I had graduated from medical school, passed the specialization exam in medicine, and had been placed in the medical internship I long dreamed of. I was on cloud nine and was dizzy with joy, but it didn’t take long for my feet to touch the ground. I soon started to complain about the spells of long surgeries and 12 shifts once a month that sometimes lasted up to 32 hours a “day.” It was not rare when we could not leave for dinner due to consecutive shifts.

I had an extraordinary experience during my watch one night. Along the corridor to the cafeteria was the Pediatric Nephrology Clinic. I saw a tearful mother sitting on a bench in front of the clinic. She was with a child who was about four or five years old and who was weeping and sobbing loudly at her lap. I approached them and asked what the child wanted, thinking he wanted an expensive toy or a bar of chocolate. I was staggered by the woman’s reply:

“Milk… he wants a glass of milk,” she said. When I replied, “Easy-peasy! Let’s get it right now,” she told the painful truth bluntly, “It’s forbidden for him because he’s a dialysis patient. e’s His kidneys are not working.”

I didn’t know what to say. I swallowed hard. My own ungratefulness, and the test that little child went through, crossed my mind. His large eyes, completely filled with tears, were fixed on me as if saying, “For God’s sake, help me!” I moved on in despair, wishing him best of health.

That was an awakening incident that reminded me of my own kidneys which started working when I was a 12-14-week-old fetus in my mother’s womb. Since then, they have been engaged on a quiet and devoted duty, active day and night without a single moment of rest. Yet, they would not cross my mind not even once a year day, let alone a day.

Our kidneys start to work while we are still in our mother’s womb and produce the urine that most of us despise. We may not be aware of how big of a share they have in every breath we take. Indeed, babies who cannot produce urine cannot breathe due to a lack of lung development and die soon after they are born. Urine, which makes up almost all of the liquid surrounding the baby in the mother’s womb, is indispensable for the healthy development of the lungs and for attaining the level of flexibility and maturity that the lungs require.

The kidneys are responsible for completing a number of miraculous tasks. They are instrumental in maintaining the body’s water and mineral balance, and their cells work like the world’s most diligent and meticulous chemists. These cells, which constitute the nephron, carefully analyze the bloodstream and measure the levels of elements such as sodium, potassium, hydrogen, calcium, phosphorus, and magnesium in the bloodstream. They then dispatch the excretion of excess materials via urine and absorb the missing substances into the bloodstream. They are also deployed to preserve the very delicate balance that exists in the composition of our blood, working in the excretion of metabolic products such as urea, uric acid, and creatinine, all of which are formed as a consequence of digestion.

However, this is not all that the kidneys do. They also regulate our blood pressure thanks to their special capabilities. Each kidney is also an endocrine (hormone secreting) organ that secretes a hormone called erythropoietin which helps with the production of red blood cells in bone marrow. Kidneys also play a vital role in activating vitamin D to have it perform its due functions in our bones.

After working their effects, drugs are disintegrated and excreted from our bodies through kidneys. This is why the dosage of some drugs should be delicately adjusted while keeping kidney patients in mind. Insulin, glucagon, and growth hormones are also broken down in the kidneys after they perform their duties.

Our kidneys turn into sugar factories for the persistence of the functions of vital organs in very challenging conditions, such as liver insufficiency, and produce glucose to prevent low blood sugar levels.

Dialysis machine

Developed to imitate the kidney’s mechanisms, a dialysis machine is much bigger than a kidney. Patients with kidney failure need dialysis to have their blood purified, and this involves “linking” a large-diameter blood vessel to the device. The patient then undergoes an operation for fashioning the vessel connection. Blood enters the machine from one end of the vein, is purified there, and is fed back into the body from the other end. Depending on the severity of the disease, a person may need a dialysis process three or four times a week. As much a great invention is this machine, it is not as perfect as the original organ we have in our body, and as a result there are unfortunate latent complications. The procedure is unnerving, and sometimes painful. No doubt the machine cannot fully accomplish the feat of the kidneys and at times fails to dispel all of the excess materials. Dialysis patients should also tolerate a regimented diet resolutely. The constant treatment takes a toll on the immune system, and frequent infections tire the body as well.

