Eggs and your heart - dispelling the myth
Ingestion of several eggs a day tends to increase blood concentrations of cholesterol, particularly the amount circulating in low-density lipoproteins (LDLs)—the so-called bad cholesterol. However, a new study indicates eating eggs can increase the amount of cholesterol in high-density lipoproteins (HDLs)—the good cholesterol, too.
The study also showed that when people ate three or more eggs per day their bodies made bigger LDL- and HDL-lipoprotein particles than when they ate no eggs. That's important because other recent studies have suggested that larger LDLs are less likely than small ones to enter artery walls and contribute their cholesterol load to artery-clogging plaque. Similarly, larger HDLs are more robust than smaller ones at hauling cholesterol out of the bloodstream and, ultimately, out of the body.
The new findings contribute to a growing body of data suggesting that eggs shouldn't be construed "as a dietary evil."
Not all people respond similarly to cholesterol. Studies have shown that 30 to 40 percent of any given population is made up of "hyperresponders." In these people, blood-cholesterol concentrations spike disproportionately in response to dietary cholesterol. The study team decided to investigate whether such people put an egg's cholesterol into different-sized lipoproteins than most other people do.
So, the team recruited 29 postmenopausal women and 13 elderly men to take part in a dietary trial. None was taking cholesterol-lowering medicine at the time of the study, the author notes, which means that for a population of middle-aged-to-elderly people, the group was relatively heart healthy.
For 30 days, each volunteer received a liquid-egg product or a fat-and-cholesterol-free, protein-rich egg substitute in portions comparable to three large eggs per day. The real-egg ration delivered some 640 mg of cholesterol; the egg substitute contained no cholesterol. None of the participants knew which food he or she was getting until the end of the study.
After a month on the first diet, all volunteers took a 3-week breather and then resumed participation. For the second phase, each person received the alternative to the product he or she had initially received.
Throughout both phases of the trial, the amount of both HDL and LDL lipoproteins remained unchanged. However, the 15 hyperresponders among the volunteers had much higher amounts of cholesterol circulating with their lipoprotein particles while they were eating real eggs. "All of the increase went into large [lipoprotein] particles."
In contrast, among normal responders, only small increases in blood cholesterol occurred during the egg diet, and the size of LDL- and HDL-cholesterol particles covered the full range of lipoprotein sizes.
Not only did the two groups handle the eggs' cholesterol differently, but the hyperresponders handled the excess that showed up in their blood "in the most anti-atherogenic way"—by depositing it in the largest lipoproteins. The take-home message is that an LDL-cholesterol reading that ignores lipoprotein size may exaggerate the heart risks posed by eggs' cholesterol.
It's time to tell your healthcare provider to update his or her dietary recommendations.
Still nervous despite studies like this one? Then, try omega-3 eggs. You can now get them at most grocery chains.
Also, consider eggs to boost weight loss.