Consider the egg: Is it a dietary demon chock-full of artery-clogging cholesterol, or a perfect food, rich in healthful nutrients?
Put to a vote, American-Idol style, "dietary demon" would probably come out on top, even though "perfect food" is closer to the truth.
Let's unscramble the egg facts and myths first.
Fact: An egg is a good source of nutrients. For about 15 cents, you get 6 grams of protein, some healthful unsaturated fats, and a smattering of vitamins and minerals. Eggs are also a good source of choline, which has been linked with preserving memory, and lutein and zeaxanthin, which may protect against vision loss.
Fact: Eggs have a lot of cholesterol. The average large egg contains 212 milligrams of cholesterol. As foods go, that's quite a bit, rivaled only by single servings of liver, shrimp and duck meat.
Myth: All of that cholesterol goes straight to your bloodstream and then into your arteries. Not so. In the average person (we'll come back to this later), only a small amount of the cholesterol in food passes directly into the blood. The liver makes most of the cholesterol that circulates in the bloodstream, largely in response to saturated and trans fats in the diet. Studies dating back to a classic 1950 experiment carried out by pioneering Harvard cardiologist Paul Dudley White and colleagues show that the amount of cholesterol in food generally has a small impact on cholesterol in the blood.
Myth: Eating eggs is bad for your heart. The only large study to look at the impact of egg consumption on heart disease -- not on cholesterol levels or other intermediaries -- found no connection between the two. In this study of nearly 120,000 initially healthy men and women, those who ate one or more eggs a day were no more likely to have had a heart attack or stroke or to have died of cardiovascular disease over a 14-year study period than those who ate fewer than one egg per week. In people with diabetes, though, egg-a-day eaters were a bit more likely to have developed heart disease than those who ate eggs rarely.Reputation RehabilitationEggs' reputation as good food took a tumble in the 1960s when researchers first made the connection between heart disease and high cholesterol levels in the blood. The American Heart Association (AHA) and other influential groups set an upper limit for daily cholesterol intake at 300 milligrams a day (200 milligrams if you have heart disease) and warned people to avoid eating egg yolks.There were two big problems with these recommendations. The upper limit of 300 milligrams a day seems to have been chosen not for a specific scientific reason, but because it was half of the average American's daily cholesterol intake at the time. And the warning on egg consumption was based on the logical -- but incorrect -- assumption that cholesterol in food translated directly into cholesterol levels in the blood.
Eggs' fall from grace may be ending. In 2000, the AHA eased up on eggs. Instead of specifically recommending that we avoid or limit eggs to a certain number per week, the association's dietary guidelines focused on limiting foods high in saturated fat and keeping cholesterol intake under 300 milligrams a day. The AHA acknowledges that you can hit this target "even with periodic consumption of eggs and shellfish."Heart associations in Canada and Australia go even further. Both include eggs in their respective Health Check and Heart Tick programs. These use checkmarks on foods or food packaging to help shoppers recognize healthier food choices quickly and easily. A similar Heart Check Mark program endorsed by the AHA doesn't include eggs.