2009年6月16日 星期二

Alcohol’s Good for You? Some Scientists Doubt It

Alcohol’s Good for You? Some Scientists Doubt It

Pier Paolo Cito/Associated Press

Published: June 15, 2009

By now, it is a familiar litany. Study after study suggests that alcohol in moderation may promote heart health and even ward off diabetes and dementia. The evidence is so plentiful that some experts consider moderate drinking — about one drink a day for women, about two for men — a central component of a healthy lifestyle.

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But what if it’s all a big mistake?

For some scientists, the question will not go away. No study, these critics say, has ever proved a causal relationship between moderate drinking and lower risk of death — only that the two often go together. It may be that moderate drinking is just something healthy people tend to do, not something that makes people healthy.

“The moderate drinkers tend to do everything right — they exercise, they don’t smoke, they eat right and they drink moderately,” said Kaye Middleton Fillmore, a retired sociologist from the University of California, San Francisco, who has criticized the research. “It’s very hard to disentangle all of that, and that’s a real problem.”

Some researchers say they are haunted by the mistakes made in studies about hormone replacement therapy, which was widely prescribed for years on the basis of observational studies similar to the kind done on alcohol. Questions have also been raised about the financial relationships that have sprung up between the alcoholic beverage industry and many academic centers, which have accepted industry money to pay for research, train students and promote their findings.

“The bottom line is there has not been a single study done on moderate alcohol consumption and mortality outcomes that is a ‘gold standard’ kind of study — the kind of randomized controlled clinical trial that we would be required to have in order to approve a new pharmaceutical agent in this country,” said Dr. Tim Naimi, an epidemiologist with the Centers for Disease Control and Prevention.

Even avid supporters of moderate drinking temper their recommendations with warnings about the dangers of alcohol, which has been tied to breast cancer and can lead to accidents even when consumed in small amounts, and is linked with liver disease, cancers, heart damage and strokes when consumed in larger amounts.

“It’s very difficult to form a single-bullet message because one size doesn’t fit all here, and the public health message has to be very conservative,” said Dr. Arthur L. Klatsky, a cardiologist in Oakland, Calif., who wrote a landmark study in the early 1970s finding that members of the Kaiser Permanente health care plan who drank in moderation were less likely to be hospitalized for heart attacks than abstainers. (He has since received research grants financed by an alcohol industry foundation, though he notes that at least one of his studies found that alcohol increased the risk of hypertension.)

“People who would not be able to stop at one to two drinks a day shouldn’t drink, and people with liver disease shouldn’t drink,” Dr. Klatsky said. On the other hand, “the man in his 50s or 60s who has a heart attack and decides to go clean and gives up his glass of wine at night — that person is better off being a moderate drinker.”

Health organizations have phrased their recommendations gingerly. The American Heart Association says people should not start drinking to protect themselves from heart disease. The 2005 United States dietary guidelines say that “alcohol may have beneficial effects when consumed in moderation.”

The association was first made in the early 20th century. In 1924, a Johns Hopkins biologist, Raymond Pearl, published a graph with a U-shaped curve, its tall strands on either side representing the higher death rates of heavy drinkers and nondrinkers; in the middle were moderate drinkers, with the lowest rates. Dozens of other observational studies have replicated the findings, particularly with respect to heart disease.

“With the exception of smoking and lung cancer, this is probably the most established association in the field of nutrition,” said Eric Rimm, an associate professor of epidemiology and nutrition at the Harvard School of Public Health. “There are probably at least 100 studies by now, and the number grows on a monthly basis. That’s what makes it so unique.”

Alcohol is believed to reduce coronary disease because it has been found to increase the “good” HDL cholesterol and have anticlotting effects. Other benefits have been suggested, too. A small study in China found that cognitively impaired elderly patients who drank in moderation did not deteriorate as quickly as abstainers. A report from the Framingham Offspring Study found that moderate drinkers had greater mineral density in their hipbones than nondrinkers. Researchers have reported that light drinkers are less likely than abstainers to develop diabetes, and that those with Type 2 diabetes who drink lightly are less likely to develop coronary heart disease.

