Way back when I was a kid, my grandma would make milkshakes and banana smoothies and drop a whole raw egg into the mix. I've since carried this on and have always popped on into my protein shakes and still do. I was talking to a mate the other day who knows a bit about nutrition, and he said it's quite bad to consume raw egg whites (I have actually heard this before but ignored it), the yolk on the other hand is fine. So what's the big problem with raw whites?
Think of raw egg whites as raw nuts with phytic acid. Raw egg white contains a protein called "conalbumin" which binds to iron (making it not biologically available to the body.) They also contains avidin, which binds to biotin and can impair metabolism of other B-vitamins. Like raw nuts and phytic acid, these proteins bind to vital vitamins and minerals rendering them unusable by the body. (Or at least far less digestible since I don't have specific numbers.)
Yolks are fine to eat raw, but whites are more bio-available to the body upon cooking.The anti-nutrient profile is eliminated/reduced rendering all major nutrients usable.
supposedly, raw egg white has some bioactive proteins and one, avidin, can cause biotin deficiency.
"...(biotin) deficiencies can be caused by consuming raw egg whites over a period of months to years. Egg whites contain high levels of avidin, a protein that binds biotin strongly. When cooked, avidin is partially denatured and becomes somewhat non-toxic. A recent study1 found that activity in fried, poached and boiled (2 min) egg white was 33, 71 and 40% of the activity in raw egg white respectively..."
You can always supplement with Biotin or get from other food sources to counter the whole raw eggs if you feel the need
edit: another different wiki link to biotin deficiency.
"...(biotin) deficiency can be caused by the consumption of raw egg whites (two or more), which contain high levels of the protein avidin, which binds biotin strongly, daily for several months, has caused biotin deficiency serious enough to produce symptoms..."
It's not bad, its just that the body can use the egg protein more if it is cooked. The yolk should be left runny and not cooked so the cholesterol in it won't get oxidized.
Rob, the big problem with eating raw egg whites is that your friend doesn't know what he is talking about. Your grandma was right and your friend is wrong. Think back 25,000 years ago. Can you imagine Oog telling Gog that eggs white were bad for him? If egg white were bad for people, there wouldn't be any people. Eggs have got to be one of the most frequently eaten items since they don't fight back. Easy nutrition with zero resistance. So we can be sure that whole eggs, even some of the shell, were a major part of the paleo diet. And you have evolved to eat whole, raw eggs.
However, this is bad advice if you are eating high carbs and are otherwise not eating and living paleo.
I heard it being bandied about for a while that consuming egg whites without the yolk prevented it from being a complete protein. That seems to have been settled more or less now.
Egg whites seem to have been lumped into this category:
"...Some foods contain all the essential amino acids on their own in a sufficient amount to qualify as a "complete protein.." - http://en.wikipedia.org/wiki/Complete_protein
I guess you'll have to decide whether a 'sufficient amount' according to the regulators is enough for you.
Raw egg whites are absolutely fine if they are sourced properly. There is zero risk of bacteria from lack of refrigeration in a pastured eggs because they do not require cold. They can stay at room temperature.
IN doing a search for enzyme inhibitors, I came across a website listing raw egg whites, peanuts, soybeans and lima beans. I separate the yolk from the white and cook the white but I would guess anyone taking nutrient supplements including enzymes wouldn't have a problem either way.
Doctor Mercola advocates eating whole raw eggs and has been doing this for years. His point is that there's enough biotin in the yolk to compensate for avidin in the egg whites. Chris Masterjohn, I know, is against the (raw) whites though. Regarding conalbumin, well, lowering iron isn't necessarily a bad thing if you get too much anyway (being paleo, let's say, you get more than enough from red meats). In fact, lowering serum iron is something that many people in the life extension space do by donating blood every two months. Too much iron could be worse than being on the low border. I think if people believe in the Paleo idea, raw whole eggs are totally okay with no debate. If you don't believe raw whole eggs are good, then obviously you should question the whole Paleo idea as well.