Osteoporosis
Osteoporosis, meaning "porous bone," is the degeneration of normal bone mineral density, mass, and strength. This process results in thinner bones and increases their susceptibility to fracture.
An estimated twenty million Americans, primarily older women, have osteoporosis or are at significant risk for it. Good bone health is a life-long process, but osteoporosis is usually prompted by the hormone changes at menopause. Early stages can be without symptoms, but the disease can progress to crippling spinal fractures and broken hips from which many do not survive.
A healthy diet can prevent or mitigate the damage caused by osteoporosis.
Eat more
Drink more
Avoid caffeinated coffee, soft drinks, refined sugar and excess meat or salt.
An estimated twenty million Americans have osteoporosis or are at significant risk for it. Osteoporosis causes at least 1.5 million fractures each year, including 250,000 hip fractures.
Hip fractures are often devastating. Nearly one-third of all women and one-sixth of all men will fracture their hips in their lifetime. Hip fractures result in death 12-20% of the time, and 50% of those who survive end up in long-term nursing home care.
Osteoporosis, meaning "porous bone," is the degeneration of normal bone mineral density, mass, and strength. This process results in thinner bones and increases their susceptibility to fracture.
Early symptoms include:
Late symptoms include:
The most reliable measurement of bone density at this time is the DEXA (dual energy X-ray absorptiometry) test. It is a safer choice because it produces less radiation exposure than other X-ray procedures for evaluating bone density.
The Osteomark-NXT test measures the levels of cross-linked N-telopeptide of Type I collagen, a compound linked to bone breakdown in urine. The Osteomark-NXT can be used to monitor the rate of bone loss and evaluate the success of therapies.
Bone is living tissue that is continuously broken down and rebuilt at the cellular level. Conventional medicine has focused on alleviating insufficient dietary calcium and the postmenopausal decline in estrogen in treating and preventing osteoporosis.
However, normal bone metabolism is the complicated interaction of over two dozen nutrients including the vitamins D, K, B6, B12, and folic acid, and the minerals boron, magnesium, and phosphorus as well as calcium.
Estrogen often overshadows the importance of progesterone in treating and preventing osteoporosis. Although estrogen regulates osteoclasts, specialized bone cells that remove dead portions of demineralized bone, progesterone influences the bone-forming cells, called osteoblasts, that use calcium, magnesium, and phosphorus from the blood to replace bone mass.
The combined levels of these nutrients and hormones create a system either promotive or preventative of osteoporosis.
Osteoporosis can develop anywhere in the skeleton, but most bone loss usually occurs in the spine, hips, and ribs. Unfortunately, these structures carry most of the body's load, thereby increasing their vulnerability to pain, deformity, and fracture.
Bone mass normally decreases 1.5% to 2% per year in both men and women after the age of 40. However, women are at greater risk for osteoporosis since their bone mass is naturally less than men's due to their smaller size and muscle mass.
Approximately one in four women suffer from osteoporosis after menopause, partly due to the perimenopausal decrease in progesterone and postmenopausal drop in estrogen, both important factors to maintaining bone mass.
Osteoporosis rarely occurs in men, but when it does, it is usually the result of underlying stresses such as long-term alcoholism, use of anticonvulsive or corticosteriod drugs, or hyperthyroidism.
Protein is important to a healthy diet, but too much protein intake, as seen in the standard American diet, chemically increases one's vulnerability to osteoporosis. Bones are at their best in a slightly alkaline body, so when a high animal protein diet makes the body acidic, the body buffers the acidity by withdrawing alkaline minerals like calcium from the bones. This means that raising daily protein intake from 47 to 142 grams doubles the excretion of calcium in the urine.
The average American consumes 150 grams of sucrose each day in addition to large quantities of refined simple sugars from processed foods and soft drinks. Refined sugar promotes acidic body chemistry like protein does, and therefore also increases the urinary excretion of calcium.
Soft drinks contain large amounts of phosphates and almost no calcium. High levels of phosphates combined with low levels of calcium result in the body again removing calcium from the bones to restore mineral balance.
