Different tasks are assigned to the egg and sperm. In recent years researchers have focused on the type of mechanisms that are utilized by a single sperm, which is in a race with millions of others to reach and enter the egg to fertilize it. Fertilization is not an event that happens by itself. It occurs depending on the interactions of sperm and egg in a very systematic way. It has been studied intensely how the molecules on the surfaces of the egg and sperm behave so selectively like orchestra conductors during fertilization. They fit together like a matching lock and key.

The proteins on the outer membrane of the egg

Mammalian sperm cells resemble a chubby arrow with a long tail. However, egg cells are found in different shapes and sizes. Millions of sperm in mammals compete with each other to be the first to reach the egg through the reproductive canal. The human egg is kept in a jelly like covering and a strong, protective membrane (or coat) called the Zona pellucida lies underneath this covering. It wraps the outer perimeter of the cell. Glycoproteins (ZP1, ZP2, ZP3, and ZP4) that function as the locks in the key-lock model are located at this protective layer. Sialyl-LewisX is a special type of tetrasaccharide carbohydrate (sugar) that binds to the proteins and lipids on this membrane. This carbohydrate is assigned with the task of making the egg’s surface sticky and this helps with the facilitation of sperm attachment to the outer receptors of the egg. In 2011, it was proved that this sugar molecule plays a critical role during fertilization.

Only a few of the sperm among the millions that joined the contest can make it to this layer. A lower sperm count as well as a sperm’s failure to cross this barrier can play a role in unsuccessful unions with the egg.

During the union of sperm and egg, the sperm becomes very active and its outer proteins are rearranged, thus getting recognized by the proteins of the outer layer of the egg (Zona pellucida). The ZP3 glycoprotein, working like a terminal gate, assists with the entry of the mammalian sperm into the egg. There is no chance for a sperm to cross the membrane once it has failed to bind to this receptor. The chemical changes initiated inside the sperm when bound to this protein trigger the secretion of acrosomal enzymes. Upon the release of enzymes, the Zona pellucida is broken down and the entry of sperm is permitted.

There are two distinct sections, called the ZP3-N and the ZP3-C, of the ZP3 molecule which is composed of 424 amino acids. The ZP3-N section of the ZP3 protein is conserved strictly as it is in the outer membranes of eggs of all animals, from fish to amphibians, birds, and mammalians. This suggests of a critical function for this protein. New birth control pills can be developed if small molecules that can attach to the ZP3 binding regions of the sperm can be discovered.

The second receptor required for the fertilization of the egg is the glycoprotein called ZP2. Certain sections of the ZP2 are responsible for sperm recognition and enabling the union. During experiments with mice, eggs were found to secrete an enzyme called ovastacin right after fertilization, destroying the binding protein (ZP2) which works outside the egg like a lock, thus disabling the egg’s ability to take up another sperm. Without this enzyme, sperms will continue to bind to the egg, even after divisions, leading to multiple fertilizations and eventually killing the embryo.

The process of fertilization is wondrous, a perfect meeting of time and circumstance. New research is revealing just how refined reproduction systems really are as they are found in nature.

How does an egg find the right sperm?

After an investigation regarding 1,880 protein encoding genes and proteins involved in reproduction, regions prone to mutation have been discovered on these genes. Mutations are found to occur frequently in ZP2 and ZP3 proteins that are directly involved with the egg and sperm interaction, along with proteins required for acrosomal reactions. There are various hypotheses being developed to unveil the causes behind the rapid mutation rate of proteins taking part in the reproduction system. These speculations range from gender dependent selection, to the development of traits by males that will be more attractive to females, and the avoidance of diseases. Reproduction is not collaboration; it is a race between millions of sperm, and only one can fertilize the egg.

At the molecular level, sperms try to accelerate this process and complete it as soon as possible, whereas the egg tries to slow it down. Therefore the needs of egg and sperm differ during fertilization: sperms fight to reach the egg and be selected, whereas the task of the egg is to be selective. The egg needs time to pick the most suitable sperm. After this selection, it must ensure the entry for the selected sperm and block access for the rest of them. Therefore, one way to achieve this successfully is via small mutations that lead to selective surface variations occurring in the structures of receptor proteins in charge of sperm recognition located on the egg membrane.

