Are eggs healthy or aren’t they? There are so many myths about eggs it can be difficult to know what to believe. Leading medical journalist Victoria Lambert looks at the science
It’s enough to scramble the brain: are eggs – power food of choice for so many and a staple of 5:2 dieters – back on the naughty list?
According to a report in the Journal of American Medical Association (JAMA) published last week, high levels of dietary cholesterol, like those found in eggs, are linked to an increased risk of heart and circulatory disease, or even death.
It’s a complete turnaround from current NHS dietary advice which states there is no limit to how many eggs you can eat. And even the researchers, from Department of Preventive Medicine at Northwestern University, Illinois, USA, admitted the link was unexpected.
One of the co-authors, epidemiologist Prof Norrina Allen said: ‘What we found in this study was that if you consumed two eggs per day, there was a 27 per cent increased risk of developing heart disease. It was surprising.’
So, what is the truth about eggs?
FICTION: Eggs give you heart disease
The British Heart Foundation (BHF) suggests we remain cautious about scaremongering headlines about eggs. ‘There has been much debate about the role of eggs in relation to heart and circulatory disease,’ Victoria Taylor, Senior Dietitian at the BHF, has said. ‘This study suggests that people who eat more eggs are at a greater risk of heart disease because of the cholesterol that is in them. But this type of study can only show an association, rather than cause and effect, and more research is needed for us to understand the reasons behind this link.
‘Eating healthily is all about balance. If you’re eating too much of one thing it leaves less room in the diet for other foods that may have more health benefit.’
Taylor added: ‘Eggs are a nutritious food and, while this study focuses on the amount we’re eating, it’s just as important to pay attention to how the eggs are cooked and to the trimmings that come with them. For example, poached eggs on wholegrain toast is a much healthier meal than a traditional fry up.’
Juliet Gray, a Registered Public Health Nutritionist based in London, agrees. ‘We know that there is a relationship between heart disease and high levels of cholesterol (called serum cholesterol) in the blood.
‘Only around a third of the cholesterol in the body comes from the diet (our bodies make the rest). And it is now generally accepted that the amount of saturated fat that we eat has a greater effect on our blood cholesterol levels than cholesterol in the diet.’
What matters is context: ‘Provided people are eating a healthy diet,’ says Gray, ‘not high in saturated fats, with plenty of fruit and veg, and wholegrains, there is no problem eating eggs.’
Warwickshire GP Dr Jeff Foster isn’t convinced the new study has much to offer. ‘It doesn’t tell us anything much new,’ he says. ‘And how do we know that the participants with CVD ate otherwise healthy diets – just more eggs? What if the eggs were fried in oil?’
He adds: ‘When eggs are prepared in a healthy fashion, the dietary uptake of cholesterol from eggs is quite low – as long as they are eaten with fibre (like wholemeal bread).’
Dr Foster would not want his patients to be concerned by the new study. ‘I would tell them that overall eggs are great as part of a balanced diet. Don’t be worried.’
Nutritionist Cat MacDonald adds: ‘Papers such as the new JAMA one are valuable but you have to consider the whole body of research, not cherry-pick individual studies. Nutritional science is about consensus.’
‘Overall, the research is very clear: the cholesterol which links to heart disease is not affected by diet, certainly not by eggs.’
FICTION: You can only eat two eggs a week
A decade ago, official advice was to eat no more than two or three eggs a week to reduce the risk of consuming too much cholesterol – and thus raising the risk of heart disease. But as the idea that cholesterol we eat is the same as the cholesterol that is carried in the blood was debunked, so advice has changed.
Now we know that most of serum cholesterol is made in the liver – and the most important dietary element is not how much cholesterol we consume, but the amount of saturated fat in the diet.
A Cochrane systematic review concluded that cutting down dietary saturated fat was associated with a 17 per cent reduction in cardiovascular events (CVD), including heart disease, on the basis of 15 randomised trials. Researchers suggested that anyone at risk of CVD should reduce saturated fat and replace it with unsaturated varieties.
Juliet Gray says: ‘The BHF and the Department of Health don’t set limits on how many eggs you can eat.
‘It’s worth considering if you are having eggs and bacon every day then that is not a healthy diet, but if you eat a boiled egg every day with wholemeal toast and fruit, then that’s a different meal.’
FACT: Full of goodness
One thing about which there can be no doubt is that eggs are nutritious.
Rich in vitamin B2 (riboflavin), vitamin B12, vitamin D, selenium and iodine, eggs also contain vitamin A and B vitamins including folate, biotin, pantothenic acid and choline, plus other essential minerals and trace elements, including phosphorus.
A medium egg (58g) contains 66 calories, 4.6g of fat (of which 1.3g is saturated) and an impressive 6.4g of protein.