If only we could recognize the worth of these exquisitely magnificent gifts in our bodies? Would it not be so amazing if we could preserve these priceless treasures that have been bestowed onto us?

Every time our heart beats, a system far more exquisite and useful than dialysis works in our bodies. It is pain-free and silent. This is just one of the countless wonders in our bodies and the universe.

Every organ in the human body has vital functions. The kidneys play fundamental roles in maintaining human health.

One of the most important functions of the kidneys is producing urine. This function is performed by nephrons, the morphological unit in our kidneys. A nephron is simply made up of the glomerulus, where urine is filtered from blood, and tiny tubes where the filtered fluid passes through and is finally turned into urine (these tubes are proximal tubule, loops of henle, distal tubule, and collector channels).

There are approximately one million nephrons in the two kidneys of an adult. Each nephron is designed to produce urine by itself. Kidneys cannot renew nephrons. The number of nephrons, therefore, decreases gradually because of kidney damage, disease, or aging. After the age of 40, the number of nephrons generally decreases ten percent every ten years, and as a result, an 80-year-old has 40% fewer nephrons than 40 years ago. This loss is not life-threatening because adaptive changes in the remaining nephrons enable them to dispose of water, electrolytes, and metabolic waste in proper amounts.

The functions of the kidneys can be stated as follows:

• Discharging metabolic waste from the body, i.e cleaning our blood. The most significant of types of waste are urea, creatine, and uric acid. The kidneys are the path to eliminating medicine and hormones from the body. Many antibiotics and hormones, or their metabolic end-products, are discharged through the kidneys.
• Maintaining the body’s water-electrolyte balance. The kidneys are charged with balancing the amounts or concentrations of water and substances conducting electricity, such as dissolved sodium, calcium, chlorine, and potassium. If there is too much water or salt, it is discharged through urine. If the amount of water or salt has decreased, then the kidneys keep them in the body by preventing their discharge through urine and hence maintain the balance.
• Establishing an acid-base balance. It is vital to balance the acid or base level of the blood and other bodily fluids. The pH of blood is maintained at 7.4. If is too low, there is an excess of acid. A great excess of acid (acidosis) can cause sudden death. If it too high – called alkalosis – it leads to many disorders.
• Regulating the osmolarity of bodily fluids. The solid substances in blood (Na, K, glucose, amino acids, protein, etc.) must have a certain density. We can talk about the collective, rather than individual, density of the solid substances. One mole of solid particle in a liter of water (6,02 x 10²³) produces an osmotic pressure of 1 osmole. All bodily fluids (intracellular fluids, extracellular fluids, and blood) have an osmolarity of 300 milliosmoles. The discharge of solid particles and water are performed by the kidneys according to this delicate balance.
• Regulating blood pressure. The kidneys perform critical functions in balancing blood pressure by increasing the amount of urine when blood pressure increases or by decreasing the amount of urine when blood pressure decreases. The amount of urine is normal during normal blood pressure. If blood pressure decreases by half, the amount of urine becomes zero. If blood pressure doubles, the amount of pressure increases eightfold.
• Secreting hormones. The kidneys act like an endocrine gland in the secretion of several hormones. One of the most important of these hormones is erythropoietin, used in the production of blood cells in bone marrow. The kidneys also play a significant role in the production of vitamin D, which has recently been considered to be a hormone rather than a vitamin. Renin is also secreted from the kidneys when blood pressure drops.
• Glyconeogenesis: This function is primarily performed by the liver. Yet we know that this process is carried out by kidneys as well. Glyconeogenesis is the production of sugar (glucose) from the glycerol of non-sugar substances and all amino acids.

What should we pay attention to if we want to protect our kidneys?

