Show 1312: Fiber, Phytonutrients and Healthy Soil

This week on our nationally syndicated radio show, we discuss the importance of fiber and phytonutrients in our food for keeping our intestinal microbes healthy. We’ll also find out why encouraging a varied and thriving microbiome in the soil is critical for producing healthy food crops.

Fiber and Phytonutrients:

Do you know what is the best diet for you? If you are a regular listener, you will have heard that many different diets can be beneficial. But the best ones have at least two things in common: fiber and phytonutrients from a meal plan full of plants. The DASH diet, the Mediterranean diet (in any of its multiple incarnations) and the MIND diet all feature a plate full of plants that provide plenty of fiber and lots of vitamins, minerals and a range of other compounds that plants make for their own purposes. These phytonutrients often have anti-oxidant or anti-inflammatory activities that help our own bodies achieve good health.

Why Fiber-Fueled Is the Path to a Healthy Microbiome:

Our guest, gastroenterologist Will Bulsiewicz, had an epiphany while struggling with his own health. He discovered that switching from a diet full of convenience foods to a more plant-based diet helped him lower his blood pressure, lose weight and improve his digestion. Intrigued, he looked into the underlying reasons and realized that feeding the intestinal microbiome what it wants–fiber–is a path to keeping it healthy. Good health for gut microbes can translate into better health for us. When the microbes consume fiber, they produce anti-inflammatory compounds called short-chain fatty acids such as butyrate and propionate.

A meta-analysis from 2019 included 58 clinical trials and 185 prospective studies (Lancet, Feb. 2, 2019). Altogether, the investigators had 136 million person-years of data on diet and health. They documented reduced rates of cardiovascular disease, type 2 diabetes, breast and colon cancer among people consuming more fiber.

As a result, the researchers concluded:

“Implementation of recommendations to increase dietary fibre intake and to replace refined grains with whole grains is expected to benefit human health.”

We first interviewed Dr. B, as his patients call him, about his book explaining this connection, Fiber-Fueled. (Check out Show 1222: How Can You Optimize Your Microbiome?) Now, to help people figure out how to accomplish the goal of increasing the fiber in their diets, he is offering The Fiber-Fueled Cookbook with lots of practical advice for those in the kitchen or at the table.

Too Much Fiber?

Some listeners may worry about the consequences of eating more fiber. Certainly, a sudden and dramatic increase of the fiber in a diet can cause some digestive disruption. The microbiome may need time to adjust so that fiber doesn’t cause too much flatulence. Treating it like a weight-lifting program and increasing just a little at a time might work best.

What About FODMAPS?

Many people with irritable bowel syndrome try to avoid foods that will make their symptoms worse. These Fermentable Oligo- Di- & Monosaccharides and Polyols (FODMAPs) are natural sugars that, like fiber, may be difficult for humans to digest. (Humans can’t digest fiber; that task falls to the microbes.) Dr. B describes how to manage food intolerances and improve the ability to handle FODMAPs.

Phytonutrients and Healthy Soil:

Beyond fats, carbohydrates and proteins, even beyond vitamins and minerals, the plants in our diets provide us with phytonutrients. Plants make these compounds to protect themselves from environmental hazards like insects, but our bodies put them to multiple uses. Some help bolster our immune response. But how does the soil plants grow in affect their ability to produce these chemicals? Without healthy soil, plants have a hard time creating phytonutrient compounds.

You may not have thought much about what makes soil healthy. Anne Biklé, gardener and environmental planner, points out that without a good range of microbes, soil isn’t healthy. Although plants can grow in such soil, they won’t thrive and they may need a lot of assistance from chemicals like fertilizers and pesticides. Instead, soil full of helpful fungi and a balance of bacteria is best. To achieve that, practices of regenerative farming are essential for health, both for plants and for humans.

This Week's Guests:

Will Bulsiewicz, MD, MSCI, is a gastroenterologist and author. He has contributed to more than 20 articles in gastroenterology journals. In addition, his books include Fiber Fueled and his most recent, The Fiber-Fueled Cookbook.  His website is: https://theplantfedgut.com/about/

The photo of Dr. Bulsiewicz is by Margaret Wright.

Anne Biklé is a biologist and environmental planner whose writing has appeared in Nautilus, Natural History, Smithsonian, Fine Gardening, and Best Health. She and her husband, David Montgomery, are the authors of
Their work includes a trilogy of books about soil health, microbiomes, and farming—Dirt: The Erosion of Civilizations, The Hidden Half of Nature, and Growing a Revolution. Their most recent book is What Your Food Ate: How to Heal Our Land and Reclaim Our Health.