Those who are familiar with my past writings know that I often rant about the common dieting practice of discarding egg yolks and eating only the white of eggs. The ostensible reason for this is that the egg white is nearly pure protein, with no fat or carbohydrates. But what is often overlooked is that nearly all of the nutrients, along with half the protein content. in eggs exist only in the yolks.These nutrients include choline, important for brain health and muscle function since it's the precursor for acetylcholine synthesis. Acetylcholine is thought to be the primary neurotransmitter in the hippocampus area of the brain, a primary site of learning and memory. Indeed, in Alzheimer's disease, the neurons or brain cells that produce acetylcholine are severely damaged, leading to the obvious memory deficits seen with the disease. Acetylcholine is also the neurotransmitter at the myoneural junction, where nerve messages from the brain are sent to muscle,allowing it to contract. The yolk also contains the most bioavailable form of lutein, a carotenoid and potent antioxidant that offers eye protection, as well as helping to prevent the oxidation of low-density lipoprotein cholesterol that is at the root of cardiovascular disease. That's just two of the nutrients that exist exclusively in the yolk portion of the egg, which is summarily discarded by misguided bodybuilders and dieters. Of more pertinence to those seeking added muscle mass, the yolks also contain half of the available protein in the egg. The cholesterol found in the yolk serves as a precursor for the synthesis of testosterone. Indeed, studies of older people show that those who eat whole eggs, and engage in a resistance exercise program, show greater gains in lean mass compared to old folks who shun eggs or eat only the whites.
A new study has provided still another reason to consume the yolks. The study identified and isolated a protein found only in the yolks called anti-lipase immunoglobulin (IgY). In the study, this protein was tested on its ability to blunt the activity of pancreatic lipases, or fat-digesting enzymes. If these enzymes are blocked, fat cannot be digested, and thus is excreted out of the body without providing any calories. Since fat, at nine calories per gram, is the most concentrated source of calories among the major nutrients (protein and carbs provide 4 calories per gram), preventing the absorption of these calories could have a major impact on fat loss. Indeed, the primary drug now available to treat obesity is Orlistat, sold under the trade name of Olestra. Six years ago, an over the counter version, Alli, was released. Orlistat also works by blocking pancreatic lipase activity. But is also comes with some severe possible side effects, These include oily stools, diarrhea, gallstones, and an interference with bile flow in the liver that results in a type of hepatitis or liver inflammation. Those who want to try a natural alternative can turn to green tea polyphenols, which also block lipase activity. However, the amount of green tea capable of providing significant effects in this regard would also place inordinate stress on the liver.
In contrast, the new IgY factor from hen's egg yolks does the same thing as Orlistat minus any side effects. And it doesn't take much to accomplish this, either. In the study, a level of only 0.2% of IgY proved more effective than Orlistat at blocking lipase in an isolated cell aspect of the study. When it was provided to obese mice made fat from consuming a high-fat diet, IgY resulted in a loss of bodyfat throughout the body of the rodents. Especially noteworthy was the loss of visceral, or deep-lying abdominal fat. This is the most dangerous form of body fat from a health point of view, since it's linked to the onset of insulin resistance, diabetes, cardiovascular disease, and cancer.
Another good thing about IgY is that producing it doesn't involve any type of animal cruelty or abuse.It can be painlessly extracted through a certain technique from hen's egg yolks without producing any pain or stress in the birds.
So those who are throwing out the yolks in favor of eating only egg whites for purposes of fat reduction are paradoxically working against themselves.You might say that the yolk is on them.
Hirose, M, et al. Anti-obesity activity of hen egg anti-lipase immunoglobulin yolk, a novel pancreatic lipase inhibitor.Nut Metabol 2013;10:70.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