There are interesting results obtained with experiments performed on the eggs of Strongylocentrotus franciscanus, the red sea urchin. Sea urchins free their eggs into open sea for fertilization. The wisdom behind this is to ensure the fertilization of different eggs by different males. Being released into open water gives the eggs many options and puts pressure on the sperms. Variations are observed in the egg recognition proteins (Bindin) of each sperm; these proteins work like a key on the outer surface to attach, punch, and cross the egg membrane. Sea urchin eggs are also equipped with molecular blocking mechanisms to prevent the simultaneous entry of two sperms. Sperms thus go through mutations regarding egg recognition proteins and new keys are developed. The mutations occurring in the genes that encode the proteins, both on the egg and sperm membranes, result in slightly different matches that do not fully conform to one another. This situation causes a delay in the entry process. This meaningful delay is to grant the egg the necessary time to close the molecular gates to block access to a second or third sperm.

The studies carried out over sea urchin populations confirmed that such events take place in nature. The mutations are accelerated in genes that encode egg-recognition proteins and variants of such proteins are produced on the surface of sperms that exist in waters with high population density. In parallel to this, mutations also take place on receptor proteins of sea urchin eggs; these act like a lock. Studies confirmed that there are sperms that both lock perfectly and just shy of perfectly with these eggs. In cases of lower sperm density, it has been revealed that conforming and easily matching variants of the egg-recognition proteins of sperms are synthesized to facilitate fertilization. And in cases of higher sperm counts, a different form of receptor protein is found to be synthesized. This adaptation is interpreted as cautionary, as it prevents the entry of multiple regular-form sperms into the egg. In other words, a mutation regarding the sperm binding receptors can develop in females, thus establishing a prevention system against fertilization. Therefore, the role of the egg in reproduction is too critical to neglect.

These findings contain significant messages for human reproductive science. For instance, these new models can explain the role of the egg in certain infertility situations. It is possible that numerous variations have developed over time for human egg and sperm proteins. Mismatches in the key-lock system (protein-protein binding) may increase with these variations, and this would inhibit fertilization. This can eventually result in a failure to reproduce. Consequently, the know-how of the egg-sperm recognition systems awaits researchers as a new field of research. The most interesting development of this research is that eggs and sperms that are far away from each other still develop key and lock mechanisms, as if they are equipped with high level intelligence, willpower, and knowledge.

In summary, fertilization depends on suitable alterations and the necessary overlap of these changes in both sperms and eggs. It does not mean that all nonconforming matches are resulting from low quality eggs. In some cases, one reason for the mismatch is due to the defense mechanism of the egg against fertilization by male members of different species.that the egg is preventing itself from a bad match. The fact that the egg is equipped with a protective system at the molecular level simply shows that nothing is left to chance in nature.

Further reading

Gaidos, Susan. 2012. “As Told by the Egg: The story of fertilization from the female point of view.” Science News Prime. December 10, 2012. www.sciencenews.org

Harming our bodies or health is a betrayal against this incredible gift. One of the major ways people harm the body is through smoking cigarettes.

Smoking harms human health in countless ways. It is one of the main causes of many diseases, such as lung and throat cancer, along with cardiovascular and respiratory track diseases, such as chronic bronchitis. According to the latest report from the World Health Organization, smoking remains the fourth of the top ten risks that threaten human health. Approximately 20-30% of adult fatalities are caused by ailments contributed to by smoking. Recent studies have shown the negative effects smoking has on human reproductive functions.

Effects on fallopian tubes

Smoking has a negative impact on female reproductive organs; this impact is determined by how long, and how much, a woman smokes. It may cause infertility by damaging the fallopian tubes that serve as a ground for the egg to be fertilized by sperm. In many studies, the risk of damage to the fallopian tubes was very high – this danger increases if a woman starts smoking a pack a day before the age of 18.

Effects on female hormones

Many toxic substances in cigarette smoke, including nicotine, directly inhibits the activity of the enzyme called aromatase, which plays a major role in the synthesis of the female hormone (estrogen) in the ovaries. Depending on the biological function, estrogen can be found in three different forms: as estrone, estriol and estradiol. Polyaromatic hydrocarbons found in cigarette smoke stimulate the microsomal cytochrome P-450 enzyme system that degrades hormones in the liver and, consequentially, increases conversion of estradiol with high biologic activity into estriol with the lowest activity. Alkaloids, one of the harmful substances found in cigarette smoke, were discovered to prevent production of progesterone in the ovaries. This plays a role in preparing the womb and in continuation of the pregnancy during the first three months. Therefore, smoking leads to progesterone deficiency during the early stages of pregnancy, causing miscarriages.

