Damaged Hearts
Pump Better When Fueled With Fats
Research Holds Promise for Heart Failure Patients
News Release:
Wednesday, May 4, 2011
CLEVELAND -
Contrary to what we’ve been told, eliminating or severely limiting fats from
the diet may not be beneficial to cardiac function in patients suffering from
heart failure, a study at Case Western Reserve University School of Medicine
reports. Results from biological model studies conducted by assistant professor
of physiology and biophysics Margaret Chandler, PhD, and other researchers,
demonstrate that a high-fat diet improved overall mechanical function, in other
words, the heart’s ability to pump, and was accompanied by cardiac insulin
resistance. “Does that mean I can go out and eat my Big Mac after I have a
heart attack,” Dr. Chandler says “No, but treatments that act to provide
sufficient energy to the heart and allow the heart to utilize or to maintain
its normal metabolic profile may actually be advantageous.” The research,
published in American Journal of
Physiology-Heart and Circulatory Physiology, suggests that for a
damaged heart, a balanced diet that includes mono- and polyunsaturated fats,
and which replaces simple sugars (sucrose and fructose) with complex
carbohydrates, may be beneficial. In a healthy person, the heart uses both fats
and carbohydrates to obtain the energy it needs to continue pumping blood 24/7.
Ideally, fats are utilized because they yield more energy. However, if a person
develops heart failure (or suffers from ischemia – a lack of blood supply), the
heart seems to prefer using glucose for fuel, because glucose requires less
oxygen to produce energy. While heart disease remains the leading cause of
death in the United States,
more people are surviving heart attacks that ever before. Survivors though pay
a price for this improved survival, living with a damaged heart that usually
progresses to heart failure. And unfortunately, medications and procedures have
yet to “cure” heart failure, or halt the deterioration of heart function. Upon
initiation of these dietary intervention studies, researchers previously
thought a high-fat diet fed to animal models that have suffered a heart attack,
would overload their tissues with fat, which in turn would have a toxic effect
on their hearts. Surprisingly, the heart’s pump function improved on the
high-fat diet. Through further testing, the researchers found that animal
models suffering from heart failure and receiving a low fat diet were able to
produce insulin and take up glucose from the blood, just as healthy hearts do.
However, the biological models with heart failure that were fed high-fat diets
showed signs of insulin resistance, exhibited by a decreased amount of glucose
taken up by the heart, as might be expected in a diabetic patient. One of the
main implications of these findings is that contrary to previously held
beliefs, a state of insulin-resistance might actually be beneficial to a
failing heart. The hypothesis, according to Dr. Chandler, is that because the
heart is being provided with excess amounts of fats, it is forced to utilize
its preferred energy source. After suffering an injury that leads to failure,
the heart cannot do this on its own, so the researchers have to manipulate its
metabolism to use the energy source that maximizes or maintain its function as
near to “normal” as possible. “We want to provide an environment for the heart
which allows it to be as effective and efficient a pump as possible, regardless
of the damage it has undergone,” Dr. Chandler says. This study was funded by
the National Institutes of Health, the American Heart Association, and the Case Center
for Imaging Research. Prepared
by Salam Kabbani, a third-year student at Case Western
Reserve University.