Good Gut Flora - The Secret To Good Health!

If your house is anything like mine there are topics better not discussed...especially at meal-times.  Even a poorly-timed use of a euphemistic phrase like "bodily functions" or the slightly unappetizing-sounding word "gastronomical" will garner me a warning look from my dear wife who was raised to believe that good manners include delicacy of deed, word, and even thought.  Nevertheless a solid understanding of human digestion is fundamental to our health and survival, so here I go again straying onto forbidden paths for the good of mankind ;-).

Digestion

The most fundamental requirement for life is the ability to efficiently convert raw fuel (in our case food and liquid) into the energy, the raw materials for a myriad of metabolic processes, and the proteins called amino-acids we use to build up and repair the electro-musculo-skeletal structure that is our body. We are, consequently, built around a miraculous digestive tract.  For some reason (that eludes many of the innately curious among us) most humans would prefer not to think about what happens to their food once it passes their lips, but the topic is not only fascinating, it is basic to our personal survival.  There is a lot of complexity involved but let's simplify things shall we?  I'll borrow from Wikipedia's entry on digestion because it is so succinct:

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a breakdown of large food molecules to smaller ones.

• When food enters the mouth, its digestion starts by the action of chewing and the contact of saliva which contains an enzyme called salivary amylase to begin digestion of starch. 
• After chewing the food forms a small round slurry mass called a bolus which travels down the esophagus to the stomach. 
• Gastric juices (hydrochloric acid and pepsin) in the stomach start protein digestion.  Maybe you were wondering why these chemicals don't digest the stomach itself?  Good question!  Mucus is secreted by the stomach to shield the stomach wall.  Amazing huh?  Your body can dissolve meat without dissolving itself!
• The stomach also mixes the food mechanically using waves of muscular contractions that move along the stomach wall which further mixes the mass of food with digestive enzymes. 
• After an hour or two a thick liquid is produced called chyme. 
• Then a valve opens and the chyme enters the duodenum and mixes with digestive enzymes from the pancreas, and then passes through the small intestine
• In the small intestine digestion continues assisted by the "gut flora" (sometimes called the "microbiome") which is a community of beneficial microorganisms which assist multiple ways in digestion and health (see below)
• When the chyme is fully digested, it is absorbed into the blood. 95% of absorption of nutrients occurs in the small intestine. 
• Water and minerals are reabsorbed back into the blood in the colon (large intestine) where the pH is slightly acidic about 5.6 ~ 6.9. Some vitamins, such as biotin and vitamin K produced by bacteria in the colon are also absorbed into the blood in the colon.
• Waste material is eliminated from the rectum during defecation.

What is "Gut Flora" and why do we need it?

The human body carries about 100 trillion microorganisms in its intestines, a number ten times greater than the total number of human cells in the body (quantitatively we are more them than we are us).  Some people have called this collection the "forgotten" organ because the metabolic activities performed by these bacteria resemble those of an organ.  Research over the past two decades has revealed that gut health is critical to overall health, and that an unhealthy gut contributes to a wide range of diseases including diabetes, obesity, rheumatoid arthritis, autism spectrum disorder, depression, and chronic fatigue syndrome.  The beneficial functions of the "gut flora" include:

• Extracts more nutrition - The microbiota process carbohydrates that humans can't digest without their help include certain starches, fiber, oligosaccharides (e.g. from beans) and other sugars providing extra nutrition, energy, mineral absorption, muscle building, protection of intestinal walls, and even cancer prevention.
• Eliminates the bad guys - Since it produces lactic acid and different fatty acids the process of fermentation lowers the pH in the colon, killing most harmful species of bacteria and facilitating that of helpful species.  The pH may also enhance the excretion of carcinogens.
• Enhances immunity - Microbiota enhance the intestine's ability to discriminate between the pathogenic and beneficial bacteria.  The intestines are the first line of defense in the body's immune system and the bacteria stimulate the lymphoid tissue associated with the gut mucosa to produce antibodies to pathogens.
• Prevents cancer - The good bacteria in your gut metabolize HCAs (cancer-causing substances produced by cooking meats at high temperatures), excessive fats and sodium chloride (table salt) which can later cause cancers of the breasts and colon.
• Reduces allergies - since helpful gut flora stimulate the immune system and "train" it to respond properly to antigens, a lack of these bacteria in early life leads to an inadequately trained immune system that overreacts to antigens.
• Prevents IBDs such as Crohn's Disease - Inflammatory Bowel Diseases have sky-rocketed in rich nations and are relatively rare in poor nations.  They are linked to good hygiene and high antibiotic use in youth, lack of breastfeeding, and consumption of large amounts of sucrose and animal fat; and are inversely correlated to poor sanitation during the first years of life (yes, our kids ate stuff they found on the floor--and they're healthier for it) and consumption of fruits, vegetables, and unprocessed foods.  The good biota in your gut help prevent them.

