Excerpted from The Fiber Effect, by Nichole Dandrea-Russert. Reprinted with permission. Lightly edited for placement.

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If you’ve been paying attention to the media, more than likely you’ve heard the news that gut health plays an important role in overall health, and it might even be directly linked to mental health. Research studies show that a healthy gut might decrease inflammation, which can decrease the risk of cardiovascular disease, cancer, diabetes and cognitive decline. The gut has also been named “the second brain” due to its signaling pathways to the brain and its impact on brain health. The gut affects every part of our bodies, from digestion to the immune system to the brain.

Your body is home to trillions of bacteria. In fact, the microbes in your body outnumber your cells 10 to one. Microbes might affect how you store fat, how your body balances blood sugar, how hunger hormones are regulated and how you respond to viruses and bacteria. Good bacteria can help to regulate mood neurotransmitters, such as serotonin, dopamine and GABA. Because the gut can play a large role in overall health and communicates with the nervous system, an imbalance of gut bacteria can disrupt the gut and its overall physical and mental health.

Unfortunately, many factors can disrupt our gut microbiota. Some examples are diet, physical environment, stress and antibiotics. Here’s the good news! Even a lifetime of unhealthy eating is fixable, at least as far as your gut is concerned. Your body can create new gut microbiota in as few as 24 hours just by changing what you eat. What you eat determines which bacteria are able to thrive in your gut. Research tells us that good bacteria get stronger when fed colorful, fibrous, plant-based foods. A 2014 study found that vegetables, fruit and whole grains fed good bacteria while meat, dairy, eggs and processed food fostered an unbalanced gut microbiota.

So, how to create a healthy gut? Think fiber, prebiotics, probiotics and nutrient-dense foods—typically, plants. Additionally, avoid things that can disrupt your gut balance: acidic foods including meat, dairy, eggs, sugar, alcohol and processed foods, as well as antibiotics and a toxic environment rife with plastics, pollution and pesticides. Red meat, high-fat dairy products and fried foods all reduce the growth of healthy bacteria and enhance the growth of bacteria linked to chronic disease. 

In other words, getting enough fiber is a key component in keeping the gut healthy, as well as consuming prebiotic and probiotic-rich foods daily. Prebiotics and probiotics help to balance your gut microbiota and improve overall health.

 

Prebiotics

Prebiotics are non-digestible carbohydrates that fuel healthy gut bacteria and help support a healthy microbiota balance. Basically, prebiotics are food for beneficial bacteria that live in or on us. Since your body cannot completely break down prebiotics, they pass through your digestive system to the colon, where they are fermented by your gut microflora. This fermentation process feeds the friendly bacteria in your gut, helping them to produce essential nutrients, including short-chain fatty acids—such as butyrate, acetate and propionate—which nourish the digestive system. The fermentation process also helps improve mineral absorption, production of vitamin K and overall health.

By feeding healthy bacteria in our gut, prebiotics might help:

• support digestion
• reduce the risk of autoimmune disease or decrease symptoms associated with it
• reduce the risk of gut infections
• support the immune system
• reduce allergy symptoms
• reduce eczema symptoms
• reduce inflammation
• decrease cholesterol
• balance metabolism
• support bone health
• balance hormones
• boost mood
• relieve stress and anxiety
• aid in weight loss or management

Prebiotics and probiotics work synergistically. While prebiotics are non-digestible foods for our gut, probiotics are live microorganisms that feed on prebiotics. Prebiotics and probiotics work together, keeping the gut healthy and communicating with other systems keeping our whole body healthy and mind clear. 

Foods that are high in prebiotics include dandelion, asparagus, bananas, apples, chicory root, Jerusalem artichokes, leeks, garlic, onion, jicama, millet, barley, oats, wheat bran, cocoa, flaxseeds, sweet potatoes, seaweed and more. There is not a specific recommendation for adequate intake of prebiotics. Therefore, a diet that includes a diverse variety of high-fiber fruits and vegetables has the most potential for obtaining adequate prebiotics. 