A diet deficient in green leafy vegetables is often a diet deficient in the vitamins and minerals necessary for bone health. These include calcium, vitamin K1, and boron.
Vitamin K1, the plant form, activates osteocalcin, the major noncollagen protein in bone. Osteocalcin anchors calcium molecules inside of the bone. Therefore, without enough vitamin K1, osteocalcin levels are inadequate and bone mineralization is impaired.
Too low calcium intake causes the parathyroid hormone to stimulate osteoclasts into breaking down bone to raise the calcium levels in the blood. When calcium levels are too high, calcitonin suppresses osteoclastic activity (removal of dead parts of demineralized bone).
Estrogen and vitamin D are less useful for maintaining bone health if they are not accompanied by sufficient quantities of boron. Without boron, the body can not convert these hormones to their most active forms.
Inadequate consumption of magnesium decreases the serum concentration of the most active form of vitamin D (1,25-(OH)2D3). Magnesium is also required to regulate the body's levels of parathyroid hormone and calcitonin, the two hormones that maintain the proper concentration of calcium in the blood.
Increased homocysteine concentrations found in postmenopausal women interfere with collagen cross-linking and can cause defective bone matrix formation. Homocysteine is the intermediate product of the conversion of amino acid methionine to cysteine caused by inadequate levels of the vitamins B6, B12, and folic acid, or a genetic defect in the enzymes responsible for this conversion.
Inadequate vitamin C consumption decreases the secretion of important intercellular substances by all cells, including those of osteoblasts (cells that build new bone).
Studies have shown that supplementing with calcium increases bone density in perimenopausal women and slows bone degeneration in postmenopausal women by an average of 30 to 50%, which translates to a significant reduction in hip fractures.
There are many forms of calcium supplements, which kind is the best? Calcium bound to citrate or other Krebs-cycle intermediates including fumarate, malate, succinate and aspartate are recommended. The Krebs cycle is a phase of the energy production process in mitochondria, the powerhouses in cells, which uses these intermediate compounds to produce energy.
These forms of calcium are much better absorbed than calcium carbonate because they are already ionized and are soluble. These Krebs-cycle intermediate bound forms are prefered because they are non-toxic, better for the absorption of all minerals, and easier on people with reduced stomach acid (a common problem accompanying aging).
About 45% of the calcium from an oral dose of calcium citrate is absorbed in patients with reduced stomach acid, whereas only 4% of calcium is absorbed from calcium carbonate (once again, in patients with reduced stomach acid). The recommended daily dosage of calcium citrate or other calcium bound Krebs cycle intermediates is 800mg for ages 25-35, 1,000mg for ages 35-50, and 1,500mg for people over 50 (1,200mg if taking HRT). Take your calcium just before or at the beginning of meals.
Sources of calcium that can harm your health are oyster shells, dolomite, and bone meal. Supplements derived from these sources may contain substantial amounts of lead. How critical is it to avoid lead toxicity? Excessive lead intake can damage the brain, kidneys, and the manufacture of red blood cells.
Children are especially susceptible to lead toxicity, which has also been directly linked to a lowered IQ and criminal behavior and proves to be a significant problem in industrialized countries including the U.S.
One of the specific bone meal calcium extracts to avoid is calcium hydroxyapatite. Not only is it a potent lead source, but studies comparing multiple forms of calcium supplementation have shown that it is not absorbed (only 20 % absorption) as well as either calcium carbonate or calcium citrate (both of which had a 30% absorption rate). All of the above studies were conducted with subjects who had normal levels of stomach acid.
Calcium-rich Foods Better than Supplements for Growing Girls and Adult Women
Studies suggest that for both young girls going through the rapid growth spurts of puberty and adult women, getting calcium from dairy products, such as cheese, may be better for building bone than taking a calcium supplement.(Cheng S, Lyytikainen A, Am J Clin Nutr; Armamento-Villareal RC, Thompson JN, Toronto Bone-Health Congress).
