deem optimal, 800–1,000 mg of supplemental calcium are generally added to diets that commonly contain between 500–700 mg calcium.

Ipriflavone is a synthetic flavonoid (isoflavone) derived from the soy compound daidzein. Ipriflavone promotes the incorporation of calcium into bone. It also inhibits bone breakdown. Many clinical studies, including numerous double-blind studies, clearly show long-term treatment with ipriflavone (along with 1,000 mg supplemental calcium) is both safe and effective in halting bone loss in post-menopausal women or women who have had their ovaries removed as well as improving bone density in cases of osteoporosis.^{48 49 50 51 52 53}

In one of the most recent studies demonstrating that ipriflavone prevents bone loss, 56 recently post-menopausal women with low bone density were assigned to receive either ipriflavone (200 mg three times per day) or a placebo for two years.⁵⁴ Consistent with most other studies with ipriflavone, all women also received 1,000 mg of elemental calcium daily. While vertebral (spine) bone density declined by 4.9% after two years in women taking only calcium, there was no change in bone density with ipriflavone supplementation.

Double-blind studies in women with osteoporosis have also shown positive effects. The most significant studies were performed in elderly women with a history of vertebral fractures due to osteoporosis.^{55 56 57} Ipriflavone therapy not only stopped bone loss, it actually increased bone density and significantly eliminated or improved vertebral fractures and bone pain.

Vitamin D increases calcium absorption, but surprisingly the effect of vitamin D on osteoporosis risk remains somewhat unclear,^{58 59} with some studies reporting little if any benefit.⁶⁰ Commonly, trials reporting reduced risk of fracture have used the combination of vitamin D and calcium compared with placebo, making it impossible to assess the specific benefit of vitamin D.⁶¹ Nonetheless, vitamin D does appear partially protective, at least in certain circumstances. Double-blind research indicates that vitamin D supplementation reduces bone loss in women who consume insufficient amounts of vitamin D from food.⁶² In a double-blind study of women who were consuming only 100 IU of vitamin D per day, supplementation with 700 IU per day for two years significantly reduced the amount of bone loss at the hip, compared to supplementation with 200 IU per day. Bone loss at the spine was similar with the two vitamin D amounts. The authors of the study concluded that 200 IU of vitamin D per day is not enough to prevent bone loss from the hip.⁶³ This study also found that vitamin D supplementation was a good way to reduce bone loss in women during winter and spring, when vitamin D levels are typically at their lowest.

Some people with osteoporosis have low blood levels of vitamin D. When a group of such patients was given very large amounts of vitamin D (50,000 IU taken twice per week), bone density improved significantly in both the hip and spine.⁶⁴ Such a high level of vitamin D must never be taken without the direct supervision of a healthcare professional.

While people who get outdoors regularly and live in sunny climates are unlikely to need vitamin D supplementation (particularly during the summer), doctors recommend vitamin D to most other people as a way to help protect bone mass despite remaining inconsistencies in the research. Typical supplemental amounts are between 400 and 800 IU per day, depending upon dietary intake and exposure to sunlight.

In a preliminary study, people with osteoporosis were reported to be at high risk for magnesium malabsorption.⁶⁵ Both bone⁶⁶ and blood levels of magnesium have also been reported to be low in people with osteoporosis.⁶⁷ Supplemental magnesium has reduced markers of bone loss in men.⁶⁸ Supplementing 250 (up to 750) mg per day of magnesium has also arrested bone loss or increased bone mass in 27 of 31 people with osteoporosis in a two-year controlled trial.⁶⁹ As a result of this research, many doctors recommend that people with osteoporosis supplement 250–350 mg of magnesium per day.

Dr. Guy Abraham conducted a trial of magnesium therapy in 26 postmenopausal women who were recruited from a menopause clinic.⁷⁰ All of the women were taking either estrogen alone or estrogen plus a progestogen. The women were given dietary advice: avoid processed foods, limit protein intake, emphasize vegetable over animal protein, limit consumption of salt, sugar, alcohol, coffee, tea, chocolate and tobacco. Each participant also received a daily supplement containing 600 mg of magnesium (oxide) and 500 mg of calcium (citrate), an unconventionally high magnesium:calcium ratio. The supplement also contained vitamin C, B-vitamins, vitamin D, zinc, copper, manganese, boron, and other nutrients.

Bone density studies before and eight to nine months after the start of the study showed an average increase in bone density of 11%, compared to only 0.7% in those who received hormone replacement alone. An 11% increase in bone density in eight to nine months is an increase unequalled in any other controlled studies. While Dr. Abraham attributes the success of his regimen to the high amounts of magnesium, that is probably only part of the story. The dietary recommendations and the other nutrients he used were very likely to have been significant factors. While there is good evidence that magnesium alone is important for bone health, further studies are needed to compare the effects of calcium versus magnesium versus the combination of the two. To date, no trial has uncovered the optimal ratio of calcium to magnesium for the purpose of maintaining bone mass.

Levels of zinc in both blood and bone have been reported to be low in people with osteoporosis.⁷¹ Urinary loss of zinc may be high in osteoporotic people, according to preliminary research.⁷² In one trial, men consuming only 10 mg of zinc per day had almost twice the risk of osteoporotic fractures compared with those eating significantly more zinc from their diets.⁷³ Whether zinc supplementation protects against bone loss has not yet been proven, though in one trial, combining minerals including zinc with calcium supplementation was more effective than calcium by itself.⁷⁴ Many doctors recommend that people with osteoporosis and those trying to protect themselves from this condition supplement 10–30 mg of zinc per day.

