Why are eggs “controversial” ?

 

Because at the same time as being a complete protein, packed with vitamins and minerals, they also contain fats and cholesterol. 

The issue is whether the cholesterol in eggs causes the cholesterol  in our blood to rise. And whether consuming eggs causes an increase in cardiac illness such as stroke or heart attacks etc. 

There is lots of research, lots of opinions…. 

So, lets give it a go. 

 

Eggs, cholesterol and risks to heart health. 

To quote Vicky Pollard from “Little Britain”, eggs and cholesterol in the scientific literature is a bit of a “ya, but no, but ya but no type situation”.

Eggs and Cholesterol

 

Eggs and Nutrition

Eggs are packed with vitamins and minerals, with the yolk containing more vitamins than egg white.

There is significant amount of fat in egg yolk, in the form of saturated and unsaturated fats as well as cholesterol and triglycerides in the egg yolk. There is no fat in egg white. 

Both the yolk and white are a great source of protein, with more protein in the yolk. 

You can read more about the nutritional information of eggs here. 

 

Things you might hear……..

“The amount of cholesterol in Eggs is too small to cause changes in your blood cholesterol”

“My mum ate eggs her whole life and had no problems with cholesterol”

Certain people are ‘hyper-responders” to dietary fats and cholesterol. Meaning, they absorb cholesterol much more easily from their diet than other people. 

Having dug through the research and the commentary on the research, hyper-responders (or indeed the opposite) are a likely explanations for the above comments.

“Cholesterol in your diet isn’t important!”

Controversial statement but there are elements of it that are true. Diets heavy in saturated fats and trans fats are much more likely to raise your cholesterol and much more damaging to your cardiovascular health than dietary cholesterol. However, when it comes to eggs, some people who eat otherwise healthy diets, i.e not much saturated fats and low in processed foods, still struggle with high cholesterol. More than likely, it is the eggs in their diet causing this. 

 

The most recent, rigorous study.

JAMA. 2019

A study that looked at data from multiple studies went to great lengths to standardise for bias and control for things that might skew the data. Specifically, with respect to this blog, they looked at both cholesterol (from any source) in the diet, and separately eggs in the diet and whether having both cholesterol and/or eggs in the diet had an effect on blood cholesterol and heart attacks and strokes. 

What this study from the Journal of the American Medical Association(JAMA) found was the following

  1. Each additional 300mg of dietary cholesterol (from any source) resulted in higher rates of cardiovascular disease and death. When they removed other cardiovascular risk factors such as weight, blood pressure, diabetes, the risk remained. There were two exceptions to these higher rates of illness and death. 
  2. When eggs and saturated fats from red meat etc were removed, there was no longer a risk. 
  3. When eggs were removed there was no longer a risk. 
  4. The risk was higher in women.
  5. The risk was stronger in those with a high saturated fat diet. 

The authors state in their study 

“…the significant association between egg consumption and incident CVD was fully accounted for by the cholesterol content in eggs..”

Diabetes.

Ah, more controversy. 

Again the studies are a bit “yes, but no but” etc. Here is an example of a study where the authors found eating eggs IS ASSOCIATED associated with the development of Diabetes. And here is one that found there is NO RISK between egg consumption and Diabetes. And there are a lot of other yes but/no but studies. 

A significant study from 2019 looked at the Women’s Health Initiative study population.

It found in post menopausal women

  1. The higher the number of eggs eaten per week, the greater your risk of developing Diabetes.
  2. When they controlled for (removed) the cholesterol in the diet from eggs, the risk no longer existed.

The authors state, 

“These results suggest that consumption of the cholesterol in eggs and other foods was responsible for much of our observed increases in diabetes risk. “

Why the Inconsistencies?

The inconsistencies from the studies on eggs and cholesterol is discussed in the literature frequently.  Researchers have found that the studies that looked eggs to be heterogenous(different and therefore difficult to compare like with like), and lacking in rigorous data analysis. 

These inconsistencies, and why everyone has a different opinion comes from a variety of things. Differences in the eligibility criteria (how people are accepted into studies), the number of studies studied(meta-analysis) and the cut off points for egg consumption.

Further more, a lot of research on food is based on ‘recall’, i.e asking people to remember what they ate last week, month, year. Or asking them to keep a diary. All of these can result in inconsistencies. 

What happens when certain studies reach the press, is you might see “Good News, Eggs Are Good For You!” or Bad News, Eggs Are Really Bad For You”

But, as we have learned, it is not really that clear cut. 

 

How do I know if Eggs are bad for MY Cholesterol?

Well, if you eat eggs regularly you’ve had your cholesterol checked its normal you might being doing fine eating eggs.

If your cholesterol is high, and you eat lots of eggs and the rest of your diet is pretty decent, eggs might well be the cause. 

The Bottom Line (For the moment!)

Eating more than 1 egg a day is probably not good for you.

Ideally just eat eggs a few times a week, maximum.

If you are struggling to get your cholesterol down with your diet and lifestyle, and you eat eggs, you might consider cutting down/ cutting them out and see how you go. (What is my cholesterol level supposed to be?)

If you have Diabetes, or have been told you are at risk of developing Diabetes, it might be worth also cutting down.

 

 

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