But the studies comparing moderate drinkers with abstainers have come under fire in recent years. Critics ask: Who are these abstainers? Why do they avoid alcohol? Is there something that makes them more susceptible to heart disease?

Some researchers suspect the abstainer group may include “sick quitters,” people who stopped drinking because they already had heart disease. People also tend to cut down on drinking as they age, which would make the average abstainer older — and presumably more susceptible to disease — than the average light drinker.

In 2006, shortly after Dr. Fillmore and her colleagues published a critical analysis saying a vast majority of the alcohol studies they reviewed were flawed, Dr. R. Curtis Ellison, a Boston University physician who has championed the benefits of alcohol, hosted a conference on the subject. A summary of the conference, published a year later, said scientists had reached a “consensus” that moderate drinking “has been shown to have predominantly beneficial effects on health.”

The meeting, like much of Dr. Ellison’s work, was partly financed by industry grants. And the summary was written by him and Marjana Martinic, a senior vice president for the International Center for Alcohol Policies, a nonprofit group supported by the industry. The center paid for tens of thousands of copies of the summary, which were included as free inserts in two medical journals, The American Journal of Medicine and The American Journal of Cardiology.

In an interview, Dr. Ellison said his relationship with the industry did not influence his work, adding, “No one would look at our critiques if we didn’t present a balanced view.”

Dr. Fillmore and the co-authors of her analysis posted an online commentary saying the summary had glossed over some of the deep divisions that polarized the debate at the conference. “We also dispute Ellison and Martinic’s conclusions that more frequent drinking is the strongest predictor of health benefits,” they wrote.

(Dr. Fillmore has received support from the Alcohol Education and Rehabilitation Foundation of Australia, a nonprofit group that works to prevent alcohol and substance abuse.)

Dr. Ellison said Dr. Fillmore’s analysis ignored newer studies that corrected the methodological errors of earlier work. “She threw out the baby with the bathwater,” he said.

Meanwhile, two central questions remain unresolved: whether abstainers and moderate drinkers are fundamentally different and, if so, whether it is those differences that make them live longer, rather than their alcohol consumption.

Dr. Naimi of the C.D.C., who did a study looking at the characteristics of moderate drinkers and abstainers, says the two groups are so different that they simply cannot be compared. Moderate drinkers are healthier, wealthier and more educated, and they get better health care, even though they are more likely to smoke. They are even more likely to have all of their teeth, a marker of well-being.

“Moderate drinkers tend to be socially advantaged in ways that have nothing to do with their drinking,” Dr. Naimi said. “These two groups are apples and oranges.” And simply advising the nondrinkers to drink won’t change that, he said.

Some scientists say the time has come to do a large, long-term randomized controlled clinical trial, like the ones for new drugs. One approach might be to recruit a large group of abstainers who would be randomly assigned either to get a daily dose of alcohol or not, and then closely followed for several years; another might be to recruit people who are at risk for coronary disease.

But even the experts who believe in the health benefits of alcohol say this is an implausible idea. Large randomized trials are expensive, and they might lack credibility unless they were financed by the government, which is unlikely to take on the controversy. And there are practical and ethical problems in giving alcohol to abstainers without making them aware of it and without contributing to accidents.

Still, some small clinical trials are already under way to see whether diabetics can reduce their risk of heart disease by consuming alcohol. In Boston, researchers at Beth Israel Deaconess Medical Center are recruiting volunteers 55 and over who are at risk for heart disease and randomly assigning them to either drink plain lemonade or lemonade spiked with tasteless grain alcohol, while scientists track their cholesterol levels and scan their arteries.

In Israel, researchers gave people with Type 2 diabetes either wine or nonalcoholic beer, finding that the wine drinkers had significant drops in blood sugar, though only after fasting; the Israeli scientists are now working with an international team to begin a larger two-year trial.

