We eat, sleep, and go to the bathroom. Yet, we never think about how all these physical needs are processed in the systems of our body when they are functioning normally.

Yes, our bodies are created with perfect systems by which our all kinds of needs are met. The digestive system is one of them. Our intestines are key elements of this system, so much so that asking someone “How are your intestines?” would be as comprehensive as asking “How are you?”

Digestive system

Food is critical to life. A human being can bear hunger for one month at most and can only endure a few days of drought. Thus, eating and drinking is crucial.

Foods as we eat them are not convenient for use by the cells. Food must be broken down into smaller pieces. This process begins in the mouth and ends at the anus, and it is called digestion.

The main task of our stomach and intestines is digestion. The teeth, salivary glands, the tongue, and the gullet – as well as swallowing – are essential secondary elements. Additionally, if the pancreas or liver fall ill, it can paralyze the whole system. While also working with the circulatory system, kidneys have the task of reabsorbing useful substances like glucose, amino acids, and water.

Our digestive system works together with the urinary system and the digestive organs like a factory. How these parts work together is still not fully understood, but more detailed research has been performed and revealed more secrets of the digestive system. By means of every discovery, it is realized that this perfect creation has a more intricate structure than is known.

The brain in the intestine

There are more neurons in our intestines than in our spinal cord and the intestines are created in a way that can move independently from the central nervous system. They have their own nervous system, known as enteric nervous system (ENS), which is also called the “second brain. “Within those yards of tubing lies a complex web of microcircuitry driven by more neurotransmitters and neuromodulators than can be found anywhere else in the peripheral nervous system. These allow the ENS to perform many of its tasks in the absence of central nervous system (CNS) control…” [1]. Thus, “… isolated segments of intestine can independently coordinate propulsive movements and propel content without any neural connections to the brain or spinal cord [2].

The intestines take action when food comes into the stomach. This movement is known as colonic migrating motor complexes (CMMC), and it moves the substances that cannot be digested, like bone and fiber. According to neurophysiologist Nick Spencer et al, “The gut wall contains a complete network of intrinsic nerves capable of propelling contents along the bowel, without any requirement of nerves originating in the brain or spinal cord” [3].

Eat different types of food

70% of our immune system cells are in our intestines. A big part of the approximately 38 trillion bacteria in our body are in our intestines, and they are useful; they have a big role in digesting food. Different groups of bacteria feed on different types of food; so for intestinal flora it is very important to have a variety of food on our table. For the ideal day on a plate Dr. Megan Rossi recommends people should “aim for at least 30 different plant species per week.” “The reason for this is that each plant contains different types of fibres and phytochemicals (the super healthy components of plants) that feed different good bacteria. The more plant variety, the more variety of gut bacteria – which is associated with health and happiness” [4].

Pets in our body

For Dr. Megan Rossi, “microbes are like our pets, so you have to take care of them and feed them” [5].

Of course, germ flora in our body is not just limited to the ones in the intestines. Bacteria, viruses, and fungi in our body are nearly scattered throughout the whole body. These living things produce pellicle on our head skin, irritate the gaps between our toes, live on our skin, are on duty among our teeth, and have ecosystems and assigned positions convenient to them. According to the situation, they keep their living spaces healthy or unhealthy. Although they number 50 trillion, they are approximately 200 grams of our body weight.  

Useful microbes

An average size human adult houses about 10¹² bacteria on the skin, 10¹⁰ in the mouth, and 10¹⁴ in the gastrointestinal tract [6].

These microorganisms are useful microbes with duties in our body. The harmless flora of microbes is generally present on the skin, mouth, teeth, nose, throat, and bowel and genital areas. There isn’t normal flora in internal organs except the large bowel. Internal organs have no microbes. If we look closely, flora is inserted in every part of our body which is dirty and has contact with the outer environment. If it was not for the useful flora, microorganisms causing illness would settle instead. Only intestinal bacteria are permanent microbes which are useful. For example, vitamin K plays a part in a crucial event like blood clotting and is produced in the intestine.

Control your stress

Research has revealed that mental and psychological stress affects the health of the intestines. Serotonin is produced automatically in case of need, and 85% of it is produced in the digestive tract. Stress suppresses the level of serotonin produced. Psychological illnesses are associated with low levels of serotonin.

Studies have shown that relaxing practices like meditation for 15-20 minutes can be good for health and reduce stress. At this point, daily prayers are a kind of therapy. Other ways to stay healthy include: avoiding things like alcohol and caffeine, and sleeping well.

