Tampilkan postingan dengan label calcium. Tampilkan semua postingan
Tampilkan postingan dengan label calcium. Tampilkan semua postingan
Minggu, 01 September 2013
Calcium and D may help burn fat
Overweight women who take supplements of calcium and vitamin D may be able to lose more body fat, but only if they weren’t getting much calcium before. Researchers writing in the British Journal of Nutrition gave 63 overweight women a calcium and D supplement and tracked them for 15 weeks while they followed a low-calorie diet. In the study group as a whole, the supplement didn’t help people lose more body fat, but women who started with low levels of calcium seemed to lose more weight and fat. When watched eating at a buffet, those women also ate less fat than they did during a meal at the beginning of the study. Women with low calcium levels at the beginning of the study who got the supplements lost an average of 13 pounds, compared to 3 pounds for those on placebos.
Rabu, 27 Maret 2013
Senin, 29 November 2010
Extra Vitamin D and Calcium Aren’t Needed, Report Says
The very high levels of vitamin D that are often recommended by doctors and testing laboratories — and can be achieved only by taking supplements — are unnecessary and could be harmful, an expert committee says. It also concludes that calcium supplements are not needed.
The group said most people have adequate amounts of vitamin D in their blood supplied by their diets and natural sources like sunshine, the committee says in a report that is to be released on Tuesday.
“For most people, taking extra calcium and vitamin D supplements is not indicated,” said Dr. Clifford J. Rosen, a member of the panel and an osteoporosis expert at the Maine Medical Center Research Institute.
Dr. J. Christopher Gallagher, director of the bone metabolism unit at the Creighton University School of Medicine in Omaha, Neb., agreed, adding, “The onus is on the people who propose extra calcium and vitamin D to show it is safe before they push it on people.”
Over the past few years, the idea that nearly everyone needs extra calcium and vitamin D — especially vitamin D — has swept the nation.
With calcium, adolescent girls may be the only group that is getting too little, the panel found. Older women, on the other hand, may take too much, putting themselves at risk for kidney stones. And there is evidence that excess calcium can increase the risk of heart disease, the group wrote.
As for vitamin D, some prominent doctors have said that most people need supplements or they will be at increased risk for a wide variety of illnesses, including heart disease, cancer and autoimmune diseases.
And these days more and more people know their vitamin D levels because they are being tested for it as part of routine physical exams.
“The number of vitamin D tests has exploded,” said Dennis Black, a reviewer of the report who is a professor of epidemiology and biostatistics at the University of California, San Francisco.
At the same time, vitamin D sales have soared, growing faster than those of any supplement, according to The Nutrition Business Journal. Sales rose 82 percent from 2008 to 2009, reaching $430 million. “Everyone was hoping vitamin D would be kind of a panacea,” Dr. Black said. The report, he added, might quell the craze.
“I think this will have an impact on a lot of primary care providers,” he said.
The 14-member expert committee was convened by the Institute of Medicine, an independent nonprofit scientific body, at the request of the United States and Canadian governments. It was asked to examine the available data — nearly 1,000 publications — to determine how much vitamin D and calcium people were getting, how much was needed for optimal health and how much was too much.
The two nutrients work together for bone health.
Bone health, though, is only one of the benefits that have been attributed to vitamin D, and there is not enough good evidence to support most other claims, the committee said.
Some labs have started reporting levels of less than 30 nanograms of vitamin D per milliliter of blood as a deficiency. With that as a standard, 80 percent of the population would be deemed deficient of vitamin D, Dr. Rosen said. Most people need to take supplements to reach levels above 30 nanograms per milliliter, he added.
But, the committee concluded, a level of 20 to 30 nanograms is all that is needed for bone health, and nearly everyone is in that range.
Vitamin D is being added to more and more foods, said Paul R. Thomas of the Office of Dietary Supplements at the National Institutes of Health. Not only is it in orange juice and milk, but more is being added to breakfast cereals, and it now can be found in very high doses in supplement pills. Most vitamin D pills, he said, used to contain no more than 1,000 international units of it. Now it is easy to find pills, even in places like Wal-Mart, with 5,000 international units. The committee, though, said people need only 600 international units a day.
To assess the amounts of vitamin D and calcium people are getting, the panel looked at national data on diets. Most people, they concluded, get enough calcium from the foods they eat, about 1,000 milligrams a day for most adults (1,200 for women ages 51 to 70).
