FROM THE INSIDE OUT

BY A. MICHAEL LUSTBERG, M.D.

THOUSANDS OF YEARS AGO, ancient cultures

took advantage of the process of fermentation to preserve food and enhance taste. In the 1800s, Dr. Louis Pasteur’s research showed that the growth of microorganisms was responsible for spoiling beverages such as milk. From this observation, he developed pasteurization, the process of gently heating certain foods and beverages to destroy harmful bacteria.

In the early 1900s, Bulgarian physician Dr. Stamen Grigorov noted that the consumption of fermented foods, such as yogurt, seemed to be associated with longevity; his work led to the discovery of the bacteria Lactobacillus. But it wasn’t until the early 2000s that science truly turned its attention to the human gut microbiome.

“Microbiome” refers to the numerous microorganisms (including bacteria and fungi) that populate the small intestine and colon, known together as the gastrointestinal tract (GIT) or gut. The typical adult small intestine, nearly 1 feet in length, contains finger-like projections called villi, which increase surface area and help absorb nutrients. This is also where fermentation occurs, which results in gas and bloating. The colon, which is typically three to four feet long, absorbs the remaining water, calcium and potassium from the small intestine. The gut microbiome can promote a healthy intestinal lining and can affect food digestion, drug metabolism and immunologic processes (such as expelling germs and battling disease).

BALANCE IS KEY

Intestinal dysbiosis — a persistent imbalance of the gut’s normal ora or bacteria is likely responsible at least in part for insulin resistance which, in turn, results in elevated blood sugar levels. This is mediated by a gut hormone called glucagon-like peptide (GLP1). GLP is released in response to food intake and helps regulate appetite, especially after eating. It also helps enhance the production of insulin. When the gut bacteria are out of balance, the production of GLP may be reduced. ytokines, which are pro-in ammatory substances secreted by white blood cells, are also secreted in higher amounts when the gut is out of balance.

These changes can lead to a whole host of health issues, including weight gain (particularly around the waist), elevated blood sugar levels and abnormal cholesterol or triglyceride levels. Heart disease, stroke, diabetes and fatty liver can result. Increased in ammation can also lead to autoimmune conditions such as rheumatoid arthritis, Crohn’s disease or ulcerative colitis.

Irritable bowel syndrome (IBS) can be caused by a condition called small intestinal bacterial overgrowth (SIBO), an alteration in intestinal bacteria. SIBO can occur after food poisoning or a viral illness, for example, and leads to more harmful intestinal bacteria, which produce excess noxious gases, such as methane and hydrogen, that can result in bloating and malodorous gas or diarrhea. lostridium di cile infection, or diff (CDF), is usually caused by antibiotics killing the good bacteria in the gut, which can leave the immune system in the gut altered and susceptible to the overgrowth of harmful bacteria. CDF can result in serious diarrhea, dehydration, bleeding, weight loss — even (rarely) death. While there are certain antibiotics that can be used to treat CDF, about one-quarter of the time the infection comes back after treatment. People of advanced age and those with a compromised immune system are more susceptible to this infection.

Research on coronary artery disease has shown an increase of unhealthy intestinal bacteria in patients. These harmful bacteria produce an elevation in an endotoxin called nitric oxide (NO) after the consumption of red meat and saturated fats. NO is then absorbed through the intestine and into the bloodstream. The Mediterranean diet may reduce the risk of cardiovascular disease by decreasing bacteria that produce NO and other pro-in ammatory substances that get absorbed into the body.

THE GUT AND WEIGHT

Intestinal bacteria consist of several thousand different species. n individual’s genetic makeup and metabolic profile in uence how these bacteria interact with the gut. The role of intestinal bacteria and diet is complex, but weight loss appears to help regulate intestinal bacteria by driving down unhealthy bacteria that result in gut in ammation. Weight loss also helps repopulate the gut with healthy bacteria, resulting in a healthier intestinal lining, which then results in higher GLP levels and less cytokine production and endotoxemia (unhealthy substances produced by the intestinal lining that cause disease throughout the body).

Healthy gut has been associated with lean body type. This may occur, in part, by reversing in ammation and increasing GLP, which then results in less insulin resistance and decreases appetite. For example, normal weight individuals appear to contain more Bacteroides species bacteria in their gut.

