Your health this month.

Your health this month.

Your health this month.

Health and medicine explained.
July 25 2006 1:26 PM

Your Health This Month

Why to drink lots of coffee, whether acupuncture works, and more.

Listen to the author reading this story here, or sign up for Slate's free daily podcast on iTunes.

Coffee: Drink more.


Effects: As I write this, I am savoring an especially enjoyable cup of coffee, made so by the knowledge that sipping it may decrease my risk of developing adult-onset diabetes (though, sadly, the slab of gooseberry pie I ate a few minutes earlier almost certainly neutralized the beneficial effect). Coffee is one of the most widely consumed beverages in the world. We like its taste and, even more, its pharmacological effects, including an increased sense of alertness and ability to counteract sleepiness. Medically, coffee's most important active ingredient, caffeine, has only a few uses: It helps some headache sufferers, and it's sometimes administered to infants (especially premature ones) who need to be pharmacologically "reminded" to keep breathing. Other effects of caffeine are not so benign. It acts on the kidneys as a diuretic and can cause jitteriness, rapid heart rate, and loose stools. Extremely large doses can cause seizures and—extremely rarely—death.

Antioxidants: Coffee ought to be beneficial by virtue of its high content of antioxidants, natural chemicals that bind and neutralize a group of unstable materials in body cells that, among other things, damage DNA, causing the effects of aging and the cellular changes that lead to cancer. Coffee contains more of these antioxidants than green tea and red wine. Sadly, it's been hard to absolutely demonstrate the value of the antioxidant properties of these beverages, though most of us doctors believe in them anyway.

Diabetes: The association between coffee-drinking and reduced risk of adult-onset diabetes, on the other hand, has now been well-established by a number of studies that followed many, many patients in a wide variety of geographical locations. Often, in big epidemiological studies, one can't tell whether the observed association is the result of causation—drinking coffee protects against diabetes—or of two loosely related phenomena. Imagine, for example, that people with heavier, diabetes-prone bodies might find undesirable a beverage that's a stimulant and mildly diuretic. Still, the coffee studies add up: If many studies produce similar findings after drawing from diverse populations and taking care to rule out other, coincidental, factors as causes, it becomes increasingly likely that we are dealing with causation, not mere association. In addition, a dose-response curve—the more coffee drunk, the less diabetes risk—adds a lot to the causation argument.

New findings: That is what we have for coffee-drinking and diabetes risk. I counted more than seven good studies reporting that reduced diabetes is associated with coffee-drinking. The most recent, a study by Mark Pereira, Emily Parker, and Aaron Folsom of the University of Minnesota, followed more than 28,000 post-menopausal women over 11 years. The research team found an almost linear decrease in the risk of developing diabetes based on how much coffee their subjects drank on average. Women who drank six or more cups a day showed the most benefit. An earlier study conducted in Finland, which has the highest per-capita consumption of coffee in the world, found the effect especially beneficial for the 16 percent of the study population who drank 10 or more cups a day. Interestingly, the new study showed that the beneficial effect could not have been due to caffeine, magnesium, or phytic acid—each of which previously had been suspected of playing a role. Actually, decaffeinated coffee does more to decrease the risk of diabetes than the high-octane version. And the Finland study found that filtered coffee was more effective than boiled.

So, though we still have no idea of what in coffee protects against developing diabetes, the drink looks like that rarity: something you desire that might be good for you.

Anemia: An assist from the umbilical cord.

Iron deficiency: You have to love a simple intervention that promises to improve the lives of many patients. Camilla Chaparro, Kathryn Dewey, and their colleagues at the University of California at Davis, the Mexican National Institute of Public Health, and the Luis Castelazo Ayala Hospital in Mexico City have given us just such a prize in a paper published in the Lancet. In developing countries perhaps half of all children become anemic by their first birthday. The cause is usually iron deficiency, related to maternal iron deficiency, maternal blood loss associated with childbirth, or early infant feeding practices using iron-poor formula or foods. The deficiency often worsens with time because of the chronic blood loss associated with many intestinal worms that infest children in the tropics, and because poor families can't afford much meat. There is some disagreement in the scientific literature, but many experts believe that anemia in early childhood has negative—and perhaps irreversible—effects on development.

The fix: Chaparro and her colleagues tested the effects on iron levels in infants of delaying the clamping of the umbilical cord until two minutes after birth. Following more than 350 infants, the researchers found that a two-minute delay (which allowed the return of about 4 ounces of the baby's blood that's temporarily held in the placenta and cord vessels) led to a substantial decrease in anemia at 6 months. The intervention was most effective for babies at greatest risk: those born to iron-deficient mothers, with low birth-weights, or who don't get iron-fortified formula.