Vitamin D is more complicated, the group said. In general, most people are not getting enough vitamin D from their diets, but they have enough of the vitamin in their blood, probably because they are also making it naturally after being out in the sun and storing it in their bodies.
The American Society for Bone and Mineral Research and other groups applauded the report. It is “a very balanced set of recommendations,” said Dr. Sundeep Khosla, a Mayo Clinic endocrinologist and the society’s president.
But Andrew Shao, an executive vice president at the Council for Responsible Nutrition, a trade group, said the panel was being overly cautious, especially in its recommendations about vitamin D. He said there was no convincing evidence that people were being harmed by taking supplements, and he said higher levels of vitamin D, in particular, could be beneficial.
Such claims “are not supported by the available evidence,” the committee wrote. They were based on studies that observed populations and concluded that people with lower levels of the vitamin had more of various diseases. Such studies have been misleading and most scientists agree that they cannot determine cause and effect.
It is not clear how or why the claims for high vitamin D levels started, medical experts say. First there were two studies, which turned out to be incorrect, that said people needed 30 nanograms of vitamin D per milliliter of blood, the upper end of what the committee says is a normal range. They were followed by articles and claims and books saying much higher levels — 40 to 50 nanograms or even higher — were needed.
After reviewing the data, the committee concluded that the evidence for the benefits of high levels of vitamin D was “inconsistent and/or conflicting and did not demonstrate causality.”
Evidence also suggests that high levels of vitamin D can increase the risks for fractures and the overall death rate and can raise the risk for other diseases. While those studies are not conclusive, any risk looms large when there is no demonstrable benefit. Those hints of risk are “challenging the concept that ‘more is better,’ ” the committee wrote.
That is what surprised Dr. Black. “We thought that probably higher is better,” he said.
He has changed his mind, and expects others will too: “I think this report will make people more cautious.”
The group said most people have adequate amounts of vitamin D in their blood supplied by their diets and natural sources like sunshine, the committee says in a report that is to be released on Tuesday.
“For most people, taking extra calcium and vitamin D supplements is not indicated,” said Dr. Clifford J. Rosen, a member of the panel and an osteoporosis expert at the Maine Medical Center Research Institute.
Dr. J. Christopher Gallagher, director of the bone metabolism unit at the Creighton University School of Medicine in Omaha, Neb., agreed, adding, “The onus is on the people who propose extra calcium and vitamin D to show it is safe before they push it on people.”
Over the past few years, the idea that nearly everyone needs extra calcium and vitamin D — especially vitamin D — has swept the nation.
With calcium, adolescent girls may be the only group that is getting too little, the panel found. Older women, on the other hand, may take too much, putting themselves at risk for kidney stones. And there is evidence that excess calcium can increase the risk of heart disease, the group wrote.
As for vitamin D, some prominent doctors have said that most people need supplements or they will be at increased risk for a wide variety of illnesses, including heart disease, cancer and autoimmune diseases.
And these days more and more people know their vitamin D levels because they are being tested for it as part of routine physical exams.
“The number of vitamin D tests has exploded,” said Dennis Black, a reviewer of the report who is a professor of epidemiology and biostatistics at the University of California, San Francisco.
At the same time, vitamin D sales have soared, growing faster than those of any supplement, according to The Nutrition Business Journal. Sales rose 82 percent from 2008 to 2009, reaching $430 million. “Everyone was hoping vitamin D would be kind of a panacea,” Dr. Black said. The report, he added, might quell the craze.
“I think this will have an impact on a lot of primary care providers,” he said.
The 14-member expert committee was convened by the Institute of Medicine, an independent nonprofit scientific body, at the request of the United States and Canadian governments. It was asked to examine the available data — nearly 1,000 publications — to determine how much vitamin D and calcium people were getting, how much was needed for optimal health and how much was too much.
The two nutrients work together for bone health.
Bone health, though, is only one of the benefits that have been attributed to vitamin D, and there is not enough good evidence to support most other claims, the committee said.
Some labs have started reporting levels of less than 30 nanograms of vitamin D per milliliter of blood as a deficiency. With that as a standard, 80 percent of the population would be deemed deficient of vitamin D, Dr. Rosen said. Most people need to take supplements to reach levels above 30 nanograms per milliliter, he added.
But, the committee concluded, a level of 20 to 30 nanograms is all that is needed for bone health, and nearly everyone is in that range.