Our body has ways of telling us when it’s not healthy. For instance, we can learn the digestive tract isn’t healthy if we have to use the toilet more than three times a day and fewer than three times a week.

References

1. Gershon, Michael D. “The Enteric Nervous System: A Second Brain.” Pdfs.semanticscholar.org.
2. Spencer et al. 2018. “Identification of a Rhythmic Firing Pattern in the Enteric Nervous System That Generates Rhythmic Electrical Activity in Smooth Muscle.” http://www.jneurosci.org/content/38/24/5507
3. http://www.flinders.edu.au/neuroscience/lab_visceral.html
4. https://www.dailymail.co.uk/femail/article-5543159/Doctor-debunks-myths-surrounding-gut-health-say-surprise-you.html
5. https://navva.org/brazil/health/why-the-bowel-is-considered-our-39-2nd-brain-39-and-other-5-amazing-facts-about-the-organ-news/
6. http://www.textbookofbacteriology.net/normalflora_3.html

An unexpected increase in flora, which is normally necessary for a healthy life, can pave the way for diseases. There are, on average, 200 grams of bacteria on an adult’s skin, 20 grams in the mouth, and 20 grams in the lungs. The gastrointestinal tract contains a dramatic amount of flora – 1.5 kg of bacteria – this equals 100 trillion organisms. This flora covers the intestinal mucosa, which is an area of approximately 300 m2. This functions as a protective layer, and is of vital significance.

Since some 90% of the microorganisms inside us are dependent on the human body to survive, their relationship with us is symbiotic. Most of this flora improves our immune system. Our body tolerates the beneficial bacteria in the flora, and it fights against the harmful organisms.

Much of our flora develops before we’re born. Since a baby is sterile prior to birth, it receives some 100 types of microorganisms from the birth tract and environment, which start building the body’s flora. Factors such as the type of delivery (natural or caesarian), the mother’s age, the baby’s health, the type of nutrition (mother’s milk and baby food), and the mother’s food intake play a determining role in the types and amount of the microorganisms that make up the flora. Babies born in the natural way have a stronger immunity than those born through caesarian sections, thanks to the flora they gain from their mother.

While nearly 700 types of microorganisms inhabit the body of a 6 month old baby, a person has a fully developed system of flora at 3 years of age.

Flora in the digestive track

The digestive track is where food and nutrients are refined for our body’s benefit. Our GI tract is about 250-400 meters in area, comparable to a tennis court. It has the second largest surface area in the body. About 60 tons of food pass through a person’s digestive track over his or her lifetime.

The part that contains the most diverse microorganisms is the mouth. Conversely, the floral density of the esophagus is low. Microorganisms that come by means of saliva and foods are found here. As the interior of the stomach is highly acidic (pH: 2), the number of microorganisms in the stomach is quite low (10thousand/per ml).

Considering the amounts of bacteria in an average adult body, one milliliter of the duodenum has ten thousand bacteria; the beginning of the small intestine has a hundred thousand, its ending has a hundred million, and the colon has about a hundred billion to a trillion microorganisms. The intestines of healthy individuals have nearly 500 different bacteria species.  The fact that trillions of organisms are found in the human body may sound a bit frightening, but 98% of them are beneficial.

The forgotten organ

The intestinal flora, which is indispensable for a healthy life and is specific to every person, is also referred to as “the forgotten organ,” since its metabolic activity is rather high.

Substances such as amino acids, vitamins, and antioxidants, found in the content reaching the large intestine, are metabolized by the intestinal flora and thus the needs of intestinal cells are met. These bacteria have the duty to stimulate cell division and prevent the reproduction of harmful bacteria, toxic substances’ passing from the guts to the bloodstream, and the emergence of skin diseases. Most of the time, we are not even aware of the presence of these marvelous helpers.

The intestinal flora stimulates the lymph tissues around it and triggers an antidote against germs. The fact that the lymphoid structure did not develop in experimental animals bred in a bacteria-free environment indicates how crucial microorganisms are for the immune system.

The spoiling of the intestinal flora can cause problems like diarrhea, constipation, gas, allergies, infection, high cholesterol, headaches, and fatigue. The toxins of the disease-causing germs damage the intestinal membrane and increase its permeability. Thus, toxins join the bloodstream and they might reach as far as the brain. These toxins can influence brain functions, and lead to problems with sight and balance, fatigue, and amnesia, as well as leading to sleep disturbances, and pains in the muscles and joints. These toxins also hinder the absorption of nutrients and can cause malnutrition.

