Eggs: Are they good for me?

Eggs are nutrient dense and have a long shelf life. Compared with many other protein sources, they’re on the cheaper side, too.

But eggs aren't as popular as they used to be. And a lot of it comes down to the debate about cholesterol.

In today’s short episode of ZOE Science & Nutrition, Jonathan and Sarah ask: What’s the truth about eggs?

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Episode transcripts are available here.

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Transcript

[00:00:00] Jonathan Wolf: Hello and welcome to ZOE Shorts, the bite-sized podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolf, and as always, I'm joined by Dr. Sarah Berry, and today's subject is eggs. 

[00:00:17] Sarah Berry: Eggs are one of the most nutrient-dense foods. They're relatively cheap to buy. They have a long shelf life and they're widely available, but they're nowhere near as popular as they used to be.  

[00:00:28] Jonathan Wolf: So Sarah, what has led to the decline of the egg?  

[00:00:31] Sarah Berry: Various factors could be at play here Jonathan, and I think I can explain why eggs have fallen out of favor and why we could be seeing a resurgence in popularity. 

[00:00:41] Jonathan Wolf: How exciting!  

Let's get to it. 

So we did some research and in the 1950s before there was any big advertising for eggs in the US here in the UK, people were instructed to go to work on an egg as part of a popular marketing campaign. The idea was that if you ate an egg for breakfast, this was the best way to start the working day. 

[00:01:05] Sarah Berry: Yeah, Jonathan, so whole eggs are nutritionally rich. They supply almost every nutrient the human body needs except fiber. They're even sources for some harder-to-source nutrients like vitamin D and vitamin B12.  

[00:01:18] Jonathan Wolf: What about their health benefits? There's been a lot of debate on the health benefits or indeed the risks of eggs. 

[00:01:26] Sarah Berry: The majority of recent research suggests that eggs pose no risk to our health than much more likely to actually provide health benefits. In fact, eating eggs alongside other food can help our bodies absorb more vitamins. They can make us feel full for longer. And one study found that adding an egg to a salad can increase how much vitamin E we get from the salad. 

[00:01:46] Jonathan Wolf: Amazing. So we also found out that at the end of World War II eggs were more popular than ever, and on average, an American consumed seven eggs a week in the USA. And we know this because, in 1909, the US Department of Agriculture began to track egg consumption.  

[00:02:03] Sarah Berry: Eggs are still popular, but there has been a decline in popularity since the end of World War II, and the most recent data from the US suggests that the average American consumes now about five eggs a week. 

Now, eggs are really popular because they're incredibly versatile products to cook on their own. And that doesn't even take into account the hundreds of recipes that include eggs.  

[00:02:23] Jonathan Wolf: So Sarah, if they're healthy, they're cheap, and they're versatile, why aren't they as popular as they used to be?  

[00:02:30] Sarah Berry: It's because of the previous link between eggs and cholesterol. 

So in 1968, the American Heart Association announced a dietary recommendation that all individuals consume less than 300 milligrams of dietary cholesterol per day, and no more than three whole eggs in a week.  

[00:02:48] Jonathan Wolf: So Sarah, you know I have a personal story about this. Basically, doctors told my dad and millions of people like him that eggs could cause high cholesterol in his blood. And so as a result he loves eggs, but he completely cut down. It became his sort of guilty weekend treat. So it's like, oh, I'm being really naughty and I'm gonna have sort of two eggs on a Sunday. Um, became the way that we all were brought up to think about eggs.  

[00:03:13] Sarah Berry: Yeah, that's a real shame. And for a long time, eggs were thought to be bad for your heart because of their cholesterol content, but in the last decade research has shown quite clearly that at normal intakes of cholesterol, so maybe around 300 milligrams a day, dietary cholesterol has actually very little influence on a person's blood cholesterol levels.  

