Plant-Based Gut Health 101: Why Immunity, Metabolism, and Longevity Start in the Gut

By: Dahlia Marin, RDN, LD and James Marin, RD, EN

Longevity, disease prevention, energy, immunity… Every health buzzword comes back to one thing:

Your gut.

Well, technically the trillions of microbes processing the nutrients from the foods you eat.

And when it comes to gut health, the plant-based diet is a superstar promoter.

Simply by consuming a variety of fruits, vegetables, greens, nuts, seeds, beans, legumes, spices, and herbs every day, you’re pumping your body with a mega-dose of fiber, macronutrients and micronutrients that play a significant role in a healthy flowing and balanced gut microbiome.

But if gut health is as easy as eating plants, why is it such a hot topic — even amongst plant-based eaters?

Because it’s not quite as easy as “just eat plants.” Painful to hear, we know.

As plant-based Registered Dietitian Nutritionists specializing in gut health, we hear from clients daily that their gut health improved tremendously with a plant-based diet…

And yet they’re still experiencing symptoms like bloating, gas, constipation, fatigue, and abdominal pains.

Or arguably worse, not experiencing the positive immune support, brain function, and energy boost that come from a gut functioning optimally.

So what’s the answer?

In this post, we’ll pull from 10+ years of experience, helping thousands of patients identify and understand their gut health problems to share the ins and outs of a healthy gut, plus the simple steps you can take today to optimize yours.

The best part? If you’re already eating a plant-based diet, you’re leaps and bounds ahead of most people. Consider the hard part done.

Now comes the fun part — simple habits to help your gut thrive!

Why Gut Health is so Critical (Even for Plant-Based Eaters)

70% of your immune system is located within your gut. Immune cells interact with the bacteria in your gut, and the more balanced that bacteria is, the happier those immune cells become.

But that’s not all — your gut also produces nearly all of your serotonin (the happiness hormone), expends up to 20% of your energy through digestion, regulates your metabolism, and so much more.

This makes improving gut health the single most important thing we can do for both our short- and long-term health.

But what does “gut health” really mean?

When we talk about a healthy gut, we are referring to the health of the microbiome and virome that resides in the digestive tract.

These are like mini-ecosystems of vast life that reside inside of us, with the microbiota being made up of countless microbes including bacteria, yeast, fungi, protozoa, and archaea playing an important role in digestion and nutrient synthesis.

Just as a diverse ecosystem of animals, insects, and plants support the circle of life in the natural world, each microbe plays its part in your gut ecosystem — supporting each other in one form or another and communicating with systemic organs including your heart, liver, pancreas, skin, reproductive organs, brain, and more.

The gut microbiome is responsible for important functions in our gut such as the synthesis of vitamins, essential amino acids, and gut-repairing short-chain fatty acids.

But let’s take a look at two of the most important functions of the gut, and how they work:

1. Immune support

About 70% of our immune cells root in our gut. An infection or imbalance in the gut can communicate stress systemically, and vice-versa.

Your good gut bacteria is also partially responsible for helping prepare your immune system to fight off viral invaders, so maintaining the balance of your gut microbiota is important to your immune system function.

2. Metabolism

Your gut microbes are responsible for the synthesis of different vitamins such as vitamins B5, B12, and vitamin K, as well as making short-chain fatty acids (SCFAs) out of unabsorbed sugars in your digestive tract.

These SCFAs are then used as fuel by your digestive tract mucosa, keeping it healthy and functioning as it should. Vitamin K helps our bodies clot our blood as well as managing the amounts of good and bad cholesterol we have in our bodies. Deficiency in B5 and B12 vitamins has actually been linked to GI discomfort, making it that much more important to keep our microbiomes diverse and flourishing.

Is Your Gut Healthy? Here Are the Warning Signs

Have you ever heard of “gut bugs?” That’s how we like to refer to gut microbes, and there are trillions of them living within your gastrointestinal tract.

The balance of these gut bugs is essential to a healthy gut, and so is the pace of their flow through your digestive tract. When gut bugs are out of balance, it can trigger warning signs like:

Regular bloating
Excessive Gas
Constipation
Nausea
Brain fog
Diarrhea
Acid reflux

Or non-gut symptoms like:

Low energy and persistent fatigue
Trouble sleeping or insomnia
Skin irritations, like eczema or dermatitis
Frequent mood changes
Anxiety
Strong food cravings for foods, including sugar, and refined carbohydrates
Joint pain
Post-nasal drip or constant throat clearing

Think of a flood happening in a natural ecosystem; some animals are driven out while others flourish. An imbalance is rarely good for the ecosystem and can lead to the dominance of a plant or animal that causes further harm to everything else.