• Proteins. They are probably the most valuable nutrients. Meat, milk, and eggs are rich in proteins, but grains like wheat and legumes contain proteins, too. Amino acids obtained from proteins are used as building blocks of the body. In this regard, proteins are essential for nutrition. When they are taken in excess amounts, however, proteins are converted into other substances (sugar and fats) or spent for energy production. Meanwhile, ammonia and then urea are produced in the liver. The urea produced in the liver is discharged by the kidneys through urine. Excess urea is considered a burden for the kidneys, so it is a risk for our kidneys to consume too much protein (particularly red meat). If there is a case or probability of renal failure, protein intake should be reduced.
• Salt. Kidneys can easily get rid of water, yet it takes some effort to discharge salt. Kidneys especially suffer when they are left without water. If kidneys cannot discharge enough salt, blood pressure rises. Therefore, if a person has a risk of heart or kidney failure or have high blood pressure, you should cut down on salt. It is crucial for anyone overweight to stop consuming salt. Foods without salt (such as minced meat and potatoes) decrease the appetite and stop a person from eating too much. Besides, meals without salt partly reduce the absorption of food in the intestines. A low-salt diet is good not only for the heart and blood pressure but also for kidneys. Yet people whose kidneys work perfectly, especially children and teenagers, run no risk when they consume salty food. It is also known that excess salt contributes to the formation of kidney stones.
• Water. It is vital for kidneys. Water helps kidneys clean the blood. It is not possible without water to cleanse blood of salt, other waste materials, and drugs. You should therefore be careful about drinking sufficient water. The daily requirement varies from person to person. Drinking 4-8 glasses, or 1.5–2 liters, of water will usually meet the body’s daily requirement. Drinks such as tea and coffee cannot be substituted for water because they increase water discharge. The minimum amount of water required for cleaning an adult body in a desert environment is half a liter. Though rare, it can also be a burden or problem for the kidneys if a person drinks too much Solid substances such as sodium, potassium, and calcium can be lost in excess as a result of overdrinking water, just like dirt is washed away by a flood.
• Acidic foods and drinks. One of the most important functions of the kidneys is to get rid of the acids produced through metabolic activities in the body and to balance the pH of blood. It is harder to discharge acids than bases. Acidic foods and drinks should therefore be consumed moderately. Pickles, sour foods, sodas, and other fizzy drinks should not be eaten in excess. It should also be remembered that acidic foods and drinks can cause kidney stones.
• Smoking. One of the primary harms of the nicotine in cigarette smoke is the fact that it causes blood vessels to contract. Smoking is the main reason for vessel stiffness. Nicotine causes kidney vessels to contract, hence a decrease in blood circulation in the kidneys. When blood circulation in the kidneys decreases, blood is no longer cleaned and blood pressure rises.
• Alcohol. Alcoholic beverages raise acid levels in the blood and causes acidosis, which damages all the organs and primarily the liver. Alcohol has the same effect as smoking on kidney vessels and causes them to contract. Not only does excessive acid damage kidneys but it also facilitates kidney stones.
• Drugs. Of the body’s organs, the kidneys are the most sensitive to drugs. Using antibiotics in high doses may lead to kidney damage and acute kidney failure. It is a common mistake in public to use antibiotics without consulting with a doctor. Using painkillers for every pain also causes chronic damage in our kidneys. It is normal for a person to have certain pains in daily life. They should consult with a doctor to identify the cause of the pain and should refrain from using painkillers unless absolutely necessary.
• Vitamins. A lack of vitamin B₆ is known to cause kidney stones. Thankfully, vitamins are among the innumerable blessings bestowed upon humanity. Vitamin B₆is abundant in sunflowers, pistachios, chickpeas, fish, and starchy vegetables.

Dear Peter, in your body, which is built like a well-functioning factory, I am the most essential sanitary device. As the heart pumps blood to take food and oxygen to all your organs, you obtain the energy you need. But do you ever think about the disposal after so splendid activities are carried out in your body? If you burn a stove, you need to dispose of the smoke and the ashes if you want to keep it working. Likewise, as you burn your calorie intake, you dispose of the smoke (carbon dioxide) with your lungs and the waste with nitrate-poisonous after a certain level of intensity-thanks to my quietly and perfectly working filters. That is, I am an organ which saves your life by removing the poisonous substances in your blood. I do not only filter your blood, but also play a role at controlling the balances of the sensitive levels of water, sugar, amino acids and different minerals in your body. In short, I am a tiny but strategic laboratory.