Finnish researchers enrolled 195 healthy girls aged 10-12 years and divided them into 4 groups. One group was given supplemental calcium (1000 mg) + vitamin D3 (200 IU) each day. The second group received only supplemental calcium (1000 mg/day). The third group ate cheese supplying 1,000 mg of calcium each day, and the fourth group was given a placebo supplement.
At the beginning and end of the study, DEXA (dual-energy X-ray absorptiometry) scans were run to check bone indexes of the hip, spine, and whole body, and the radius and tibia were checked by peripheral quantitative computed tomography.
At the conclusion of the study, girls getting their calcium from cheese had higher whole-body bone mineral density and cortical thickness of the tibia than girls given supplemental calcium + vitamin D, supplemental calcium alone, or placebo. While the researchers noted that differences in the rate at which different children naturally grow might account for some of the differences seen in bone mineral density, they concluded: "Increasing calcium intake by consuming cheese appears to be more beneficial for cortical bone mass accrual than the consumption of tablets containing a similar amount of calcium."
Estrogen and bone-health expert Reina Armamento-Villareal, M.D. of the Washington University School of Medicine led a team that examined calcium intake in three groups of women, the members of which got their calcium in one of three different ways:
Results of the study, presented at the Toronto Bone-Health Congress, support suspicions that high calcium intake does not by itself ensure stronger bones. The women in the "food only" group enjoyed the greatest bone benefits. Among the "food only" group, BMD (bone mineral density) for both the spine and femur (thigh bone) were significantly higher compared to those taking only supplements, even though average dietary calcium intake was lower in "food only" group than in those receiving calcium from supplements only.
Women in the "food only" group also showed signs of higher body levels of estrogen, which promotes bone building in childhood and adolescence and inhibits post-menopausal osteoporosis.
Another highly beneficial finding was that the ratio of 2OH/16OH estrogen metabolites seen in the "food only" women was significantly lower. Since the 2OH metabolite of estrogen is thought to be protective against breast cancer, while the 16OH form is associated with increased risk, this suggests that dietary calcium may beneficially affect estrogen metabolism. The study needs to be repeated for a longer duration, and Dr. Armamento-Villareal plans a longer-term, two-to-three year study.
More Research Confirms Calcium from Food Builds Stronger Bones than Calcium Supplements
Women who get most of their daily calcium from food have stronger bones than women who rely on supplements as their main source of calcium-even though supplement takers have a higher average calcium intake.
Researchers studied 168 postmenopausal women, asking them to meticulously record their normal diet and calcium supplement intake, and tested their bone mineral density (BMD) and urinary concentrations of estrogen metabolites. Estrogen, which is involved in maintaining BMD, is metabolized in the liver into several forms, some of which are more active than others. Urinalysis showed that women who were getting at least 70% of their calcium from food (the "diet group") had a higher ratio of more to less active estrogen metabolites and higher BMD in their spines and hips than those getting most (at least 70%) of their calcium from supplements (the "supplement group"), even though the "diet group" took in the least calcium, an average of 830 mg a day, compared to about 1,030 mg per day consumed by the "supplement group." "Only about 35% of the calcium in most supplements ends up being absorbed by the body. Calcium from the diet is generally better absorbed, particularly from dairy foods," noted lead researcher Reina Armamento-Villareal, who suggests that individuals with dairy sensitivities consume other calcium-rich foods such as calcium-fortified orange juice and soy foods, and dark green leafy vegetables. Am J Clin Nutr. 2007 May;85(5):1428-33.
Concentrated food sources of calcium include dairy products, kelp, bok choy, spinach, greens (collard, mustard, turnip), nuts and seeds (sesame seeds, almonds, chestnuts, walnuts), beans (garbanzo, soy, tofu). Foods from the cabbage family, kale and collards, contain very absorbable calcium. The boiling of foods like spinach in water for a short period of time (3-5 minutes) may slightly reduce their oxalate content.
