Egg-cellent benefits of the humble egg

In 1952, Marilyn Monroe was photographed, wrapped in a bedsheet, making what she termed her usual breakfast: two eggs beaten into milk and warmed on a hot plate in her motel room. A drink that provides a third of an adult’s daily protein in one glass.

“When it’s hot,” the actress said, “I break two raw eggs into the milk, whip them up with a fork and drink them while I’m dressing.

“I supplement them with a vitamin pill, and I doubt if any doctor could recommend a more nourishing breakfast for a working girl in a hurry.”

Seven decades on, raw eggs for breakfast would not be recommended by most health professionals, but after a rocky number of years, the humble egg is back where it belongs on menus.

For decades, eggs got a bad rap - outlawed as a risk factor for heart disease because of their cholesterol content.

But modern research has positioned eggs back as an important element of a healthy whole-food diet.

Eggs are so nutritious that they are sometimes called ‘nature’s multivitamin’.

They provide high-quality protein and healthy fats.

Their generous protein content makes them filling, which means they can be a useful aid to maintaining a healthy weight.

Not only is the yolk stuffed with vitamins and minerals, it also contains choline, lutein and zeaxanthin.

Choline is what is known as an essential nutrient, which means it is required for normal bodily function and human health. The liver can make small amounts, but the majority must come from the diet.

It is a key component for optimal liver function. It plays an important role at the cellular level, delivering messages between cells, and in the movement of cholesterol from the liver.

Inadequate choline can lead to the build-up of fat and cholesterol in the liver.

Choline plays a role in the formation of acetylcholine, an important neurotransmitter involved in memory, muscle movement and regulation of the heartbeat.

Lutein and zeaxanthin are antioxidants that accumulate in the retina of the eye.

A paper in Nutrients (2022) outlined the role of these antioxidants in reducing the risk of eye diseases like cataracts and macular degeneration. Egg yolks contain large amounts of both lutein and zeaxanthin.

Eggs are also high in vitamin A. A deficiency of this is a common source of blindness worldwide.

Cholesterol

Eggs are high in cholesterol, but the evidence now shows that this may not adversely affect blood cholesterol or risk of heart disease, although the research behind this is still mixed.

A recent study in Nutrients (2023) concluded that the balance of evidence points to eggs being a nutritious food, suggesting there are broad health benefits from including them in the diet at intakes higher than currently consumed by European populations.

The Healthy Ireland food pyramid recommends that eating up to seven egg yolks per week and any amount of egg whites will not raise cholesterol levels in healthy adults.

Individual response to cholesterol in the diet can also vary. A paper in Nutrients (2022) described how some people will have raised blood cholesterol after consuming it, where others will have none or only mildly raised cholesterol after consumption.

Others with a genetic predisposition to high cholesterol, such as familial hypercholesterolaemia or carriers of the gene variant APOE4, may consider moderating their egg consumption.

The bottom line is that the jury is still out on the impact of eggs on cholesterol, and that some people’s cholesterol may react differently to eggs.

The impact of egg consumption on the risk of heart disease is also mixed, with some studies linking egg consumption with an increased risk of death from heart disease and all-cause mortality.

More research is needed to confirm the benefits of egg consumption to heart health.

Protein

High protein diets are on trend at the moment, and eggs are a great source of high-quality protein with all the essential amino acids that are key components of all sorts of tissues and molecules that form the main building blocks of the human body.

Eating enough protein is linked with maintaining a healthy body weight, building muscle, lowering blood pressure and optimising bone health.

A study in the European Journal of Clinical Nutrition (1995) listed the foods that maximised satiety or a feeling of fullness.

Eggs were found to score highly on the satiety index, reducing the need for snacking hours later.

A study in the Journal of the American College of Nutrition (2020) found that eating eggs was linked to a reduced risk of excessive body fat by over a third (38%) and a similar reduction (34%) in risk of visceral fat around the abdomen, that is a risk factor for metabolic syndrome.

Versatility

Another benefit of eggs is that they are incredibly versatile. They make a great start to the day – boiled, poached or scrambled.

Eggs can also be added to porridge in what is termed ‘savoury oatmeal’ – one of Friends actress Jennifer Aniston’s favourites. Vegetables and herbs can be added for extra flavour.

Lunch can be made in minutes with eggs slow-cooked in a skillet and mixed with onion, tomatoes, mushrooms, herbs and a sprinkle of cheese as a filling frittata.

They can be boiled and sliced on top of a salad or scrambled and wrapped in a fresh tortilla when you are in a rush.

Wrap your burrito in some tin foil and for extra flavour, throw in some sliced vegetables, grated cheese or salsa.

Eggs are a nutritional powerhouse: rich in quality protein, B12, choline (for brain and liver health), lutein, (great for the eyes) and vitamin D.

Combine them with plenty of vegetables, legumes, seafood and extra virgin olive oil and you have a diet that supports heart health and longevity.

Time to put the myths around eggs to rest and place them where they belong – in the eggcup, or on the plate.

Dr Catherine Conlon is a public health doctor in Cork.