How to nurture your gut flora and improve your health:

There are several things you can do to improve your gut flora and improve your health -

• Avoid Antibiotics - antibiotics seem like miracle drugs with no side effects, but they kill the good bacteria as well as the bad so excessive use (especially in childhood) can have severe consequences to your gut flora and your health.  Sometimes antibiotics are lifesavers but too often they have been used as placebos because of anxious parents who want "something" to help their child with a viral infection.  BTW, you can unwittingly get antibiotics by consuming animal products (e.g. meat, milk, eggs etc.) from animals that have been treated with antibiotics which is not uncommon.
• Breastfeed Your Babies - research has shown that breastfed infants have a more acidic environment in their gut during the first six weeks of life. Their tiny guts become naturally full of healthy bifidobacteria and naturally low in potentially harmful bacteria such as E. coli, Bacteroides, Clostridia, and Streptococci.
• Reduce Meats Fats And Refined Foods - These promote the bad types of bacteria in your gut and stress the good types.  For instance a late-breaking study shows that there is a gut-bacterial connection to heart-disease in people who eat a lot of red meat even if it is lean.  People who frequently eat red meat have a higher level of a particular type of bacteria which metabolizes a compound called TMAO which slows the removal of cholesterol that accumulates on arteries' walls and so contributes to heart disease.
• Increase Fruits Vegetables And Whole Foods - These promote good types of bacteria, generate more nutrition, and contribute to intestinal immunity (the intestine is where up to 70% of the immune system's work is done).
• Eat Uncooked Fermented Foods or Other "Probiotics" - Foods such as yogurt, kefir, and lacto-fermented vegetables (stay-tuned for a post on those) contribute large quantities of the good bacteria that populates your gut.  It's especially helpful when taking an antibiotic.  For a price you can buy probiotic capsules at health-food stores, though my preference is to medicate myself through the food I eat (or avoid) as much as possible.
• Stop Obsessing About Germs - I know this runs counter to what your mother taught you, but it's right in line with the way your great-grandmother lived.  Children and adults in poorer countries have better gut flora than those in wealthier countries.  Studies have shown the cause to be that lower standards of hygiene in the poorer countries enable a much rich and more active gut flora and an ENHANCED immune system.  It may seem ironic that LESS hygienic practices can be harmful but the body was designed to thrive in a filthy world and deliberately sparing ourselves exposure to the natural world ends up circumventing our bodies own immunological capabilities and weakening our immune response.  It's like never exercising a muscle so you won't "hurt it"--it atrophies and fails.

Maintain a healthy gut flora...it seems like a simple concept and yet our western diet and way of life has been waging war on our microscopic friends.  The result has been distress and disease.  Some people's gut flora is so unbalanced that researchers in the past two decades have turned to a technique they are calling "Fecal Microbiota Transplantation" FMT (I heard one researcher wryly call it a "transpoosion") in which fecal material from a healthy individual is transplanted via a retained enema to an unhealthy individual.  The healthy gut flora establishes itself in the unhealthy individual's intestinal tract.  Success rates in improving multiple health conditions have been seen in the 90% range.  This technique was first performed by a pioneering Italian anatomist and surgeon named Fabricius of Acquapendente (1537–1619).  In modern times it's been practiced since 1958.

Nurture the good bacteria in your body in order to fight off the bad bacteria.  Make the suggested changes above...you'll feel and be healthier!