Green Tea Provides Bone Benefits Similar to Calcium or Exercise
Australian researchers report that bone mineral density (BMD) is 2.8% greater in tea drinkers than non-drinkers. The study involved 1,500 women (age range from 70-85) in a 5-year prospective trial looking at the effects of calcium supplements on osteoporotic fracture. Not only was tea drinkers' total BMD 2.8% higher than non-tea drinkers, but over the course of 4 years, tea drinkers lost an average of 1.6% of their total hip BMD, while non-tea drinkers lost more than twice as much (4%).
The 4 primary polyphenols in tea (epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin) were identified as being responsible. Green tea contains between 30-40% of water-extractable polyphenols, while black tea contains between 3-10%. "A recent review suggests that flavonoids from green tea may be associated with increases in BMD via a potent stimulatory effect on osteoblast function," noted lead researcher Amanda Devine. (Osteoblasts are the cells responsible for producing new bone.) Am J Clin Nutr. 2007 Oct;86(4):1243-7.
Many studies of postmenopausal women using vitamin D, especially in its most active form, D3, have shown that it stimulates the absorption of calcium, increases bone mineral density, and reduces the risk of hip fracture.
Vitamin D is especially helpful for people who don't get sufficient sun exposure due to living in northern latitudes, staying indoors most of the time, always wearing sunscreen, having dark skin color, or being confined to a nursing home. In 1997, the recommendation for the daily dosage of vitamin D3 was 400 IU(International Units), but the latest research suggests this amount may not be adequate. For a full discussion of these issues, please read our vitamin D profile.
Very good food sources of vitamin D include shrimp and fortified cow and soy milk. Sunlight is a great source of vitamin D.
Women with osteoporosis have low bone magnesium content and other signs of magnesium deficiency. A two-year study of magnesium supplementation in postmenopausal women found that those receiving magnesium had a slight improvement in bone density while those receiving the placebo lost some of their bone density.
Without sufficient magnesium, vitamin D is less concentrated in the body and the body can not convert it to its most active form. Magnesium also mediates the secretion of parathyroid hormone and calcitonin, the two hormones that maintain proper calcium concentration in the blood. The recommended daily dosage of magnesium is 400-800 mg. Chard and spinach are two excellent food sources of magnesium.
Boron is another trace mineral required to convert estrogen and vitamin D to their most active forms (17-beta-estradiol and 1,25-(OH)2D3 respectively). Studies have shown that boron provides protection against osteoporosis and reproduces many of the positive effects of estrogen therapy in postmenopausal women. Estrogen levels drop after menopause causing osteoclasts to become more sensitive to parathyroid hormone, which signals them to break down bone.
A diet deficient in fruits and vegetables is probably a diet deficient in boron. The U.S. Second National Health and Nutrition Examination survey found that less than 10% of Americans meet the minimum recommendation of 2 fruit and 3 vegetable servings per day, and 51% of Americans eat only one serving of vegetables per day.
The best dietary source of boron is fruits and vegetables, but their boron richness can vary based on the boron content of the soil in which they were grown. Therefore, supplementation is recommended and has been shown effective. One study of postmenopausal women concluded that supplementation with 3 mg of boron per day reduced urinary calcium excretion by 44%. The recommended daily dosage of boron (as sodium tetrahyrdoborate) is 3-5 mg.
Boron is easily consumed through most fruits and vegetables provided that the soil they were grown in was not deficient in boron.
Peri-Menopausal and Early Post-menopausal Women Need More Vitamin K for Healthy Bones
Results of a University of Michigan School of Nursing study show that typical intake of vitamin K may not be enough to support bone health in the perimenopausal and early menopausal years. (Lukacs JL, Booth S, Menopause)
Vitamin K is richly supplied in green and green leafy vegetables, but many women don't consume sufficient amounts to promote bone health. And taking a supplement is not the answer: Few multivitamins even contain vitamin K, and those that do have minimal amounts of the nutrient.
According to lead author, Jane Lukacs, the current intake recommendation of 1 ug/kg/d, which is based on Vitamin K's role in promoting healthy blood clotting, may not be adequate for bone health in the peri- and early menopausal years. .
"What is becoming apparent is that what is adequate for blood clotting may not be adequate for bone health," said Lukacs.
