November 1, 2007

You Literally Are What You Eat Part II: The GI System: Bile and Liver Function


By Dr. Howard Glicksman

The Competition
It was the final round of the competition and all of the components of the body had gathered to see which one would be determined to be the best and the most important. The organs were represented by the eyes hoping to impress everyone with what they can see outside the body. The structural tissues had decided to enter the bones because of their necessity for body support and activity combined with housing the bone marrow. The proteins had opted for the clotting factors since they are vital for maintaining the integrity of the circulation by preventing spontaneous blood loss. The fluids of the body had originally planned on being represented by blood but at the last second had instead made a strategic change by deciding upon bile, which is made in the liver.

The eyes were first to show what they can see with their vision and the audience and judges were mesmerized by their beautiful demonstration. Then the bones clanked out on stage pointing out that the body would just be a lump of immobile tissue without their support and turning to the eyes reminded them that it was the eye sockets that were responsible for protecting them. Next up were the numerous clotting factors who, by a tag-team effort, in rapid succession showed how their coordinated actions prevent bleeding throughout the body. As they simultaneously bowed in a coordinated fashion they gazed over at the eyes and the bones with a collective look of superiority.

The judges were now to consider the striking but superficial nature of eye function vs the important internal support of the bones vs the vital integrity of the clotting factors since they had already written-off bile because they couldn’t see how it could stand up to these three important components of body function. They all agreed that if the body fluids had put in blood instead, then maybe they would have been more challenged to decide among those four contestants. “But bile? Give us a break !!

Finally, despite the catcalls and hissing from the crowd, the green slimy bile slithered onto the stage. In the audience, the tongue complained to all who could hear, that “it tastes so vile.” And the nose, turning away in disgust, reminded everyone that “that’s what’s responsible for the smell of feces.” The judges looked at each other and smirked wondering what on earth the bile could say that would change their minds about having it immediately washed off the stage by the contents of the urinary bladder. “What could the body fluids have been thinking when they chose to select bile over blood?”

Nevertheless, the bile shimmied up to the microphone and looking at its opponents emphatically said just two words, “fat-soluble vitamins”. With that the well-preened eyes glanced away and rolled off the stage. On hearing what the bile had had to say the once proud bones immediately began to crumble and shakily crawled out of sight. The clotting factors all looked at each other with surprise and then in unison bowed down low to the slimy green bile while reverently removing themselves from the spotlight. Now only the bile was on stage while the audience and judges looked on in utter disbelief.

Fat-soluble Vitamins
Last time we talked about the basic structures of the gastrointestinal system and some of the parts and proteins needed to help in digestion and absorption of what we need to survive: carbohydrates, proteins, fats, vitamins, minerals, and water. Although lipase enzymes from the pancreas help to digest complicated fats the body also needs the detergent action of bile in order to be able to properly absorb fat molecules since they do not dissolve in water.

Of course fat molecules have many functions within the body, particularly being a component of neural tissues and membranes, supporting and protecting various organs, and being an important metabolic source of heat and energy. But it is also important to remember that three very necessary chemicals that we need enough of for efficient function and survival, namely, vitamins A, D & K, come from fat containing sources.

Now consider the contest described above between the eyes, the bones, the clotting factors, and bile. The ability for the eyes to have visual function is dependent on the presence of an adequate amount of Vitamin A in the body. Vitamin A is the molecular basis for the photosensitive tissue in the retina that allows for vision. Without enough bile to efficiently absorb fatty molecules containing Vitamin A, such as from dairy products, oily fish, eggs or liver, vision would be compromised. That’s why the eyes immediately saw the light and exited the competition.

The same can be said for the bones which are dependent on an adequate amount of Vitamin D to manage calcium absorption, metabolism, and bone growth. Although some Vitamin D can be made from precursors in the skin we also need to take in fish oil and dairy products to be sure we have enough. So the bones’ hopes of winning began to crumble when bile spoke the truth about how bone integrity is dependent on its function.

Finally, many of the clotting factors which are made in the liver, are directly dependent on Vitamin K absorption from such foods as green vegetables. The medication called Coumadin (Warfarin), also known as rat poison, is an anti-Vitamin K drug which is used to therapeutically thin the blood of people who may be prone to excessive clotting. In the absence of bile, proper Vitamin K absorption would be compromised thus negatively impacting clotting. That’s why they collectively bowed and bled off the stage.

