We live in a world made from matter. Matter is made up of atoms and molecules that follow the laws of nature. All life is made up of atoms and molecules that are organized into cells. Our body has trillions of them. Everybody knows that we need to have enough red blood in our circulation to stay alive. And most people know that it is the red blood cells in the blood that makes it look red. There are even some people who know that the red blood cells look red because of the hemoglobin within them that carries oxygen. But what most people do not know is that it is the iron inside hemoglobin to which oxygen attaches that makes it and the red blood cells and our blood look red. And because most people do not know this they also do not understand that, unless they are resisted by some sort of innovation, the laws of nature do not cause life, as evolutionary biologists would have us believe, but death. The human body's need for iron is a good example of this truth. In other words, the same chemical element that is used to make most of the tools and machines in the world also plays a major role in our survival. In fact, having the right amount of iron in the body can be a matter of life and death. So, let’s take a look at the innovative role iron plays in enabling the body to live within the laws of nature.
The Oxygen Dilemma
The cells of the body need a lot of energy to live. They can get some energy by partially breaking down glucose without using oxygen. But this does not provide enough energy for them to survive. For if the cells of the body do not have enough energy the laws of nature take over and cause them to malfunction and die. To get enough energy to survive
the cells of the body must fully breakdown glucose with the help of oxygen. But how much oxygen does the body actually need to be able to work properly? At complete rest, the average man needs about 250 milliliters of oxygen per minute to keep his organs and tissues working properly. Think of it like how much gas a car uses while it sits idling. And when the average man is very active, trying to win the battle for survival, his body needs about 3,500 milliliters of oxygen per minute or more. Just as the faster a car moves, the more energy it needs and the more gas it uses up, so too, the more active the body, the more energy it needs and the more oxygen it uses up as well.
Oxygen must enter the body through the lungs. Normal lungs have the capacity to bring in the amount of oxygen the body needs whether it is at rest or very active. But that only solves part of the problem. For once the oxygen enters the body it has to be transported to the tissues. This is done by the blood. The dilemma for the body is that, as opposed to glucose and salt, oxygen does not dissolve well in blood. In fact each liter of blood can only hold 3 milliliters of oxygen in solution. And since the heart pumps about 5 liters of blood per minute at rest, this means that if the body were to rely solely on the dissolved oxygen in the circulation it would only be able to provide the tissues with 15 milliliters of oxygen per minute (3 x 5). This represents only 6% of the 250 milliliters of oxygen per minute the body actually needs at rest. The problem becomes even worse when the body is very active. The maximum cardiac output is about 25 liters of blood per minute. And if the body were to rely solely on the oxygen dissolved in the blood this means that the tissues would only receive 75 milliliters of oxygen per minute (3 x 25). This represents only about 2% of the 3,500 milliliters of oxygen per minute the body needs to be able to fight in the battle for survival. Clearly this is inadequate and life must have come up with some sort of innovation or else we wouldn't be here in the first place.
The Oxygen Dilemma Solved
The innovation the body uses to provide the adequate transport of oxygen in the circulation is a complex protein called hemoglobin. The hemoglobin molecule consists of four smaller subunits each made up of an iron-containing heme group and a protein part called globin: see http://www.diatronic.co.uk/nds/webpub/haemoglobin_structure.htm. Hemoglobin is formed in developing red blood cells in the bone marrow which are later released into the blood. Each molecule of hemoglobin is able to bind with four molecules of oxygen by having them join up with the iron in each of its four heme groups. When maximum binding of oxygen to the hemoglobin in the red blood cells takes place (like in the systemic arteries) the blood looks bright red. However, after the blood returns from the tissues where the hemoglobin has released some of its oxygen (like in the veins on the surface of the hands) it appears much darker, usually blue or even purple.
Due to its content of iron, one gram of hemoglobin is able to bind to 1.34 milliliters of molecular oxygen. There are about 150 grams of hemoglobin in a liter of a man’s blood. If that blood can carry 1.34 milliliters of oxygen per gram of hemoglobin that means that it can carry about 200 milliliters of oxygen per liter (150 x 1.34). And since at complete rest the heart pumps about 5 liters of blood per minute, this means that the average man’s circulation can carry about 1,000 milliliters of oxygen per minute to the tissues (200 x 5). This amount easily meets the 250 milliliters per minute of oxygen his body needs at complete rest. Moreover, since with maximum activity the heart pumps about 25 liters of blood per minute, this means that the average man’s circulation can carry about 5,000 milliliters of oxygen per minute to his tissues (200 x 25). This also meets the 3,500 milliliters per minute of oxygen his body needs with maximum activity.
