ZOE Science & Nutrition - Eggs: are they good for me?

Episode Date: February 23, 2023

Eggs are nutrient-dense and have a long shelf life. Compared with many other protein sources, they’re on the cheaper side. But they’re not as popular as they used to be. And a lot of this comes down to a debate about cholesterol. In today’s short episode of ZOE Science & Nutrition, Jonathan and Sarah ask: What’s the truth about eggs? Follow ZOE on Instagram: https://www.instagram.com/zoe/ Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Episode transcripts are available here. Want to create your own podcast? Contact Fascinate Productions to bring it to life. 

Hello, and welcome to Zoe Shorts, the Bite Size podcast, where we discuss one topic around science and nutrition. I'm Jonathan Wolfe, and as always, I'm joined by Dr. Sarah Berry. And today's subject is eggs. 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, they have a long shelf life and they're widely available. But they're nowhere near as popular as they used to be. So Sarah, what has led to the decline of the egg? Various factors could be at play here, Jonathan, and I think I can explain why eggs have fallen out of favour and why we could be seeing a resurgence in popularity.

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. 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. What about their health benefits? There's been a lot of debate on the health benefits or indeed the risks of eggs.

The majority of recent research suggests that eggs pose no risk to our health and 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 salad can increase how much vitamin E we get from the salad. 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. 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. So Sarah, if they're healthy, they're cheap, and they're versatile, why aren't they as popular as they used to be? 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. 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 going to have sort of two eggs on a Sunday, became the way that we all were brought up to think about eggs. 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.

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 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 white rice. 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. And so is this why there are still people eating egg white omelettes? 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 going to 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'd describe as a complete protein. And I've never heard that term before, Sarah. What is a complete protein? So it's something in 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 in the human diet. And amino acids, simply put, are the building blocks of protein. Got it. So it's got all the bits that you need in order to give all the protein that I would need as a human being.

Correct. Can you explain a little bit more about the difference between the yolk and the white? 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 the high protein content. 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 going to have the egg, you know, having this whole bundle. Yeah, you know, this is the problem with nutrition misinformation is the amount of

misconceptions based on either old research or incorrect research and eggs is a great example. What about egg whites that we can buy, you know, in a supermarket out of a carton? Does that have the same nutritional value as egg whites from a freshly cracked egg that we might do when we're, you know, baking and separating the yolk from the white? 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 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're getting. And I guess one of the magical things about an egg, right, is that there's been no processing and it just can sit there for weeks before you eat it. It's quite rare for a food. And, you know, in some senses, it is nature's sort of ready, prepared processed food, isn't it? Yeah, I think they're a great convenience food. And unfortunately, in a 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 food that can also be great for our health as well. We do now have to talk about how many eggs. You've stated that eggs are overall good for us.

Is it possible that we could have too much of a good thing? Like with anything, you can still get too much of a good thing. 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 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're 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 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. 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, scrambled eggs or fried egg or whatever for my

brunch, I shouldn't really be that worried about it. Yeah, I think it also depends very much on your background diet, so people's other components of their diet. So when they looked, for example, at the population in America, they actually found that the 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 with 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 meal, as might be the case,

for example, typically in the US. And I guess, you know, in the US and the UK, we tend to associate eggs with like this big fried breakfast, with all of these foods that we know are really bad for you, as opposed to something where you're having these eggs with otherwise like whole food and plants and all the rest of it, I guess you're in a very different sort of a overall dietary pattern, Sarah. 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 have 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 a day, even if you're someone that's slightly more sensitive to dietary cholesterol, is acceptable. The last thing on this that you often talk about is sort of the substitution, right? So what would you eat otherwise? I now eat more egg and less bread. So historically, I would have had like a lot of bread, one or maybe

two eggs. And actually, I'm now probably having a lot less egg. 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 the impact of the blood sugar when I'm eating the bread, actually, I'm pretty confident I've switched to something that is 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 going to 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. Yeah, it's a really important point, Jonathan, that adding protein and fat to any carbohydrate-rich meal is going to have a number of 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 because 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 individuals 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 of time, despite having the same calorie intake. And we know that there's the unfavorable effects as well of high carbohydrate bagel on its own in a way. So that's like a double benefit as well. 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? I think it's 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 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 it's possible for you to opt for free range eggs. But I do know that this is difficult at the moment due to bird flu. Now, Sarah, at the time of recording this, there's actually a nationwide egg shortage in both the US and the UK,

linked to bird flu, as you've just mentioned. And many large stores are limiting the number of eggs that can be purchased by customers. You mentioned the stigma around eggs, their cholesterol levels as part of the reasons that egg fell in popularity. But it seems like demand is actually higher than it was a decade ago. 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 a concern. And in that year alone, we saw a 6% rise in egg consumption in the US. Here in the UK, we know that the demand for eggs spiked during the COVID pandemic, probably because a lot more people are doing home cooking and home baking.

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. Fantastic. So Sarah, if you're going to wrap all of this up together, what would your advice be for a listener who's trying to figure out, okay, you okay, can I have eggs tomorrow morning? 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're perfectly healthy and it's actually a good component of your diet. 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. Any time that you're eating a food where first of all,

you're having to grow 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 is much higher. So I think we need to recognize that. And I think also some very fair questions around animal welfare for chicken and for many other animals. But if we think, I think, directly about the health impact of the egg, it sounds to me, Sarah, as though the egg

manufacturers of America and Britain should be throwing you a ticker tape parade. I must say that none of my research has ever been funded by the egg industry. 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 slash podcast. I'm Jonathan Wolfe.

And I'm Sarah Berry. Join us next week for another Zoe podcast.