Effects on the maturation of the egg

The concentrations of the FSH hormone that is involved in the maturation of reproductive cells in the ovaries are especially high in young female smokers. In other words, a resistance develops against the FSH hormone in the ovaries and higher FSH hormone levels are required for the maturation of the egg. Thus, fertilization problems and missed periods can occur because of an absent reproductive cell. During the treatment of such patients with insufficient egg cell maturation, there is a 50% decrease in the success of the implantation (placement of the fertilized egg into the womb) and the continuation of the pregnancy in smokers when compared to nonsmokers. This means smoking significantly reduces ovarian functions, and ovarian stimulation becomes inadequate at earlier ages in women.

The negative effects of smoking on the reproductive system are also observed during the implementation of reproduction methods such as in vitro fertilization and assisted fertility technologies. The presence of high androgenic hormone levels (pre-metabolites of gender related hormones: androstenedione, DHEAS and testosterone/SHBG) in female smokers has been found to decrease the possibility of pregnancy during in vitro fertilization efforts.

Effects during pregnancy

There are many harmful consequences of smoking during pregnancy, especially for older women who are pregnant. Some of these consequences are premature birth, miscarriage, retardation of development, inadequate baby weight, perinatal mortality, ectopic pregnancy, placental praevia, and placental abruption. Placental praevia is the abnormal placement of placenta in the womb. In this case, depending on the excessive bleeding that occurs after the eighth month of gestation, the lives of the mother and fetus become imperiled, and fetal development is hindered. Placental abruption occurs depending on the premature separation of placenta from the womb, causing excessive bleeding that can also endanger the lives of the mother and baby.

In pregnant smokers, the postnatal ratio of infant mortality and disability increases as a consequence of deficiencies involving lung function and nerve development. These effects are directly proportional to how much a woman smokes. There are also negative impacts when a pregnant woman is exposed to second hand smoke by a spouse or close friend. Harmful metabolites of nicotine reach the baby via the placenta. Furthermore, nicotine is degraded slowly in the liver of a pregnant woman. Inadequate baby weight is related to smoking dosage and time.

Due to smoking in the early stages of pregnancy, the hormone levels of estriol, estradiol, progesterone and hCG, hPL which is secreted from the placenta, have been found to decrease. This reduction, which is observed in parallel with the amount of smoking, can result in miscarriages.

Toxic polyaromatic hydrocarbons have been found to accumulate at elevated ratios in the wombs of women who were exposed to cigarette smoke for a long time. During pregnancy, this situation leads to the deterioration of sertoli cells located in the reproductive glands of male fetuses. These glands assist in sperm production during adulthood, and damage to them can therefore cause a reduction in sperm generation.

An insufficient placental development occurs because of the negative effects of nicotine, cadmiums, and polyaromatic hydrocarbons damage the reproduction of trophoblast cells that make up the placenta. This situation explains the increasing miscarriage ratios among female smokers.

The free T4/TSH ratio in the serum of the umbilical cord, which connects the fetus to the placenta, increases in the babies of smokers compared to those of nonsmokers. This means that in babies of smokers, the thyroid glands may become overactive during birth. Depending on a mother’s smoking habits, this hyperactivity of the fetal thyroid increases the metabolic speed and the amount of consumed oxygen in the body, thus leading to the inadequate development of fetus.

Menopause occurs two-to-four years earlier due in women who smoke, as compared to non-smokers. This is due to the aging of the eggs. The risk of entering menopause before the age of 45 in women who quit smoking at least ten years prior is 87% less than smokers who don’t quit. Therefore, the earlier a woman stops smoking, the lower the risk of early menopause.

Effects of smoking on men

In research studies, it has been discovered that smoking has many harmful effects on testicular development and functions. These effects can be summarized as follows:

• Reduction of semen volume and quality, increase in its adhesiveness, delay in its becoming liquid, and resulting deformation of the sperm.

• Reduction in the number and mobility of sperm cells.

• Delayed sperm nucleus maturation, deteriorated DNA integrity.

• Decrease in the production of testosterone from Leyding cells.

• Decrease in the egg fertilization capacity of the sperm.

