By Nigel Kinbrum
Eggs. Love ’em or hate ’em, you just can’t beat ’em. Hang on a minute, you can beat eggs! Questions about eggs are among the most frequently asked questions on MT which is why this article has been written.
How much protein is there in an egg/white/yolk?
Click www.nutritiondata.com/facts-C00001-01c201n.html and set serving size to 1 large (50g) to see what nutrients there are in a raw whole egg.
Click www.nutritiondata.com/facts-C00001-01c201o.html and set serving size to 1 large (33g) to see what nutrients there are in a raw egg white.
Click www.nutritiondata.com/facts-C00001-01c201p.html and set serving size to 1 large (17g) to see what nutrients there are in a raw egg yolk.
The amino acid scores for whole egg, white and yolk are 136, 145 and 146 respectively. Eggs are a good source of complete protein, because the yolk and white need to contain everything necessary for a growing chick embryo.
Can I eat my eggs raw to save time?
Another question that comes up frequently is about doing a ‘Rocky’ and necking down raw whole eggs or egg whites. There are three potential problems with this:
- Salmonella poisoning. Unless you’re pretty sure of the hens that the eggs came from, there is a risk of poisoning from raw eggs. This doesn’t apply to pasteurised eggs from suppliers like www.eggnation.co.uk. I guess the scene with Rocky sitting on the loo clutching his stomach in agony and with the world falling out of his bottom ended up on the cutting room floor.
- Poor absorption of egg white protein. According to http://jn.nutrition.org/cgi/content/full/128/10/1716, only 51% of raw egg white protein is absorbed during digestion compared to 91% for cooked egg white protein. According to http://ajpgi.physiology.org/cgi/content/full/277/5/G935, the figures are 65% and 94% respectively. The second study used 100g of white and one yolk. I don’t believe that there is a problem with the absorption of raw egg yolk, though problem 1 still remains. Pasteurised egg white protein is well-absorbed.
- Poor biotin absorption. Raw egg white contains a glycoprotein called avidin which binds to biotin (vitamin B7 or H) in the yolk and prevents its absorption. Cooking or pasteurisation denatures (changes the 3-D structure of) the avidin and renders it harmless.
What about all the cholesterol in egg yolks?
At regular intervals, someone mentions current ‘Healthy Eating’ guidelines that we should eat no more than three egg yolks/whole eggs per week. This is based on the erroneous assumption that dietary cholesterol always increases serum cholesterol and that this is always a bad thing. According to www.ajcn.org/cgi/reprint/32/5/1051.pdf, adding or not adding 500mg of dietary cholesterol from two large eggs per day made no significant difference to serum cholesterol or triglycerides in 116 healthy male subjects, some went up and some went down.
Eddie Vos at www.health-heart.org/cholesterol.htm reckons that you’d have to eat 20 whole eggs per day to get as much dietary cholesterol as the liver produces each day (5g).
Egg yolks do contain some fat and this should be factored into your total diet.
There is a problem with modern eggs though, and it’s caused by the food that’s fed to the hens. Grains contain about 50 times more linoleic acid (omega-6) than alpha-linolenic acid (omega-3) and this raises the omega-6 : omega-3 ratio of the eggs that the hens lay. Hens eating a natural diet of bugs, grubs and vegetation lay eggs with a 1:1 ratio of omega-6 : omega-3, but grain-fed hens lay eggs with an omega-6 : omega-3 ratio of >10:1. A high omega-6 : omega-3 ratio in the diet is associated with increased risk factors for heart disease, cancer and insulin resistance (pre-type 2 diabetes). Therefore, if large numbers of cheap eggs are eaten, it’s advisable to supplement with omega-3 fats.