Osteoporosis Bone Health
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Osteoporosis: Improving & Maintaining Bone Health

researched and written by the ProjectAWARE group, 2001

Exercise
Lifestyle
Nutrition
  Boron Acid-alkaline Balance & Potassium
  Calcium: Supplementation EFAs (Essential Fatty Acids)
  Calcium: Nutritional Phytoestrogens
  Vitamin A  |  Vitamin D Protein
  Vitamin B12  |  Vitamin K Sodium
   

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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Improving & Maintaining Bone Health
Foods, Herbs & Supplements at a Glance
References
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