As a consequence of these negative effects, male infertility can occur. As the amount of daily cigarette consumption increases, the number, strength, and types of anomalies also increase. In a study conducted in 2010, smoking has been showed to decrease zinc levels in the seminal plasma. As a result of this decrease, oxidative agents populate and DNA breaks take place, thus causing a disruption of sperm functions and infertility. Zinc deficiency at the same time leads to the destruction of seminiferous tubule cells where sperm cells are produced. Paternal smoking generates negative results during the application of assisted fertility methods (such as in vitro fertilization). The damage in the sperm DNA of the father can disrupt the embryo development. The risk of anomalies, cancer, and genetic diseases increases for the fetus.

Cigarette smoking clearly occupies a position as one of the worst enemies of mankind because of its destructive effects on the body. In this case, it does not make any sense to try finding excuses for smoking, for it is harmful to the body that has been loaned to us as a gift and a temporary property.

Cihanoglu is a professor of medicine in KATU, Trabzon, Turkey.

The 300 to 500 sperms which strive to enter into egg meet with the cell layer (corona radiata) which is being serially positioned around the zona radiata. A liquid is secreted from this zona radiata which punctures the euchromosome¹ placed on tip of sperm. Each of various enzymes set free following the puncture of euchromosome is assigned to overcome a separate obstacle before the sperm. Duty of the hyaluronidase enzyme, for instance, is to puncture the outer cell layer (corona radiata) which is assigned to protect the egg. Resultantly, the sperm passes through this cell layer and sticks onto the zona radiata (zona pellucida). The quasi-trypsin dissolutive (proteolytic) enzymes are employed for overcoming the zona radiata. Only one or rarely two of the few sperms which stuck onto this zona radiata manages to penetrate into the egg. It has been estimated that plurality of sperms around the egg, contrary to their rarity, facilitates their entry into the egg.

The sperm penetrates into the egg with its tail but tail membrane stays outside. The protective membrane of the ovum (zona pellucida) starts diffusing calcium within the very first minutes of sperm’s penetration and resultantly, granules are released, receptors are exterminated and the egg becomes structurally transformed. Consequently, a thick layer is formed over the protective membrane (zona pellucida) for prevention of penetration of another sperm.

Following the sperm’s penetration into egg (cytoplasm), the “fusion” process starts. Fusion is the unification process of sperm and egg cells (pronuclei) each of which are separately containing 23 chromosomes. Thus, construction of a genetical library which is containing 46 chromosomes and being prerequisite of formation (creation) of a new human baby is completed. Afterwards, the first mitotic division gives way to a double-celled zygote and the embryo starts forming while settling into the secure base of the uterus. As the outcoming child is going to be a mixture, i.e., a genuine and particular blend of the genetic codes available in the inherited gene pool, he/she will have resemblance to his/her parents and thus to their reciprocal kins (paternal and maternal grandparents, uncles and aunts and etc.).

Prophet Muhammad and Genetics

Prophet Muhammad, peace be upon him, pointed in his various sayings and explanations to the fact that the baby in mother’s womb carries a number of genetic features (characteristics) which are being inherited from the parents:

When a Jewish person asked Him, “what is man created from?” he replied: “Man is created from a blend (mixture) of zygotes of both man and woman.” Then the Jew said: “Moses as well said the same before you.”²

Prophet Muhammad, peace be upon him, also shed light onto the fact of resemblance or inheritance of character by way of genes:

“Is bathing a must for women?” asked Umm Sulaim to the Prophet.

“Yes, it is a must when her seminal fluid outflows and seen,” he replied.

“Do women have wet dreams?” she asked.

“May God grant you goodness! How otherwise a child resembles to his/her mother?” He replied.³

….

As seen and understood by His above hadith (saying), He who was the great teacher of mankind was the first person who said that women do also see wet dreams.

He has also been the first person who articulated the concept of “dominancy,” which was not understood before 1850s.

