Eggs Demystified

by Bill Willis, PhD on June 1, 2013

June 2013: Eggs Demystified

With some of the highest biological value protein obtainable from a whole-food source, whole-egg protein is gram for gram one of the best muscle-building proteins out there. In recent years, the variety eggs available through local farms and grocery stores have literally exploded, however. A quick trip to the grocery isle yields a dizzying array of different types of eggs and egg-products, which can make choosing the right type of egg a challenge. A quick Google search of “free range eggs” yields around 1,470,000 hits for this keyword, with most articles taking an impassioned stance one way or another. You will find articles that state, nutritionally speaking, “an egg is an egg” and on the other side, there are plenty of impassioned arguments against conventional eggs commonly found at the supermarket. It can be tough to sort through this type of information overload, so for the article for this month we will sort through the egg-confusion, and come to a consensus: what really is the best type of egg to eat?

Types of eggs commonly available:

Cage-free Eggs

Cage free eggs are from chickens that were not raised in cages. Not to be mistaken with free range eggs (see below), “cage free” chickens can be packed into very close quarters with many other hens, or they can enjoy lots of space. It all depends on the farm. Cage free chickens are usually kept in the open-floor area of a large barn, with bedding material such as pine shavings, and perches and nest-boxes available to lay their eggs.

Free-range Eggs

Free range eggs come from hens that have the opportunity to roam and lay their eggs as they please. If kept in a barn, they have the freedom to travel in and out of their living quarters whenever they want. It is best to be familiar with the source when purchasing free range eggs: The US department of agriculture only requires that chickens spend part of their time outside for their eggs to be labeled and sold as “free range”. Keep this in mind when spending the extra $ for free range eggs from a large grocery store chain, where the local source is often unknown.

Organic Eggs

Although organic eggs typically come from hens that are raised in a cage-free- or free range environment, they can technically be kept in any kind of caging system. To qualify for the USDA organic certification, grains used in the hens’ diets must be produced on land that has been free from the use of chemical pesticides and fertilizer for at least three years. Although genetically engineered crops are permitted for use as feed, these chickens are always maintained without the use of hormones or antibiotics.

Vegetarian Eggs

Vegetarian eggs come from hens that are fed a vegetarian-only diet, which is free from any type of fish or meat byproducts. Practices used when raising vegetarian eggs varies by the farm. Because chickens will happily eat insects, grubs, or worms that they encounter outdoors, true vegetarian eggs come from chickens that are strictly kept indoors, in cages or in cage-free setups. Many farmers who raise free range chickens will label their eggs as vegetarian anyways, as long as their provided feed isn’t derived from any animal byproducts.

Omega-3 eggs

Omega 3 eggs come from chickens that have been fed a diet enriched with omega-3 fatty acids, which significantly raises the omega 3 content in their eggs. Typically chickens raised to produce omega 3 eggs are fed a strictly vegetarian diet, and are kept indoors in cages- or cage-free conditions.

Pasteurized Eggs

Pasteurized eggs have been put through a pasteurization process, which completely kills any bacteria or viruses that may be present without cooking the egg. By law, all egg products in the US are pasteurized to reduce the risk of salmonella or other bacterial infection. Although eating raw eggs is generally not recommended, if you are going to do so (or for recipes such as eggnog that require raw eggs) pasteurized eggs are the best choice. After pasteurization, the eggs are coated with food-grade wax to maintain freshness and stamped with a “P” in a circle to distinguish them from unpasteurized eggs. Pasteurized eggs are currently sold under the “Davidson’s Safest Choice” brand name, which is available at some grocery stores. Pasteurized eggs are generally recommended as the safest choice for anyone who may have a weakened immune system, to reduce the risk of contracting salmonella infection. Many people dump these into their protein shakes for extra protein. It is often said that you get about 60% absorption when not cooked fyi.

Now, for a clarification. If you were to obtain your eggs from a farmer where you could see the quarters of the hens, how they feed, etc. then your chances of obtaining any kind of sickness dwindle to near nothing. Many a bodybuilder in the old days went to farms to get their eggs and drank them Rocky style, that’s for sure. With how poorly the animals are raised now though, you would want to be sure.

Organic free range eggs: The “gold-standard”

Now that we have defined all of different types of eggs available, let’s get right to the point: the best types of eggs to buy, hands down, are organic free range eggs. Free range chickens are happier, healthier, enjoy a more natural diet, and overall lead better lives. From that standpoint, choosing free-range over other varieties of eggs is commendable from an animal welfare standpoint, but this also equates to better nutrition. As the saying goes: you are what you eat, ate. Free range chickens enjoy a more natural diet, and pass this on in the form of more nutritional value in their eggs. Free range isn’t enough however- it is also important to choose organic eggs. “Organically” raised chickens are not exposed to any antibiotics or hormones, which can show up in trace amounts in the eggs of conventionally raised hens. Furthermore, (non-organically raised ) “free range” chickens which are allowed to graze in pesticide-treated pastures can absorb toxic chemicals such as dioxins and dioxin-like polychlorinated biphenyls (1), which also show up in trace levels in their eggs. This is a big concern, because dioxins and other pollutants like them enter the body mainly through food intake, are potential carcinogens, and are also known to cause immune-and reproductive toxicity (2) if allowed to accumulate to sufficient levels.

