: Scientists found that periodic fasting may decrease the risk of coronary artery disease and diabetes, and also causes significant changes in heart-disease risk factors like cholesterol, blood-sugar, and triglyceride levels, which hadn't been linked to fasting before. "We've shown it is not a chance finding. Fasting is not just an indicator for other healthy lifestyles," says lead researcher Benjamin Horne of the Intermountain Medical Center Heart Institute. "It is actually the fasting that is working to reduce the risk of disease." How the Heck:
What's the News
In the first recent study on fasting and heart disease, the researchers surveyed people in Salt Lake City, where a majority of citizens are Mormons and fast once a month for 24 hours. They discovered that the people who answered "yes" when questioned whether they abstain from food and drink for an extended time had a lower rate of coronary disease and diabetes.
In the second study, scientists monitored 230 people who fasted for 24 hours. Physical measurements and blood tests indicate that fasting decreased the subjects' triglycerides and blood sugar levels. In addition, they found that human growth hormone, which is associated with metabolic balance, increased by upwards of 2,000%. Both bad cholesterol (LDL-C) and good cholesterol (HDL-C) increased as well. Because the study was short-term, the researchers can't say for sure how long the benefits of fasting last.
Although the doctors focused more on correlating fasting and heart health, rather than the mechanisms at work, Horne surmised that fasting causes stress on the body, which makes it release more cholesterol, therein letting the body burn fat instead of glucose for fuel.
Burning fat cells means that in the long run, the body has lower cholesterol and a lower risk of diabetes and coronary artery disease.
What's the Context:
Coronary artery disease is the leading cause of death among American men and women.
This present study builds on a 2007 study that first discovered the link between fasting and reduced coronary artery disease risk. It's new because it also looked at the effects of fasting on triglycerides, weight, and blood sugar levels. "[The new study has] shown it is not a chance finding. Fasting is not just an indicator for other healthy lifestyles," says Horne. "It is actually the fasting that is working to reduce the risk of disease."
Fasting (or at least cutting calories) has also been linked to better memories.
Recent research has linked BPA, an ingredient in plastics, with heart disease.
And other studies look at the heart-healthy benefits of drinking wine.
Not So Fast:
The monitoring study only looked at the effects of fasting over a 24-hour period, so we shouldn't extrapolate too much from this because we don't yet know the long-term effects of fasting on indicators of heart health.
As for the survey study, it’s subject to the limits of that kind of research, namely that it’s very hard to disentangle all of the psychosocial factors behind why some Mormons fast, per their religious belief, and some do not.
"We're not ready to prescribe fasting in a medical framework," Horne says. (Though he does apparently prescribe it to himself, since he says that he fasts for 24 hours once a month.)
Fasting decreases triglycerides in the body, according to this study, and though triglycerides have been linked to heart disease in "some people," it's more of a risk factor than a direct cause of all heart disease.
Next Up: Now the researchers want to study how fasting affects patients who've already been diagnosed with coronary heart disease. Reference: American College of Cardiology. Annual Scientific Session. New Orleans. 3 April 2011.
Image: flickr / Vintage Collective