He said:

“The child resembles to either side of the parents whose seminal fluid comes to the fore and surpasses the other’s in mother’s womb during the intercourse. If there is an equilibrium, then, resemblance is also in equilibrium for both sides.”⁴

“If, during the intercourse, seminal fluid of the man precedes and surpasses that of the woman, then, the child resembles to the father, and if semimal fluid of the woman precedes and surpasses that of the man, then, the child resembles to the mother.”⁵

“If seminal fluid of the woman surpasses that of the man, then, the child resembles to his/her maternal uncles, and, if seminal fluid of the man surpasses that of the woman, then, the child resembles to his/her paternal uncles.”⁶

In another one of His sayings, He points out to the fact that the recessive characters (features) in the grand ancestorial gene pool would dominantly and collectively emerge after following a couple of generations:

“A man having a blackish baby boy approached and said to the Prophet:

“I am suspecting my wife.”

“Do you have camels?” the Prophet asked him.

“Yes,” he replied.

“Then, how are their colors?” The Prophet asked.

“Red.”

“Is there any one with grey color among them?”

“Yes, there is.”

“Then, where did this grey color come from?” asked the Prophet.

“Presumably from a line of its ancestors,” the man responded.

“Here you are! This child of you is also presumed to be coming from a line of your ancestors,” the Prophet told the man.⁷

Dr. Arslan Mayda is a medical doctor at Sifa Hospital in Izmir, Turkey.

Notes and References

1. An euchromosome zone enriched by lysosome enzymes is noticed on stem of a mature sperm cell. The lysosome enzymes penetrate into the egg cell and impregnate it.

2. Ahmad Bin Hanbal, Aynee, Ramouz Al Ahadeeth, Kanz Al Ummal, Jami’ul Saghir

3. Bukhari, Muslim, Abu Dawoud, Aynee, Ahmad Bin Hanbal.

4. Muslim, Ibn Majah.

5. Bukhari, Ahmad Bin Hanbal.

6. Bukhari, Muslim, Abu Dawoud.

7. Abu Dawoud, Muslim, Ahmad Bin Hanbal, Ibn Majah.

The name cholesterol originates from the Greek chole- (bile) and stereos (solid), and the chemical suffix -ol for an alcohol, as researchers first identified cholesterol in solid form in gallstones in 1784.1 Cholesterol is a soft and waxy sterol (a combination steroid and alcohol) found among the lipids (fats) in the bloodstream of all animals and humans. Trace amount of cholesterol also exist in plants. Even though cholesterol can be found in almost every cell, it is mostly found in the brain, heart, bowels, and liver. It is an important part of a healthy body because it is used to form cell membranes and some hormones, and is needed for other functions. A small amount of cholesterol circulating in the blood is enough for the body to undertake all these important functions. But a high level of cholesterol in the blood-hypercholesterolemia-is accepted as a major risk factor for coronary heart disease, which may lead to heart attack. As cholesterol and other fats dissolve, in normal conditions, only in oil, they cannot dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are several kinds of these, but the ones to focus on are low-density lipoprotein (LDL, so called bad cholesterol) and high-density lipoprotein (HDL, or the good cholesterol).

The American Heart Association suggests that the risk of coronary heart disease increases in adults with total cholesterol and LDL greater than 200 mg/dl and 130 mg/dl, respectively. It is also advised to keep HDL greater than 35 mg/dl to avoid cholesterol-related diseases. HDL level for young healthy adults is found to be, on average, around 55 and 45 mg/dl for women and men, respectively. Aging, diet, obesity, and menopause are among the factors which increase cholesterol, especially LDL, in addition to hereditary causes. While exercise helps in reducing LDL and increasing HDL, smoking, alcohol, and stress cause the opposite effect.

As you eat, cholesterol from food is absorbed by your digestive tract. It then makes its way into your liver and can circulate through your body in your bloodstream. That is one source. There is also a little-known second source of cholesterol-your body. Cholesterol from food is hard to get away from, even though you may be watching your diet. All foods of animal origin contain cholesterol, including eggs, red meat, and shrimp. Generally, it is also suggested to limit foods that are high in saturated fats or trans-fats. Egg is one of the most controversial foods in our fight against coronary heart disease. On average, one egg contains 66% water, 12% protein, 11% minerals, 10% fat, and 1% carbohydrate. The cholesterol level in one egg ranges from 180–210 mg based on its weight. It is found that each egg cause a temporary cholesterol spike of 3–4 mg/dl in the body, which tend to normalize after its digestion.

