Doctor’s Tip: Encourage healthful microorganisms in your gut |

Doctor’s Tip: Encourage healthful microorganisms in your gut

Dr. Greg Feinsinger

Dr. Greg Feinsinger
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The study of the human microbiome is in its infancy. In the past, medical scientists thought of bacteria in our guts in terms of pathogens that cause infectious diseases such as dysentery and cholera. In the past few years, however, scientists have discovered that we humans have trillions of bacteria in our guts, which can be our friends or our enemies, depending on what we eat. Humans are made up of 10 trillion cells, and although estimates vary, it is thought that we have at least that many bacteria in our intestines (especially our colons), if not more.

Technically, the term microbiota refers to the microorganisms in or on us, most of which are bacteria (there can be other types of microorganisms as well, such as viruses and fungi). The term microbiome refers to the collective genetic makeup of all these organisms. However, microbiome is often used inclusively, to cover both.

There are non-gut microbiomes, such as on the skin, in the oral cavity, in the lungs, and in the vagina. But this column is about the gut microbiome. The fetal environment and fetal gut is sterile. As the baby is delivered through the vaginal canal, the infant’s gut is populated by vaginal flora (another word for microbiome). C-section babies don’t have this exposure, and it’s thought that this can result in certain health problems later. The gut microbiome matures over the first few years of life, and we end up with about three pounds of gut microorganisms. Some scientists consider the microbiome to be another organ, because of all the functions it performs.

As humans evolved over millions of years, they developed a symbiotic relationship with their gut microbiome, meaning that both the microorganisms and the humans benefited. However, it turns out that what we eat influences the types of bacteria in our microbiomes, and unfortunately most of Americans and other populations on a Western diet don’t eat what we were genetically programed to eat. In particular, health-promoting bacteria feed on fiber and resistant starch (the part of starchy whole foods such as beans that is resistant to digestion), and a large majority of Americans don’t eat enough of either.

Here are some examples of what health-promoting gut flora can do for you:

• protect against obesity by influencing metabolism

• decrease inflammation and cancer

• enhance your immune system

• prevent pre-diabetes and diabetes

• improve mood by affecting neurotransmitters such as serotonin

• protect the brain and nervous system

• manufacture vitamin K and the B-vitamin niacin

• protect against pathogens

• improve digestion and conditions such as irritable bowel syndrome.

Here are examples of the problems that can result from disease-promoting gut flora:

• They can cause instead of prevent all the above conditions.

• When gut bacteria are exposed to L-carnitine in meat or choline in eggs or dairy or seafood, TMAO is produced, which promotes atherosclerosis, the cause of heart attacks and most strokes.

• allergies, asthma, autoimmune diseases such as type 1 diabetes

• inflammatory bowel disease (ulcerative colitis, Crohn’s disease), and celiac disease

• fatty liver and cirrhosis

• Hydrogen sulfide is produced by animal-based-diet bacteria, which causes foul-smelling gas and stool.

What disrupts a healthy gut microbiome?

• antibiotics

• eating animal products, mainly because of the products themselves but also because antibiotics are often used in raising beef and other domesticated animals to promote growth (antibiotics you get from eating meat or by taken directly can promote growth in you too)

• being obsessive about being clean and avoiding contact with health-promoting bacteria.

Stool transplanted from lean to obese people results in weight loss, but since most of us would rather not go there, what else can you do to ensure a health-promoting gut microbiome?

• Eat lots of plant-based food, including vegetables, fruit and whole grains, thereby consuming plenty of fiber and resistant starch that feed your good bacteria.

• Fermented foods such as kimchee and kombucha have health-promoting gut bacteria but should be consumed only in moderation, and aren’t necessary if you are plant-based.

• Avoid antibiotics unless they are absolutely necessary.

• If you have to take antibiotics, take a probiotic during and after the course of antibiotics.

• Make contact with dirt with activities such as gardening.

• Don’t use products that say “anti-bacterial” because “good bacteria” promote health.

To learn more, go to Dr. Micheal Greger’s website and search microbiome. Books are now available about this subject as well.

Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at

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