The average age at which women reach menopause is 51 years, according to the National Osteoporosis Society. The menopausal years are characterized by a loss of estrogen production, which accelerates bone loss. One of the earliest ways in which declining estrogen results in bone loss is by impairing vitamin K function in bones, even before bone loss from menopause can be measured.
Vitamin K is essential for healthy bone. With the help of this vitamin, the protein osteocalcin is chemically modified through a process called carboxylization, which enables it to bind to calcium in the bone, where it becomes an important part of bone structure.
In this study, 59 healthy women were divided into three groups: 19 women aged 40-52; 21 women aged 20-30; and 19 untreated women between 40-52 years. The latter group were found to have the highest percentage of insufficiently carboxylated osteocalcin, indicating that these women were deficient in vitamin K-despite the fact that their vitamin K levels were within the range generally thought to be adequate.
The researchers' conclusion was that the amount of vitamin K currently said to be adequate in healthy women is, in fact, insufficient to support bone health at the onset of menopause.
Women with health conditions for which anticoagulant medications, such as Warfarin (Coumadin), have been prescribed are advised to be consistent in the amount of vitamin K they consume since either an increase or reduction in blood levels of vitamin K can necessitate changing the amount of medication needed.
But for all other healthy women, the take-action message conveyed by this study is clear: calcium alone cannot protect the health of your bones. Vitamin K-rich greens are an essential part of a bone-protective diet, especially during the years surrounding menopause. To ensure your vitamin K levels meet your bones' health needs, make vitamin K-rich vegetables, such as parsley, kale, spinach, Swiss chard, Brussels sprouts, broccoli, cabbage and green beans, part of your healthy way of eating. For some great vitamin K-rich recipes, just use our Recipe Assistant and select vitamin K from the "Nutrients to require" list.
Ipriflavone is a drug approved for the treatment and prevention of osteoporosis in Japan, Hungary, and Italy. This semisynthetic flavonoid similar to soy isoflavonoids increases the effects of calcitonin on calcium metabolism. The hormone calcitonin, usally signaled by high levels of calcium in the blood stream, stops osteoclasts from breaking down old bone.
A number of studies of ipriflavone have shown remarkable results. One study of 100 women with osteoporosis found that 200 mg of ipriflavone taken three times daily increased bone density by 2% after 6 months and 5.8% after 12 months. Another one-year study of women with osteoporosis found that 600 mg of ipriflavone per day raised bone density by 6%, while the placebo group lost 0.3%. The recommended daily dosage is 600 mg.
A double-blind, placebo-controlled study involving 203 postmenopausal Chinese women, aged 48 to 62 years old, suggests that soy isoflavones can help women with low bone mineral content prevent hip fractures in postmenopause years. The trial, reported in the October 2003 issue of the Journal of Clinical Endocrinology and Metabolism, randomly divided women into three treatment groups which received daily either a placebo, a medium dose of isoflavones (40 mg isoflavones) or a high isoflavone dose (80 mg isoflavones). All three groups were also given 500 mg of calcium and 125 IU vitamin D daily. At the beginning of the study and one year later, researchers measured bone mineral density (BMD) and bone mineral content (BMC) of the whole body, spine and hip.
Women receiving the high dose of isoflavones had mild, but a significantly higher improvement in BMC at the total hip and trochanter compared to those in the placebo and mid-dose groups, even after adjustments for potential confounding factors. Further analyses revealed that soy isoflavone supplementation was only beneficial among women who started out with average or lower bone mineral content measurements. The researchers concluded, " soy isoflavones have a mild, but significant, independent effect on the maintenance of hip BMC in postmenopausal women with low initial bone mass," -in other words, soy isoflavones improve bone density in women who need it, while having little effect on the bones of those whose bone density is already adequate.
The results of this study provide additional support for the findings of a review study published in the September 2003 issue of the American Journal of Clinical Nutrition. In their review, Drs. Kenneth Setchell, one of the foremost researchers in soy's effects on health, and Eva Lydeking-Olsen examined 17 in vitro studies of cultured bone cells, 24 in vivo animal models for postmenopausal osteoporosis, 15 human observational/epidemiologic studies, and 17 dietary intervention studies. Their conclusions: "the collective data suggest that diets rich in phytoestrogens have bone-sparing effects in the long term, although the magnitude of the effect and the exact mechanism(s) of action are presently elusive or speculative."
