Up there with high cholesterol, high blood pressure and other major risk factors for heart disease, is stress. Studies have shown that anxiety, depression and other negative emotional states may help pave the way for heart disease by disturbing normal blood flow through the heart, causing arrhythmias (heart beats that are too fast, too slow or have an irregular rhythm) and other triggers.1
It also appears that there may be an indirect way that stress hurts your heart: by packing on excess pounds. And what do we tend to turn to when we’re stressed? Junk food. Recent animal research at Georgetown University in Washington, D.C., indicates that the combination of junk food and stress may lead to obesity, at least in mice.2
You may be wondering how it’s possible to test stress in mice. It’s actually not much different from humans: Researchers placed the test mice with a more aggressive “alpha mouse” (sound a little like your boss?) for 10 minutes daily in a cage. They also made the test mice stand in cold water for an hour a day. The control group, on the other hand, led a relatively stress-free existence. Both groups of mice were given either regular mouse food or the typical American junk food diet. Only the frazzled mice that feasted on junk food became obese. The combo of stress and regular mouse chow didn’t cause weight gain, nor did junk food and a stress-free life.
Unfortunately, it’s not just a couple of extra unwanted pounds that we have to worry about: Previous research from the National Institutes of Health and elsewhere found that women who said they were stressed out and/or had higher levels of cortisol (a hormone that rises in times of stress) had more belly fat.3 This type of fat is deep in the body, surrounding your organs and may be linked to heart disease, diabetes and other illnesses. Surprisingly, their weight didn’t matter. Women who were stressed out—whether they were slim or overweight—still had more belly fat than those who were less stressed and/or had lower cortisol levels.
According to the Georgetown study, cortisol isn’t working alone. Another chemical, neuropeptide Y (NPY), which was found in excess supply in the fat of stressed-out mice, sends a message to the body to store fat. This was essential to our survival centuries ago, when stress often meant periods of famine; belly fat converts more quickly to energy than hip, thigh or other types of fat. But if it just stays there, as it now does with most overweight Americans, then it may become a huge health problem.
The obese mice were no different. After just three months on the stress-and-junk-food regimen, they developed high blood pressure, early diabetes and high cholesterol. But the good news for the meaty mice is that researchers may have found an easy fix. Injecting mice with a substance that blocks NPY helped shrink their fat by 40 to 50 percent in just two weeks.
That begs the question: Will blocking NPY help humans? And, of course, will it be safe? Unfortunately, the answers to these questions will require several years of research. In the meantime, chuck the junk food and break out your yoga mat!
Soufer R, Burg MM. (Feb. 2007) Cleve Clin J Med, 74 Suppl 1:S59-62.
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