“The last thing we want to do as researchers and physicians is expose people to something that might harm them, and it’s that fear that has prevented us from doing a trial,” said Dr. Sei Lee of the University of California, San Francisco, who recently proposed a large trial on alcohol and health.

“But this is a really important question,” he continued. “Because here we have a readily available and widely used substance that may actually have a significant health benefit — but we just don’t know enough to make recommendations.”

2009年6月1日 星期一

Rooting Out The Facts On An Immune Booster: astragalus黃耆



科 學研究發現黃耆能夠改善免疫系統﹐但這些研究基本上都是亞洲進行的﹐西方國家的相關研究很少。馬薩諸塞州劍橋的天然標準研究協會(Natural Standard Research Collaboration)評估了黃耆提高免疫能力的證據﹐並按照從A到F的評分標準給黃耆打分為C。這個協會是一家評估天然療法的科學家組織。天然標 準協會的創始人之一、波士頓馬薩諸塞州總醫院的主治藥劑師烏爾布里奇(Catherine Ulbricht)說﹐C的評分意味著沒有明確的或存在衝突性的科學信息﹐還沒有定論。


研 究報告的共同作者之一、俄勒岡州波特蘭美國自然醫學院(National College of Natural Medicine)的免疫學家茨維奇(Heather Zwickey)說﹐顯然黃耆確實能夠刺激人的免疫系統。但她又說﹐這不一定就意味著黃耆能夠提高人體抵御疾病的能力。茨維奇是美國自然醫學院旗下非盈利 性機構赫夫戈特研究院(Helfgott Research Institute)的研究主管。她介紹說﹐免疫細胞通常針對的都是非常具體的病原體﹐因此整體提升免疫活性並不一定就能帶來特定的益處﹐比方說提高防禦 甲型H1N1流感的能力。

黃耆價格不貴﹐可以從很多製藥商處買到。紐約製藥商Telomerase Activation Sciences Inc.銷售的一種藥濃縮提煉出了黃耆的一種有效成分。這家公司說﹐研究顯示﹐它得到加州企業Geron Corp.授權後生產的藥劑TA-65可以促進免疫系統。該公司認為﹐這種藥的功效原理是刺激一種能夠延長端粒的酵素﹐端粒是染色體尾端的序列。TA Sciences說﹐當端粒太短的時候﹐細胞就不能再分裂了﹔研究顯示﹐TA-65能夠幫助延長免疫細胞的端粒。TA-65目前被用於一種包含多種檢測的 綜合性治療﹐6個月的治療費用為6,725美元。TA Sciences表示﹐這些檢測可以幫助公司積累數據﹐向客戶顯示治療正在提高他們的健康狀況。


Laura Johannes

2009年 06月 02日 10:36
Rooting Out The Facts On An Immune Booster

A Chinese herb called astragalus can boost your immune system and help you fend off infections, from the common cold to swine flu, according companies that sell it. Scientists say astragalus boosts the immune system, but it isn't known if that translates to any health benefit.

The root of a perennial called astragalus has long been used in Chinese medicine to boost the body's defenses, often with other herbs. In the U.S., it is available in teas, tinctures and as a dietary supplement.

Scientific studies, mostly in Asia, have found the herb boosts the immune system in humans, but Western studies are scant. Natural Standard Research Collaboration, a Cambridge, Mass., scientist-owned group that evaluates natural therapies, reviewed the evidence for the immune-boosting properties of astragalus and gave it a 'C' on a scale from A to F. 'A grade of C means unclear or conflicting scientific information,' says Catherine Ulbricht, senior attending pharmacist at Massachusetts General Hospital in Boston and a co-founder of Natural Standard. 'The jury is still out.'

One of the few Western studies on the immune-boosting properties of astragalus was published in 2007, using 16 human subjects. Within 24 hours, biological markers in the group that took an astragalus tincture showed the activity of white blood cells, a key part of the body's defenses against invaders, rose significantly compared with a group on a placebo.