In addition to hemoglobin there are other very important proteins in the body that need iron in their chemical structures to work properly as well. One of these is myoglobin, a protein found in skeletal and heart muscle. Myoglobin is able to store oxygen in these muscle cells by binding it to the iron in its heme component. When there is a shortage of oxygen in the muscle, like during heavy and prolonged exercise, myoglobin is able to release this stored oxygen so it can obtain enough energy to continue to contract and function for a little while longer. Another of these proteins that need iron to function properly are the cytochromes which are located in the mitochondria of the cells. It is inside the mitochondria where the cell gets the energy it needs, by releasing it from glucose in the presence of oxygen, and the cytochromes play a major role in this process.
In summary, to survive within the laws of nature the cells of the body need to have enough energy. And to have enough energy they need to have enough oxygen. Blood does not have the capacity to dissolve enough oxygen to meet the energy needs of the body. So the blood has to have enough red blood cells, containing enough hemoglobin, to carry enough oxygen to the tissues for the body to survive. However it is the iron within the hemoglobin molecule to which the oxygen actually attaches. Therefore, the body needs to have enough iron so it can have enough hemoglobin to carry enough oxygen to the tissues. Also, the body needs to have enough iron for the myoglobin in its skeletal and heart muscle so they can work properly and the cytochromes within the mitochondria of its cells for cellular respiration as well. So how does the body get its iron and make sure that it not only has enough of it but not too much as well?
Iron: Intake, Control, Transport And Storage
Next to aluminum, iron is the most abundant metal in the earth’s crust. We get iron from meat, fish and poultry in addition to fruits, vegetables, dried beans, nuts and grains. Iron is mainly taken into the cells that line the upper part of the intestine. To enter the blood from here the iron must then pass out of the intestinal cell through a specialized protein in its plasma membrane called ferroportin. But just because iron comes into the intestinal cell does not mean that it will automatically pass out through ferroportin into the blood. It is by controlling how much iron leaves the intestinal cells, through ferroportin, that the body controls its intake of iron and its total iron content as well.
One of the main ways the body is able to control its intake and iron content was only discovered within the last decade or so. To accomplish this task the body uses a hormone, made in the liver, called hepcidin. Hepcidin works by locking onto ferroportin and blocks it from letting iron out of the intestinal cell into the blood. The liver cell is able to detect its own content of iron and matches this with the amount of hepcidin it releases into the blood. The more iron that is stored in the liver cell the more hepcidin it releases. More hepcidin results in less iron passing from the intestinal cells through ferroportin into the blood and prevents the body from having too much iron. And the less iron that is stored in the liver cell the less hepcidin it releases. Less hepcidin results in more iron passing from the intestinal cells through ferroportin into the blood and helps keep the body’s iron level where it should be. The iron that remains in the intestinal cells due to the effect of hepcidin on ferroportin eventually leaves the body when these cells die and slough off within a few days. This seems to be the main way the body controls its intake and total content of iron.
However, just like oxygen, iron needs to be transported in the blood by a specialized protein so it can go to where it is needed in the body. This protein, also made in the liver, is called transferrin. The production of transferrin is inversely related to the amount of iron stored in the liver cell. The more iron present in the liver cell the less transferrin it produces and the less iron stored in the liver cell the more transferrin it produces. So when the cells have enough iron there is less of a need for transferrin and when the cells don’t have enough iron there’s more of a need for transferrin. Transferrin carries iron to the bone marrow and other organs and tissues as well. The cells of the body have specific receptors for transferrin in their plasma membranes. They lock onto transferrin, with its cargo of iron, so they can unload the iron into the cell. The number of transferrin receptors a given cell has is inversely related to how much iron it has stored within it. The less stored iron it has the more transferrin receptors it has so it can collect more iron. And the more stored iron it has the less transferrin receptors it has so it will not take in too much iron. In particular, the developing red blood cells in the bone marrow, which constantly use iron to make the hemoglobin the body needs to carry oxygen, have a very high concentration of these specific receptors which allows them to pick up most of the iron that is carried to the tissues by transferrin. Since red blood cells only live about 100 days this means that about 1% of them are broken down and their iron is released and picked up by transferrin. Most of this iron is recycled back to the bone marrow and is used to make hemoglobin in the developing red blood cells. Finally, any iron that is not used right away is stored mainly in the bone marrow, the liver, and the spleen in a protein called ferritin.