Isoflavone-rich Soyfoods Protect Menopausal Women's Bones
Two meta-analyses of randomized clinical trials, one considering 9 studies involving a total of 432 subjects, and the other reviewing 10 studies with a total of 608 subjects, have shown that consuming isoflavone-containing soy foods significantly inhibits bone loss and stimulates bone formation in menopausal women.
The first meta-analysis, published in the European Journal of Clinical Nutrition found that women whose daily diets provided soy isoflavones had much lower amounts of deoxypyridinoline (Dpyr, a bone resorption marker) in their urine, and much higher amounts of bone-specific alkaline phosphatase (BAP, a bone formation marker) in their blood. And these bone-protective effects occurred even if the women were consuming less than 90 mg of soy isoflavones per day or if the intervention lasted less than 12 weeks. (Ma DF, Qin LQ, et al.)
The second meta-analysis, published in Clinical Nutrition found that bone mineral density increased significantly (+27 mg/cm) in the spine of women whose diets provided soy isoflavones, even in amounts less than 90 mg/day, compared to those who did not. When more than 90 mg/day of isoflavones from soy foods was consumed for at least 6 months, improvements in spine bone mineral density became even more significant, increasing 28.5mg/cm. (Ma DF, Qin LQ, et al.)
Practical Tip: Enjoying soy foods daily for just 6 months can be enough to exert beneficial effects on bone in menopausal women. All the traditional soyfoods (tofu, soy milk, tempeh and miso) provide 30 to 40 mg per serving. Roasted soybeans are an especially good source; just one-half cup contains 167 mg of isoflavones. However, neither soy sauce nor soy oil contain isoflavones.
The bone-sparing effects of olive polyphenols revealed in studies conducted by a special team at INRA (France's National Institute for Agricultural Research) are so dramatic that a new Belgian firm, BioActor, has licensed INRA's patents to use olive polyphenols for osteoporosis prevention in food, supplements and herbal medicines.
The World Health Organization calls osteoporosis its biggest global healthcare problem with aging populations also beset by obesity, a condition now known to greatly increase inflammation throughout the body, including in bones where it significantly contributes to osteoporosis. Today, a woman's lifetime risk of osteoporotic fracture is 30-40%, and even men face about a 13% risk.
INRA researchers, inspired by epidemiological evidence that people eating a traditional Mediterranean diet were less likely to develop osteoporosis, began investigating the effects of olive oil and different compounds in olive leaves on bone metabolism.
Their early studies revealed that two olive polyphenols, oleuropin and hydroxytyrosol, greatly lessen the inflammation-mediated bone loss involved in osteoporosis.
One of their most recent studies, published in the July 2004 issue of the British Journal of Nutrition, shows that both oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia (bone-thinning) in rats whose ovaries have been removed-an animal model designed to simulate senile osteoporosis, the bone-wasting condition that affects the elderly, as it combines both hormone deficiency with chronic inflammation.
Although the animals did not fully recover all their bone density compared to controls, those rats fed oleuropin (0.15g/kg) or olive-oil (50 g/kg) daily for 3 months recovered 70-75% of their bone density-a 50% improvement compared to control animals, which were given 25g/kg peanut oil and 25 g/kg rapeseed oil daily.
BioActor and INRA are now collaborating to confirm these results in a human validation study, due to begin early 2006. The results of this study underscore the importance of knowing how to select, store and serve your olive oil to maximize its polyphenol content. For all the information you need, see our How to Select and Store section in Olive oil below.
Silicon cross-links collagen strands to strengthen the connective tissue matrix of bone. The presence of concentrated silicon at calcification sites in growing bone may indicate that sufficient levels of silicon are required for bone remodeling.
