Vitamin E tied to higher risk of prostate cancer
Men taking daily vitamin E were more likely to get prostate cancer than those not taking the dietary supplement, according to a study of close to 35,000 North Americans.
This means that over a decade, one or two men out of 100 taking vitamin E would be expected to get prostate cancer, said the researchers, whose findings were published in the Journal of the American Medical Association.
“If you have enough of these vitamins in your system…extra doesn’t help you any, and too much of something like this can be harmful,” said Eric Klein from the Cleveland Clinic, one of the study’s authors, to Reuters Health.
The findings come on the heels of a study suggesting that older women who take multivitamins have slightly increased death rates compared to those who don’t.
“There’s a theme here that taking vitamins is not only not helpful but could be harmful” in people who are not deficient in vitamins, Klein added.
But one researcher who wasn’t part of the new study said he doubted it means vitamin E causes prostate cancer.
“It’s an interesting finding. I’m not sure I believe it,” said Neil Fleshner, from the University of Toronto, adding that the result may have been a chance finding or false positive.
For the study, men in the United States, Canada and Puerto Rico were randomly assigned to one of four groups. Starting between 2001 and 2004, about 9,000 men in each group took daily supplements of 400 international units (IU) of vitamin E, 200 micrograms of selenium, vitamin E and selenium together or a vitamin-free placebo pill.
The study was halted in late 2008 when the researchers saw a hint of an increased risk of prostate cancer in the men taking vitamin E. But they kept monitoring men for cancer after they stopped taking the supplements. It turned out that the extra risk became clearer over time.
By mid-2011, about seven percent of men who had taken vitamin E only had gotten prostate cancer, compared to six percent of those assigned to placebo pills.
The researchers did not find an extra risk of prostate cancer in men who took only selenium or vitamin E together with selenium.
Klein and his colleagues said it’s not clear how vitamin E would increase the risk of prostate cancer, and that not all past studies have shown it does any harm to the prostate. Some have even found a lower prostate-cancer risk with vitamin E.
He added that the new findings aren’t definite proof that vitamin E causes extra prostate cancers, but that there wasn’t anything else that could explain why men taking the vitamin were more likely to be diagnosed with cancer — for example, they weren’t screened more frequently.
The supplement doses, he added, are much higher than what’s in most over-the-counter multivitamins, which typically contain 15 to 25 IU of vitamin E.
Fleshner said that either way, vitamin E doesn’t seem to be beneficial for prostate health.
“There’s certainly no major evidence that vitamin E helps, so why bother?” he said.
While vitamin supplements are known to prevent disease in people who have vitamin deficiencies, so far studies haven’t found much extra benefit in people who already get enough vitamins through their diet. Specifically, vitamin E has not been shown to protect against heart disease, colon cancer or lung cancer.
On the other hand, there is a growing body of evidence suggesting supplements may be harmful in high doses.
“Vitamins are not innocuous substances,” Klein said.
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Source > Reuters-路透社，October 12, 2011
Translated by > BlogHost
Word Count > approx. 600 words in English
Taking vitamin E linked to osteoporosis: Japanese research
Japanese scientists say they have found a link between consumption of vitamin E and the degenerative bone condition osteoporosis, in a study likely to shed new light on the use of supplements.
Researchers found that giving mice increased doses of the vitamin to a level similar to that found in supplements caused the animals’ bones to thin.
The mice developed osteoporosis after eight weeks on the diet, which had levels of vitamin E significantly higher than those found in a mouse’s natural diet, according to the study, published in the journal Nature Medicine.
The team, led by Shu Takeda of Keio University, said vitamin E stimulates the generation of bone-degrading cells, which normally work with bone-forming cells to maintain bone strength.
Osteoporosis is a disease that causes the thinning of bone tissue and loss of bone density over time. It often affects older people, particularly women, who may become more prone to bone fractures.
Vitamin E is found naturally in various foods including vegetable oil, nuts and some leafy vegetables.
It is also a popular health supplement as an antioxidant, and is widely believed to enhance health and slow problems related to ageing.
The study called for greater research into how enhanced levels of vitamin E affect human health.
“It is possible that with the volume (of vitamin E) contained in health supplements, bones may become fragile,” Takeda told the Mainichi Shimbun newspaper.
The findings come after researchers found mice that had been genetically modified to be deficient in vitamin E had a high bone density.
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Source > Agence France-Presse-法新社, March 6, 2012
Translated by > BlogHost
Word Count > approx. 280 words in English
Vitamin D supplements can lower risk of dying
Boosting the level of vitamin D by using supplements for someone who is vitamin D deficient can lower his risk of dying by 60 percent, a new study found.
Analyzing data on 10,889 patients, University of Kansas Hospital researchers found that 70 percent of them were deficient in vitamin D, with levels below the 30 nanograms per millilitre considered necessary for good health.
After taking into account the patients’ medical history, medication and other factors, the cardiologists found that people with deficient levels of vitamin D were more than twice as likely to have diabetes. 40 per cent more likely to have high blood pressure and about 30 percent more likely to suffer from cardiomyopathy-diseased heart muscle-as people without this deficiency.
Overall, those who were deficient in vitamin D had a three-fold higher likelihood of dying from any cause than those who were not deficient, the researchers reported in the American Journal of Cardiology.
When the tem look at people who took vitamin D supplements, their risk of death from any cause was about 60 per cent lower than the rest of the patients, although the effect was strongest among those who were vitamin D deficient at the time they were tested.
Vitamin D deficiency has been linked to a range of illnesses, but few studies have demonstrated that supplements could prevent those diseases.
Dr.James L.Vacek, a professor of cardiology at the University of Kansas Hospital and Medical Center, said : “We expected to see a relationship between heart disease and vitamin D deficiency; we were surprised at how strong it was.”
堪萨斯州大学医院和医疗中心心脏病科教授Dr.James L. Vacek说：“我们有准备看到心脏疾病和维生素D缺乏症之间的关系，但关联之紧密让我们感到惊讶。”
But the study does not prove that vitamin D is the cause of the effects seen. Other factors, such as disease, could be responsible both for the differences in health and the differences in vitamin D levels.
Still, people should get about 90 per cent of vitamin D from the sun and about 10 per cent from food, Dr Vacek said.
The human body makes vitamin D in response to skin exposure to sunlight. At least 10 minutes of full-body exposure to sunlight each day is required to get a sufficient amount of vitamin D, Dr Vacek said.
Certain types of food, such as oily fish, eggs and enriched milk products, are also good sources of vitamin D.
The findings mean that adults should consider getting their vitamin D levels checked through a simple blood test and take vitamin D supplements if they are deficient, said Dr Vacek.
He said: “If you’re not deficient, vitamin D is not a magic pill that will make you live longer. Its benefit is in people who are deficient.”
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Source > Newspaper Article
Translated by > BlogHost
Word Count > approx. 500 words in English