Cancer. Panic swept this coffee-dependent nation in 1981 when a Harvard study tied the drink to a higher risk of pancreatic cancer. Coffee consumption temporarily plummeted, and the researchers later concluded that perhaps smoking, not coffee, was the culprit.
In an international review of 66 studies last year, scientists found coffee drinking had little if any effect on the risk of developing pancreatic or kidney cancer. In fact, another review suggested that compared with people who do not drink coffee, those who do have half the risk of developing liver cancer.
And a study of 59,000 women in Sweden found no connection between coffee, tea or caffeine consumption and breast cancer.
Bone loss. Though some observational studies have linked caffeinated beverages to bone loss and fractures, human physiological studies have found only a slight reduction in calcium absorption and no effect on calcium excretion, suggesting the observations may reflect a diminished intake of milk-based beverages among coffee and tea drinkers.
Robert Heaney of Creighton University says that caffeine’s negative effect on calcium can be offset by as little as one or two tablespoons of milk. He advised that coffee and tea drinkers who consume the currently recommended amount of calcium need not worry about caffeine’s effect on their bones.
Weight loss. Here’s a bummer. Although caffeine speeds up metabolism, with 100 milligrams burning an extra 75 to 100 calories a day, no long-term benefit to weight control has been demonstrated. In fact, in a study of more than 58,000 health professionals followed for 12 years, both men and women who increased their caffeine consumption gained more weight than those who didn’t.
HEALTH BENEFITS
Probably the most important effects of caffeine are its ability to enhance mood and mental and physical performance. At consumption levels up to 200 milligrams (the amount in about 0.5 liters of ordinary brewed coffee), consumers report an improved sense of well-being, happiness, energy, alertness and sociability, Roland Griffiths of the Johns Hopkins School of Medicine reported, although higher amounts sometimes cause anxiety and stomach upset.
Millions of sleep-deprived Americans depend on caffeine to help them make it through their day and drive safely. The drug improves alertness and reaction time. In the sleep-deprived, it improves memory and the ability to perform complex tasks.
For the active, caffeine enhances endurance in aerobic activities and performance in anaerobic ones, perhaps because it blunts the perception of pain and aids the ability to burn fat for fuel instead of its carbohydrates.
Recent disease-related findings can only add to coffee’s popularity. A review of 13 studies found that people who drank caffeinated coffee, but not decaf, had a 30 percent lower risk of Parkinson’s disease.
Another review found that compared with noncoffee drinkers, people who drank four to six cups of coffee a day, with or without caffeine, had a 28 percent lower risk of Type 2 diabetes. This benefit probably comes from coffee’s antioxidants and chlorogenic acid.
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