Probiotics

The International Scientific Association for Probiotics and Prebiotics defines probiotics as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”

Colonized in the gut, probiotics can help inhibit the growth of pathogens, enhance mineral absorption, synthesize vitamins, reinforce the gut barrier, increase enzyme activity and neutralize toxins. They might help keep you healthy by:

• Decreasing the number of bacteria in your gut that can cause infections or inflammation
• Stabilizing the digestive tract’s barriers against unwanted bacteria or producing substances that hinder their growth
• Replacing the body’s “good” bacteria that have been lost, for example, when you take antibiotics
• Restoring the body’s microbiome balance, which then helps to keep your body functioning properly

 

Where Are Probiotics Found?

Probiotics are found naturally in our intestines. It is estimated that 500 to 1000 different bacterial strains live in the human gut. A lack of diversity in probiotic strains has been linked to obesity, digestive issues and many other health issues.

Fermented foods, such as miso, tempeh, sauerkraut, kimchi, pickles, olives and plant-based yogurt and kefir, might contain probiotics. Fermentation is a natural process through which microorganisms like yeast and bacteria convert complex molecules like starch and sugar into alcohol or acids. Through fermentation, beneficial bacteria such as probiotics are formed. Still, the final food product does not always contain probiotics. Pasteurizing and cooking fermented foods can destroy healthy probiotics. For example, some sauerkraut is pasteurized before landing on grocery store shelves. These foods will still be nutritious and have fiber, so don’t disregard them. Just know that you will not get the probiotic benefit. Look for the terms “live cultures,” “unpasteurized” or “raw” to ensure live probiotics are in the product. Tempeh is also cultured; however, since it’s important to cook tempeh before consuming it, probiotics are no longer present when we consume it. However, tempeh is one of the most nutrient-dense foods, so I still highly recommend it!

Some probiotic supplements contain many strains of probiotics, but more is not always better. Each strain has different functions and might or might not be what you need. There are strains specific for gastrointestinal health, immune function, cognitive function and more. Research is still needed and emerging on the many functions of the various strains and species of probiotics. Most healthy people tolerate probiotic supplements without any issues, but immuno-compromised and critically ill individuals might not tolerate them. Infections have been seen in those with a weakened immune system.

If you are considering a probiotic, start small. High doses—in quantity and in the number of different strains—can potentially create gastrointestinal upset. Just like increasing fiber in your diet, start with lower quantities of probiotics. Probiotic supplements are not regulated, so when you’re choosing one, look for good manufacturing practices or third-party verification from USP, NSF International or ConsumerLab.com. Doing so can help you ensure that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.

Personally, I don’t recommend probiotic supplements in my practice since there are so many species, and we really don’t know if the species in the supplement is what’s needed. Instead, I recommend whole, plant-based foods, organic whenever possible, and daily consumption of fermented foods or foods with probiotics. 

Putting It Into Practice

Synbiotics bring prebiotics and probiotics together, either in food or supplemental form. It makes sense, since they work together, that they would be consumed together for optimal health. For healthy individuals, I recommend optimizing gut health naturally through whole plant-based foods. That means following these recommendations:

• Eat 30–40 grams of fiber a day from a variety of plant-based foods, such as fruits, vegetables, legumes, whole grains, nuts and seeds. Fiber is essential for gut health. Choose organic whenever possible. 
• Incorporate a variety of prebiotic foods daily. For example, cook with garlic, add onion to a sandwich, include asparagus in your stir fry or eat oatmeal in the morning.
• Add 1–2 tablespoons of a probiotic food to your diet daily. You can add kimchi to avocado toast, add sauerkraut to a sandwich, make a miso sauce or salad dressing to use throughout the week or snack on probiotic-rich coconut yogurt daily, for example.
• Drink plenty of water.

Things that interfere with good gut health include:

• sugar
• alcohol
• animal products (dairy, meat, eggs)
• processed foods
• fried foods
• stress
• environmental toxins, such as plastics, pollution, and pesticides

For individuals interested in preventing or treating conditions such as Crohn’s disease, irritable bowel syndrome or ulcerative colitis, please check with your physician or dietitian nutritionist as there might be specific strains that can help. ❧

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A 25-year registered dietitian nutritionist with a focus on plant-based lifestyles, Atlantan Nichole Dandrea-Russert, MS, RDN, has been featured in Yoga Journal, Veg News and The Atlanta Journal-Constitution. Visit PurelyPlanted.com, her plant-based wellness blog.