In summary, iron is present in the food we eat and is brought into the cells of the upper intestine. These cells then release a certain amount of this iron into the blood through a specialized protein in their plasma membrane called ferroportin. Hepcidin is a hormone made in the liver in an amount directly related to its iron content which controls the amount of iron the intestinal cells export into the blood. The iron is picked up by transferrin, a protein made in the liver, and is carried to the tissues. The cells there have transferrin receptors in an amount that is inversely related to their iron stores and they attach to the transferrin to unload its iron cargo. The iron left over in the intestinal cells eventually leaves the body when they die and slough off in a few days. Ferritin is the protein that stores any iron in the cell that has not been used and is mainly found in the bone marrow, the liver and the spleen.
Iron: The Consequences Of Having Too Little And Too Much
The total absence of iron is incompatible with human life. The body loses only a small amount of iron through the shedding of cells from the gastrointestinal and genitourinary tracts and the skin on a daily basis. This can usually be replaced by the iron that is taken in daily by the intestine. Although, as noted above, the body can store iron, if it loses too much, usually from chronic bleeding from the digestive system, or in women, from heavy monthly periods, then these iron stores can be totally depleted. With the loss of its stores of iron this results in there not being enough iron in the body to make enough red blood cells with enough hemoglobin. When the red blood cell and hemoglobin counts are below normal the body is said to be anemic. And when it is due to chronic blood loss resulting in the loss of its iron stores it is said to have iron deficiency anemia.
Recall, the oxygen carrying capacity is directly related to how many red blood cells, with hemoglobin, are inside the blood. With worsening iron deficiency anemia the body will experience increasing fatigue, weakness and loss of stamina. And if the anemia drops below certain levels the body may become dizzy upon standing, have shortness of breath with limited levels of activity and may even die. This takes place because although the lungs may be bringing in adequate amounts of oxygen the tissues can’t get enough of it because the blood’s oxygen carrying capacity has been severely reduced due to anemia. Nowadays iron deficiency anemia can easily be treated with oral supplements of iron and even iron infusions if necessary. Of course, if the underlying cause of the chronic blood loss can be corrected, then once the anemia has resolved and the body has enough stores of iron, supplementation can often be discontinued.
On the other hand, if the cells of the body store too much iron, then it is said to be in a state of iron overload. One of the more common causes for this is condition is called hereditary hemochromatosis. Medical scientists have only recently discovered that this type of iron overload is often related to a malfunction of the proteins hepcidin and/or ferroportin which results in too much iron being taken into the body through the intestine. Too much iron in the cell can be toxic and can result in not only malfunction but even cell death. The main parts of the body affected by iron overload are the liver, the heart, the pancreas, the thyroid gland, the gonads and the joints. This results in liver cirrhosis, heart failure, diabetes, hypothyroidism, impotence and infertility and severe arthritis. Iron overload usually develops over many years and it often doesn’t manifest in men until they are over 20 years old and in women until after menopause (since women constantly lose iron due to their monthly periods). Before early diagnosis was available people with hereditary hemochromatosis died within two years of developing weakness. Nowadays the main treatment for this condition is the regular removal of blood by phlebotomy to keep the iron levels down to prevent further organ damage.
In summary, the body needs to have the right amount of iron so it can live, grow and work properly. Too little iron results in iron deficiency anemia which leads to fatigue, weakness, loss of stamina, dizziness, shortness of breath and even death. And too much iron results in multi-organ malfunction which can also lead to severe debility and death. Our hominid ancestors, who were trying to win the battle for survival, would have had to have had the right amount of iron to survive. For they didn’t have the benefit of modern medicine to diagnose and treat conditions like iron deficiency anemia and iron overload.