The acid-base balance in your body and the amount of water and different salts are significant values which concern all of your bodily activities. When their balance is upset, different troubles arise in different units of your bodily mechanism. I am such a blessing, which works so sensitively to adjust the levels of water and mineral salts in your body while you don’t even realize it.

A watery environment is needed for the thousands of biochemical activities taking place in your body. In addition, activities like the contracting of the muscles and transmission of electrical stimuli between your neurons are realized with the presence of a pinch of mineral salt you don’t even give a thought about. Sometimes you sweat due to running or hot weather. The white stains on your shirt are the salts you lose after the water evaporates. When you suffer from diarrhea, you lose salt again, for the salt in the nutrients are thrown out without being absorbed. Especially when little children are concerned, this loss is of vital importance. The transfer between the blood and the liquid in the tissues is mainly realized through the concentration differences which are kept in a certain balance. If your body holds too much water, your tissues swell. You particularly feel it when you press your finger over the flesh near your shins.

Dear Peter, I will not list all of my duties in detail in order not to confuse you. However, let me tell you one more. Since not everyone knows this duty of mine, they just see me as an organ of liquid disposal. But I also take part in controlling the blood production! Surprised? Well, I also have the duty of secreting the hormone which stimulates blood production in the bones. I must always stay alert and maintain this balance in the best way; if you start losing blood, for instance, I must increase the hormone and accelerate blood production.

Yes Peter, I’ve told you about a few of my basic duties, but haven’t told you about how wonderfully designed I am. I am a bean-shaped organ and a single kidney like me weighs 130-160 grams on average. We are approximately 10 grams lighter in female bodies. I am surrounded by a soft but protective membrane. I need 35 grams of daily oxygen supply to survive and I use 13 % of your total body energy.

As an army is made up of individual soldiers, I am like a complex army, and a single soldier of mine is called a “nephron,” which does the real job. Thus, you can see me as a body of nephrons. Millions of these nephrons are brought together to make up one kidney.

A single nephron is a thin tubular structure with closed ends, and its length is about 3-4 cm. So the total length of my nephrons is about 50 km. The cup-like sac at the beginning of a nephron is named the “Bowman’s capsule.” The main artery bringing blood to the kidneys branch into smaller units, and one road leads to every nephron. The knot of capillaries (glomerulus) inside this double-walled capsule is more complicated than any road map you might have seen. The total length of the capillaries is nearly 25 km. The unwelcome substances in the blood are passed to the capsule thanks to blood pressure, and they proceed through the tubule. The total surface area of my tubules is about 20 m2. Within five minutes the whole of your blood passes through us. That is to say, an average of 1.2 liters of blood per minute, and 1800 liters a day are filtered by my nephrons, leaving the toxic substances in me. As this amount of blood (nearly 400 times the normal amount in your body) pass through my tubules and return to the veins they leave behind an average of 180 liters of liquid in me. In this case, you could be supposed to throw out 180 liters of urine a day. However, if you really did that, you would neither be able to find a sufficient supply of water nor salt. Fortunately, Providence granted you the mechanism to absorb back nearly 178.5 liters of this filtered substance. This way, the thickened urine throws out the toxic nitrogen-containing byproducts together with a little amount of water. Therefore, I give you back the substances you need with an amount of 1.5 liters of liquid disposal a day. This reabsorbing is realized in what you call the Henle loop. The cells in the walls of my tubules have neither intellect, nor consciousness, nor any knowledge of physiology; in spite of this, they work as if they were perfectly aware of their duty to adjust the amounts and types the substances to be kept or released. To give you an idea, you can think about the huge dialysis machines your engineers design to fulfill the job my tiny tubules do. You decide which one of us is the perfect work of engineering.