'Certainly it does work to stimulate your immune system,' says study co-author Heather Zwickey, an immunologist at National College of Natural Medicine in Portland, Ore. But that doesn't necessarily translate into a better resistance to disease, says Dr. Zwickey, who is director of research at the college's nonprofit Helfgott Research Institute. Immune cells often target very specific pathogens, so a general boost in immune activity doesn't necessarily translate into a specific benefit, such as a better ability to fight off swine flu, she says.

The herb is inexpensive and available from a variety of makers. A concentrated version that isolates one of its component ingredients is sold by Telomerase Activation Sciences Inc. of New York. The company's formulation, called TA-65 and licensed from Geron Corp., of Menlo Park, Calif., has been shown in unpublished work to boost the immune system, says TA Sciences. The company believes its supplement works by stimulating an enzyme that lengthens telomeres, sequences at the ends of chromosomes. When telomeres get too short, cells can no longer divide; research suggests TA-65 may help lengthen telomeres on immune cells, the company says. The herb is sold as part of a package that involves extensive testing; cost is $6,725 for six months. The testing helps the company accumulate data and show clients that it is improving their health, TA Sciences says.

Astragalus isn't recommended for people with autoimmune diseases such as lupus or multiple sclerosis, where activating the immune system could be harmful. Anyone allergic to peas is likely also to be allergic to astragalus, adds Dr. Ulbricht. Like other herbs, check with your doctor before using it with other medicines.

tobacco products

WHO pushes for graphic warnings on tobacco products

The World Health Organization (WHO) has urged governments to require that all tobacco packages include pictorial warnings to show the sickness and suffering caused by tobacco use.

The WHO will mark its No Tobacco Day with events across the globe and the kickoff to a new campaign promoting the use of pictorial warnings on tobacco products. "Show the truth, picture warnings save lives," is the message and theme of this year's No Tobacco Day.

When the WHO says the truth, it means bleeding brains, blackened gums and bulging neck tumors. A healthy lung on the left with a diseased lung on the right with the warning Bildunterschrift: Großansicht des Bildes mit der Bildunterschrift: Warnings on British cigarette packages may include disturbing images like this one

"Although some people question the need for such pictures, the evidence is absolutely clear that they convince people to quit," said Douglas Bettcher, the head of the WHO's Tobacco Free Initiative.

"Disgust, fear, sadness or worry" triggered by the graphic images can effectively discourage smoking.

Bettcher said the images are the most effective way to communicate the risks of smoking to those who are unaware of the dangers as well as to those who try to block such worries from their mind when they smoke.

According to the WHO, such warning images are already used in more than 20 countries, including Britain, Belgium, Iran, Peru and Malaysia, although nine out of ten people live in countries that do not require their use.

Smoking a global issue

The WHO Framework Convention on Tobacco Control obliges its 160 signatory countries to require health warnings on packaging, which describe the harmful effects of tobacco use. The convention does not make it mandatory for warnings to also include pictures.

People pass over a no smoking sign in the Madrid undergroundBildunterschrift: Großansicht des Bildes mit der Bildunterschrift: Many EU countries have passed laws banning smoking in public places

In addition to compelling warnings, the WHO campaigns to cut tobacco use internationally by eliminating smoking in public buildings, imposing high taxes on tobacco products and banning tobacco marketing and sponsorships.

Today, 80 percent of the world's smokers live in developing countries, a number that has risen in recent years due to increased marketing and production in those countries.

Different events are taking place across Europe to promote a tobacco free world. In Bosnia-Herzegovina ,there will be a performance by the Sarajevo Drum Orchestra, information and advice booths as well as games in the main square in Sarajevo.

In Italy, there will be a conference on Italian health policies, the prevention and treatment of tobacco-related illnesses and the promotion of a smoke-free culture.

In the Czech Republic, a group of about 80 people will climb Snezka, the country's highest mountain and a symbol of clean air.

Editor: Greg Benzow