[00:03:34] Jonathan Wolf: However, because of all of this guidance and sort of public health information, the idea that eggs were an unhealthy food was widespread. And again, personally, you know, I grew up thinking that eggs were much less healthy than, you know, highly processed carbohydrates such as, you know, white bread or pasta or, or white rice.  

[00:03:55] Sarah Berry: Yeah, once a food gets a bad name, Jonathan, it's really hard to shake it. And eggs have really struggled with this labeling for the last 50 years, mainly because of this misconception around dietary cholesterol. 

[00:04:08] Jonathan Wolf: And so is this why there are still people eating egg white omelets?  

[00:04:12] Sarah Berry: Um, I think there's a couple of reasons. I think firstly because most of the cholesterol is in the yolk, so people think, oh, if I don't eat the yolk, then I'm not gonna get high blood cholesterol, which like I've said is not the case, but also a lot of people choose to consume only the white part of the egg because it's really high in protein. 

So it's really high in what we describe as a complete protein.  

[00:04:34] Jonathan Wolf: And I've never heard that term before, Sarah, what is a complete protein?  

[00:04:38] Sarah Berry: So it's something can nutrition we use a lot. And a complete protein is a food source that contains each of the nine essential amino acids that are necessary for the human diet and amino acids simply put are the building blocks of protein. 

[00:04:53] Jonathan Wolf: Got it. So it's got all the bits that you need to, you know, give all the protein that I would need as a human being. 

[00:05:00] Sarah Berry: Correct.  

[00:05:01] Jonathan Wolf: Can you explain a little bit more about the difference between the yoke and, and the.  

[00:05:05] Sarah Berry: Yeah, so the biggest difference between the two is that the egg whites have almost no fat content. It also contains a wide range of important minerals, and it's actually the most concentrated part of the egg in terms of the minerals, whereas the white contains really low concentrations of these nutrients, but then does have a high protein content.  

[00:05:24] Jonathan Wolf: So it does feel like another one of these examples where you're throwing away a lot of the nutritional value of the food because of this health scare 50 years ago. Sounds to me like you're probably better off if you're gonna have the egg, you know, having this whole, whole bundle.  

[00:05:40] Sarah Berry: Yeah. You know, this is the problem with nutrition misinformation is the number of misconceptions based on either old research or incorrect research, and eggs are a great example.  

[00:05:52] Jonathan Wolf: What about egg whites that we can buy, you know, in a supermarket out of a carton, does that have the same nutritional value [00:06:00] as egg whites from a freshly cracked egg that we might do when we're, you know, baking and separating the yoke from the white? 

[00:06:08] Sarah Berry: So I think they're really handy for some people who are going to discard the egg yolk. But often these egg whites have gone through a pasteurization process and they often contain other ingredients or fillers. They might have gums or artificial coloring, for example. So it's really smart to look at the ingredients as you should really with any processed foods, just to make sure you know what you are getting. 

[00:06:30] Jonathan Wolf: And I guess one of the magical things about an egg right, is that there's been no process seen and it just can sit there for weeks before you eat it. It's quite rare for food. Um, and uh, you know, in some senses it is nature's sort of ready, um, prepared processed food, isn't it?  

[00:06:47] Sarah Berry: Yeah, I think they're a great convenience food, and unfortunately, the food environment that we live where most great convenience foods are actually really not great for our health. I think eggs are a really good example of a great food for our health as well.  

[00:07:06] Jonathan Wolf: We do or now have to talk about how many eggs you've stated the eggs are overall good for us. Is it possible that we could have too much of a good thing?  

[00:07:15] Sarah Berry: Like with anything you can still get too much of a good thing? Um, but I think actually before we get really into how many eggs we can or we can't eat, we need to be really clear that the current research shows that blood cholesterol levels are not related to your dietary cholesterol intakes within normal ranges, and this is because the reason that the eggs were given a bad rap was because of the cholesterol content of eggs.

