The study, published in the American Journal of Physiology-Heart and Circulatory Physiology, investigated whether heart functioning is compromised in response to physiological stress, by evaluating gene expression profiles of rats fed high dietary fat after a heart attack.
The research team, from Case Western Reserve University School of Medicine, USA, demonstrated that a high-fat diet improved overall cardiac mechanical function (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? […] 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,” said Dr Margaret Chandler, assistant professor of physiology and biophysics at Case WesternChandle, who led the research.
Heart disease is a leading cause of death worldwide, however more people are surviving heart attacks than ever before.
In a healthy person, the heart uses both fats and carbohydrates to obtain the energy it needs to continue pumping blood 24/7. However, Chandler and her colleagues explained that when a person develops heart failure, or suffers from ischemia (a lack of blood supply), the heart prefers to use glucose as a fuel – because glucose requires less oxygen to produce energy.
The authors said that survivors of heart disease pay a price for such improved survival rates – living with a damaged heart that usually progresses to heart failure.
The authors noted, for example, that a reduced ability for the heart to contract and pump efficiently “is a hallmark of heart failure”.
Previous studies have reported that high fat feeding in mild to moderate heart failure is associated with improved contractile function at baseline.
The new study investigated the impact of either a normal chow or high-fat chow diet in rats for eight weeks whether, on heart functioning.
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.
However, in the new study heart functioning was seen to improve on the high-fat diet.
Chandler and her team observed that in addition to better heart functioning the fed high-fat diets also showed signs of insulin resistance, as shown by a lower take up 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,” they said.
Source: American Journal of Physiology-Heart and Circulatory Physiology
Volume 299, Issue 2, doi: 10.1152/ajpheart.00270.201
“The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure”
Authors: Jessica M. Berthiaume, M.S. Bray, T.A. McElfresh, X. Chen, S. Azam, M.E. Young, et al