Understanding the Human Digestive System:
Bifidus and the Large Intestine
Welcome to section four of our Journey to Better Nutrition!
In this conversation we continue to deepen our knowledge about the human digestive system.
Click here to review part 2 of Understanding
the Human Digestive System
"Alexander Fleming, who discovered penicillin, did caution his fellow scientists at the
time that penicillin did not kill all bacteria, and that certain strains would easily
become penicillin-resistant in time. What Fleming and the other microbe-hunters did
not realize was that antibiotic-resistance (on the part of pathogenic bacteria) was not
their only worry. They failed to see that when antibiotics kill or inhibit the growth
of harmful disease-causing bacteria, (strep, staph, e-coli, etc.), they also kill or
inhibit the growth of helpful (probiotic) strains like acidophilus and bifidus.
When this occurs, the garden within is so altered that in many persons, the weeds start
to take over (the weeds are the pathogenic and unfriendly bacteria and other negatively
inclined and very opportunistic microbes). One of the most common weeds is a yeast called
Candida albicans. Another is an organism called Clostridium, which is the source of
toxins that cause botulism. Others include those that cause salmonella and Shigella
diarrheas. These opportunistic organisms, once they gain a foothold and start growing,
can cause a wide range of health problems, ranging from recurring yeast infections to
depression, chronic fatigue, sinusitis, and a complex array of illnesses and diseases.
It should also be noted that this is not just a problem for humans. Veterinarians,
farmers, and microbiologists see problems of a similar nature in cows, horses, poultry,
and a variety of pets when they receive feed containing antibiotics."
Keith W. Sehnert, M.D. The Garden Within
The Physiology of Digestion…
In sections two and three we began our exploration and discovery of the physiology of the human digestive system. We talked about digestive enzymes in section two, and the all-important initial stages of digestion in the mouth and stomach. In section three, our journey took us down the long and winding road of our small intestine, as we learned the important role that beneficial bacteria in general, and acidophilus in particular, play in helping us maintain a properly functioning digestive system. Let's see what happens next…
By the time the digested food (chyme) reaches the end of the small intestine, 95% (or more) of the nutrients have been absorbed. If the small intestine is working properly, of course! At the end of the small intestine exists a very interesting and important physiological juncture: the ileocecal valve. The ileocecal valve marks the intersection of the final section of the small intestine (the ileum) and the beginning section of the large intestine (the cecum), called the ascending colon.
The ileocecal valve, like its predecessor valves from earlier in the gastrointestinal (GI) tract, is a fleshy partition that opens and closes, allowing digested food to pass through. At this particular juncture most of the nutrients have already been absorbed and assimilated and what remains is mostly waste and water. It's important to normal metabolic functioning that some of this water is reabsorbed into the body…but none of the waste! The large intestine (or colon) is primarily responsible for the rapid transit and effective removal of waste that is a by-product of human digestion.
Also at this junction (of the large and small intestines) is a very familiar piece of our anatomy and physiology: the appendix. It was thought for years to be largely unnecessary in function and therefore medically expendable and useless. But the appendix now appears to play a crucial role in the final stages of digestion by storing and secreting a variety of substances that support the rapid transit and removal of toxic waste from the body and inhibit the growth of any pathogenic bacteria. We are finally learning that when it comes to the miracle of the human body, there are no expendable parts…only essential pieces of a magnificent puzzle that we do not yet fully understand.
Bifidus and the Large Intestine
Bifidus ( Bifidobacterium bifidus ) is the dominant probiotic bacteria inhabiting the large intestine and is vital to its proper functioning. Let's take a closer look at the basic structure and function of the large intestine and the role that bifidus is designed to play.
There are three primary sections of the large intestine. Each section is about two feet in length: the ascending colon, the transverse colon, and the descending colon. The last six to nine inches of the descending colon is called the sigmoid colon which is a reference to its shape, in that it moves in two directions, like the letter "S"). When the sigmoid colon is working smoothly and the entire large intestine is healthy, waste matter can be eliminated quickly and easily. The entire intestinal tube terminates with the rectum and anus. The anus is defined by its fleshy sphincter-like ability to expand and contract and is related in form and function to all the other digestive system "valves" that have preceded it.
Unlike its predecessor, the large intestine is relatively short and only about six to seven feet long and about one and a half to two inches wide.
