24Drs好健康報:喝咖啡能額外帶來健康？
好健康熱頭條 ─ 喝咖啡能額外帶來健康？ Coffee's Health Perks Get Attention
好健康小單字 – 糖尿病 (Diabetes Mellitus)
好健康熱頭條 ─ 喝咖啡能額外帶來健康？
科學研究可能很快就能讓咖啡的不健康飲料形象稍有改善，或者，至少那是販售咖啡的大企業所希望能有的效果。
美國人每天喝掉數千萬杯的咖啡來讓自己趕走睡意，正在進行的一批研究試著從全美為之上癮的咖啡裡找出其對健康的優、缺點。
咖啡的形象在1982年時跌至谷底，當時有一項大型的研究總結指出，經常飲用咖啡會提高胰臟癌的風險；從那時起，咖啡商就投資愈來愈多的經費贊助研究，以找出咖啡實際上可能會帶來健康益處的有利證據。
然而，其中有些研究支持某些關於咖啡的健康警示，有愈來愈多的研究指出，每天喝咖啡，可能降低第二型糖尿病的風險。
根據加州大學洛杉磯分校的營養流行病學家Lenore Arab博士表示，其他的研究提出的還尚未成定論，例如咖啡在降低肝癌的風險、帕金森氏症，甚至是大腸癌都是有益的；Arab博士表示，更有其他研究指出，孕婦喝大量的咖啡，會讓其腹中的胎兒，暴露在白血病的風險中。
Arab博士於在華盛頓召開的美國國家實驗生物學會（Federation of American Societies of Experimental Biology）年會中演講，他主述兩項大型研究，一個是來自加拿大，另一個則是烏拉圭，其中顯示經常喝咖啡的人，罹患膀胱癌的風險升高60% 至70%。
Arab博士表示，整體來看，罹癌的狀況是好壞參半；卡夫食品公司的科學公關人員Dan Steffen指出，基本上，看來是中立不偏頗的。
【糖尿病上的益處】
然而，咖啡商則是對指出咖啡可能有助於預防糖尿病最為感到興奮。
哈佛大學研究員Rob M. van Dam博士表示，他於2005年對8項大型研究進行分析所作的總結是，每天喝6至7杯咖啡的成人，相較於每天喝2杯的人，糖尿病風險降低了三分之一。
van Dam博士表示，去年的某項研究顯示，每天2或3杯的咖啡，使女性的糖尿病風險降低了13%，喝4杯或更多杯咖啡，則降低風險超過40%。
van Dam博士指出，至少有另外七項研究提出相似的益處。
這許許多多的研究發現，讓研究人員感到困擾，因為數種咖啡因的個別成份，包括咖啡因在內，會升高膽固醇，並降低血糖代謝，如此將會不利於糖尿病，而非有益。
van Dam博士指出，我們並不是在談咖啡因，似乎真的是因為咖啡這種飲品，而非咖啡因本身；他及其他研究人員提出建言，指出幾乎該研究所有的證據，是來自於以一般大眾為基礎的研究，而非經過嚴格控管、隨機取樣，能夠分辨出真實因果關係的臨床試驗。
咖啡有數千種的成分，其中大部分是未被充分研究的，況且，歐洲的研究對每天僅數杯咖啡飲用量所顯示出的益處，如此樂觀的結論是否適用於美國大量飲用咖啡的廣大消費者，尚有許多可議之處。
毒物學私人顧問並曾作過咖啡業科學研究員的James Coughlin博士表示，一杯咖啡的量到底是多大？它是否為一杯美國星巴克的特大杯，還是迷你杯？。
van Dam博士也強調，他不建議咖啡作為預防糖尿病的輔助飲品，他表示，若是你想降低糖尿病的風險，最好是採全穀類飲食、多做體能活動，並且減肥。
Coffee's Health Perks Get Attention
Scientific research may soon help coffee shed some of its image as an unhealthy drink. Or at least that's what the big companies that sell it are hoping it will do.
With tens of millions of cups of coffee jolting Americans awake each day, a bevy of research is under way trying to tease out the health advantages -- and disadvantages -- of the nation's coffee fixation.
Coffee's image took a hit in 1982 when a major study concluded that frequent use increased the risk of pancreatic cancer. Since then, coffee companies have funded more and more research seeking to show the opposite: that coffee may actually have some health benefits.
While studies are backing up some of the health warnings, a growing body of research is suggesting that daily coffee consumption may lower the risk of type 2 diabetes.
According to Lenore Arab, PhD, a nutritional epidemiologist at UCLA, other studies suggest less conclusively that coffee could help lower the risk of liver cancer, Parkinson's disease, and possibly colon cancer. And Arab says other research suggests high coffee intake by pregnant women can put their children at risk of leukemia.
Arab spoke at the Federation of American Societies of Experimental Biology annual meeting in Washington. He says two major studies, one from Canada and the other from Uruguay, showed a 60% to 70% increased risk of bladder cancer among regular coffee drinkers.
"Cancer -- the total picture -- is somewhat mixed," Arab says.
"Basically, it's neutral," says Dan Steffen, a scientific public relations official with Kraft Foods.
Diabetes Benefits
But coffee companies are most excited about evidence suggesting coffee could help prevent diabetes.
Rob M. van Dam, PhD, a Harvard researcher, says his 2005 analysis of eight major studies concluded that adults who consume six to seven cups of coffee per day lower their risk of diabetes by one-third over those who drink two cups per day.
Van Dam says a study last year showed two or three cups per day lowered women's diabetes risk by 13%. Four or more cups per day cut the risk by more than 40%.
At least seven other studies suggest similar benefits, says van Dam.
The findings are puzzling to researchers because several of caffeine's individual components, including caffeine, raise cholesterol and lower sugar metabolism. That should make them worse for diabetes, not better.
"We're not talking about caffeine," van Dam says. "It really seems to be the coffee, rather than the caffeine."
Stronger Data Needed
Van Dam and other researchers warn that almost all of their evidence comes from population- based studies, not the kind of controlled, randomized clinical trials that can better determine true cause-and-effect relationships.
Coffee has thousands of components, most of which are not well studied. It's not even clear that European studies on the benefits of a few daily cups of coffee offer any good conclusions for America's legions of consumers.
"What the heck is a cup? Is it a Starbuck's 20-ouncer, or is it a 5-ounce teacup?" says James Coughlin, PhD, a private toxicology consultant and one-time coffee industry scientist.
Van Dam also stresses that he does not recommend coffee as a diabetes prevention aid. "If you want to lower the risk of diabetes, you'd better focus on whole-grain consumption, physical activity, and weight loss," he says.
SOURCES: Dan Steffen, PhD, Scientific and Regulatory Affairs, Kraft Foods. Lenore Arab, PhD, nutritional epidemiologist, David Geffen School of Medicine, UCLA. Rob M. van Dam, PhD, research scientist, department of nutrition, Harvard School of Public Health. James Coughlin, PhD, Coughlin & Associates.
WebMD Medical News
By Todd Zwillich
Reviewed by Louise Chang, MD
好健康小單字 – 糖尿病 (Diabetes Mellitus)
當我們身體不能分泌胰島素時，或體內細胞對胰島素反應不好時，除了因葡萄糖不能進入細胞所產生的血糖上升外，體內的脂肪、蛋白質和碳水化合物的代謝都會發生異常現象，當血糖升高到某一程度，超過腎臟所能回收的極限時，葡萄糖就會從尿液中排出，因此稱為糖尿病。
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