A rich network of veins surround the Heinle loop and the reabsorbed substances are released into the bloodstream. The drops to be disposed of are collected and then passed to your bladder. When the liquid in your bladder amounts to a certain value it tightens the bladder walls. The muscles blocking the way out give way and the urine is disposed of. However, know that the bladder has the capacity to expand as large as 1.5 liters when you cannot find the proper time and place.

Peter, most people take for granted the blessings they enjoy. If you visit the nephrology service in a hospital and talk to the patients waiting to be dialyzed, you understand what I mean better. Do not forget that many people who suffer from kidney failure need that huge machine to filter the whole of their blood and they pray for a kidney suitable for transplantation to be found at once.

Incidentally, thinking of chronic kidney failure recalled various reasons which ruin me: long lasting infections, long-term use of certain medicine, different chemicals like ethylene and mercury, heavy loss of blood, high blood pressure, serious burns, and wrong blood transfers etc. In such cases I can receive irreparable damage.

Another issue which troubles me is the formation of kidney stones. The stones which form owing to failures in different metabolic processes really hurt. When excessive decrease of liquids or increases of salts in the body upset my sensitive balance, some dissolved substances remain, begin to collect, and form stones. These stones hinder urine flow and might cause infections. You may drink water abundantly to prevent these stones. Most importantly do not wait too much before going to the toilet. If you excuse me, I also strongly recommend you to urinate in sitting position; this helps emptying your bladder completely and reduces the risk of kidney stones.

I do my job properly until I lose 90 % of my working capacity. When a considerable part of me loses its capacity, the remaining good part boosts its activity to make up for the loss. When one of our twins are taken out with an operation, the other one does not complain at all; it grows a bit bigger and keeps working.

As the nature of honey depends on the nectars bees collect, the ingredients of the urine I produce depend on what’s in your body. Therefore, a urine analysis tells much in the case of illness. For example, I normally do not release valuable substances like glucose and protein in your blood into the urine, but return them to the bloodstream. As my friends cannot fulfill this function in diabetic patients, their urine analyses reveal glucose. As for medicines, I throw them out right away since they are alien substances to me.

Peter! You are young and healthy but be careful and do not get cold around the waist, otherwise I might trouble you. There’s a lot to tell you Peter, but I do not want to confuse you. Like any other organ, I do not like being taken for granted and I just wish for you to appreciate what a blessing I am. Let me note that my perfect cooperation with the rest of your body is another wonder in itself. Anyway, the urea in your blood is increasing, so I must go help my twin now. Goodbye Peter!

Irfan Yilmaz is a professor of biology at Dokuz Eylul University, Izmir.

The hectic life style that many of us lead today causes stress which is likely to result in diseases of the heart or nervous system. The fast food culture has become a part of our lives due to our busy work schedules; this sort of a diet obviously causes an excess intake of fat. Office hours spent sitting on a chair without effective physical activity result in the storage of unused energy in the body. Thus, cardiovascular diseases have become one of the most common life-threatening risks for people living in developed countries. In the last five decades, much research has been devoted to investigating and preventing the risk factors that lead to coronary artery diseases.

The mushroom is a food with a rich nutritious content. Some species are known for having characteristics that are helpful in regulating the immunity system, preventing tumor formation, and reducing blood pressure without producing any known side effects. 88–91% of the physical make-up of a mushroom is water, thus fresh mushrooms are rich in proteins which can be more easily digested than many other vegetables. In addition to such proteins that are necessary for general health, mushrooms consist of B-complex vitamins and mineral materials.

Some species of mushrooms act as sources of healing in many ways. Polysaccharide-protein complexes obtained from species like Pleurotus spp., Ganoderma lucidum (Reishi), Grifola frondosa (Maitake), Lentinula edodes (Shiitake) have been found to prevent the spread of tumor cells and AIDS. It has also been discovered after research that mushrooms have antiviral, antibacterial, and antifungal effects; they are useful in the treatment of illnesses like cold, stomach and head aches, and hepatitis B; they can help reduce fatigue and sleeping problems as well as blood cholesterol levels. Mushrooms can also have a positive effect in diseases like arteriosclerosis, kidney failure and high blood pressure, as well as helping in strengthening the immunity system, thus delaying unfavorable conditions of aging.

