By SUSAN CALLAHAN, Associate Editor and Featured Columnist
To egg or not to egg, that is the question. The reputation of eggs as a part of a healthful diet has swung wildly up and down over the past 20 years. At the moment, the arrow points downward because of egg’s known high cholesterol count. The fear of developing heart disease from eating too many eggs has converted millions of us into “egg white omelette” and “egg-white tuna salad” eaters. But did we go too far? Have we eschewed the egg needlessly? What is the truth about how eggs affect our risk for heart disease?
Eggs are a mainstay of our diets. This is so, despite their reputation as a food that increases heart disease risk. In the US, each of us eats 258 eggs per year, according to the American Egg Board. Eggs are the go-to source of protein at breakfast. And though some religions forbid meats of certain types, eggs are one protein source that almost all religions allow.
Do Eggs Really Raise Your Cholesterol?
Now let’s turn to the chief complaint against eggs. Eggs reputedly raise your cholesterol.
True, eggs contain cholesterol. Eggs contain between 200 to 300 mg of cholesterol per 100 gram of egg. Since 100 grams of eggs is about 2 eggs, you would get up to 300 mg of cholesterol if you ate a breakfast of 2 scrambled eggs.
Eggs also contain approximately 3 grams of saturated fat per 100 grams of eggs. Each egg weighs about 50 to 57 gram, so 2 eggs would give you 3 grams of saturated fat on average.
Not all cholesterol is created equal. The cholesterol which clogs your arteries is LDL (low density lipoprotein). In contrast, HDL (high density lipoprotein) actually is protective of your heart.
Since saturated fat raised our LDL levels, the American Heart Association advises us to limit the daily amount of saturated fat --- for those of us who need to lower our cholesterol -- to 5 to 6 percent of total calories. This works out to be 11 to 13 grams of saturated fat for a 2000 calories diet.
If you eat 2 eggs, you are eating 3 grams of the max 13 grams of saturated fat you’re allowed for the day. So far, so good. You just need to keep the rest of the day’s saturated fat under 10 grams.
Do eggs raise your cholesterol levels? This is a simple question with not so simple and answer.
One well-publicized study has found that eating eggs do not raise your blood cholesterol levels significantly.
This study was led by Dr. Sigal Eilat-Adar of the Zinman College for Physical Education & Sports in Israel and and Dr. Tali Sinai of The Hebrew University of Jerusalem. This study surveyed all other then-existing studies on a wide range of foods and diets to determine what evidence linked these diets and individual foods to heart disease risk.
In the section on eggs, the study makes the point that no large, population study has been able to link egg consumption with an increase in risk for cardiovascular disease. Note the caveats --there is no “large”, “Population study” that has linked eggs with increased heart disease risk.
On the other hand, another large study disagreed. In a 21,275 person study from researchers at Brigham and Women’s Hospital, Harvard Medical School, scientists found that eating eggs 7 days a week increased the participants’ risk for heart failure by 28%.
Eating 2 or more eggs a day was associated with a 64% increase in heart failure risk. But here again, there was a hidden contradicion. The researchers noted something strange -- egg consumption up to 6 times per week was not associated with incident heart failure. Only egg consumption of 7 or more per week raised the risk of heart failure.
It’s worth taking a look at these types of population studies. The study looks at the health and diet records of a massive number of people. It then charts how many of them eat eggs and how often. It then notes which people died by the end of the study. Thus, if 300 people died of heart failure, it then notes their egg consumption. It compares that to the death rate of people who ate no eggs. But what these studies cannot do very well is to separate out the effects of other foods on the results. For example, people who eat 2 eggs a day --- the ones with the 64% increased risk for heart failure --- also probably didn’t just stop at eggs as their sole source of saturated fat. They probably also ate steaks, hamburgers, fried chicken, french fries and so on. It’s hard to say, therefore, what part eggs played in all this.
The Upside Down World of Cholesterol Warnings
In 1999, Dr. Frank Hu of the Harvard School of Public Health conducted a study which found that a diet that includes eggs 7 days a week does not harm your cardiovascular health. The only exception to this general rule is for men with diabetes.
This study, as you might well expect, caused quite a stir. It was followed by numerous other studies endorsing the conclusion that eggs --- and cholesterol --- are not the boogeymen they were once thought to be in terms of your heart health.
So compelling were these studies and so large was the weight of authority touting eggs as harmless that, in the 2015 Guidelines published by the Department of Agriculture dropped its warning against eating food with too much cholesterol.
So, conventional wisdom, which once held that cholesterol was tantamount to wishing heart disease on yourself has now completely reversed itself to a belief that in terms of heart disease risk, eggs, bah humbug, are meaningless, harmless, nothing here, move on.
The Evidence That Eggs And Your Heart Health Do Not Make a Happy Marriage
Let’s go back to the premise that evryone agrees with ---LDL raises your risk for heart disease. So, do eggs raise your levels of LDL? Some studies say no. But others say, loudly, yes.
For example, in 2010, Dr. J. David Spence of the Stroke Prevention & Atherosclerosis Research Centre in London and Dr. David Jenkins of St Michael’s Hospital in Ontario conducted a comprehensive study to survey the evidence for and against eggs in terms of heart disease.
Dr. Spence was alarmed at the growing consensus among health authorities in the US and the UK that eggs do not change heart disease risk.
This study led by Dr. Spence noted a highly important fact. For 4 hours after you eat a diet high in saturated fat or cholesterol, your endothelium (the smooth inner wall of your arteries) becomes dysfunctional.
We repeat: a single meal of fatty foods and high cholesterol disrupt the normal functions of your arteries for 4 hours after you eat the meal.
This fact has been established by a 1997 study from the University of Maryland School of Medicine. In this study, Flow-dependent vasoactivity of the arteries --- meaning the amount of blood flow the arteries can handle --- decreased from by 50% after participants ate a single meal of 50 grams of saturated fat.
What’s more, the arterial dysfunction is probably caused by oxidation, Dr. Spence theorized. He based his conclusion here on evidence from another study (1997 University of Maryland School of Medicine) that showed that people who take a multivitamin before eating the single high fat meal do not suffer as much arterial dysfunction.
The antioxidants in the supplements and vitamins counteracted the destructive oxidative effects of the high fat meal. The anti-oxidants that blocked the arterial dysfunction were oral administration of vitamins C (1 g) and E (800 IU), taken before the high fat meal.
So can you just down some OJ to block the harmful effects of eating too many eggs. A single orange has 86 mg of Vitamin C while the antioxidant supplement that the study used had 1000 mg (1 gram). So don’t count on getting enough anti-oxidants by drinking OJ to reverse the arterial dysfunction caused by your scrambled eggs.
The bottom line is, you should not eat eggs if you are at high risk for heart disease or if you have diabetes. Eggs have saturated fat which causes arterial dysfunction. If you are not at risk for heart disease, the jury is still out on eggs but in no event should you exceed 6 eggs per week.