Every other week, new studies appear that either demonize or eulogize the mighty roasted bean. Are there grounds for concern under the aromatic froth?

Pros

Diabetes:A study of 14,000 people in Finland (the world's greatest per-capita consumer of coffee) found that women who drank three to four cups a day cut their risk of developing diabetes by 29 percent. For men, it was 27 percent. Researchers aren't sure why, but suspect that the antioxidants in coffee help deliver insulin to the body's tissues.

Cancer:In Japan, a study of 90,000 people revealed those who drank coffee every day for ten years were half as likely to get liver cancer. Meanwhile, German scientists have identified an active compound in coffee called methylpyridinium that boosts enzymes thought to prevent colon cancer.

Parkinson's Disease:Researchers in Hawaii monitored the health of more than 8,000 Japanese-American men for 30 years and discovered that those who drank a cup of coffee a day had less than half the incidence of Parkinson's disease. A possible clue as to why: caffeine promotes the release of dopamine, a substance involved with movement and usually depleted in Parkinson's sufferers.

Gallstones:A US study of 46,000 men who drank two to three cups of coffee a day over a ten-year period revealed they had a 40 percent lower risk of developing gallstones. Researchers believe it is because caffeine stimulates the gall bladder, flushing out substances that could turn into gallstones.
Cons

Heart Attack and Stroke:There's hot debate on whether drinking coffee is a cardiac risk. A Greek study of more than 3,000 people found coffee drinkers had higher levels of inflammatory substances (which have been associated with increased rates of stroke and heart attack) in their blood than non-drinkers. But Harvard researchers looking at the health of coffee drinkers over 20 years could not pinpoint any extra coronary problems. Nevertheless, a study of 2028 Costa Ricans found those with a gene variant that processes caffeine four times slower than average, and who also drank two to three cups of coffee a day, upped their heart-attack risk by 36 percent. As this group metabolises caffeine slower, it remains in the body for longer—possibly pushing up blood pressure.

Rheumatoid Arthritis:A Finnish study of 19,000 people revealed those who drank four or more cups of coffee a day were twice as likely to develop rheumatoid arthritis. Researchers believe some as-yet-unidentified ingredient (particularly in unfiltered coffee) could trigger the disease.

Osteoporosis:A Californian study of 980 post-menopausal women found that those who drank two cups of coffee a day suffered a greater loss in bone density than those who didn't. How come? Because caffeine acts as a diuretic, increasing the amount of calcium excreted in urine.

The Verdict

For most of us, the humble cup of coffee is simply a harmless and enjoyable way to kick-start the day or give us an excuse for some time out. No more, no less. However, it is important to remember that different people exhibit different tolerance levels to caffeine—it is, after all, a drug.

So, while a mid-morning cappuccino will give one person a pleasant buzz, it could make another person edgy and irritable. To play it safe, it's best to err on the side of caution. Whatever your choice—espresso or latte—keep a watch on your consumption for the sake of both your short-term and long-term health.

每周都會出來些新的研究反對這種萬能烤豆子，下一周又會有研究出來贊美它。這些隱藏在香濃的泡沫之下的擔心，有沒有確鑿的證據呢？

支持：

糖尿病：芬蘭（世界人均消費咖啡最高的國家）一項有14000人參加的研究發現，每天喝三到四杯咖啡，女性罹患糖尿病的可能要減少29%，對與男性來說，要減少27%。研究人員不確定原因，不過他們推測咖啡中的抗氧化物質可以幫助胰島素傳到到身體的各部分組織中。

癌癥：在日本，一項有90000人參加的研究發現，那些十年來每天喝一杯咖啡的人，罹患肝癌的可能性要降低一半。德國的科學家也確認了咖啡中一種名叫methylpyridinium的活躍成分可以提升酶，這被認為可以預防結腸癌。

帕金森癥：夏威夷的研究者們通過三十多年對于8000多名日裔美籍男性的健康監測發現，那些每天喝一杯咖啡的人罹患帕金森癥的情況不到那些不每天喝咖啡的人的一半。一種可能的原因是：咖啡因促進了多巴胺的分泌，這種物質和運動有關，在帕金森患者中它的分泌通常被消耗掉了。

膽結石：美國一項研究，研究了46000名每天喝2-3杯咖啡超過10年的男性，他們發現這些人出現膽結石的危險要低40%。研究人員們相信，這是因為咖啡因刺激了膽管，排出了那些可能會轉化成結石的物質。

反對：

突發心臟病和中風：關于喝咖啡是否對心血管有危害的爭論十分激烈。一項超過3000人參加的希臘研究發現，喝咖啡的人血液中的炎癥物質（與中風和突發心臟病有關）比不喝咖啡的人要高。但是哈弗大學的研究者通過20多年跟蹤喝咖啡的人的健康情況，他們沒有發現更高的冠心病發病率。另外，一項關于2028位哥斯達黎加人的研究發現，那些基因決定消化咖啡因的速度比常人慢4倍的人，如果他們每天喝2-3杯咖啡，他們突發心臟病的危險要高36%。對于這些代謝咖啡因慢的人，咖啡因在體內時間更長，這可能會提高血壓。

類風濕關節炎：一項關于19000人的芬蘭研究發現，那些每天喝超過4杯咖啡的人，罹患類風濕關節炎的可能要高出一倍。研究人員相信，一些還沒有被確認的物質（尤其是未過濾的咖啡中），可能會引發這種疾病。

骨質疏松癥：加利福尼亞州的研究者，研究了980名更年期之后的女性，他們發現那些每天喝兩杯咖啡的女性骨密度的流失要更高。為什么？因為咖啡因有利尿的作用，這使得通過尿排出的鈣質更多。

最終決議

對于我們中的大多數人來說，一杯暖和的咖啡，僅僅是一種無害而享受的方式，來開啟一天的工作或者找借口休息一下。不多也不少。不過，要謹記這一點，不同的人對于咖啡因的耐受性并不相同——畢竟，咖啡因是一種藥。

所以，上午的一杯卡布奇諾可能給你帶來的是愉快的好心情，但對有些人來說，可能就是煩躁和壞脾氣。安全起見，最好小心行事。不論你如何選擇——濃縮咖啡還是拿鐵——注意你喝的量，不論是對你短期還是長期的健康，都有好處。