What are Prebiotics? Feeding the Good Guys.

There’s a saying among organic gardeners: “Feed the soil and the soil will feed the plants.” That healthful process goes on inside our bodies, too, where special plant substances called prebiotics feed the beneficial probiotic bacteria that make up our gut biome. But what are prebiotics exactly? We break it down.

We can think of our probiotic gut biome the way we think of good garden soil. Both are composed of trillions of bacteria in every handful. Soil bacteria grow strong and healthy when fed on vegetable matter that has lots of plant fiber. They unlock the nutrients in that vegetable matter and feed them to the roots of the garden’s crops.

Our gut bacteria dismantle the food we eat into its constituent nutrients and feed them to us through the walls of our large intestine. The bacterial inhabitants of our gut biome are very sensitive to what we eat. If we feed them a diet of processed foods, heavy on salt, fat, and sugar and lacking in the probiotic bacteria found in things like fermented foods, we won’t ring up the health benefits that they can give us. And wow, can they give us health benefits!

Fed lots of fruits, root vegetables, leafy greens, and whole grains, the beneficial bacteria in a healthy gut biome play a central role in strengthening our immune system, producing serotonin (the feel-good hormone), and bolstering the health of all the metabolic systems in our bodies.

The Right Balance

Establishing the right balance among those bacteria is the key. What are prebiotics doing down in the gut? Prebiotics are the foods rich in short-chain fatty acids that are a specific type of dietary fiber. This fiber is what the good guys in your gut biome thrive on. It’s their food of choice. When they get enough of it, the beneficial gut bacteria grow healthy and strong, their populations increase, and the gut ecology hits on all cylinders. Basically, they do the job nature intends for them, and that’s to make you happy and healthy, full of life and energy.

Consider what happens if someone eats a lot of white sugar every day. Almost all of this sugar quickly passes into the bloodstream through the upper digestive tract, including the mouth, stomach, and small intestine. where it can contribute to obesity, type 2 diabetes, and cardiovascular disease. Very little reaches the large intestine at the end of the digestive tract where the probiotic biome lives. Prebiotic dietary fiber, on the other hand, is largely indigestible in the upper digestive tract. It passes down to the large intestine where the health-giving gut biome does have the power to digest it, and in so doing, sets up the right mix of bacteria for optimum health.

Some food supplement manufacturers sell prebiotics, but we think it makes much more sense to get your prebiotics from real foods that contain the living microbes that make up a healthy gut biome. After all, the bulk of these bacteria—bifidobacteria and lactobacillus—are the miracle workers that transform bland raw vegetables into gloriously delicious and nutritious foods like kimchi, sauerkraut, sriracha, and salsas that wildbrine crafts so you can get your gut biome jump started. We also use prebiotic foods in many of our recipes so that the probiotic bacteria are supplied with their favorite foods as soon as they set up shop in the large intestine.

what are prebiotics - these are a few of them
A whole bunch of prebiotic foods. Photo courtesy of Monash University.

What are Prebiotic Foods?

There are many foods that are rich in the necessary dietary fiber that promotes gut health. Here’s a short list of the richest. The average person needs about six grams (1/4 ounce) of dietary fiber each day. Just a few ounces of these foods will supply it.

  • Chicory root is the richest. About half of its fiber is from the prebiotic fiber inulin.
  • Dandelion greens can be used in salads. Just three ounces of them provide almost all the daily need for prebiotics.
  • Jerusalem artichokes, also known as sunchokes, have been shown to increase beneficial bacteria in the colon even better than chicory root.
  • Garlic not only contains two kinds of good dietary fiber, but also prevents disease-causing bacteria in the gut from growing.
  • Onions and leeks, both in the same family as garlic, have similar amounts of inulin dietary fiber, and have antioxidant properties as well.
  • Asparagus has about half your daily need for good dietary fiber in just 3.5 ounces of spears.
  • Barley is a popular grain that contains from 3 to 8 grams of beta-glucan prebiotic fiber.
  • Whole rolled oats also contain good stores of beta-glucan prebiotic fiber.
  • Apples contain pectin that increases butyrate, a prebiotic fiber that feeds healthy gut bacteria and suppresses the populations of harmful bacteria.
  • Cocoa is an excellent source of flavanols, which increase healthy gut bacteria, lower cholesterol, and support heart health.

Other food sources rich in prebiotics include burdock root, flaxseeds, wheat bran, jicama, and seaweed.

With wildbrine Sriracha, you get prebiotic garlic. Our sauerkraut contains garlic. Our kimchi not only contains garlic, but also prebiotic sea vegetables and onions. And the probiotic live cultures in our Salsa Verde are accompanied by garlic and onions.

Seaweed is a regular part of the diet in Japan, and up to 85 percent of seaweed’s fiber can be metabolized by specialized gut bacteria that have been acquired by Japanese folks over the centuries. Westerners evidently don’t eat enough seaweed to have acquired these bacteria in their gut biome, as yet. But here at wildbrine, we’re working on it by offering products like our organic Arame-Ginger Sauerkraut, packed with beneficial bacteria and a portion of arame—a species of kelp seaweed—for flavor and to lure those seaweed-digesting bacteria into their new home: you.

Nine out of every ten cells in our bodies are found in our gut biomes. When they’re happy, we’re healthy. Send them some love and support with fermented foods.

About the Author: Sonoma County resident Jeff Cox is the author of 24 books, including The Essential Book of Fermentation (Avery, 2013)

One thought on “What are Prebiotics? Feeding the Good Guys.

  1. Nancy

    Sun chokes are very easy to grow in the north east, but will be invasive. I found out this year that just the peal of a sun choke is enough to grow the plant. So I wouldn’t put it in your compost unless you know for a fact that your compost is hot enough to cook the skins. It grows into a 20’ plant with beautiful Daisy like flowers.


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