By Dr. Joseph Mercola
Notice: Important 2009 Raw Egg Update Since publishing this article in 2005, I have more carefully studied the issue of whether to consume WHOLE raw eggs or only egg yolks ... and my recommendation is to eat the WHOLE egg raw, as I originally advised in 2002. Avoiding raw egg yolks is the conventional nutritional dogma as raw egg whites contain a glycoprotein called avidin that is very effective at binding biotin, one of the B vitamins. The concern is that this can lead to a biotin deficiency. The simple solution is to cook the egg whites as this completely deactivates the avidin. The problem is that this also completely deactivates nearly every other protein in the egg white. While you will still obtain nutritional benefits from consuming cooked egg whites, from a nutritional perspective it would seem far better to consume them uncooked. Two groups brought me to back this: pet owners who feed their pets raw foods and Aajonus Vonderplanitz, who wrote the raw food book We Want to Live. Both feel quite strongly that raw eggs are just fine to eat. After my recent studies it became clear that the egg's design carefully compensated for this issue. It put tons of biotin in the egg yolk. Egg yolks have one of the highest concentrations of biotin found in nature. So it is likely that you will not have a biotin deficiency if you consume the whole raw egg, yolk and white. It is also clear, however, that if you only consume raw egg whites, you are nearly guaranteed to develop a biotin deficiency unless you take a biotin supplement. So to be clear, my advice is that you can safely eat WHOLE raw eggs, from a healthy fresh source. Personally I eat four whole raw eggs each morning with my breakfast. For more information on eating raw eggs, including salmonella fears, please read my earlier article on raw eggs.
Well folks, it is time for a major update on my recommendations for eating raw eggs. First, before I review the update, I want to dispel the common myth that raw eggs are bad for you. Most people fear them because of the risk for salmonella contamination. If you are still concerned about this please read my earlier article on raw eggs.
As part of that article I had stated that one should never consume raw egg white alone without the yolks, as a component in them called avidin binds to the B-vitamin biotin, potentially creating a deficiency in your body. However, my position shifted when one consumed whole raw eggs, both the yolk and the white together.
One of my raw food mentors convinced me that there was more than enough biotin in raw egg yolks to compensate for this problem, and I revised my previous recommendation to say that eating whole raw eggs would not pose a problem. This idea made sense to me as many wild animals consume raw eggs with no apparent problems.
However, recently a subscriber, Dr. Sharma, PhD, who is a biochemist with Bayer, contacted me about this issue. His investigation into the matter revealed that there is not enough biotin in an egg yolk to bind to all the avidin present in the raw whites. He found that 5.7 grams of biotin are required to neutralize all the avidin found in the raw whites of an average-sized egg. There are only about 25 micrograms -- or 25 millionths of a gram -- of biotin in an average egg yolk.
This is obviously not nearly enough to do the job. For this very reason, controlled diets of only raw egg whites lead to severe biotin deficiency.
New Egg White Recommendations
So is this the 'end' for the healthy consumption of raw egg whites? If you naturally tend to be biotin deficient or are pregnant then the answer is yes. However, raw egg whites (the white 'Yin' to the yolk's 'Yang') are part of the important combined nutritional balance of the egg.
The nutritional breakdown of the egg white is rather impressive. With 9.8 grams of varied protein, high riboflavin, magnesium and potassium, plus a whopping 25 percent the daily value of selenium, there are options to have your white and eat it too! If you decide to eat whole raw eggs, here are my suggested options:
My primary new recommendation, and the one I now follow, is to separate the yolks from the whites so you can cook the whites and consume the yolks uncooked, or raw. The white can be cooked and eaten on its own. Although cooking the white reduces the nutrient quality and perhaps increases allergic sensitivities to some, the avidin in the egg white breaks down when cooked to 100 degrees Centigrade, therefore releasing the biotin back for your absorption and virtually eliminating any risk of biotin deficiency.
Supplement with biotin. Safe and adequate recommendations for biotin use are about 30 to 300 micrograms per day in adults, and 10 to 30 micrograms per day for infants and children. Typical therapeutic doses are anywhere between 100 micrograms and 16 milligrams per day.
Studies have shown daily doses as high as 100 milligrams caused no adverse effects in otherwise healthy individuals. No studies to date have been done using intakes anywhere near 5.7 grams, but for those who are interested Allergy Research Group has a 5,000-mg biotin capsule, and, depending on your overall egg consumption, there's also an 8,000-mg capsule by Thorne. You would theoretically need about 5,000 mg of biotin per egg white to 'neutralize' the avidin in the average large egg.
You can also get limited amounts of biotin from your food. Animal livers are by far the richest sources.
Don't eat raw egg whites every day. Allow your biotin reserves to rebuild and eat only raw yolks or an alternative breakfast.
Eat yolks one day then whites the next. Remember that the biotin loss occurs in your digestive tract when the two molecules bond together before it is even absorbed. Eating the yolk and the white separately will greatly reduce the problem.
Keep your intestinal flora healthy. Probiotics should always be used. The GI track is long and has evolved different biotin strategies at different locations. A 1989 study showed quality biotin absorbed most effectively at the upper bowel. Keeping this region healthy and functioning optimally with plenty of good bacteria is a must to speed up the nutrient uptake of high-quality, small molecules such as biotin versus the 'lumbering' avidin at the start of digestion.
Additionally, a healthy lower bowel will produce limited biotin on its own and absorption may even be possible.
Detection and Treatment of a Biotin Deficiency
If you have been consuming whole raw eggs like I have, you may be concerned that you are now deficient in biotin. You need not worry too much as it takes months to years of severely deficient biotin intake to cause any noticeable symptoms, and these symptoms will clear up quickly if you stop eating raw egg whites and take a biotin supplement for a few weeks.
Common symptoms of biotin deficiency include:
Less common symptoms of biotin deficiency include:
A definitive diagnosis of biotin deficiency can be made if the symptoms in question resolve by supplementing with biotin, or by measuring and detecting a reduction in urinary excretion of biotin.
The Bottom Line
One of the problems with being on the leading edge of natural medicine is that occasionally one will veer off course a bit, but with time the direction always swings back to the truth. Many readers have appreciated my openness to modifying my views based on new information. This is in direct contrast to the conventional medical model that can be quite dogmatic and rigid about considering new data to modify their current beliefs.
When eating any part of an egg raw, I also recommend that you read my guidelines on how to ensure that you are consuming fresh high-quality eggs.