Are Eggs Bad For You?

Written by Dr. Steve Chaney on . Posted in Are Eggs Bad for You

Do Eggs Increase Heart Disease Risk?

Author: Dr. Stephen Chaney

 

are eggs bad for youThe “eggfusion” (That’s short for egg confusion) continues.

  • First there were the warnings that eggs were bad for your heart because egg yolks contained cholesterol, and cholesterol was to be avoided at all costs.
  • Then experts decided that dietary cholesterol wasn’t all that bad for you. It was saturated fats, obesity, and lack of exercise that raised “bad” (LDL) cholesterol levels in your bloodstream.
  • That was followed by several US studies suggesting that eggs in moderation (one per day) did not affect your risk of heart disease.
  • Then, about a year ago, a major study claimed that an egg a day actually lowered your risk of heart disease.

Now, the latest headlines claim that eggs increase your risk of heart disease, and you should avoid them. Are eggs bad for you? No wonder you are confused. Let me review the latest study and put it into perspective by comparing it to previous studies.

How Was The Study Done?

are eggs bad for you studyThis study (WW Zhong et al, JAMA, 321: djw322, 2017 combined the data from 6 clinical trials in the United States that assessed dietary intake and measured cardiovascular health outcomes. In all, these studies included 29,615 adults who were followed for an average of 17.5 years.

The diet of the participants was assessed upon entry into each of the clinical trials. The primary variables derived from the dietary information were cholesterol and egg consumption. Diet was not assessed at later times in these studies.

The primary outcomes measured were heart disease and all-cause mortality. In this study heart disease was an umbrella term that included fatal and non-fatal heart attacks, stroke, heart failure, and death from other heart-related causes.

The association of cholesterol and eggs with heart disease and mortality were similar. Similarly, the effect of cholesterol and eggs on both heart disease risk and mortality were similar. Most people know how many eggs they eat but have no idea how much cholesterol they consume. Thus, for simplicity I will just focus on the association between egg consumption and heart disease risk.

 

Do Eggs Increase Heart Disease Risk?

do eggs increase heart attacksHere are the main findings from this study.

  • Each additional half an egg consumed per day (which is equivalent to 3-4 eggs per week) was associated with a:
  • 6% increased risk of heart disease. While that doesn’t sound like much, the increased risk was over 13% for one egg per day and almost 27% for two eggs per day.
  • The increased heart disease risk associated with one half egg per day was greater for:
  • Women (13% increase) than men (3% increase)
  • People who already had high blood cholesterol (7% increase) than people who already had low cholesterol levels (0% increase). This suggests that the effect of eggs on heart disease risk primarily affects people who are already having trouble controlling their blood cholesterol levels – either due to genetics or due to diet & lifestyle.

Of course, the question is whether it was the eggs that increased the risk of heart disease or was it something else in the diet. This study attempted to answer that question by systematically subtracting out other variables that affect heart disease risk to see whether that correction eliminated the association between egg consumption and heart disease risk. When this was done:

  • The association between egg consumption and heart disease risk disappeared after correcting for dietary cholesterol intake.
  • The association between egg consumption and heart disease risk remained significant after correcting for other components of the diet, such as fats, animal protein, fiber, sodium, or overall “diet quality”. There were 3 main measures of diet quality.
  • The Med diet score measures how closely the diet resembles the Mediterranean diet.
  • The DASH diet score measures how closely the diet resembles the DASH diet.
  • The Healthy Eating Index (HEI) measures how closely the diet aligns with the USDA Dietary Guidelines For Americans. Basically, the HEI recommends a whole food diet containing foods from all 5 food groups with a heavy emphasis on fruits, vegetables, whole grains, and legumes. It also recommends limiting saturated and trans fats, added sugars, and sodium.

In simple terms these data suggest that the effect of eggs on heart disease risk was primarily due to their cholesterol content and was not influenced by other components of the overall diet.

What Are The Strengths And Weaknesses Of The Study?

are eggs bad for you strength weakness studyThe strengths are obvious. This was a very large study (29,615 participants) and the people enrolled in the study were followed for a long time (an average of 17.5 years). The primary variables in the study (cholesterol consumption, egg consumption, heart disease, and all-cause mortality) were accurately measured in each of the clinical trials included in the study.

However, there were some significant weaknesses as well:

  • Cholesterol and egg consumption were only measured by a single dietary survey when people entered the study. This study assumes they did not change over the course of the study. That is very unlikely. Both cholesterol intake and egg consumption in the US population have waxed and waned over the years, in part due to variations in dietary guidelines.
  • The measurements of diet quality used were based on US and European food preferences. That is significant because the only studies showing that egg consumption lowers heart disease risk were performed in China and Japan, where the diet is closer to semi-vegetarian than to US or European diets.

 

Are Eggs Bad For You?

thumbs downAre eggs bad for you?

This is very large, well designed study that combines the data from 6 clinical trials spanning the years 1974 to 2013.

The strongest conclusions from the study are:

  • In the context of a Western diet (the US diet) egg consumption slightly increases your risk developing heart disease. The increased risk is ~6% for 3-4 eggs/week, ~13% for 1 egg per day, and ~27% for two eggs per day.
  • The increased risk of heart disease appears to be almost entirely due to the cholesterol content of eggs.

The significance of this study needs to be weighed in the context of:

  • Recent studies in the US and Europe showing eggs do not increase heart disease risk.
  • Studies in China and Japan (where the diets can best be described as semi-vegetarian) showing that eggs decrease heart disease risk.

The significance of this study also needs to be weighed in the context of:

  • Studies showing that obesity, saturated fat, and physical inactivity have bigger effects on serum cholesterol levels and heart disease risk than dietary cholesterol from foods like eggs.