Research has shown that mushrooms, with their B-complex vitamins, have a positive influence on the nervous system. The mushroom offers a good alternative for anemia, a disease that arises from a deficiency in folic acid and it also helps to regulate the blood sugar level. Mushrooms are often recommended for patients with liver and kidney diseases, as well as being a good source of protein for patients suffering from gout, for it causes the formation of only a small amount of uric acid at the end of the digestion metabolism. Here we provide more specific information about certain species of mushrooms:

Shiitake (lentinula edodes)

This species is cultivated and sold in Japan and China, where it is known as “the elixir of life” or “the secret of long life.” It is traditionally used in wedding meals. This mushroom is effective primarily in the prevention of apoplexy and arteriosclerosis. It is also used in many cancer research programs, due to its antitumor activity. A polysaccharide known as lentinan that is found in this species can suppress sarcoma 180, a solid type tumor, a feature that adds to the value of this mushroom. Patients are advised to consume shiitake mushrooms during chemotherapy.

In Japan, around fifty different types of enzymes have been derived from the shiitake mushroom. These enzymes include pepsin and tripsin, which are used in the treatment of some gastric diseases, as well as asparaginase, which makes up a part of leukemia treatment for children. This species is rich in proteins, vitamins, and minerals. The consumption of 100 grams of fresh mushroom generates only 28 calories, thus making it a good alternative as a food that has limited energy intake. Mushrooms have only a small amount of A and E vitamins, but a large quantity of ergosterol (provitamin D2); this can change to D2 vitamin under sunlight or artificial light. D2 vitamin can adjust the phosphor and calcium balance, thereby contributing to bone and muscle development and preventing rickets. It has been found that the eritadenine compound that is contained in this mushroom reduces blood cholesterol at a rate of 25–45%. This species is known to be useful for all the health problems listed above (regulating blood circulation, apoplexy, arteriosclerosis, kidney failure, and high blood pressure; destroying bacteria, virus, pathogenic fungi).

Pleurotus spp.

This species is rich in proteins, only being surpassed by legumes. Mineral salts, like calcium, phosphor, and iron are contained in this species, in amounts that are proportionally twice as much as those found in beef or fowl. Among mushrooms, pleurotus has the highest levels of B1 vitamin (tiamin) and B2 vitamin (riboflavin).

Hemagglutinin, a substance that causes the agglutination of red blood cells, is contained in pleurotus ostreatus and pleurotus spodoleucus species. Eight of the eighteen amino acids found in pleurotus ostreatus are essential for human life. Extracts obtained from pleurotus spores trigger the formation of interferon, which is the first defense mechanism against viral infections. These spores have been found to help prevent flu and paralyses in laboratory animals.

Some mushroom species have been shown to be effective in strengthening the immune system. Chemotherapy applications used primarily in cancer and some other diseases are known to have many side effects, some of which are severe and can lead to other diseases. The toxic effects of some medications might pave the way for other infections, damaging the kidneys and liver. It is thanks to God, the Healer, that the mushroom is one among millions of other sources of healing that can be found in nature, waiting for us to discover them.

Basic nutrients for Agaricus bisporus %

Fat 0.35

Protein 3.43

Carbohydrate 3.78

Ash 0.71

Humidity 91.73

Minerals (ppm)

Zinc 5.46

Copper 1.59

Potassium 2445.50

Iron 8.73

Calcium 39.60

Chromium Iz

Phosphorus 882.30

Vitamins dissolved in water (mg/100g)

B1 (Tiamin) 0.094

B2 (Riboflavin) 0.396

Folic acid 0.078

C (Ascorbic acid) 2.29

Niasin 5.35