Vitamin D is being added to more and more foods, said Paul R. Thomas of the Office of Dietary Supplements at the National Institutes of Health. Not only is it in orange juice and milk, but more is being added to breakfast cereals, and it now can be found in very high doses in supplement pills. Most vitamin D pills, he said, used to contain no more than 1,000 international units of it. Now it is easy to find pills, even in places like Wal-Mart, with 5,000 international units. The committee, though, said people need only 600 international units a day.
To assess the amounts of vitamin D and calcium people are getting, the panel looked at national data on diets. Most people, they concluded, get enough calcium from the foods they eat, about 1,000 milligrams a day for most adults (1,200 for women ages 51 to 70).
Vitamin D is more complicated, the group said. In general, most people are not getting enough vitamin D from their diets, but they have enough of the vitamin in their blood, probably because they are also making it naturally after being out in the sun and storing it in their bodies.
The American Society for Bone and Mineral Research and other groups applauded the report. It is “a very balanced set of recommendations,” said Dr. Sundeep Khosla, a Mayo Clinic endocrinologist and the society’s president.
But Andrew Shao, an executive vice president at the Council for Responsible Nutrition, a trade group, said the panel was being overly cautious, especially in its recommendations about vitamin D. He said there was no convincing evidence that people were being harmed by taking supplements, and he said higher levels of vitamin D, in particular, could be beneficial.
Such claims “are not supported by the available evidence,” the committee wrote. They were based on studies that observed populations and concluded that people with lower levels of the vitamin had more of various diseases. Such studies have been misleading and most scientists agree that they cannot determine cause and effect.
It is not clear how or why the claims for high vitamin D levels started, medical experts say. First there were two studies, which turned out to be incorrect, that said people needed 30 nanograms of vitamin D per milliliter of blood, the upper end of what the committee says is a normal range. They were followed by articles and claims and books saying much higher levels — 40 to 50 nanograms or even higher — were needed.
After reviewing the data, the committee concluded that the evidence for the benefits of high levels of vitamin D was “inconsistent and/or conflicting and did not demonstrate causality.”
Evidence also suggests that high levels of vitamin D can increase the risks for fractures and the overall death rate and can raise the risk for other diseases. While those studies are not conclusive, any risk looms large when there is no demonstrable benefit. Those hints of risk are “challenging the concept that ‘more is better,’ ” the committee wrote.
That is what surprised Dr. Black. “We thought that probably higher is better,” he said.
He has changed his mind, and expects others will too: “I think this report will make people more cautious.”
Selasa, 03 Juni 2008
Calcium, vitamin D and cancer risk
In a study conducted in 2007, researchers found that women taking a combination of calcium and vitamin D supplements had a 60 percent lower incidence of all cancers than women not taking the tested supplement.
Research in the June 2007 issue of the American Journal of Clinical Nutrition has shown a reduction in cancer rates among postmenopausal women taking vitamin D combined with calcium.
This four-year, double blind, randomized placebo-controlled study involved over 1,100 postmenopausal women who were divided into three treatment groups. The first group received a supplement containing calcium and vitamin D, the second group received just calcium, and the third group received a placebo. The researchers found that the women taking the calcium and vitamin D supplement had a 60 percent lower incidence of all cancers than women not taking the supplement.
This new study takes an important step in extending several decades of research involving the role of vitamin D in health and disease. The results further strengthen the case made by many specialists that vitamin D may be a powerful cancer preventive and that it is commonly found lacking in the general population, particularly the elderly.
Source: Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial, Lappe et al, The American Journal of Clinical Nutrition 2007 June;85(6):1586-91
Research in the June 2007 issue of the American Journal of Clinical Nutrition has shown a reduction in cancer rates among postmenopausal women taking vitamin D combined with calcium.
This four-year, double blind, randomized placebo-controlled study involved over 1,100 postmenopausal women who were divided into three treatment groups. The first group received a supplement containing calcium and vitamin D, the second group received just calcium, and the third group received a placebo. The researchers found that the women taking the calcium and vitamin D supplement had a 60 percent lower incidence of all cancers than women not taking the supplement.
This new study takes an important step in extending several decades of research involving the role of vitamin D in health and disease. The results further strengthen the case made by many specialists that vitamin D may be a powerful cancer preventive and that it is commonly found lacking in the general population, particularly the elderly.
Source: Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial, Lappe et al, The American Journal of Clinical Nutrition 2007 June;85(6):1586-91
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