All Posts tagged bone

Tomato juice helps stop osteoporosis

Tomatoes are rich in cell-protecting antioxidants. Antioxidants are known cancer-fighters, such as prostate and breast cancer. And now lycopene – one of the antioxidants found in tomatoes – is being linked to reduce risk of osteoporosis. Osteoporosis is a degenerative bone disease, usually developing in old age, especially in post-menopausal women.

But the new study at the University of Toronto in Canada, says drinking tomato juice may help stave off osteoporosis. Published in the journal Osteoporosis International, scientists claim consuming 30mg of lycopene from tomato juice (about two glasses) is enough to help prevent osteoporosis. For the research, experts restricted a group of post-menopausal women, ages 50 to 60, from consuming anything containing lycopene for one month, then the study participants were split into four groups for four months. Groups were given either a 15mg lycopene supplement, a glass of tomato juice naturally containing 15mg of lycopene, a gourmet tomato juice with 35mg of lycopene, or a placebo.

After four months, results showed supplementing with lycopene raised serum lycopene, compared to the placebo group. The women consuming lycopene had significantly increased antioxidant capacity, decreased oxidative stress, and decreased bone markers for osteoporosis.

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Premenopausal Visceral Fat a Risk Factor for Osteoporosis

Young premenopausal women with excessive amounts of visceral fat are at increased risk for osteoporosis, according to new research presented at the Radiological Society of North America 96th Scientific Assembly and Annual Meeting. For years, it was believed that obese women had a lower risk of developing osteoporosis and that the mechanical loading from excess weight was good for their bones. It now appears that having too much fat, particularly deep abdominal fat, might be damaging to bone health, Miriam A. Bredella, MD, from Massachusetts General Hospital and Harvard Medical School, Boston, told meeting attendees. “With this ongoing obesity epidemic, we were actually seeing more and more young women breaking their forearms or their wrists, and the single biggest risk factor in this group was actually increased body weight,” she told Medscape Medical News. “We thought we should look take a closer look at whether obesity really did protect against osteoporosis.”

Dr. Bredella and her team studied 50 premenopausal women whose mean body mass index was 30 kg/m2 (range, 19 to 46). The women underwent assessment of L4 bone marrow fat with magnetic resonance (MR) spectroscopy as a measurement of lumbar bone density. In addition, abdominal subcutaneous, visceral, and total fat depots and trabecular bone mineral density of L4 were assessed using quantitative computed tomography. “Using MR spectroscopy was a new thing that we did in this study. MR spectroscopy is a technique that is more sophisticated than the regular bone density test. It does not involve radiation,” Dr. Bredella explained. “With this test, we could actually look inside the bones and see how much fat was in the bones.”

These examinations revealed an inverse association between visceral fat and bone mineral density (r = –0.31; P = .03) and between vertebral bone marrow fat and bone mineral density (r = –0.45; P = .001). The researchers also found that there was a positive correlation between bone marrow fat and visceral fat (r =.28; P = .04) that was independent of bone mineral density.

However, there was no significant correlation between either subcutaneous fat or total fat and bone marrow fat or bone mineral density. “The more deep belly fat you have, the more fat you have in your bones, and the more fat you have in the bones, the weaker they will be,” Dr. Bredella said. “All things being equal, if you have 2 obese women and one has a lot of deep belly fat and the other one has exactly the same weight but her fat is distributed more superficially around the hips and thighs, then the woman with the deep belly fat will have weaker bones.”

She suggested that belly fat weakens bones because this type of fat secretes adipokines, which weaken bones. “It is important for people to be aware that obesity is a risk factor for more than diabetes and cardiovascular disease,” she said. “Now they need to know that excess belly fat is a risk factor for bone loss.”

Radiological Society of North America (RSNA) 96th Scientific Assembly and Annual Meeting: Abstract SSJ17-05. Presented November 30, 2010.