(For more information on the eyes and vision, the bones and calcium metabolism, and the clotting factors see my previous columns on The Retina, Hamlet meets Modern Medicine Part 1, and Hemostasis, respectfully)

Macroevolution??
It is not unusual to encounter stupendous explanations of how vision from the eyes, body support and mobility from the bones, and hemostasis from the clotting factors, all came into being merely by the purposeless forces of natural selection acting on random variation. But those who are properly informed about some of the necessary precursors and functions that are required for any of these components to come into being and function in the first place (namely the bile-dependent ability to absorb fat-soluble vitamins like A, D, & K) should now be able to question these proposals which never take into account the big picture and by all rights should be seen as overly optimistic and simplistic. Certainly bile would not take this sitting down or slithering around. But what exactly is bile? How is it produced and controlled? And what about the gall bladder and its function: where does it fit into all of this?

The Bile
Bile is a fluid that is produced in the liver. It contains a similar amount of water and ions such as Na+ (sodium), Cl - (chloride) and HCO3 - (bicarbonate) like regular serum. But it also consists of bile salts, bile pigments, cholesterol, mucus, and phospholipids like lecithin, which together allow it to help the body absorb fat. The liver produces about 500-1,000 cc of bile daily and it either drains directly into the duodenum through the common bile duct or is stored in the gall bladder for later use. (see fig 1)

taken from Encyclopedia Britannica online

The bile salts themselves are derived from cholesterol. After being released into the intestine (duodenum) and having done their emulsifying job allowing fat absorption in the jejunum, most of them are reabsorbed downstream in the ileum and are returned to the liver for recycling. This is the main driving force for liver production of bile. Bile also contains bile pigments such as bilirubin which are derived from the breakdown of hemoglobin and are responsible for the colors of bile and feces.

The gall bladder stores bile and further concentrates it by absorbing some of its fluid.

Most of the bile produced by the liver remains in the gall bladder between meals since there isn’t a lot of fat in the intestine to be absorbed. But once the stomach and the intestine are stimulated by food, especially fats, a combination of nervous and hormonal stimulation results in gall bladder contraction to place concentrated bile where it is needed in the intestine to aid in fat absorption. Since the gall bladder removes water from bile this allows the concentration of the bile salts and other chemicals to increase to a large degree which makes them susceptible to coming out of solution and forming stones similar to what can happen in the kidney which makes concentrated urine.

The Liver: “I Get No Respect !!”
As a final exercise in humility let’s take a look at the liver, the organ that does so much for our survival but is given very little recognition and honor in human culture. In many ways it surpasses the heart: which is mainly just a pump: the lungs: which largely just bring in oxygen and get rid of carbon dioxide: and the brain which materialists tell us is a complex circuitry run solely by our genes that tells everything and everyone what to do. The liver just keeps churning away, producing numerous proteins and chemicals that are needed for our survival and performing tasks that we just take for granted.

Besides being involved in fat metabolism, storage of fat-soluble vitamins, and producing bile and the clotting factors, the liver, which is the largest organ in the body, performs several other vital functions for our survival. Here are just a few of them. Please note that if any one of these functions were severely compromised or absent we would not be alive.

Mr. Darwin: Control is the Key
Besides producing vital biomolecules and performing numerous functions for our survival it is important to note that these do not take place within a vacuum. The liver, by virtue of its size and functional capacity, participates as do other organs, many of them often under neural and hormonal control, in keeping us alive by virtue of there being detection systems in place that “know” when and how to act in certain situations and through various mechanisms can be turned off when necessary. All explanations of how macroevolution could have resulted in life without intelligent agency, makes broad assumptions of how this or that biomolecule or organ system could have come about without detailing how the necessary control could have developed over time and remained functional each step along the way. For as I’ve said repeatedly in the past:

the mere existence of parts should not assume a system of function, and the mere existence of a functioning system should not assume survival capacity.

Each and every function of the liver mentioned above is vital for our survival and the liver’s capacity to perform them would seem to require an inherent knowledge of what is necessary for life. Modern evolutionary biologists might believe in macroevolution based on what they have found so far and the hope of being able to explain these things in the future. But based on what we know about the functional complexity of, and the control mechanisms contained within, the human body, this indeed requires a lot of faith. A faith that I just can’t bring myself to commit to given our knowledge of disease, dysfunction, and death, and how easy it is for us to be knocked out of the competition for the survival of the fittest. See what you think !!

Next time we’ll be looking at kidney function and how it ultimately controls fluid balance in the body along with a whole lot of other things as well. Just be ready to exercise your wonder on this one ! I’ve already got a headache just thinking about it !

Dr.G.
drhglicksman@yahoo.com

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. Comments and questions about this column or any of the previous ones are welcome at drhglicksman@yahoo.com

Copyright 2007 Dr. Howard Glicksman. All rights reserved. International copyright secured.
File Date: 11.01.07

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