Copper is needed for normal bone synthesis. A recent controlled two-year study reported that 3 mg of copper per day prevented bone loss.⁷⁵ Although evaluation of the importance of copper for people with osteoporosis requires further research, many doctors recommend 2–3 mg per day, particularly if zinc is supplemented. (Supplemental zinc significantly depletes copper nutriture, thus people taking zinc supplements for more than a few weeks generally need to supplement copper.) All minerals discussed so far—calcium, magnesium, zinc, and copper—are sometimes found at appropriate levels in high-potency multivitamin/minerals.

A preliminary trial found that supplementation with 3 mg per day of the trace mineral boron reduced urinary loss of both calcium and magnesium,⁷⁶ but both outcomes have been contradicted by more recent research.⁷⁷ Moreover, there is evidence that people taking magnesium supplements see no further calcium-sparing effect when adding supplemental boron.⁷⁸ Finally, in the original report claiming that boron reduced loss of calcium,⁷⁹ the effect was achieved by significantly increasing estrogen and testosterone levels, hormones that have been linked to cancer risks. Therefore, until evidence appears suggesting that the combination of boron plus magnesium has any advantage over magnesium supplementation without boron, it makes sense for people with osteoporosis to supplement with magnesium instead of, rather than in addition to, boron.

Interest in the effect of manganese and bone health began when famed basketball player Bill Walton’s repeated fractures were prevented with manganese supplementation.⁸⁰ A subsequent unpublished study reported manganese deficiency in a small group of osteoporotic women.⁸¹ Since that time, a combination of minerals including manganese was reported to halt bone loss.⁸² However, no human trial has investigated the effect of manganese supplementation alone on bone mass. Nonetheless, some doctors recommend 10–20 mg of manganese per day to people concerned with maintenance of bone mass.

Silicon plays a significant role in bone formation.⁸³ Supplementation with silicon has increased bone formation in animal research.⁸⁴ In preliminary human research, supplementation with silicon increased bone mineral density in a group of eight women with osteoporosis.⁸⁵ Optimal levels remain unknown, though some multivitamin/mineral supplements now contain small amounts of this trace mineral.

Strontium is also believed to play a role in bone formation, and preliminary evidence suggests that women with osteoporosis may have reduced absorption of this trace mineral.⁸⁶ (The supplement considered here, sometimes called "stable strontium," is not the dangerous radioactive form of strontium people are more familiar with.) Many years ago in a preliminary uncontrolled trial, 32 people with osteoporosis given 1.7 grams of stable strontium for between three months and three years reported significant reduction in bone pain, supported by x-rays, suggesting an increase in bone mass.⁸⁷

Increased bone formation and decreased bone pain were also reported in a group of six people with osteoporosis given 600–700 mg of stable strontium per day.⁸⁸ Although levels used in preliminary research have been quite high, optimal intakes remain unknown. Some doctors recommend a few milligrams per day (1–3 mg)—less than many people currently consume from their diets, but an amount that has begun to appear in some mineral formulas geared toward bone health.

Folic acid, vitamin B6, and vitamin B12 are known to reduce blood levels of the amino acid homocysteine in the body, while homocystinuria, a condition associated with high homocysteine levels, frequently causes osteoporosis. Although some healthcare practitioners have suggested these B vitamins might help prevent osteoporosis by lowering homocysteine,⁸⁹ no research has yet explored this relationship. For the purpose of lowering homocysteine, amounts of folic acid and vitamins B6 and B12 found in high-potency B-complex supplements and multivitamins should be adequate.

Vitamin K is needed for bone formation. Those with osteoporosis have been reported to have both low blood levels^{90 91} and low dietary levels of vitamin K.⁹² One study found that post- (though not pre-) menopausal women have reduced urinary loss of calcium after taking 1 mg per day of vitamin K after just two weeks.⁹³ In controlled trials, people with osteoporosis given large amounts of vitamin K2 (45 mg per day) showed an increase in bone density after six months⁹⁴ and decreased bone loss after one year.⁹⁵

In a group of eight young women, those with estrogen deficiency (but not those with a normal menstrual cycle) showed evidence of increased bone formation when given 10 mg of vitamin K per day for one month.⁹⁶ Doctors frequently recommend 1 mg vitamin K1 to postmenopausal women as a way to help maintain bone mass, though optimal intake remains unknown.

Herbs that may be helpful: Horsetail is a rich source of silicon, and preliminary research suggests that this trace mineral may help maintain bone mass (see Diet and Other Natural Therapies section above). Effects of horsetail on bone mass has not yet been studied.

Black cohosh has been shown to improve bone mineral density in animals fed a low calcium diet,⁹⁹ but it has not yet been studied for this purpose in humans.

Information about the effects of a particular supplement or herb on a particular condition has been qualified in terms of the methodology or source of supporting data (for example: clinical, double blind, meta-analysis, or traditional use). For the convenience of the reader, the information in the table listing the supplements for particular conditions is also categorized. The criteria for the categorizations are: "Primary" indicates there are reliable and relatively consistent scientific data showing a health benefit. "Secondary" indicates there are conflicting, insufficient, or only preliminary studies suggesting a health benefit or that the health benefit is minimal. "Other" indicates that an herb is primarily supported by traditional use or that the herb or supplement has little scientific support and/or minimal proven health benefit.

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