The American Heart Association recommends reducing daily intake of dietary cholesterol to reduce the risk of coronary heart problems. However, there are quite a few studies to suggest the contrary2–6. The “dietary cholesterol equals blood cholesterol” view is a standard of dietary recommendations, yet few consider whether the evidence justifies such restrictions.4 Over fifty years of cholesterol-feeding studies show that dietary cholesterol does have a small effect on plasma cholesterol concentrations. The 167 cholesterol feeding studies in over 3,500 subjects in the literature indicate that a 100 mg change in dietary cholesterol changes plasma total cholesterol by 2.2 mg/dL.4 In 1999, Frank B. Hu of the Harvard School of Public Health and his colleagues reported no increased risk of coronary heart disease or stroke in people who ate more than one egg per day. The analysis compared diet and cardiovascular risk among nearly 38,000 participants of two long-running epidemiologic studies.3, 5 In a separate study, Dr. Song and colleagues from the University of Michigan analyzed the diets and blood-cholesterol data of more than 27,000 people selected carefully to be a representative cross-section of the US population.5 They reported that cholesterol was lower in people who ate more than four eggs per week than among people who avoided eggs in their diet. However, a researcher cautioned, “this study should not be used as a basis for recommending higher egg consumption for regulation of serum cholesterol.” Nonetheless, until recently, there were no scientific findings to explain why it is so. Studies have shown that vitamin A, E, B, B6, B12 and folate, which can be found in egg, reduce the risk of coronary heart disease. But it was not until recently that we knew the scientific reasons behind the findings of all the earlier studies. Recent studies have shown that our body is quite intelligent in managing the extra cholesterol increase after eating eggs in a way that limits damage to the heart.

It is well known that the consumption of several eggs a day does tend to increase blood concentrations of cholesterol, particularly the amount circulating in LDLs. However, a new study from the University of Connecticut showed that eating eggs can also increase the amount of cholesterol in HDLs.2 When people ate three or more eggs per day their bodies made bigger LDL- and HDL-lipoprotein particles than when they ate no eggs. That is important because other recent studies have suggested that larger LDLs are less likely than small ones to enter artery walls and contribute their cholesterol load to artery-clogging plaque.3, 4, 6 Similarly, larger HDLs are more effective than smaller ones at moving cholesterol out of the bloodstream and, ultimately, out of the body. In addition, researchers from the University of Connecticut found that not all people respond similarly to cholesterol. Studies have shown that 30 to 40 percent of any given population is made up of “hyperresponders.” In these people, blood-cholesterol concentrations increase disproportionately in response to dietary cholesterol. Surprisingly, such people are found to put an egg’s cholesterol into larger-sized lipoproteins than most other people do. In contrast, among normal responders, only small increases in blood cholesterol occurred during the egg diet, and the size of LDL- and HDL-cholesterol particles covered the full range of lipoprotein sizes.2 These results suggest that any LDL-cholesterol reading that ignores lipoprotein size may exaggerate the heart risks posed by eggs’ cholesterol. Several recent studies have also shown that healthier people tend to package relatively more of their cholesterol in these large LDLs than do people with diabetes or heart disease and the differential effects of small and large LDL lipoprotein particles could be used as a marker for coronary heart disease risk.4, 6

In conclusion, limiting eggs or other foods in our diet cannot be the solution to reduce cholesterol level and thus the risk of coronary heart diseases. Our fight against any disease requires a holistic approach, better understanding of our body and the world around us in addition to choosing a more balanced diet and stress-free lifestyle. Recent scientific findings allow us to put an important question: Is it too simplistic to believe that the One who placed the cholesterol in the egg yolk is the One who created a defense mechanism in the body in a way that limits its damage to the heart?

Bulent Aydogan, PhD, is a research fellow at the University of Chicago Department of Radiation and Cellular Oncology.

Notes

1. http://en.wikipedia.org/wiki/Cholesterol.

2. Greene CM, Waters D, Clark RM, et al. Plasma LDL and HDL characteristics and carotenoid content are positively influenced by egg consumption in an elderly population1. Nutr Metab (Lond) 2006;3:6.

3. Hu FB, Stampfer MJ, Rimm EB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. Jama 1999;281:1387–1394.

4. McNamara DJ. The impact of egg limitations on coronary heart disease risk: do the numbers add up? J Am Coll Nutr 2000;19:540–548.

5. Song WO, Kerver JM. Nutritional contribution of eggs to American diets. J Am Coll Nutr 2000;19:556–562.

6.Yeomin Yoon JS, Hyung Doo Park, Kyoung-Un Park and Jin Q. Kim. Significance of small dense low-density lipoproteins as coronary risk factor in diabetic and non-diabetic Korean populations. Clinical Chemistry and Laboratory Medicine 2005;43:431–437.