And it was believed that if you increase how much cholesterol you eat, you increase your blood cholesterol. We now know that for most healthy adults, the evidence shows it's safe to eat one to two eggs a day. Although it will depend a little bit on how much other cholesterol you are having in your diet. So if you are consuming loads of liver, for example, also has loads of cholesterol, you might be wanting to eat less than one a day. There is another myth out there, Jonathan, about if you've got high cholesterol or other risk factors for heart disease, you need to cut eggs out of your diet.

Now again, you need to be a little bit more mindful if you have high cholesterol about consuming really high cholesterol, uh, content foods such as eggs and such as liver. But the evidence would show that at low intake, so one or less a day, it's still perfectly safe to consume eggs. 

[00:08:29] Jonathan Wolf: And I think I would just add that although I don't have eggs every day, having discussed this a lot with you and Tim, I certainly came away feeling pretty comfortable that if I want to have, you know, three eggs as scrambled eggs or fried egg or whatever for my brunch, I shouldn't really be that worried about it.  

[00:08:45] Sarah Berry: Yeah. I think it also depends very much on your background diet. So when they looked, for example, at the population in America, they actually found that. Egg consumption was associated with an increased risk of cardiovascular disease.

When they looked at Europe and Asia, they found that there was no association between egg consumption and cardiovascular disease. So when they delved a little bit deeper, they disentangled that actually, it wasn't anything to do with the eggs, it was to do with the other kinds of foods that people consume in America when they typically consume an egg.

So it's the different ways in which the eggs are used, whether it's as part of an ingredient or whether it's part of a more ultra-processed, uh, meal, as might be the case. For example, typically in the US.  

[00:09:29] Jonathan Wolf: And I guess, you know, in the US A and the UK, we tend to associate eggs with like this big fried breakfast. 

[00:09:35] Sarah Berry: Yep.  

[00:09:36] Jonathan Wolf: With all of these foods that we know are really bad for you as opposed to something where you're having eggs with otherwise like whole food and plants and all the rest of it. I guess you're in a very different sort of overall dietary pattern, Sarah? 

[00:09:49] Sarah Berry: Yeah. And this is why we need to be really careful when we look at headlines in the newspaper because the food we eat is so complex and it's very much shaped by all of the other foods that are in our diet. But also something else I think that's really interesting, Jonathan, is we know that people respond differently as well to dietary cholesterol, and they also make cholesterol in their liver differently.

So it brings up this whole concept that you and I often talk about around personalization. It might be that some people can consume a lot more dietary cholesterol and it has no impact on their blood cholesterol. Whilst other people might need to be a little bit more mindful.

But despite this, I still think that the evidence shows having an egg day, even if you are someone that's slightly more sensitive to dietary cholesterol, is um, acceptable.  

[00:10:41] Jonathan Wolf: The last thing on this that you often talk about is, is sort of the substitution, right? So what would you eat otherwise? I now eat more eggs and less bread. So historically I would've had like a lot of bread one or maybe two eggs.

And actually, I'm now probably having a lot fewer eggs. I'm having olive oil on it instead of butter. If I'm frying the eggs, I'm frying in olive oil. And so my sort of view is, well, maybe I'm having the three eggs and that's maybe that's a bit more than I should have on one day.

But actually, if I think about that total plate, I know as somebody who struggles with, um, the impact of the blood sugar when I'm eating the bread, actually I'm, I'm pretty confident I've switched to something much better for me, and it's because of the, well, what would you eat?

You know, if you took the eggs off the table, you know, if you're gonna put bread and jam on it, you're probably in a, you know, in a worse place for most people, right? Rather than in a better one.  

[00:11:31] Sarah Berry: Yeah, that's a really important point, Jonathan, that adding protein and fat to any carbohydrate-rich meal is going to have several favorable effects. It's going to first reduce your post-meal blood sugar spike, which we know has unfavorable effects in terms of inflammation. We also know that it reduces your blood sugar dips, which is what some people get about two to three hours after consuming carbohydrates.