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Low Vitamin D levels common in breast cancer

More than half of women with breast cancer have low vitamin D levels, British researchers report.”Women with breast cancer should be tested for vitamin D levels and offered supplements, if necessary,” says researcher Sonia Li, MD, of the Mount Vernon Cancer Centre in Middlesex, England. The findings were presented at the San Antonio Breast Cancer Symposium.

Some studies have suggested a link between low vitamin levels and breast cancer risk and progression, but others have not, she says. No studies have proven cause and effect. Previous research suggests a biologic rationale for vitamin D putting the brakes on breast cancer development and spread, Li says. Breast cancer cells have vitamin D receptors, and when these receptors are activated by vitamin D, it triggers a series of molecular changes that can slow cell growth and cause cells to die, she says. Even if it does not have a direct effect on the tumor, vitamin D is needed to maintain the bone health of women with breast cancer, Li says. That's especially important given the increasing use of aromatase inhibitors, which carry an increased risk of bone fractures, she says.

Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health.

For the study, Li and colleagues collected blood samples from 166 women with breast cancer and measured their levels of vitamin D. Of the total, 46% had vitamin D insufficiency, defined as levels between 12.5 and 50 nanomoles per liter (nmol/L) of blood. Another 6% had vitamin D deficiency, with levels lower than 12.5 nmol/L. When ethnicity was considered, vitamin D levels were lower in Asian women than in white or other women: an average of about 36 nmol/L vs. 61 nmol/L and 39 nmol/L, respectively.

The researchers theorized that vitamin D levels would be higher in the summer, when there are more daylight hours, but the study showed no association between vitamin D levels and seasons. Last month, the U.S. Institute of Medicine issued updated guidelines stating that a blood level of 50 nmol/L (or 20 nanograms/milliliter) is sufficient for 97% of people.

This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the “peer review” process, in which outside experts scrutinize the data prior to publication in a medical journal.

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Vitamin D affects more than 200 genes

Working in the laboratory, the scientists isolated fragments of DNA in cells to study the effects of exposure to calcitriol, the “active” form of vitamin D. Their findings are published in the journal Genome Research.

Vitamin D influences DNA through a “go-between” protein called the vitamin D receptor (VDR). The protein is activated by the vitamin and attaches itself to DNA at the binding sites the researchers identified. VDR binding was enriched in disease-associated regions of the genetic code and also areas linked to traits such as tanning, height and hair colour.

Study leader Dr Sreeram Ramagopalan, from the Wellcome Trust Centre for Human Genetics, at Oxford University, said: “There is now evidence supporting a role for vitamin D in susceptibility to a host of diseases. Vitamin D supplements during pregnancy and the early years could have a beneficial effect on a child's health in later life. “Some countries, such as France, have instituted this as a routine public health measure.”

Vitamin D is chiefly made in the body as a result of the skin's exposure to sunlight. A small number of foods also contain the vitamin, including oily fish and eggs, but 90% comes from being in the sun. In many northern countries, a lack of sun can lead to vitamin D deficiency. Over-zealous use of sunscreen can also prevent vitamin D production. It is estimated that more than half the UK population do not get enough vitamin D, and worldwide a billion people may be deficient in the vitamin. Lack of vitamin D affects bone growth and development, leading to rickets in children and bone fractures in adults.

The study supports the theory that lighter, more sun-sensitive skins evolved as people migrated north out of Africa to maximise vitamin D production in the body. A significant number of the VDR binding sites were in DNA regions where genetic changes are commonly found in people of European and Asian descent.

“Vitamin D status is potentially one of the most powerful selective pressures on the genome in relatively recent times,” said co-author Professor George Ebers, also from the Wellcome Trust Centre for Human Genetics. “Our study appears to support this interpretation and it may be we have not had enough time to make all the adaptations we have needed to cope with our northern circumstances.”

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Cause of Osteoporosis in Celiac patients

People with celiac disease may develop osteoporosis due to immune-system attacks on bone tissue (N Engl J Med. 2009; 361:1459-1465). Although osteoporosis is a known complication of celiac disease, scientists have always believed that it occurred because celiac patients cannot properly absorb calcium and vitamin D from their diet and were therefore unable to maintain healthy bone tissue.