The walls of the large intestine are lined with a layer of mucus providing essential lubrication for the rapid transit of waste. Where the small intestine was marked by the presence of protruding villi and microvilli by the millions, the large intestine is made up of a continuous series of very muscular pouches (haustra) which contract due to intestinal peristalsis. These muscular waves of motion move the waste forward to its final destination.
When bifidus and other probiotics, enzymes, and water are absent from this final and most important stage of digestion and elimination, the mucus lining of the large intestine becomes weak or disappears altogether. This situation causes the remaining fecal matter (waste) to become dry and hard. This causes the fecal transit time to slow down allowing for the proliferation of pathogenic bacteria, which in turn allows for the accumulation of fecal matter in the various folds and pouches of the lining of the large intestine. This situation is responsible for the condition we call constipation, which is basically the result of a sluggish, ill-functioning and weakened bowel. This situation is also responsible for the thickening and expansion of the large intestinal wall, called diverticulosis, and for the swelling and inflammation of the same, called diverticulitis and colitis. There are several other maladies that can occur as a result of this situation, these are only the most well-known and most commonly experienced.
What are the specific benefits attributed to Bifidus?
A high concentration of Bifidus in the large intestine can help prevent all the various symptoms of an irritable bowel, and can provide the following important benefits.
- Bifidus bacteria help to regulate and maintain
the proper pH of the large intestine. This balance is essential
for normal functioning. The proper pH of various parts of our
internal ecology is one of the most important means the body has
in maintaining homeostasis (or systemic balance).
- Bifidus bacteria are helpful in serving as co-factors
to various other beneficial bacteria, as well as various food
and digestive enzymes, in making sure that all waste matter is
thoroughly broken down and stays relatively soft and moist and
able to be easily transported up, across, down, and then out of
the large intestine.
- Bifidus bacteria inhibit the growth of pathogenic
bacteria, by their sheer numbers on the one hand and by their
secretion of natural antibiotics on the other.
- Bifidus bacteria live in and support the health
of the mucus lining of the large intestine. It is the gradual
weakening of this lining, through the absence of bifidus bacteria,
and the presence of many other toxic and insulting factors, that
is primarily responsible for the many problems that can occur
in the colon.
- Bifidus bacteria service and protect the many
lymph nodes that line the large intestine. These lymph nodes are
essential components of the human immune system and are currently
the target of much research on the topic of gut-brain-immune function.
Insults to our probiotic and digestive system health can include:
Antibiotics, alcohol, antacids, all drugs, coffee, tea, all sources of caffeine, chlorine in our drinking water (and in our bathing water), chronic dehydration, lack of exercise, too much negative stress in the forms of worry and anxiety, not enough sleep, overeating, anti-depressant drugs, carbonated beverages of all kinds (even carbonated water!), cigarettes, any inhaled tobacco smoke, chewing tobacco, most commercial grade tobacco products, processed foods in general, food additives such as preservatives, coloring agents, flavor enhancers, and artificial sweeteners, dairy products, microwave ovens, excess sugar in any form, excess consumption of fruit juices from concentrates, excess meat consumption, excess flour products consumption (breads, pastries, baked goods using flour, etc.), exposure to environmental pollutants, solvents, chemical cleaning agents, pesticides, herbicides, fungicides, etc., petro-chemical out-gassing from plastics in various building materials and supplies including carpets, flooring, and wallboards, glues, magic markers, clothes made from certain synthetic fibers, paints, paint thinners, eating too late at night, eating or drinking anything too cold, not chewing enough, and the list goes on.
Of course there is much more we can learn about the human digestive system and how best to nourish, support, and strengthen it. We trust that this part of our journey to better nutrition has inspired your curiosity and interest in taking actions that support the proper functioning of this all-important system of the human body, the Digestive System.
In the next section, find out about what challenges our bodies are confronted with once all of our fabulous micro-nutrients have been successfully digested, absorbed, and assimilated. Learn about free radical scavengers and oxidative stress and some miraculous, naturally occurring nutritional substances called antioxidants.
Action Steps for Section 4!
- Learn more about New Earth's
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- Fill out your Weekly
- Identify an insulting habit in your diet or lifestyle
and minimize its impact. You could eliminate the insult altogether
or simply modify it. Just try it one day at a time, for one week,
and see if you notice improvements in your health and energy.
Review the Habits of Naturally Healthy People
for ideas and suggestions.
- Do you have questions?
- Make sure you do something that really makes you
laugh every day!
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