High-fat diet in short term may help minimise heart attack damage, study
A high-fat diet, eaten one day, one week or two weeks before a heart attack may reduce heart attack damage by about 50 per cent, according to a new study from Loyola University Chicago School of Medicine.
The study, published in the American Journal of Physiology — Heart and Circulatory Physiology in February 2015, found that mice that ate a high-fat diet in the few days before a heart attack benefitted from a ‘protective effect’ from the diet. The study was led by W. Keith Jones, PhD, from Loyola University Chicago Stritch School of Medicine.
“The study improves our understanding of the relationship between diet and health,” Dr Jones said. “Learning about how fat, in the short run, protects against heart attacks could help in the development of better therapies,” he said.
However, Dr Jones emphasized the study was “not a license to eat a lot of cheeseburgers and ice cream”.
The study may provide new insight into the “obesity paradox”: Obesity is a major risk factor for heart disease,” Dr Jones said. “But once a heart attack or heart failure does occur, moderately obese patients tend to live longer,” he said.
In the study, mice were given a high-fat diet (60 percent of calories from animal fat) before experiencing heart attacks. Mice that consumed a high-fat diet for either one day, one week or two weeks before the heart attack experienced about half as much heart damage as mice that ate a control diet. The benefit was greatest among mice that ate a high-fat diet for one week before the heart attack.
However, in mice that ate a high-fat diet for six weeks, the protective effect disappeared.
Dr Jones said further research was needed to understand why this is the case. He said the reason may be due to the bad effects of a persistent high-fat diet.
Protective mechanism identified
Dr Jones said that in the short-term, a high-fat diet protects the heart through a mechanism called autophagy, which works somewhat like a garbage truck. Proteins damaged by the heart attack are removed from heart cells as if they were garbage, thus increasing the chances the cells will survive.
Acutely, a high-fat diet increases levels of a molecule in the blood that activates protective pathways in heart muscle. This increases the readiness of the “garbage trucks,” which means that the cell becomes resistant to damage when the heart attack occurs. As a result, more heart muscle survives.
Dr Jones’s team is studying the nature of the blood-borne molecule and will report results of this research in a later publication.
Study provides ‘new perspective’ on acute effects of high-fat diet
First author of the research paper Lauren Haar, PhD and other researchers wrote that the the current study “opens a new perspective on the acute effects of a high-fat diet.”
“Future work will determine whether these effects are linked to the obesity paradox and whether studying the mechanism can identify therapeutic targets for cardioprotection,” the researchers wrote.
The researchers said that, given the increasing number of obese people in both developed and developing countries, understanding the relationship between fat intake and heart health was “critically important.”
Dr Jones is professor and chair of the Department of Molecular Pharmacology and Therapeutics of Loyola University Chicago Stritch School of Medicine. In addition to Dr Jones and Dr Haar, co-authors from Loyola University Chicago and the University of Cincinnati are Xiaoping Ren, Yong Liu, Sheryl E. Koch, Jillian Goines, Michael Tranter, Melinda A. Engevik, Michelle Nieman and Jack Rubenstein.