What Did This Study Miss?

are eggs bad for you breakfastIf, as this study suggests, the effect of eggs on heart disease risk is due to their cholesterol content, this study (and most previous studies) missed a very important point. The effect of dietary cholesterol on blood cholesterol levels is not strongly affected by the overall composition of the diet. It is affected by the composition of the diet at the time foods containing dietary cholesterol are eaten.

  • The kind of fiber found in certain fruits, vegetables, whole grains, and legumes bind to dietary cholesterol, preventing it from being absorbed as it passes through the intestine.
  • Certain phytonutrients in plant foods affect how dietary cholesterol is utilized by the body.
  • Our gut bacteria depend on the fiber we eat. They utilize the fiber for energy and release metabolites that affect how dietary cholesterol is utilized by the body.
  • However, to blunt the effect of dietary cholesterol on blood cholesterol levels, the fiber and phytonutrient-containing foods must be consumed at the same meal.

Simply put, if your breakfast consists of eggs, sausage, biscuits, and hash browns, the cholesterol in the eggs will likely increase your blood cholesterol level, which in turn increases your risk of heart disease. This will occur even if you eat lots of fruits, vegetables, whole grains, and legumes with your other meals.

If, on the other hand, your breakfast consists of eggs and fiber-rich plant foods like oatmeal and beans, the cholesterol in the eggs will likely have a much smaller effect on your blood cholesterol levels and your heart disease risk.

The fact that previous studies have not looked at what foods were consumed along with the eggs may explain some of the variation in their conclusions about the effect of egg consumption on heart disease risk.

 

The Professor’s Story

professor owlLet me share my story with you. About 25 years ago, my doctor told me that my cholesterol levels were getting high and wanted to put me on statins. I didn’t stop eating eggs for breakfast. I changed breakfast.

Now I soft boil my eggs or fry them in olive oil. I eat them along with oatmeal, which contains a fiber that binds cholesterol, and walnuts, which contain omega-3s and phytonutrients that lower blood cholesterol. I also include whatever fruit is in season. Finally, I take a supplement providing 2 grams of plant stanols and sterols, which block cholesterol absorption from the intestine.

My blood cholesterol levels have been low ever since. I have not had to take statins, and I get to enjoy the taste and health benefits of an egg every day. Of course, what worked for me may not work for you. The effect of dietary cholesterol on blood cholesterol levels is also affected by genetics, weight, and fitness, just to name the top three.

 

Are Eggs Bad For You or Good For You?

thumbs upOnce you get past the cholesterol problem, eggs are a very healthy food.

  • Studies have shown that egg protein results in better blood sugar control, better satiety (feeling of fullness), and reduced subsequent food intake in healthy and overweight individuals. In layman’s terms that means egg protein can help you achieve and maintain a healthy weight.
  • Egg yolks are a good source of lutein and zeaxanthin. We think of lutein and zeaxanthin as good for eye health. They also play an important role in protecting against oxidation, inflammation, and atherosclerosis.
  • Egg yolks also contain choline. We think of choline as good for brain and nerves. But, choline and other phospholipids in the yolk also raise HDL levels and enhance HDL function.
  • Eggs are a good source of vitamin A, vitamin D, vitamin B12, riboflavin, selenium and iron.
  • Eggs contain almost twice as much monounsaturated and polyunsaturated fats as saturated fats.

What Does This Mean For You?

  • what does this mean for youThe latest study suggests that eggs may increase your risk of heart disease, and this is due to their cholesterol content.
  • This study needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.
  • It is also important to consider that egg consumption in China and Japan is in the context of a semi-vegetarian diet. This suggests that diet plays a role in determining the effect of egg consumption on heart disease risk.
  • However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:
  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
  • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels.
  • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.
  • Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:
  • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
  • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

If we wish to reduce our risk of heart disease, this is where we should focus most of our attention. We can minimize the effect of egg consumption on heart disease risk by changing the foods we eat with the eggs. For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths.”

 

The Bottom Line

  • The latest study suggests that eggs increase your risk of heart disease because of their cholesterol content.
  • This was a very large study. It combined the data from 6 clinical trials spanning the years 1974 to 2013. It followed 29,615 people for an average of 17.5 years. However, it has two significant weaknesses:
  • It only determined cholesterol intake and egg consumption at the time people entered the clinical trials. Both cholesterol intake and egg consumption have waxed and waned considerably over the years covered by these clinical trials.
  • It did not measure what foods were consumed along with the eggs. Foods consumed along with eggs have a strong influence on how much the cholesterol in the eggs influences blood cholesterol levels, which, in turn, influences the effect eggs have on heart disease risk.
  • This study also needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.
  • However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:
  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
  • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels.
  • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.
  • Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:
  • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
  • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

If we wish to reduce our risk of heart disease, these are the areas where we should focus most of our attention. We can minimize the effect of egg consumption on heart disease risk by changing the foods we eat with the eggs. For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths.”

For more details and to learn how the professor does about egg consumption, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (1)

  • Geoff Lamdin

    |

    Hi Steve,

    Good discussion today on eggs and cholesterol. I recall my Dad was interested in these inter-relationships (eggs/cholesterol/overall diet) back when he was VP of Science at the Heart Association. I also seem to remember, perhaps not correctly, a study done in the 1990s? that looked at eggs and cholesterol content. The finding suggested that the “healthier” the chicken – i.e. a plant -based, free-range, non-animal feed diet, the lower the native cholesterol in the egg. Does this ring any bells with you?

    Reply

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Latest Article

Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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