Eggs and Cholesterol

I have a confession to make. I like eggs. From my head down to my legs. So it's possible I am biased on this topic. But here's my thinking on eggs and cholesterol.

The relationship between eggs and cholesterol is not what most people have been led to believe. Not only do eggs not always raise cholesterol, sometimes they lower it.

About one-third of the population is unusually sensitive to the cholesterol in egg yolks. Medical researchers at the University of Connecticut gave a population of men and women over the age of 50 either three eggs a day or an equivalent serving of cholesterol-free egg substitute. None of the participants in the trial was on any medication to lower cholesterol

Among the two-thirds of the participants in the trial who were not especially sensitive to the cholesterol in egg yolks, eating three eggs a day not only did not raise cholesterol, total cholesterol went down. In the majority of test participants, eating three eggs a day slightly lowered LDL cholesterol and triglycerides, and slightly increased HDL cholesterol. Conversely, eating an equivalent amount of egg substitute caused slight increases in LDL, total cholesterol, and triglycerides, and a slight decrease in the beneficial HDL.

In the one-third of the participants the researchers labeled hyper-responders, the opposite occurred. For this smaller group, eating three eggs a day raised cholesterol, but in a heart-healthy way. LDL levels increased, but the additional LDL was the larger, less clogging variety of LDL. HDL levels also increased, and also were the larger, less dangerous particles. Moreover, eating eggs increased bloodstream concentrations of eye-protective lutein and zeaxanthin.

Eggs have a similarly unexpected effect on cholesterol levels in overweight men. One study found that when eggs are consumed with a high-carbohydrate meal, they seem to accelerate the release of sugars from the carbohydrate, but also to accelerate the release of insulin from the pancreas. The extra insulin “covers” the extra glucose released from digestion. The problem is, insulin stores fat as well as sugar, so eating eggs with carbohydrates seems to increase weight gain.

Another study found that eating eggs as part of a low-carbohydrate diet, on the other hand:

Reduces body weight,
Increases insulin sensitivity,
Increases HDL-C cholesterol, the kind of “good” cholesterol that “catches” other cholesterol particles so the liver can remove them from circulation,
Increases adiponectin, a hormone that fights atherosclerosis, and
Reduces C-reactive protein, a marker of arterial inflammation,

also in tests conducted with overweight men.

A study of 9,734 men and women aged 25 to 74 at the Zeenat Qureshi Stroke Research Center of the University of Medicine and Dentistry of New Jersey found that eating more than 1 egg a day does not significantly raise the risk of either heart attack or stroke.

Since 2000, even the American Heart Association has recognized that Cholesterol-rich foods that are relatively low in saturated fatty acid content (notably, egg yolks, and, to a lesser extent, shellfish) have a (small) effect on LDL. The effects of dietary cholesterol on plasma LDL levels appear to be greater at low versus high levels of cholesterol intake. In other words, for most people, if you consume more cholesterol, your body just uses it faster.

The exceptions to this rule seem to be male doctors and female nurses. The widely publicized Physicians Health Study reported in April 2008 that male doctors who ate more than one egg a day were more likely to suffer heart attack or stroke, especially if they were diabetic.

The study also found that doctors who ate the most eggs also were older and fatter. They ate less breakfast cereal but more vegetables. They were more likely to smoke and drink and less likely to get regular exercise. It is just possible that excessive consumption of eggs was only part of a pattern of excessive consumption of everything else in this group of 21,337 middle-aged male doctors—do you suppose?

For most of us, eggs are not heart-harmful, and if you avoid excess sugars, they are heart-healthy. If you do not have familial hypercholesterolemia or some other rare condition causing excessive cholesterol, regular consumption of eggs is likely to have a beneficial effect on your triglycerides, LDL-C, and HDL.