And the reason we want to stop this dip is cause we know people that have this dip have an increase in hunger and energy intake and it also increases or suppresses our appetite. And so there was a really interesting study where they fed the individual's bagels with egg, and the other day they had bagels without egg, but they made them isocaloric, so they had equal energy.

The people that had the egg on top of their bagel felt fuller for a lot longer, so they had their appetite suppressed for a longer period despite having the same calorie intake. And we know that there are unfavorable effects as well of high carbohydrate bagels on their own. Anyway, so that's like a double benefit.  

[00:12:43] Jonathan Wolf: Amazing. So having, I think, done quite a lot of work today, Sarah, to rescue the egg, are there any other downsides to eggs that we should be aware of? 

[00:12:53] Sarah Berry: I think it is worth noting that from a planetary health point of view, so thinking about carbon emissions for example, as well as an animal welfare point of view, some people may choose to avoid eggs. I think personally it's really important to say that, you know, conditions. Continue to be terrible. And this is even in the UK and the EU, where laws are really strict. So I'd suggest if you can opt for free-range eggs. Um, but I do know that this is difficult at the moment due to bird flu. 

[00:13:28] Jonathan Wolf: Now, Sarah, uh, At the time of recording this, there's actually a nationwide egg shortage in both the US and the UK, you know, linked to bird flu, as you've just mentioned. Uh, and many large stores are limiting the number of eggs that can be purchased by customers. Uh, you mentioned the stigma around eggs, and their cholesterol levels, as part of the reasons that eggs fell in popularity. But it seems like demand is actually higher than it was, you know, a decade ago.  

[00:13:54] Sarah Berry: Yes, Jonathan. So in 2016, the US government dropped its warning regarding eggs and regarding dietary cholesterol, which I think is a real stamp of approval that it's no longer, um, a concern. And in that year alone, we saw a 6% rise in egg consumption here in the UK we know that the demand for eggs spiked during the COVID pandemic probably cause there are lots more people, uh, doing home cooking and home baking. Um, but numbers are still nowhere near as high as they used to be. But it does seem that public opinion is changing on eggs and sales are continuing to rise. 

[00:14:32] Jonathan Wolf: Fantastic. So Sarah, if you were gonna wrap all of this up together, what would your advice be for a listener who's trying to figure out, okay, you know, can I have eggs tomorrow morning?  

[00:14:43] Sarah Berry: So I think that they're a great source of nutrients for adults and for kids. They're a really easy and accessible food. They're a great complete source of protein, and I think that they can be enjoyed as part of a really healthy diet. I would suggest don't overdo it, but I think at a level of one egg a day, you are perfectly healthy and it's actually a good component of your diet.  

[00:15:08] Jonathan Wolf: And I think, as Sarah said, I think we, of course, do recognize the planetary impact. You know, we had a whole podcast talking about this. Anytime that you're eating food, where first of all, you're having to grow, uh, a whole bunch of vegetables, then it's going through an animal. It's extremely inefficient.

So that means that the carbon impact and the footprint are much higher. I think we need to recognize, uh, that, and I think also some very fair questions around, you know, animal welfare for chicken and for many other animals. But if we think, I think directly about the health impact of, of the egg, it sounds to me Sarah, as though, uh, the egg manufacturers of America and Britain should be throwing you a ticker-tape parade.  

[00:15:48] Sarah Berry: Uh, I must say that none of my research has ever been funded by the egg industry. 

[00:15:53] Jonathan Wolf: I appreciate that clarification. Wonderful. Well, if you'd like to understand your own responses to fat and discover how many eggs are good for you, you may want to try ZOE's personalized nutrition program to improve your health, you can get 10% off by going to joinzoe.com/podcast. I'm Jonathan Wolf.  

[00:16:13] Sarah Berry: And I'm Sarah Berry.  

[00:16:14] Jonathan Wolf: Join us next week for another ZOE podcast. This podcast was produced by Fascinate Productions.