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Marathons Tough on the Ticker?Beans Benefit the Heart

Beans have been a source of jokes for years, but new research shows that their potential heart protective properties are nothing to laugh at.

Researchers looked at food-frequency questionnaires and medical records of 9,632 men and women who participated in the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study. Over an average 19 years of follow-up, 1,802 of the subjects were diagnosed with coronary heart disease (CHD) and 3,680 were diagnosed with cardiovascular disease (CVD). Legume consumption was significantly and inversely associated with CHD and CVD. Those who consumed legumes four times or more per week had a 22 percent lower risk of CHD and 11 percent lower risk of CVD, compared with those who consumed legumes less than once a week. None of the subjects had heart disease when the study began.

The researchers note that people who eat nutritious food generally have other healthful habits, which can help maintain heart health. In this study, the legume-eaters were thinner with lower blood pressure and cholesterol levels; ironically, however, they also were more likely to smoke and eat more saturated fat than those who ate legumes less frequently. The researchers accounted for all heart disease risk factors in their calculations.

In addition to their potentially heart-healthy properties, beans are low in fat, high in soluble fiber, and a major source of folic acid. This research was first published in the Archives of Internal Medicine (November 26, 2001).When running first gained popularity in the 1970s, skeptics maintained that runners would soon be falling down dead from heart attacks in the middle of their runs. While a recent study doesn’t validate this train of thought, it does show that a number middle-aged men who complete marathons temporarily increase their risk of heart attacks following the race.

The results of a study, printed in the American Journal of Cardiology (October 15, 2001), found that middle-aged men who had just completed the Boston Marathon had temporarily high levels of C-reactive protein and creatine kinase-MB. A high level of C-reactive protein is a risk factor for clotting and a heart attack, while a high level of creatine kinase-MB is a marker for muscle injury.

The subjects, all physicians, averaged 47 years, with no reported history of smoking or heart disease. They were faster than average runners for their age groups and logged at least 40 to 50 miles per week.

The study’s lead author, Arthur Siegel, MD, said that C-reactive protein increases whenever muscle damage occurs—either from an overworked heart or other muscle. Since most marathoners tax their skeletal muscles in the race, he believes the muscle inflammation caused the overproduction of blood-clotting factors found in the subjects’ postrace blood samples. But even though the heart was not necessarily the overtaxed muscle, the chemical changes could
still predispose a runner to a heart attack.

In a related study, also published in the same issue of the American Journal
of Cardiology
, Siegel found that the marathoners’ levels of blood proteins called troponins—late-stage indicators of potential heart attacks—remained at indeterminate levels postrace. Siegel speculated that troponins might be more
reliable indicators of heart attack risk than creatine kinase-MB levels.

According to Benjamin Levine, MD, a cardiologist and physiologist at the Institute for Exercise and Environmental Medicine in Dallas, even if marathoners temporarily increase their heart attack risks, they still suffer them less often than in the course of everyday activities. “People who exercise regularly are still at less risk for a heart attack than those who don’t,” he says.

Information for this article was taken from an article in the Washington Post (October 30, 2001).

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