Every other week, new studies appear that either criticize or praise the roasted bean. Are there grounds for concern under the fragrant foam? Some people believe that coffee bean can lower the incidence of some diseases. First, the disease is diabetes. A study of 14, 000 people in Finland which is 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. Second, it can lower 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 that boosts enzymes thought to prevent colon cancer. Finally, it can also lower 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 consumed in Parkinson's sufferers. On the contrary, there's hot debate on whether drinking coffee is a cardiac risk. A Greek study of more than 3, 000 people found coffee drinkers has higher levels of bad substances in their blood than non-drinkers. But Harvard researchers looking at the health of coffee drinkers over 20 years could not localize any extra coronary problems. Nevertheless, a study of 2, 028 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. 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. What is mainly discussed in the text?