No RDA currently exists for silicon, but the suggested daily requirement falls in the range of 5-20 mg. It may be appropriate for patients with osteoporosis to increase silicon supplementation, but use caution until more is discovered about the role and requirements for silicon.
These three B vitamins, in which the elderly are commonly deficient, are involved in the conversion of the amino acid methionine to cysteine. Defective conversion enzymes, or deficiency in any of these vitamins will increase the levels of the intermediate compound homocysteine. Homocysteine, found in higher levels in postmenopausal women, obstructs collagen cross-linking, which results in poor bone matrix and osteoporosis.
All three of these vitamins interact with the enzymes and chemicals in complex ways to successfully complete the conversion. Yet one study showed that postmenopausal women who were not considered deficient in folic acid lowered their homocysteine levels simply by supplementing with folic acid by itself. The recommended daily dosage is 400 mcg of folic acid, 400 mcg of vitamin B12, and 25-100 mg of vitamin B6.
Excellent sources of vitamin B6 include bell peppers, turnip greens, and spinach. Excellent sources of folate include spinach, parsley, broccoli, beets, turnip greens, asparagus, romaine lettuce, lentils and calf's liver. Excellent food sources of vitamin B12 include calf's liver and snapper.
Attention users of barbituate anticonvulsant drugs: Folic acid and B6 can dampen these drugs thereby increasing the risk of seizures. Supplementation with these B vitamins must be monitored carefully.
Potassium appears to counteract the increased urinary calcium loss caused by the high-salt diets typical of most Americans, thus helping to prevent bones from thinning out at a fast rate. A clinical trial of 60 postmenopausal women on high-salt diets found that those whose daily intake of potassium was equal to the amount found in seven to eight servings of fruits and vegetables had a reduced level of calcium loss than those whose diets were not supplemented with potassium. Excellent sources of potassium include spinach, chard, and button mushrooms.
New research provides evidence that omega-3 fatty acids can significantly decrease bone turnover rates. In women, these beneficial omega-3 fats work with estrogen to stimulate bone mineral deposits and slow the rate of bone breakdown.
This research has now been confirmed in a human study in which alpha linolenic acid, the omega-3 fat found in walnuts and flaxseed, was shown to promote bone health by helping to prevent excessive bone turnover-when consumption of foods rich in this omega-3 fat resulted in a lower ratio of omega-6 to omega-3 fats in the diet. (Griel AE, Kris-Etherton PM, et al. Nutrition Journal)
In addition to the rat study above, other studies have shown that diets rich in the omega-3s from fish (DHA and EPA), which also naturally result in a lowered ratio of omega-6 to omega-3 fats, reduce bone loss. Researchers think this is most likely because omega-6 and omega-3 fats are converted into different types of prostaglandins- hormone-like chemical messengers.
Omega-6 fats (concentrated in meat, and corn, palm and peanut oils) are converted into the pro-inflammatory Series 2 prostaglandins, which can trigger increased activity by osteoclasts, the cells whose job it is to break down or "resorb" old bone. Omega-3 fats (concentrated in flaxseed, walnuts and cold water fish) are metabolized into anti-inflammatory Series 3 prostaglandins.
In this study, 23 participants ate each of 3 diets for a 6-week period with a 3 week washout period in between diets. All 3 diets provided a similar amount of fat, but their ratio of omega-6 to omega-3 fats was quite different:
Diet 1 provided 34% total fat with omega-6 and omega-3 fats in amounts typically seen in the American diet: 9% polyunsaturated fats (PUFAs) of which 7.7% were omega-6 and only 0.8% omega-3 fats, resulting in a pro-inflammatory ratio of 9.6:1.
Diet 2, an omega-6-rich diet, provided 37% total fat containing 16% PUFAs of which 12% were omega-6 and 3.6% omega-3, a better but still pro-inflammatory ratio of 3.3:1.
Diet 3, which provided 38% in total fats, was an omega-3-rich diet, containing 17% PUFAs, of which 10.5% were omega-6 and 6.5% omega-3, resulting in an anti-inflammatory ratio of 1.6:1.
