Dietary Fiber and Your Microbiota

Dietary Fiber and Your Microbiota

Dr. Danielle Phillips-Dorsett, ND


Just when dietary fiber was becoming a cold, wet mess of oatmeal in your breakfast bowl, new exciting research is showing us why making the effort to incorporate fiber into each meal of the day is a foundation to good health.  Americans average 15 grams of fiber daily, while it is recommended to get at least 28 grams daily by the FDA.  So this means that most of us are not getting enough, negatively impacting our health in the process.

New studies are pouring out about how whole grains, vegetables and fruit, high in soluble and insoluble fibers, can alter the gut flora in positive ways. The emerging thought is that a reason fiber is beneficial, such as, lowering cholesterol, lowering blood sugars, and maintaining a healthy weight is due to fiber feeding beneficial bacteria. Some forms of fiber act as pre-biotics, meaning they are the food source for the gut flora. Once these good bacteria are fed what they need to thrive, they can change metabolic factors in our gut, which then impact our health in positive ways.

Cellular Metabolism published a study in 2015 showing fiber improved glucose metabolism (regulation of blood sugars) due to increasing abundance of Prevotella, a species of bacteria in the large intestine. A study published in BMC Gastroenterology showed that alterations of gut flora, by dietary fiber, improved metabolic markers in those with non-alcoholic fatty liver disease (a condition with no known surgical or medication intervention). In the Clinical Journal of the American Society of Nephrology, pre and probiotics altering the microbiota were shown to decrease harmful products in the blood of chronic kidney disease patients. And, there are many more studies like these. So, what to do about that?

Fiber tips:

  • There is no fiber in refined grains, meat or dairy products. Sad, but this means you need to add, or even substitute, some oatmeal, vegetables or fruit for your morning cheesy eggs with bacon and hash browns.
  • When eating fibrous foods, it is important to get adequate water intake so that stool does not dry and become more difficult to pass.
  • When you start increasing fiber in your diet, do so slowly or you may experience either diarrhea or worsening of constipation. Over time your body will be able to tolerate fiber more easily.
  • Situations fiber may not be for you: when your doctor recommends a low-fiber diet, inflammatory bowel disease, certain cancer treatments, traveler’s diarrhea, diverticulitis and after intestinal surgeries.

Signs you may not be getting enough fiber in your diet:

  • Straining to have a bowel movement, bloating, or going more than 1-2 days without having a bowel movement. Note, prolonged or painful constipation may be a sign of a more serious health problem and you should seek medical evaluation.
  • Feeling hungry within an hour or two after eating and weight gain. Foods with more fiber will increase your satiety and results in less calorie intake per meal.

Bottom line, fiber is important for many health reasons and most of us do not get enough.  Eat your apple, kale, quinoa, beans, broccoli and drink plenty of water!!