I was pleased to learn about a recent meta-analysis published in the British Medical Journal that will hopefully put to rest one of the biggest diet myths—that eggs are bad for your heart. The analysis analyzed data from eight clinical studies involving almost half a million people, and found no association between high egg consumption and risk of heart disease or stroke.
Yes, eggs contain cholesterol. But you know what? Cholesterol is a crucial component that serves a number of functions in the body, including hormone production, nervous system protection, and bile production, which benefits digestion. Cholesterol is found in every cell in your body.
Many people are under the impression that a diet high in cholesterol raises cholesterol levels. You may have been told to not eat eggs every morning as a way of controlling cholesterol levels. This notion is mistaken.
Cholesterol is obtained two ways: The body produces cholesterol (much of it in the liver), and cholesterol is absorbed from the small intestines, either from food or from bile salts passing through the intestine from the gallbladder. To balance out the production and absorption of cholesterol, the body constantly uses cholesterol to produce hormones and to maintain the integrity of cell membranes.
The body also gets rid of some cholesterol through the production of bile salts in the liver. Bile salts, made of cholesterol and other steroid acids bound to sodium, are sent from the liver to the gallbladder, where they are held until needed for digestion of fat. When you eat a fatty meal, bile is secreted into the small intestine from the gallbladder, and lipase is secreted into the small intestine by the pancreas, both to help break down fat. In this way, some cholesterol is excreted from the body with intestinal waste, and some of this cholesterol is reabsorbed into the bloodstream so that it can be reused.
Although some cholesterol is absorbed from food, dietary cholesterol has little impact on blood cholesterol levels. This is because the body’s process of cholesterol recycling is regulated in such a way that when there is an increase in cholesterol from the diet, the body will make less. Conversely, if there is not enough cholesterol taken in from food, the body will make more cholesterol to compensate. Because of this cholesterol recycling process, dietary cholesterol intake contributes less to blood cholesterol levels than we are led to believe.
“Since eggs are a major source of dietary cholesterol, with one large egg containing almost 210 mg of cholesterol, the public has been recommended to limit egg consumption unless the intake of other foods high in cholesterol is restricted,” stated lead researcher Liegang Liu. “However, eggs are also an inexpensive and low-calorie source of many other nutrients, including minerals, proteins, and unsaturated fatty acids, which could lower the risk of cardiovascular disease.”
In their study, consumption of up to one egg per day was not associated with heart disease or stroke risk. However, people with higher egg intake and diabetes may be at higher risk, based on a small number of studies analyzed. Restricting egg intake may be prudent in people with diabetes until we know more.
For more information about factors that contribute to heart disease, watch my PBS special Heart of Perfect Health.