In order to keep the intestinal flora balanced, it is necessary to keep away from antibiotics, carbonated beverages, refined food, and alcohol.  Eating various kinds of food during the same meal may cause difficulty for the digestive system and the flora. Fruits eaten at night burden the digestive system, causing irregularity in the flora and the formation of gas. For this reason, it is wiser to eat fruit half an hour before, or two hours after, a meal.

Our probiotic friends

Probiotics are beneficial microorganisms that balance the intestinal flora. Probiotic products are foods with added beneficial microorganisms. As the microorganisms in normal flora turn carbohydrates into the suitable form to be used by the body, they are known as friendly bacteria. These microorganisms, which form 95% of the flora in little infants, synthesize certain vitamins, and protect the baby against some diseases.

Fermented foods, such as yogurt, cheese, kefir, olives, vinegar, naturally fermented pickles, and sourdough bread, enrich the intestinal flora. However, increasing foods’ shelf life with methods as UHT or pasteurization can negatively affect the intestinal flora.

Probiotic bacteria are resistant to stomach acid, bile salt, and lysozyme. They produce antimicrobial substances such as lactic acid, acetic acid, and bacteriocin to prevent the proliferation of undesirable microorganisms in the intestine. In addition, they form a protective layer on the intestinal walls against toxic substances.

Antibiotics, alcohol, junk food, stress, a poor diet, and intestinal surgeries can all lessen the amount of probiotic bacteria in the gut.

Today, probiotic capsules with differing benefits are on the market. A diet rich in natural foods such as vegetables, fruits, meat, and eggs, along with probiotic foods such as yogurt, are good for the intestinal flora. It is thought that some diseases which cannot be treated could perhaps be cured with probiotics.

The intestines and our health

During the development of the embryo, some of the same groups of cells are used for forming the brain and the digestive system. These structures are in constant communication with the vagus nerve.

There are 100 million nerve cells in the structure of the intestines. After the brain, the intestines have the highest amount of nerve cells in the body. As such, the digestive tract plays a big role in determining a person’s mood. The toxins it secretes can cause a person to feel bad. This is why some scientists humorously say that we have a second brain in our belly. Some states of worry, excitement, and emotional intensity have corresponding gut pains. There is more of the hormone serotonin, which balances a person’s mood, in the intestines than in the brain. When there is a pain in the body, benzodiazepine – a pain-alleviating substance used in anti-depressants – is produced by the intestines. This is why the intestines work faster in times of pain.

Some of the different bacteria in the intestines need sugary nutrients and others need oily nutrients. In order to obtain these nutrients, bacteria send signals to the secretive glands and nervous system, and make the person feel like consuming certain foods.

A person needs healthy intestines to lead a healthy life – they need balanced flora for healthy intestines. New food technologies in the last century, changes in dietary habits, chemical pollutants, antibiotics used in agriculture, and other chemical substances in food and beverages, have all upset the balance of the digestive track’s flora. This imbalance is causing an increase of related diseases. In order to reduce these diseases, our body needs more of its old, friendly bacteria.

References

• Berg RD. The indigenous gastrointestinal microflora. TrendsMicrobiol 1996; 4:430-435.
• de Vrese M, Schrezenmeir J. Probiotics, prebiotics and synbiotics. AdvBiochemEngBiotechnol. 2008;1111:1-66.
• Macfarlane GT andCummings JH: Probiotics and prebiotics: can regulating the activities of intestinal bacteria benefit health? BrMed J. 318:999-1003,1999
• O’Sullivan GC, Kelly P, O’Halloran S. Probiotics: an emerging therapy. Curr Pharm Des 2005; 11: 3-10.
• Penner R, Fedorak RN, Madsen KL. Probiotics and nutreceuticals: non-medicinal treatments of gastrointestinal diseases. Curr Opin Pharmacol 2005; 5: 1-8.
• Sathyabama S, Khan N, Agrewala JN. Friendly pathogens; preventor provoke autoimmunity. CritRevMicrobiol. 2014;40:273-80.
• Tannock GW. Can the gut microflora of infants be modified by giving probiotics to mothers? J Pediatr Gastroenterol Nutr 2004; 38: 244-246.