Points To Ponder
It was the extremely high improbability of any one of the thousands of biologically significant molecules, like ferroportin, hepcidin, transferrin and its receptor being formed by just chance and the laws of nature (never mind the need for the untold millions of each one of them to allow for life) that alerted scientists to there having to be an intelligent agent within the cells telling them how to make them. This is what first motivated scientists to search for and find the DNA molecule and everything else connected to it that has been, and continues to be, discovered. But, paradoxically, modern evolutionary biologists see all of the information packed into the DNA molecule and still conclude that it all came about by just chance and the laws of nature alone rather than “a mind at work” i.e. an intelligence. In other words, scientists, using their ability to detect intelligence, recognized that there had to be an intelligent agent inside the cell instructing it on how and when to produce these complex and vital molecules, but after finding it concluded that this intelligent agent itself had come about by chance and the laws of nature alone. Alternatively, many people now believe and teach that it was nature itself, as the intelligent agent, that through evolution brought about DNA and all the innovations needed for life because that was what was needed. They seem to forget that, by definition, evolution is a blind process which has no goals.
Without having the right amount of iron the body cannot survive within the laws of nature. It needs the iron in hemoglobin to carry enough oxygen in the blood to the tissues because oxygen does not dissolve well in plasma. Moreover, the body needs the iron in myoglobin to provide the heart and muscles with an extra supply of oxygen when they are working long and hard so it has a chance to win the battle for survival. Finally, the body needs the iron in the cytochromes of the mitochondria to get enough energy from cellular respiration to survive. Notwithstanding their own levels of complexity, having the right amount of iron and getting it to where it is needed in the body is much more complicated than just having digestive and circulatory systems. It requires several other innovations to make sure the body does not suffer from iron deficiency nor iron overload as well.
In addition to having intestinal cells that can bring in iron from the digestive system through the plasma membrane these same cells must also have (1) ferroportin in the plasma membrane through which they can release iron into the blood. But to make sure the right amount of iron is being put into the blood from the intestinal cells the body also needs (2) hepcidin which is produced in (3) liver cells that are able to detect their own iron content. In addition, to transport the iron to where it is needed in the body requires another protein made in the liver called (4) transferrin. And the cells that receive the iron need to have (5) transferrin receptors so they can identify and attach to it to unload its cargo. Moreover, to make sure the cells get the amount of iron they need they must have (6) the right number of transferrin receptors as well. Finally, to make sure that any extra iron is not left sitting around in the cell to cause toxicity, the body needs to have an efficient way of storing it and it does this through a specialized protein called (7) ferritin. Each of the parts mentioned above is needed and if any one of them were to be missing or not working properly our hominid ancestors would not have been able to survive long enough to reproduce. Dr. Michael Behe has called a system where the absence of any one part renders it useless as being irreducibly complex. The system our body uses to obtain and control its iron demonstrates irreducible complexity.
One must then wonder how an irreducibly complex system with so many vital parts could have come into existence? Does it make sense that this system could have come about one step at a time? For example, the intestinal cell and ferroportin, but no hepcidin or transferrin and its receptor, or hepcidin without ferroportin and transferrin without its receptor? The idea is totally absurd. They must have all come together as a system to perform a function to keep the body alive. And which system came first? The ones mentioned previously to control oxygen transport, blood glucose, water content, the levels of sodium, potassium, hydrogen ion and calcium, blood pressure, temperature and sexual function, or this one for iron? Remember, without any one of these systems working properly, we, as individuals, or as a race, die. In addition to these there are many other irreducibly complex systems in the body each of which is absolutely vital for life. But if a system is irreducibly complex does that make it automatically capable of supporting life? If you think about it you’ll realize that there’s one more piece of the puzzle that’s needed, a piece that goes beyond irreducible complexity, to enable these systems to keep us alive within the laws of nature.