A healthy and balanced diet is key to maintaining a healthy and balanced gut microbiome. Western diet, which typically includes more processed foods, fats and sugars, encourages elevated blood sugar levels and gut in ammation resulting in an increased risk for metabolic related diseases. Healthy eating plans, such as the Dietary Approaches to Stop Hypertension

DASH DIET (Dietary Approaches to Stop Hypertension) is designed to help treat or prevent high blood pressure. Studies have shown the DASH diet can lower blood pressure in as soon as two weeks. It can also lower LDL or bad cholesterol. DASH diet is high in vegetables, fruits and whole grains. It includes moderate amounts of fish, poultry and mixed nuts.

prioritizes plant-based foods, such as whole grains, vegetables, legumes, fruits, nuts, seeds, and herbs and spices. Olive oil is the main source of added fat. Fish, seafood, dairy, and poultry are included in moderation. Red meat and sweets are eaten only occasionally. The main benefit of a Mediterranean diet is that it contains relatively few energy-dense foods, such as processed carbohydrates and sugars, and it contains healthy fats, such as omega-3 fatty acids. The Mediterranean diet results in a reduction in cardiovascular risk and improvement in overall health.

WESTERN DIET is generally characterized by high intakes of red meat, processed meat, pre-packaged foods, butter, candy and sweets, fried foods, conventionally raised animal products, high-fat dairy products, eggs, refined grains, potatoes, corn (and high-fructose corn syrup) and high-sugar drinks, along with low intakes of fruits, vegetables, whole grains, pasture-raised animal products, fish, nuts and seeds. Some studies indicate a Western diet could impair the immune system in the gut in ways that could increase risk of infection and inflammatory bowel disease.

PROBIOTICS are microorganisms that are intended to have health benefits when consumed or applied to the body. They can be found in yogurt and other fermented foods, dietary supplements and some beauty products. PREBIOTICS are nutrient carbohydrates and act like food to help the healthy bacteria grow.

ANTIBIOTICS are medicines (such as penicillin or its derivatives) that inhibit the growth of or destroy microorganisms. Antibiotics are prescribed for the treatment of a bacterial infection; they are not e ective against viruses.

(DASH) diet and the Mediterranean diet, which emphasize eating vegetables, fruits, whole grains and lean proteins that contain healthy fats and tend to limit sugar, processed carbohydrates, salt and saturated and trans fats. (For more information, see “You Are What You at page 1 .) KNOW WHAT YOU NEED

There are certain gastrointestinal conditions for which probiotics are used as a prescribed treatment. However, at this time, due to a large variation in how scientific studies have been performed, few specific recommendations are available. Other studies have examined prebiotics, which are derived from food nutrient substances, to help promote the growth of healthy gut bacteria. (For more about probiotics and prebiotics, see Definitions, above).

Common symptoms of gastrointestinal distress are gas passage and bloating. Intestinal gas may be produced by either decreased digestion of carbohydrates or excess production of noxious gases. Decreases in intestinal digestive enzymes occur naturally with time (examples include lactose or fructose intolerance). This results in bacterial fermentation, which causes bloating and odorless gas. These conditions can be diagnosed with a breath test ordered by your health care provider.

SIBO can also be diagnosed with a breath test that measures the production of foul-smelling gases caused by the condition. Administration of an antibiotic called rifaximin can help bring the intestinal bacteria into the proper balance. Herbal medications may help as well. ifidobacterium and other probiotics appear to help prevent the recurrence of the symptoms.

A novel study published by Nature magazine in September 201 found that mice that had their gut bacteria transplanted from other mice developed the weight of their donors (“Bacteria from Lean Cage-mates Help Mice Stay Slim”). The authors of the study were able to demonstrate an association between gut microbiota and a physical feature such as lean or obese body type. ecal microbiota transplant gives the purified stool from one individual or individuals to another person either through an endoscopy or capsule. Fortunately, fecal microbiota transplant restores the healthy bacteria in the gut and, most of the time, is able to treat people who have not responded to initial or recurrent courses of antibiotics in response to CDF. Hospitals now routinely start probiotics any time antibiotics are given to prevent CDF. As always, see your health care provider if you’re experiencing chronic diarrhea, rectal bleeding or rapid and unexplained weight loss. Stool or blood tests may be the first step in diagnosis, as could a referral for colonoscopy or endoscopy.

BETTER DAYS AHEAD

The future of medicine is more personalized care, wherein specific treatment will be tailored to the individual needs of a patient based on their bacterial and genetic makeup. Currently, there are several commercial labs that perform a whole gut stool analysis of bacteria and in ammatory markers that can be ordered by your health care provider. There is also ongoing research studying specific types of bacteria and how they interact with the gut in specific disease states. With proper medical supervision, healthy intestinal bacteria can be supplemented or altered through diet and probiotics to improve the GIT and overall health.

About the author: Dr. A. Michael Lustberg is a fellow in the American Gastroenterological Association. He practices gastroenterology at Sutter Medical Group of the Redwoods.