Food/Nutrition Columnist
Hi! I’m Your Friendly Bacteria
Oct 21, 2013 - 12:05:05 AM

( - We all have them - trillions of microbial friends. It is your personal collection of more than 10,000 species of bacteria, fungi, and viruses that live in your gut, nose, mouth, throat, skin, and urogenital tract. They make up 3% of your body weight. Your internal pets require care and feeding. In return, if kept healthy, your microbes service your body. They extract energy (calories) from food you are unable to digest, they absorb and produce vitamins and amino acids (protein fragments), and they protect you from infectious invaders. Research is also showing that these organisms might help to: prevent obesity, heart disease and cancer; stimulate your immune system; and break down dangerous toxins -- all while boosting your overall health.

Good bacteria survive the trip through your digestive tract living on foods, mostly fiber, that pass through undigested. They form colonies along the intestinal wall where harmful pathogens might otherwise stop to park. Good bacteria also produce substances that drive off or kill invading organisms.

Everyone's microbiome (collection of internal organisms) is unique and it can be modified by what you do or do not eat. There is a relationship between our intestinal microbes, food, and the hormones that direct food absorption and use. When all is working correctly it plays like a symphony producing rich melodies

Organisms in your digestive tract appear to influence whether you store or burn fat. This is a very intriguing idea. If you change the makeup of your microbes would you burn more calories rather than store them and could this tip the balance toward weight loss? Researchers have learned from gastric bypass patients that the surgery promotes weight loss not only by reducing food intake but also by encouraging gut bacteria to process fat in a certain way.

What you eat affects the action of your microbes and the function of your immune system. We know that eating fiber-rich grains appears to reduce inflammation in the body which helps to reduce the risk for heart disease and cancer. Drs. Simin and Mohsen Meydani, at Tufts University, are attempting to map the connection between diet, microbes and disease risk. Whole grains may spur certain gut bacteria to make short chain fatty acids which have anti-inflammatory effects. Microbes plus fiber might also increase the acidity of the gut which may be unfavorable to harmful microorganisms.

Your microbes also function as a vitamin-production plant. Gut bacteria make vitamin B12 and vitamin K. Vitamin K is needed for blood clotting and there are wide variations in the levels of the vitamin in the general population. How much vitamin K is made by gut bacteria is unknown. If someone simply adjusted their diet to add more fiber, would their vitamin K levels increase? Sarah L. Booth, PHD, at Tufts, is attempting to find out if eating more whole grains and dietary fiber will modify your gut bacteria to produce more vitamin K.

Not all gut bacteria is beneficial. Certain microbes inflame the lining of the intestinal tract promoting cancer growth. Does a high fat diet or obesity shift your microbial community increasing your risk for intestinal cancers? We do know that people who eat more vegetables, beans, chocolate, cranberries and green tea, all rich in phytochemicals, have a lower risk for cancers of the GI tract. Polyphenols are not absorbed well in the small intestines. They may actually be better absorbed into the body with the help of the microflora in the colon. Polyphenols could have a prebiotic role, feeding and nourishing colon microbes, and perhaps even changing the microbes to act in an anti-cancer capacity.

All of this research is contributing to our knowledge about our internal hitchhikers who play a major role in protecting our health. Understanding the connection between the human microbiome, diet and health can open new avenues for disease prevention and treatment. It could turn out that the littlest among us has the biggest effect.

© NRH Nutrition Consultants, Inc.
Jo-Ann Heslin, MA, RD, CDN is a registered dietitian and the author of the nutrition counter series for Pocket Books with sales of more than 8.5 million books.

Look for:

The Most Complete Food Counter, 3rd ed., 2013

The Calorie Counter, 6th Ed., 2013

The Complete Food Counter, 4th ed., 2012

The Diabetes Counter, 4th Ed., 2011

The Protein Counter, 3rd Ed., 2011

The Ultimate Carbohydrate Counter, 3rd Ed., 2010

The Fat Counter, 7th ed., 2009

The Healthy Wholefoods Counter, 2008

The Cholesterol Counter, 7th Ed., 2008

Your Complete Food Counter App:

For more information on Jo-Ann and her books, go to:


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