After each diet, subjects' blood levels of N-telopeptides, a marker of bone breakdown, were measured, and were found to be much lower following Diet 3, the omega-3-rich diet, than either of the other two.
The level of N-telopeptides seen in subjects' blood each diet also correlated with that of a marker of inflammation called tumor necrosis factor-alpha (TNF-alpha). Diets 1 and 2-the diets which had a significantly higher ratio of omega-6 to omega-3 fats-also had much higher levels of TNF-alpha than the Diet 3, which was high in omega-3 fats from walnuts and flaxseed. Practical Tip: Protect your bones' by making anti-inflammatory omega-3-rich flaxseed and walnuts, as well as cold water fish like salmon, frequent contributors to your healthy way of eating.
Phloridzin, a Flavonoid Unique to Apples
A flavonoid found only in apples called phloridzin may help prevent bone loss associated with menopause, suggests a study published in the November 2005 issue of Calcified Tissue International..
A side effect of the sex hormone changes that occur during a woman's transition through menopause is a tendency towards increased inflammation and free radical production, which in turn, promotes bone loss.
Because of their anti-inflammatory actions, polyphenols have been suggested as one means of protecting against bone loss during this pro-inflammatory time in women's lives.
To test this theory, French researchers ovariectomized lab rats (to simulate menopause) and divided them into two groups, which were given either a control diet or a diet supplemented with phloridzin for 80 days. Three weeks before the animals were sacrificed, 10 animals in each group were put into an inflammatory state by subcutaneous injection with talc.
While all the animals on the control diet lost bone, and those injected with talc to induce more inflammation, lost even more bone, the rats receiving phloridzin not only did not lose bone, but actually increased bone mineral density-even if they were injected with talc to promote inflammation! If you're moving through menopause, eating an apple a day may help you keep bone loss at bay.
Do you drink more than 2 cups of coffee to make it through the day? Unfortunately, staying awake means a greater short-term calcium loss through urine. This may be enough to have a significant impact on older people with already low calcium levels, but can be buffered somewhat by drinking coffee with milk.
Eating more than 4 oz. of meat on a daily basis may be weakening your bones. High protein diets result in an acidic body chemistry. Since calcium is alkaline, the body pulls it out of the bones to restore the slightly alkaline chemistry needed for most metabolic chemical reactions.
Drinking soft drinks regularly: To balance the phosphates in soft drinks, the body leaches calcium from the bones, which is then excreted in the urine.
Salty foods will cause your kidneys to evacuate additional calcium through urination. Over 90% of the sodium ingested in the typical American diet is excreted from the body, requiring excess calcium excretion. For every 500 mg of sodium excreted, you lose 10 mg of calcium in your urine.
Sugar isn't just bad for your teeth; it's bad for all of your bones. Eating too much refined sugar increases urinary calcium loss.
Consume 3 servings of vegetables daily including at least 1 cup of green leafy vegetables: These vegetables contain vitamins and minerals necessary for bone formation.
What should you eat to combat or prevent osteoporosis? The medical profession stresses the importance of taking calcium supplements, but don't rely only on supplements; recent studies (see above) suggest that natural food sources of calcium may be even more effective.In addition to low-fat dairy products, such as low fat yogurt, cottage cheese, kefir and cheese, eat lots of green leafy vegetables, especially kale, collard greens, parsley, and lettuce (excluding iceberg).
Leafy greens are rich sources of calcium, vitamin K1, and boron, and are especially important for people who do not consume dairy products.
Vitamin K-rich foods include dark green leafy vegetables (broccoli, lettuce, cabbage, spinach), and green tea. Other good sources include asparagus, oats, whole wheat, and fresh green peas.
Soyfoods, for their content of both isoflavones and ipriflavone, are also recommended.
Olive oil, for its phenols, and apples, which contain a unique flavonoid called phloridzin, have also been shown to help protect against the inflammation-related bone loss that occurs with menopause.
What to avoid? Once again, staples of the American diet are contributing factors in the development of osteoposoris. Avoid excessive amounts of salt, sugar, animal protein, soft drinks, alcohol, and coffee, all of which increase calcium excretion.