The study found that coffee, is high in antioxidants and compounds such as vitamins that fight damage to cells and to DNA.
This is probably just as well as the study also found that Americans are not eating enough fruits and vegetables, the main sources of antioxidants as well as fiber and other nutrients that dietitians, scientists and doctors recommend.
Joe Vinson of the University of Scranton in Pennsylvania and colleagues studied the antioxidant content of more than 100 different food items, including vegetables, fruits, nuts, spices, oils and common drinks.
They then examined a U.S. Department of Agriculture database on how much Americans eat of each type of food item.
Vinson says that Americans get far more of their antioxidants from coffee than any other dietary source.
Vinson, who presented his findings to a meeting of the American Chemical Society in Washington, says this does not mean that coffee was necessarily the best source of antioxidants.
But unfortunately, the average American is still not eating enough fruits and vegetables, which are better from an overall nutritional point of view, due to their higher content of vitamins, minerals and fiber.
Apparently dates, cranberries and red grapes have high concentrations of antioxidants, but Americans do not eat much of these foods.
Vinson found black tea was the second-leading source of antioxidants in the U.S. diet, with bananas, dry beans and corn placed third, fourth and fifth.
Phelan, co-author of the book, "Mean Genes," conducted his dissertation at Harvard University 10 years ago on caloric restriction and on why it works in extending the lives of rodents.
"When you restrict the caloric intake of rodents, the first thing they do is shut off their reproductive system," said Phelan, citing a finding from his dissertation. A normal rodent reaches maturity at one month of age, and begins reproducing its body weight in offspring every month and a half. If humans shut off reproduction by severely limiting calories, "our reduction in wear and tear on the body is minimal," he said.
The rodents placed on severely restricted diets bit people who tried to hold them, and had an unpleasant demeanor, unlike the more docile animals given more "normal" amounts of food, Phelan said.
"I think about food all the time," he said. "I'm not going to be so extreme that I become the mouse that bites anyone who touches me. My advice about food is be sensible, and don't be a fanatic about it because the payoffs are not worth it."
While the relationship between how much you eat and your life span is not so dramatic, there are very real costs of being overweight -- including greater risk for heart disease and other life threatening illnesses, Phelan said.
The human data factored into the mathematical model include the caloric intake of people in Japan, and their longevity, compared with sumo wrestlers, who consume more than twice the normal male diet, and men in Okinawa, Japan, who consume less than the average Japanese male.
ucla/