And if so, what about blue or green eggs??? http://www.poultry.allotment.org.uk/Chicken_a/egg_shell_color/index.php
What is behind it? Many people believe that brown eggs are healthier than white eggs. While brown bread and brown rice are usually better for you than white bread and white rice, this is not true for eggs. Like dogs or cats (or almost any other domestic animal), there are different breeds of chicken (there are well over 100 breeds). The colour of the shell is determined by the breed of the hen. Most of the chickens that produce eggs for grocery stores are Leghorns, which lay white eggs, but chicken eggs can also be light to dark brown, blue, green, and even pink. And it doesn’t even have to be Easter.
What does the Science Say? All eggs start off white when they are still in the hen and pigments called porphyrins get added before they are laid. The pigment tints the whole shell and doesn’t just sit on the surface. Porphyrin is the same pigment that makes the red blood cells red. In chickens that lay brown eggs, the pigment is called protoporphyrin and comes from the hemoglobin in the blood. Araucanas are one of the few breeds that lays blue eggs, and the blue pigment is called oocyanin. It gets produced by the liver. Which pigment goes into the shell is determined genetically and crossing a brown egg layer with a blue egg layer produces hens that lay green eggs.
The take home message. Unless you eat the shell, the nutritional value of eggs depends on what is inside, and that depends on the bird’s diet, not genetics. Free-range eggs are in fact better for you than commercial eggs, because free chickens eat a better diet. Once thought to increase LDL cholesterol in your blood (which is bad), experts now say that eggs are good for you. The connection between the cholesterol you eat and what’s in your blood is not as clear cut as we once thought so eating cholesterol does not automatically turn into blood cholesterol. In fact, they are one of the few foods that contains nearly every nutrient we need.
We’ve known for some time that on average, women live longer than men. Here’s a theory for why.
photo: (C) 2007 K.Becker
What is behind it? How do you live to be 100? When researchers compared Rottweilers that had lived to be at least 13 years old (their average lifespan is 9) they found that “female Rottweilers that kept their ovaries for at least six years were four times more likely reach exceptional longevity” than those who had been spayed before they were 4. When it comes to people, women are more likely to reach 100 than men – 4 times more likely in fact. But when they looked at women who lost their ovaries before they were 50 they lost the usual female survival advantage. In other words their life expectancy became the same as men.
What does the Science Say? Clearly many issues are involved in aging, but the ovaries are more important to women’s health than we thought. We don’t yet know enough about the science of aging, and it is time to ask some new questions about the processes that influence the rate of aging. Postmenopausal women have the same rates of cardiovascular disease as men, and women who have their ovaries removed before age 50 do too. Curiously, the researchers also found that removing the ovaries before menopause increases the risk of dying from lung cancer. Go figure.
The take home message. Doctors used to remove people’s tonsils to avoid serious throat infections but we have since discovered that tonsils actually play a role in preventing infections. Many doctors tell women to have their ovaries removed when they’re done having kids because it helps prevent breast and ovarian cancer. Now it seems that ovaries play a role in women’s health that goes beyond reproduction, in ways we don’t understand. The message here is: don’t have anything removed that doesn’t really need to be. (Note: Women with a family history of breast or ovarian cancer should talk with their doctor about the issues of having their ovaries removed.)
I wonder if there is something we can learn from this to benefit aging in men?
More info: Center For Exceptional Longevity Studies