• Despite a long history of being labelled unhealthy, eggs are nutrient-rich and now considered a valuable part of healthy eating habits
• Scientific understanding of relationships between cholesterol in food, cholesterol in the blood, fat intake and overall health continues to evolve such that many beliefs are being challenged
• Eggs are an excellent source of protein, essential fats, B vitamins and choline, and up to three eggs may be eaten daily
• The best source for eggs will be from pasture-raised hens, preferably locally-sourced
Eggs are one of those foods that often raise debate among health professionals, and the ubiquitous “is this good/bad for me?” question from the general public. Although widely-labelled as “unhealthy” for at least a generation, eggs have recently been subject to resurgence in popularity as scientific understanding evolves about the role of fat and cholesterol in the diet in relation to health. However, due to mixed messages through public health advice and media, confusion remains amongst the public about the daily consumption of eggs, so please have a read of the FoodFlicker stance on eggs.
Why are eggs considered the bad guy and deleterious to our health?
The logic goes as follows: the “Lipid Hypothesis” put forward in the late 1970s suggested that elevated levels of cholesterol in the blood result in increased risk of heart disease*. Because egg yolks contain cholesterol, then eating eggs must contribute to heart disease – simple, isn’t it? Except that cholesterol, in terms of total quantity, is probably not a risk factor for heart disease, but rather the relative amounts of good and bad cholesterol (see below) are the important markers and determine the risk of disease. Moreover, it turns out that dietary cholesterol (the cholesterol in the food we eat) is not a good predictor of the levels of cholesterol in the blood. In fact, as you might expect, the body is a lot more complicated than that, and a multitude of dietary factors and lifestyle habits are a stronger influence on total cholesterol and types of cholesterol in blood than simply the cholesterol that we eat.
What is cholesterol?
Cholesterol is a tiny molecule and type of fat that is present in the body and in certain foods that we eat. In general, cholesterol plays a vital role in many biological processes in the body. These include building and maintaining cell membranes, and the synthesis of steroid hormones and vitamin D. Cholesterol is transported in the blood primarily by two main proteins called high-density lipoproteins (HDL) and low-density lipoproteins (LDL). When cholesterol is measured in the blood, a measurement is made to see how much of the total cholesterol is being transported by HDL or LDL. HDL cholesterol is often referred to as “good cholesterol” and so having higher amounts is suggested to help protect the cardiovascular system, whereas having higher LDL cholesterol [“bad cholesterol”, and in particular, very-low density lipoproteins (VLDL)] is linked with a greater risk of heart disease.
As mentioned above, the degree to which the blood cholesterol levels are affected by cholesterol in the food we eat depends on a multitude of factors including genetics, other dietary components such as the presence of refined carbohydrates or a lack of fibre, and a lack of physical activity. That dietary cholesterol from foods such as eggs contributes very little to total cholesterol levels in the blood provides just another example of how genuinely healthy foods can mistakenly get a bad name. The current consensus is that that cholesterol intake from eggs does not increase LDL cholesterol or the risk for heart disease, and combined with an active lifestyle and healthy eating habits, eggs can promote favourable shifts in HDL, which may reduce the risk of heart disease in the long run.
Of particular interest for those aiming to control body weight are studies** that demonstrate that eating eggs at breakfast assist with this goal by reducing appetite and energy intake for the rest of the day, and leading to more weight loss if consumed five days a week as part of an energy-restricted diet. At least compared to bagels for breakfast… The suggestion is that, as a source of protein and healthy fats, eggs have a satiating effect, which in turn helps to control snacking in the lead-up to lunch.
“One a day” I hear you say?
According to the European Food Information Council (EUFIC) eggs are nutritious and safe to eat and a good source of selenium, iodine, molybdenum, phosphorus, vitamin B5, vitamin B12 and vitamin D. Aside from these vitamins and minerals, eggs also provide a complete protein source (6 g per average egg) and essential fats.
Several years ago, a case published in the prestigious New England Journal of Medicine described an apparently healthy 90 year old man who reported consuming about 25 eggs per day for the previous 15 years – but no one is suggesting that this is normal practice!
A recent analysis suggested that one egg per day is safe across all populations in terms of stroke and heart disease risk, whereas in people with existing diabetes, higher intakes were associated with small effects on risk for stroke and heart disease. In terms of higher intakes in the general population, there is no clear consensus on the number of eggs that you can or should consume daily, but we, like others, suggest that up to three eggs daily is probably a safe guideline***. Studies beyond three eggs per day are rare and unreliable, and therefore there is no evidence either way at present.
Are all eggs created equal?
Central to the FoodFlicker philosophy is knowing where your food comes from, and in the case of animal products, what the animal has been fed. If you are eating animal products, then you are what you eat eats! In the case of eggs, how the hens, ducks or other fowl have been raised and fed impacts the nutrition profile of the egg. For instance, pasture-raised eggs from a hen that picks grass and eats house scraps will have a better nutrient profile in terms of micronutrients and fat profile (including omega-3 fat) compared to eggs from a caged hen fed on a pellet-based diet.
Don’t believe the science? Next time that you can get your hands on pasture-raised eggs (from a farmer that you trust), check out the difference by comparing the yolks side-by-side with a non-free range egg. The darker yellow-orange of the pasture-raised egg is a result of a greater level of the antioxidant beta-carotene that is present because the hen has been eating a diet higher in grass and other greenery.
This does pose a challenge when trying to choose the best eggs as not everyone has access to pasture-raised eggs. When buying your eggs, at the very least choose Bord Bia Quality Assured free-range eggs (and beware that organic does not always mean free-range or pasture-raised), or keep an eye out for fresh pasture-raised farm eggs in local shops and butchers.
Now, how to eat them
In short, eggs are one of nature’s best foods. They are extremely versatile and can be used as snacks, main meals and even desserts. For too long, eggs were labelled as unhealthy, but now you can be rest assured that you can enjoy your eggs. 25 per day? Maybe not, but check out our egg recipes by clicking here, or go over to An Bord Bia’s egg recipe webpage on which we recently collaborated. You won’t be disappointed.
* A similar and often confused with concept is the “Diet-Heart Hypothesis”, which holds that high amounts of saturated fat in the diet cause heart disease.
** These studies were funded by the American Egg Board, and compared a 340 kcal “egg breakfast” – two eggs and two slices of toast with fruit spread – to an equal energy “bagel breakfast” – bagel, cream cheese and non-fat yoghurt.
*** Assuming eggs are sourced from pasture-raised hens, and of course that the consumer has no egg intolerance issues.