At the heart of this development is the protein osteoprotegerin, which plays a crucial role in maintaining bone health by controlling the rate at which bone tissue is removed. Researchers from the United Kingdom's University of Edinburgh and University of Liverpool detected autoantibodies against osteoprotegerin in several patients with celiac disease.

“Such autoantibodies may be associated with the development of high-turnover osteoporosis, but whether autoantibodies against osteoprotegerin commonly contribute to the pathogenesis of osteoporosis in patients with celiac disease remains to be determined,” the investigators conclude.

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Diet Cola Sucks Calcium Out of Wormen’s Bones

In an earlier investigation, the researchers had looked at the hormonal effects of diet cola ingestion on parathyroid hormone, calcium, phosphorus, insulin, alkaline phosphotase, and ghrelin.

The researchers thought that because of the phosphorus load, PTH would surge, but they found exactly the opposite, “which was that it comes down and sort of comes back to baseline; alkaline phosphatase increases also,” Larson said. “We thought, 'Well, that suggests there's some turnover of bone going on, and maybe there's some calcium being mobilized and it's going out in the urine and that might partially account for the fracture risk and decreased bone density that's being described.”

With results from that earlier study as the impetus, Larson and colleagues undertook the current study, for which they recruited 20 healthy women, ages 18 to 40.

Exclusion criteria were fracture within the prior six months, known bone disease or vitamin D deficiency, steroid or diuretic use, breast-feeding, and vitamin D supplementation above the current U.S. recommended daily allowance.

The participants were randomized to drink 24 ounces of either water or diet cola on two study days. Urine was collected for three hours after ingestion of the designated beverage and assayed for calcium, phosphorous, and creatinine using standard assays.

Data were analyzed on 16 participants; four were excluded because of lab error or failure to comply with the study protocol, the researchers said.

In addition to the higher calcium and phosphorus excretion, the investigators also found that normalized calcium and phosphorous excretion per gram of creatinine showed a trend in the same direction as total calcium and phosphorous per three hours. That figure did not achieve statistical significance, however.

Although the study was small, “it does look like there was a statistically significant rise in urine calcium,” said Larson. “The important part about that is that Diet Coke has no calcium content.”

Compared with milk, which also causes a rise in urine calcium but is replacing calcium at the same time, diet colas “would [create] an overall negative body calcium balance and that could partially explain why they appear to be bad for bones,” she said.

Although the study is too small to draw any firm conclusions, “certainly my personal practice among adolescent girls who tend to be concerned about their weight — and who drink diet beverages while they are in that critical period of bone formation — is to just try and counsel them to set habits of drinking calcium-containing beverages and maintaining adequate vitamin D,” said Larson.

Elizabeth Barrett-Connor, MD, of the University of California San Diego, called the study “fabulous.”

Barrett-Connor, who was not involved in the study, said that although it was a small and short-term trial, “it fits with all my preconceived ideas” about the nutritional problems with diet soda. “This [is new] but it just makes sense.”

The study was funded by the Walter Reed Department of Clinical Investigations.

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Low Vitamin D Levels Linked To Parkinsons

Writing in an editorial in the US journal Archives of Neurology, Marian Evatt, assistant professor of neurology at Emory University School of Medicine, says that health authorities should consider raising the target vitamin D level. “At this point, 30 nanograms per millilitre of blood or more appears optimal for bone health in humans. “However, researchers don't yet know what level is optimal for brain health or at what point vitamin D becomes toxic for humans, and this is a topic that deserves close examination.”

Dr Kieran Breen, director of research at Parkinson's UK, said: “The study provides further clues about the potential environmental factors that may influence or protect against the progression of Parkinson's. “A balanced healthy diet should provide the recommended levels of vitamin D. “Further research is required to find out whether taking a dietary supplement, or increased exposure to sunlight, may have an effect on Parkinson's, and at what stage these would be most beneficial.”

