April 10, 2013
Eggs Found To Lower Blood Pressure, Further Rebounding Their Reputation
Brett Smith for redOrbit.com - Your Universe Online
Once derided as an unhealthy indulgence, the reputation of the “incredible edible egg” has been on the rebound in recent years with the release of numerous studies showing its health benefits.
One of those studies, presented at the 245th National Meeting & Exposition of the American Chemical Society (ACS) in New Orleans, showed that a component of egg whites can actually lower blood pressure.
"Our research suggests that there may be another reason to call it 'the incredible, edible egg,'" said study leader Zhipeng Yu, from Jilin University in China.
"We have evidence from the laboratory that a substance in egg white — it's a peptide, one of the building blocks of proteins — reduces blood pressure about as much as a low dose of Captopril, a high-blood-pressure drug."
For years the high-cholesterol content of egg yolks were linked to cardiovascular disease. This new study reinforces the benefits of eating only the egg white, something health conscious individuals have been doing for years.
In the study, Yu and colleagues from Clemson University examined an egg-white peptide called RVPSL. Previous research had shown that the substance is an angiotensin-converting-enzyme (ACE) inhibitor, which is an active ingredient in blood pressure medications such as Captopril, Vasotec and Monopril. ACE is produced in the body naturally and constricts blood vessels, effectively raising blood pressure.
To examine RVPSL's effects, the research team used laboratory rats with high blood pressure. The rats were orally administered RVPSL and their blood pressure was evaluated using a tail-cuff device. Both the systolic blood pressure and the diastolic blood pressure were measured before and after administration of various doses of the peptide.
The results of the experiments were generally positive, showing that RVPSL is non-toxic and capable of lowering blood pressure in small doses by the same degree as low doses of Captopril.
"Our results support and enhance previous findings on this topic," Yu said. "They were promising enough to move ahead with further research on the effects of the egg white peptide on human health."
In his presentation, Yu said that the research was performed with RVPSL that was heated to almost 200 degrees Fahrenheit during preparation, which is slightly lower than the temperatures at which eggs are typically cooked. However, he also cited evidence from previous research that showed egg whites have positive effects on blood pressure even after they are fully cooked.
For example, a study published in the ACS'“¯Journal of Agricultural and Food Chemistry, indicated that fried egg protein demonstrated greater capacity to lower blood pressure than eggs cooked at 212 degrees Fahrenheit.
Yu said he thinks that egg white peptides could become valuable as a supplement to blood-pressure drugs. He added that people with hypertension should check with their physician before making any adjustments to their diet.
Yu also noted that his team´s study adds to the recent rehabilitation of eggs´ reputation. Other recent studies have found that many people can include eggs in their diet without raising their blood cholesterol levels, while benefiting from their low-cost protein, vitamins and other nutrients.