The first thing you will notice when you crack open an organic free range egg, is that the yolk is typically a very rich yellow/golden color, compared to the pale-yellow color of yolks from conventional eggs. The color of the egg is actually an indicator of what the hen has been eating. Carotenoid-compounds found in the diet make egg yolks yellow. The type of diets that free range chickens naturally enjoy are also typically enriched in naturally occurring carotenoids, which makes their yolks a rich, golden yellow color. Traditionally, pale-yellow yolks were associated with sick hens, worm infestation, or poor feed. Only well-nourished hens stored a large supply of carotenoids (mostly in the form of vitamin A) in their yolks. In modern times, not much has changed; cage-raised chickens fed standard chicken feed are far less healthy than free range chickens, and the nutritional value of their eggs suffers as a result.

Unlike mammalian eggs, which rely 100% on nutrition filtering through the womb from the mother, chicken eggs contain everything an embryo needs to develop into a chick. Eggs are a great source of protein and also certain micronutrients for this reason. Due to their better living conditions and more-natural diets, organic free range eggs also tend to be better sources certain micronutrients including B-vitamins, selenium, and vitamin E.

Conventionally raised hens, whether kept in cages or cage-free, are fed a diet that consists mostly of grains, which tend to be high in omega-6 fatty acids. Naturally, the eggs produced from these hens are also enriched with omega-6 fatty acids. On the other hand, pasture-fed free range chickens enjoy a more natural diet, eating grass and bugs which tend to be more enriched in omega 3 fats. The health benefits of eating a balanced diet in terms of omega 3:6 fats could be the subject for another article entirely (or even a book), but for our purposes here, suffice it to say when the omega 3:6 ratio in your diet leans too much toward the ‘6’ side and away from the ‘3’ side, things start to go downhill. Too many omega-6 fats relative to omega-3 fats promotes inflammation, which is increasingly becoming associated with just about every chronic disease you can think of (cancer, diabetes, autoimmune diseases, “metabolic syndrome”, etc.) People are getting sicker because they are eating animals and animal products that were fed a diet highly enriched with omega-6 containing grain. It’s cheap and cost-effective to sustain the animals, but a screwed up fatty acid profile gets passed down the food chain. You are what you eat, ate.

What about the cholesterol issue?

I try to avoid wading too deep into the waters of the cholesterol/saturated fat debate. There is a lot that we just don’t know yet, and there are (some) valid points on both sides the argument. With hotly contested issues such as this one, the more sensational/impassioned arguments on either side also tend to rely more on belief systems and less on hard evidence. That said, one thing is for sure: the human body is capable of making way more cholesterol than anyone could ever obtain from dietary sources, and cholesterol is not the dietary demon that it is commonly made out to be. While eggs contain more cholesterol relative to other foods, in the absence of any underlying genetic disorder that causes high levels of cholesterol or blood lipids, pathologically high cholesterol levels are caused by excessive energy intake, not from eating too many eggs.

Egg safety

The terms free range, cage, free, organic, etc have little to do with contamination. Buying the best free range/organic eggs available is all for nothing if your eggs are contaminated with salmonella. To ensure safety, follow these tips to minimize contamination:

Immediately refrigerate eggs to 45F or below: if bacteria are present, they won’t be able to multiply, which gives your immune system a better chance of dealing with them
Cook eggs thoroughly until both the white and yolk are firm, and no longer liquid. This kills salmonella.
If you happen to have your own chickens, wash all eggs thoroughly in hot/soapy water before refrigerating.
For recipes that call for raw eggs, be sure to use pasteurized eggs.
When buying fresh eggs from a local farmer’s market, be sure to ask whether the eggs have been washed and refrigerated within 36 hours of being collected… this cuts the risk for salmonella contamination.

Wrap-up: eggs demystified

Eggs are a convenient, high powered protein that can be used at any meal, for any type of nutrition plan. Egg protein is also loaded with leucine, making it one of best muscle- building proteins out there. There are lots of choices out there when it comes to eggs, but organic/free range is the “gold standard” because the chickens are happier and healthier, their eggs are free from dangerous contaminants, and they are nutritionally superior. If buying from a local grocery store instead of a local farm, be sure to know the source. USDA standards for “free range” aren’t very stringent, which opens up the potential for dishonest advertising. At any rate, you can easily tell the quality of the eggs you have by cracking them open. Look for a rich, darker yellow- to golden colored yolk as an indicator of the overall quality of the hen’s diet, which also indicates a better egg. You are what you eat, ate.

Reference List

Schoeters G, Hoogenboom R. Contamination of free-range chicken eggs with dioxins and dioxin-like polychlorinated biphenyls. Mol Nutr Food Res 2006;50:908-14.
Safe S. Polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and related compounds: environmental and mechanistic considerations which support the development of toxic equivalency factors (TEFs). Crit Rev Toxicol 1990;21:51-88.