Health: Body News.

Degrees of Smoking

For smokers attempting to quit, cutting back on the number of cigarettes smoked doesn't substantially reduce the intake of cancer-causing chemicals, a new study suggests. The reason may be that smokers compensate for the decrease by taking longer or more frequent drags, says Stephen S. Hecht of the University of Minnesota Cancer Center in Minneapolis. He and his colleagues monitored 102 smokers as they gradually scaled back on the number of cigarettes they smoked by 25 percent, 50 percent, 75 percent, and more over 26 weeks. The researchers also measured the body's breakdown of a compound in tobacco called NNK, which mutates DNA. Smokers who reduced their cigarette consumption by 75 percent decreased their levels of this carcinogen by just a third. Even people who cut back by 90 percent, from an average of 24.7 cigarettes a day to 2.6, lowered their NNK levels by only 46 percent. Other research has demonstrated that halving cigarette intake lessens carbon monoxide levels by just a third. "The only sure way to reduce the smoking risk is to quit," Hecht says.

Coffee Boon

Drinking several cups of coffee a day isn't usually considered a healthful habit, since it's linked with high blood pressure, insomnia, and miscarriage. But it may help ward off type 2 diabetes, a disease that affects roughly 17 million Americans and raises the risk of health complications such as heart problems. This finding is based on a study of more than 125,000 adults by the Harvard School of Public Health in Boston. During the 12- to 18-year study period, the risk of developing diabetes was about 30 percent lower in women who reported drinking four or more cups of caffeinated coffee per day compared with those who drank none. (The benefit did not occur for women who drank three or fewer cups per day.) There was also an association, though weaker, between decaffeinated coffee and lower risk. The reasons are not yet understood, says the study's lead author, Frank B. Hu, but "it is possible that ...