Original article: Kim P. et al, ACS Nano (2012, online ahead of print)

Frost formation on aircrafts at high altitudes poses major safety threats and high-maintenance costs. Now, Joanna Aizenberg with her research team present a solution in their recent publication reporting on outstanding capabilities of a surface coating to prevent frost formation on metal surfaces. The technology called SLIPS (Slippery, Liquid-Infused Porous Surfaces) was inspired by the slippery surface of the carnivorous pitcher plant, which enables the plant to capture insects. “Some of the most extreme examples in biology can provide the most amazing and unexpected ideas…” says Aizenberg, who is a professor at the Wyss Institute for Biologically Inspired Engineering at Harvard University. Rendering surfaces slippery is not new to scientists, and the earlier inspirations also came from biology. Mimicking the surface of the leaf of another plant (Nelumbo nucifera, or commonly known as the Lotus plant), scientists have been successful in fabricating surface coatings that would repel water-based dirt, but Lotus-inspired coatings failed for oily substances. On the other hand, Aizenberg’s SLIPS technology offers a single solution for repelling any type of accumulated unwanted material. The pitcher plant thus offers a solution that virtually proves to be the “silver bullet” in generating non-sticky coatings as described again in Aizenberg’s own words: “In following its example, we should be able to develop a platform that works for almost any sticky problem, no matter how seemingly unrelated, whether it’s ice accumulation, bacterial attachment, environmental contamination, clogging of pipes, marine biofouling, or graffiti, rather than having to come up with a host of individual solutions.” Thanks to the wondrous design in the pitcher plant, it looks like doctors will be delivered from replacing bacteria-contaminated arterial stents, and we can all give a kiss goodbye to frosty freezers.

2- Airborne bird flu virus possesses a great risk

Original articles: Herfst S. et al, Science 336, 1534 & Russell C.A. et al, Science 336, 1541.

Science magazine recently published a special issue (June 22, 2012 issue) on the H5N1 infection (a.k.a. bird flu) with two reports revealing the pandemic (a disease prevalent throughout an entire country, continent, or the whole world, such as AIDS) potential of bird flu. Bird flu virus has so far killed millions of birds and many more millions of birds were culled to stop the propagation of the virus. Thankfully, this virus has not yet caused a pandemic in humans mainly because of its inability to spread easily among humans. One mechanism that makes viruses highly contagious is their ability to spread through air, such as through the nose and mouths of people when they cough and sneeze. Viruses that spread through air are called airborne viruses. One big difference between bird flu virus and the more recent swine flu virus (H1N1) was that swine flu is an airborne virus and bird flu is not, and therefore swine flu caused a mild pandemic in 2009. As reported in these studies, researchers identified several genetic mutations that will cause bird flu virus to become airborne. Viruses undergo mutations all the time and unfortunately some of these identified mutations have already started taking place in circulating virus strains. This poses a great risk. One important aspect of these reports is that they were written about a year ago but withheld since now, because of concerns about misuse of this information to pose a threat to humanity. Now that the information is public, our hope is that it will be used to monitor the virus closely and be prepared if bird flu virus transforms into an airborne virus.

3- Not all bacteria are the same after all

Original article: Chung H. et al, Cell 149, 1578 (2012)

The impact of our own bacteria on human life has been intensely researched in recent years. One of the common ground is that humans acquire many useful bacteria over their existence. However, this microbial flora constantly changes as the conditions do. Therefore, the real number of 500 to 1000 microbial species inhabiting mammals is anybody’s guess. Nonetheless, some scientists did not shy away predicting a connection between having a specific microbial flora to avoid certain diseases. A recent article by Chung et al presented an interesting clue why constant change in microbial flora, especially if that leads to a loss of important bacteria, may be linked to the increase in human autoimmune disorders. “For every cell in your body that is you, that contains your specific genetic information, there are approximately nine foreign bacterial cells, primarily in your digestive tract and even on your skin,” said Dennis Kasper, professor at Harvard Medical School and senior author on the paper. To address the question if microbial affects immune system development, authors compared two groups of mice, both of which had never had bacteria in their intestine before the experiment. One group of mice received mice microbial flora and the other received human microbial flora. Both groups had similar number of bacteria in their digestive tracks. However, authors observed a stark contrast between the two groups in terms of the level of immune cells in intestinal tissues. Mice that received human flora had surprisingly low number of immune cells compared to the mice that received mouse flora, which is native to mice. When this experiment was repeated with rat microbial flora, astonishingly, similar immune deficiency was observed. “I was very surprised to see that. I would have expected more of a half-way response,” Chung said, considering how closely rats and mice are related. The study points out that we really need to preserve our own microbial flora that has been tailored for us. Disrupting this balance by means of current antibiotics overuse may have detrimental effects in the future.