For Juliet Gray, that high level of protein is the most important number.
‘Eggs are an amazing source of high-quality protein,’ she says, ‘which can be used very efficiently by the body. They contain the full range of amino acids our bodies need to make new protein – they are incredibly useful for growth.
‘That’s especially true for babies and children, but also older people. We all lose muscle as we age, particularly once through the menopause. So, eggs are great for those who are 60-plus; including high protein foods at every meal becomes more important at that age.’
Gray also points out that eggs contain the nutrient lutein which is important for muscle growth and in post-exercise recovery – particularly useful in muscle growth and for fitness fans.
‘If you have been working out,’ she says, ‘having eggs on wholemeal toast afterwards is a great post-exercise recovery meal.’
Amongst the other nutrients found in eggs, Gray highlights its Vitamin D content. ‘A high proportion of Britons don’t get enough vitamin D; we’ve been scared off going out into the sun thanks to concerns about skin cancer. But once you’re covered in sunscreen, you’re not making any natural vitamin D.’
She also notes that eggs are full of B vitamins including riboflavin and folate.
‘The latest figures say that women are not getting enough folate as we don’t eat enough fruit and vegetables, which is where we might otherwise stock on this nutrient.
‘And although we know women need to take folic acid supplements in pregnancy, many are starting to conceive with low levels.’
FICTION: Eggs are not good for your waistline
You may have been told eggs were fattening as they contain 9g of fat per 100g. As the average woman aged 19-64 years should eat no more than 20g of saturated fat a day, according to NHS guidelines it’s easy to see how a three-egg omelette could take up almost a whole day’s allowance.
On the other hand, most high protein diets succeed or fail depending on whether the slimmer likes eggs. Whether you are a fan of Paleo diets, the Atkin’s or like to fast for two days a week, an egg eaten plain can fill you up perfectly.
Cat Macdonald is in no doubt of the value of eggs when you are trying to lose weight. ‘Eggs are very satiating,’ she says. ‘There are studies which show if you eat an egg-based breakfast as opposed to a cereal or grain-led breakfast, you will consume fewer calories throughout the day.’
She adds: ‘Studies have shown this is the same for lunch too.’
There is also a growing belief that energy density (the amount of energy in a given weight of food or drink, ie calories per gram) has an effect on satiety.
According to the British Nutrition Foundation, we should all aim to eat more foods with lower energy densities (like eggs) and fewer foods of high energy density (like sweets) so that we feel fuller for longer.
FACT: Runny eggs are safe
Recent advice in pregnancy and for the very young or old has been to avoid runny yolks for fear of getting food poisoning from the bacteria salmonella.
But now, dippy eggs and toast soldiers are back on the menu for everyone thanks to safety measures brought in by farmers.
The change dates back to 1998, explains Cat MacDonald, with the re-introduction of the British Lion Quality mark which denoted eggs which came from hens which had been vaccinated against salmonella. The British Lion code of practice covers the entire production chain and ensures strict food safety controls throughout.
‘Over the past 20 years,’ she says, ‘the industry has worked really hard to improve safety. It has made such a massive difference that in 2017, the Food Standards Agency advice changed to reflect that.’
One group which has benefited in particular is infants, she adds. ‘Dippy eggs are a great food when weaning at six months. Babies seem to love them.’
She adds: ‘It’s even safe for pregnant women to eat fresh mayonnaise, as long as British Lion eggs have been used.’
FACT: Eggs don’t increase the risk of type-2 diabetes
One of the most interesting areas of research has been into the connection between eating eggs and type 2 diabetes.
Last May, University of Sydney researchers in Australia found that eating up to 12 eggs per week for a year did not increase cardiovascular risk factors in people with pre-diabetes and type 2 diabetes.
The study, which was published in the American Journal of Clinical Nutrition, was led by Dr Nick Fuller from the University’s Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders.
‘While eggs themselves are high in dietary cholesterol,’ Dr Fuller said, ‘and people with type 2 diabetes tend to have higher levels of the ‘bad’ low density lipoprotein (LDL) cholesterol – this study supports existing research that shows consumption of eggs has little effect on the levels of cholesterol in the blood of the people eating them.’
Cat MacDonald says that this doesn’t mean eggs will ward off type 2 diabetes but that eating them as part of a well-balanced diet is fine for anyone with the condition.
She adds: ‘Every case of type 2 is different so you should check with your health professional first.’
Victoria Lambert is an international award-winning journalist, columnist and author specialising in health and lifestyle. She writes for most of the UK’s national press, principally the Daily Telegraph, the Guardian and the Daily Mail, and her work is syndicated round the world. She is the author of Boundaries – How to Draw the Line in Head, Heart and Home written with psychotherapist Jennie Miller (Harper Collins, £12.99).