It was 1927. The warm days of spring had arrived in the beautiful village of Bark. The fine weather brought visitors from distant lands. One special guest would enjoy the long tranquil summer. She would nest in a high chimney near the mosque and wake to the voice of the muezzin calling the faithful to prayer and then recite her own long ballad. The sounds echoed through the hills. There was a longing sound in her voice. After mating and giving birth, the majestic visitor would normally have returned to her homeland to maybe come back the following year

The stork’s hopes were as long as her thin legs and protracted beak. She was young and beautiful and attracted the eye of a strong and handsome male. After their wedding, held in the deep blue sky, they flew away to build a new life together. The protective male proudly and jealously looked after her. She made her nest and began to lay her eggs one by one. The male counted them every day and protected them carefully. They anxiously awaited their chicks. But something happened. A mischievous hand interfered with the eggs. It was not a child. It was a cunning adult. He examined the eggs, and chose the best one. He stared at it and laughed through his rusty teeth. Holding his hat so as not to lose it to the wind, he climbed down from the tree, his evil prank completed.

He rushed to the coffee house and began to boast about what he had done. He had replaced the stork egg with a duck egg. With a cigarette in one hand and the egg in the other he bragged: ‘I took this egg and put a duck egg in the nest. Soon, we will see flying ducks’.

He returned home and showed off the egg to his children. They looked at it in astonishment. He put some butter in a pan and prepared to fry it. It sizzled as it struck the hot metal. At that very moment, the heart of the mother sizzled as she was struck by a burning desire to return to her nest. Like the man, they too returned to their nest to look after their young. Unaware of what had happened, the male sang his beautiful song and eased the worries of his mate.

Waiting for a new life is not easy. The male stork flew away early in the morning, and after searching near and far would return with all sorts of delicacies for his wife. When the chicks eventually hatched, cracking the shells one by one, she noticed that one was different. They were all cute and lovely, but one was different She looked at it again and again, but could not find any resemblance with the others. Her heart filled with compassion and took pity on it.

‘It grows up with the others,’ she said to herself. What was the difference apart from its short legs and beak? She could not throw it away. It would surely die and a soul would be lost. This poor chick would never survive. She dared not mention it to her proud and handsome mate.

As the chicks grew, the differences became more apparent. The male had not noticed at first and used to watch them all with great pride. Then, one day, he noticed the duckling. Everything changed. He frowned and became angry. He stared at his wife fluffing out his feathers. She understood what this meant and what he was thinking. She shrunk away and was unable to make a sound. She wanted to say ‘I pitied this chick and wanted to protect it.’ but she couldn’t.

The male stork fluttered his wings, rose, and came down on his wife violently this was an infidelity and an insult to himself and his generation. He could not bear it. He could not ignore it. He did not care that the others were not jealous. He was extremely jealous and very angry. Although he loved his wife a great deal, his jealousy turned to hate. A female is beautiful and beloved if she protects the honour of the male. As he struck her, his beak filled with her feathers. She would never leave the chick. She was a mother. She could never do such a thing. He struck her again, more violently this time. Her body bled. With the third blow she looked at her chicks, as if seeking help, but they could not understand what was happening.

He flew away to seek the views of the other storks. They decided. An unfaithful female has to be executed. She made no sound. She was at the mercy of the law. He got his revenge. They took her body to the village square and dropped it there as a kind of warning. The dead stork became a play thing for the children.

The man who had swapped the egg saw it. Now, he wasn’t laughing. A flame burnt inside. He felt a heaviness on his heart. It wouldn’t go away. He took to drink and couldn’t talk to his family. He was overcome by embarrassment at the way he boasted in the coffee house. The villagers became sad upon hearing the yelling of the chicks in the high chimney. No adult dared touch the corpse. The village felt sorry for its guest, but no one would remove her body

The cruel man could not leave his house. He pulled the curtains and took refuge in darkness. The pangs of conscience exhausted him. He could only go outside in the evenings. One night, with a bottle in his hand, he went to the village square. He was talking to himself. The beak of the stork stood upright like a knife. In his drunkard state he lost his balance and fell on it. The beak pierced his heart.