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Those who exercise when young have stronger bones when they grow old

The researchers also looked at bone density and structure in the lower leg in around 360 19-year-old men who had previously done sports but had now stopped training. They found that men who had stopped training more than six years ago still had larger and thicker bones in the lower leg than those who had never done sports.

“This result is particularly important, because we know that a bone with a large circumference is more durable and resistant to fractures than a narrower bone,” says Nilsson.

The researchers also studied bone density throughout the body in around 500 randomly selected 75-year-old men. Those who had done competitive sports three or more times a week at some point between the ages of 10 and 30 had higher bone density in several parts of the body than those who had not.

The researchers have therefore established that there is a positive link between exercise while young and bone density and size. The connection is even stronger if account is taken of the type of sports done.

“The bones respond best when you're young, and if you train and load them with your own bodyweight during these years, it has a stimulating effect on their development,” says Nilsson. “This may be important for bone strength much later in life too, so reducing the risk of brittle bones.”

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Benefits of Calcium and Vitamin D

Led by researchers at Copenhagen University in Denmark, Robbins and an international team of colleagues analyzed the results of seven large clinical trials from around the world to assess the effectiveness of vitamin D alone or with calcium in reducing fractures among people averaging 70 years or older. The researchers could not identify any significant effects for people who only take vitamin D supplements.

Among the clinical trial results analyzed was Robbins' WHI research, which was part of a 15-year, national program to address the most common causes of death, disability and poor quality of life in postmenopausal women such as cardiovascular disease, cancer and osteoporosis. Those trials were primarily designed to study the effect of calcium and vitamin D supplementation in preventing hip fractures, with a secondary objective of testing the supplements on spine and other types of fractures, as well as on colorectal cancer. The results were published in the Feb. 16, 2006 edition of the New England Journal of Medicine.

Fractures are a major cause of disability, loss of independence and death for older people. The injuries are often the result of osteoporosis, or porous bone, a disease characterized by low bone mass and bone fragility. The National Osteoporosis Foundation estimates that about 10 million Americans have osteoporosis; 80 percent of them are women. Four of 10 women over age 50 will experience a fracture of the hip, spine or wrist in their lifetime, and osteoporosis-related fractures were responsible for an estimated $19 billion in health-related costs in 2005.

“This study supports a growing consensus that combined calcium and vitamin D is more effective than vitamin D alone in reducing a variety of fractures,” said Robbins. “Interestingly, this combination of supplements benefits both women and men of all ages, which is not something we fully expected to find. We now need to investigate the best dosage, duration and optimal way for people to take it.”

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Osteoperosis may be a paediatric disease

The researchers fed 12 piglets a calcium-rich diet and another 12 piglets a calcium-deficient diet during the first 18 days of their lives. When the researchers examined samples of bone marrow, organs, and hind leg bone at the end of the study, they found that the piglets fed a calcium-deficient diet had compromised bone density and strength. The bone marrow tissue of these same piglets also seemed to be predisposed to become fat cells rather than osteoblasts (bone-forming cells). The presence of fewer osteoblasts during infancy may result in a reduced ability of bones to grow and repair themselves during later years.

Osteoporosis affects an estimated 10 million men and women in the United States, with about 80 percent of cases diagnosed in women. According to the National Osteoporosis Foundation, approximately 34 million additional people are believed to have low bone mass, which places them at increased risk for osteoporosis. Most people who have osteoporosis or low bone mass do not even know they have it, and the first clue is often a fracture associated with a fall or, in severe cases, simply bending over or turning around.

The lead researcher, Dr. Chad Stahl, an associate professor in the Department of Animal Science at North Carolina State University, noted that maintaining good calcium nutrition for children and adolescents is known to be important, but that this recent study “suggests that calcium nutrition of the neonate may be of greater importance to life-long bone health due to its programming effects on mesenchymal stem cells” (bone marrow tissue from which osteoblasts are formed). This idea might cause healthcare professionals “to begin thinking about osteoporosis not so much as a disease of the elderly, but instead as a pediatric disease with later onset.”

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