When dealing with the laws of nature real numbers have real consequences. Take for example the Saturn V rocket and the Apollo XI mission to the moon. There must have been thousands of pages of blueprints detailing the different parts of the Saturn V rocket with instructions on how to put it all together. But if once ignited its propellants could not have provided enough thrust for the Apollo XI to escape the earth's gravitational pull then the mission to the moon would have been as good as dead. So too, the body may have all the components it needs to bring iron into the blood and send it to the cells. But if at complete rest it can’t get the 250 milliliters per minute of oxygen it needs because it doesn't have enough iron to make enough hemoglobin to carry enough oxygen to the tissues then the body is as good as dead as well. Moreover, if our hominid ancestors hadn’t had enough iron to make enough hemoglobin to carry the 3,500 milliliters per minute of oxygen they would have needed to stay active enough to survive then they probably wouldn’t have been able to reproduce. Furthermore, if the body has too much iron resulting in liver, heart, pancreas, thyroid, gonad and the joint malfunction, then its chances of surviving and reproducing are essentially nil.
Real numbers have real consequences when it comes to dealing with the laws of nature. Not just any amount of iron will do. It has to be the right amount. Just because a system is irreducibly complex does not automatically mean that it will be able to function well enough to allow for life. Besides being irreducibly complex systems that allow for life must also have a “natural survival capacity”. By this I mean that each system must give the organism the capacity to survive by taking into account the laws of nature. This usually involves having a knowledge of what is needed to keep the organism alive within the laws of nature and then being able to do what needs to be done. The systems in the body that bring in iron, transport it to the tissues, allow it to enter the cell and stores it safely seems to inherently know what the iron needs of the body are and manages it naturally. The same can be said for the many other control systems in the body, each of which is necessary for survival.
Given what we know about how life actually works and how easily it dies when it doesn’t have the right amount of iron, it is evident that there must have been several innovations within intermediate organisms with respect to their need for iron-dependent biomolecules like hemoglobin, myoglobin and the cytochromes. What those innovations were and exactly how these organisms were able to live and control their iron content in these intermediate phases may never be known. This is because further changes which may have come about have since gone by the wayside of evolution and we can only see what is present now. This is one way to explain how having the right amount of iron in the body may have evolved without having to seriously consider the physiology of the now extinct intermediate organisms. But this is not Science, where every aspect of the reverse engineering needed to come up with a plausible explanation for life should be explored before a theory is proclaimed to the public. No, this is just faux science and wishful thinking. It’s also how evolutionary biologists have been able to convince themselves, and others, of the supposed irrelevance or even impossibility of irreducible complexity. Some scientists have argued that the positions of intelligent design and irreducible complexity are arguments from ignorance which lack enough imagination. I would submit that the concerns put forth above are based, not on ignorance, but on what we actually do know about how life actually works and how easily it dies. But I wholeheartedly agree that based on current evolutionary theory in the face of the incredible complexity of life that the scientists involved do indeed have very good imaginations. Alas, we who believe that the design seen in nature is real, and not an illusion, are forced to limit our imaginings to what is already known about what it takes for life to survive within the laws of nature. Case in point is the innovation of having enough iron to produce enough hemoglobin, myoglobin and the cytochromes without causing toxic iron overload.
The laws of nature have put up many obstacles to prevent life from existing. Just as a car can die from not having enough gas for energy, or oil for seizing parts, or anti-freeze for engine overheating, so too, all physicians know that there are many different pathways to death. If you really want to begin to understand how life came into existence, you first have to understand how easily it can become non-existent. Did life really come about solely by random chemicals coming together to form cells, then simple organisms, and then complex ones like us? In other words, without “a mind at work” to make it happen?
Do you think scientists just left it up to chance and the laws of nature when it came to the Saturn V rocket propelling Apollo XI to the moon? No, when it comes to the origin of life it seems to me that Science still has a lot of explaining to do. Meanwhile, as we wait for evolutionary biologists to admit the deficiencies within their theories our children and the whole world continue to be misled!
Be sure to catch all of the articles in Dr. Glicksman's series, "Beyond Irreducible Complexity."
Howard Glicksman M. D. graduated from the University of Toronto in 1978. He practiced primary care medicine for almost 25 yrs in Oakville, Ontario and Spring Hill, Florida. He now practices palliative medicine for a Hospice organization in his community. He has a special interest in how the ethos of our culture has been influenced by modern science’s understanding and promotion of what it means to be a human being.
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