In your body, these uncomfortable symptoms can be caused by dysbiosis (the imbalance of bacteria living in the gut) or dysmotility (suboptimal gut flow) and should be given special attention.

And when dysbiosis or dysmotility are present, even the purest whole food plant-based eaters may run into these uncomfortable symptoms.

Fortunately, most of the common symptoms can be resolved through minor lifestyle and nutrition tweaks. We see this over and over again in the patients we work with…

Take Danny, for example (a real patient with a really made-up name). Danny is a professional plant-based chef who had been following a whole food plant-based diet for 10 years prior to coming to us.

She was fed up with her symptoms of daily uncomfortable gas, bloating, and constipation, which interfered with her even wanting to taste the delicious plant-based recipes she was creating.

Or there’s Gina, a 3-year plant-based eater who wanted to reduce the bloating she experienced after meals as she works as a yoga instructor.

Or Anna, a plant-based chiropractor who had trained in some of the world’s most renowned plant-based facilities, learning the specifics of optimal plant-based eating, yet still couldn’t get to the bottom of what was driving her daily stomach discomfort.

In each of these situations, a few minor lifestyle tweaks like the ones outlined below lead all three of these patients to experience an over 80% reduction in their symptoms in a relatively short period of time.

8 Simple Ways to Improve Your Gut Health

1. Introduce more ‘good gut’ foods.

In our house, foods fall into one of two categories:

Good Gut Foods, which are typically high in fiber and micronutrients and contribute positively to the gut.
Other ‘sometimes’ foods that don’t contribute to gut health too well, that we consume in moderation.

The simplest thing you can do to support gut health is to introduce more Good Gut Foods into your diet and reduce the ones that aren’t. Seasonal foods and nutrient-dense produce are a great way to feed your healthy gut bugs.

Here are some of the foods that top our “Good Gut Food” list:

Veggies and Greens:

Arugula
Bok Choy
Broccoli florets
Carrots
Japanese Sweet Potato
Okra
Radishes
Sprouts
Zucchini
Winter squash

Fruits:

Bananas (especially greener bananas, which are higher in resistant starch, which is so good for your gut!)
Blackberries
Blueberries
Clementine
Kiwis (green or golden)
Papaya
Pomegranate
Prickly Pear

Nuts and Seeds:

Almonds
Baru nuts
Brazil nuts
Chia seeds
Flax seeds
Hemp seeds
Pumpkin seeds
Walnuts

Beans and Legumes:

Lentils
Chickpeas
Edamame (soybeans)
Mung Beans
Adzuki Beans
Tofu
Tempeh (fermented soybeans)

Whole Grains

Buckwheat
Millet
Oats
Quinoa
Amaranth
Fonio
Sprouted wheat

Other:

Cilantro
Ginger
Miso (fermented soy or chickpea paste)
Parsley
Peppermint
Fermented foods like kimchi or sauerkraut
Tahini (sesame seed paste)
Vinegars

2. Eat 30+ plants per week (at least!).

The American Gut Project found that individuals who consumed 30 or more different plant foods each week had a significantly more diverse gut microbiome compared with those who ate 10 or fewer per week.

This has been correlated with increasing your microbial production of short chain fatty acids (SCFAs) and decreasing antibiotic resistant microbes (superbugs). Combined, these mean healthier gut structure and a possible decrease of intestinal inflammation.

In other words, eating a plant-based diet is one of the best first steps you can take to improve your gut health, but variety is just as important.

On the surface, 30 may sound overwhelming, so let’s break down an example day and see how many we can get:

Breakfast: Carrot Cake Overnight Oatmeal with fruit and nuts (soaking oats overnight increases the resistant starch and activates soluble fiber)

Oats (we like oat groats or steel-cut oats)
Flax seeds
Chia seeds
Complement protein powder
Walnuts
Shredded carrots
Raisins
Dates
Cinnamon

Snack: Fruit & Protein

Apple or pear
Almond butter
Celery

Lunch: Grain Bowl

Quinoa
Lentils
Sprouts
Red bell pepper
Cucumber
Tomato
Carrots
Yummy plant-based dressing of choice

Snack: Smoothie

Banana
Orange
Spinach
Zucchini
Soy milk
Hemp seeds

Dinner: Veggie and Bean Pasta and Mixed Greens Salad

Chickpea pasta
Broccoli
Onion
Garlic
Basil
Kale
Romaine lettuce
Red leaf lettuce
Beets
Snap peas
Sunflower seeds
Vinegar
Herbs & spices

That’s 39 different plants in a single day.

When you account for each plant, herbs, and spices, suddenly 30 plants before the end of the week doesn’t seem as challenging!

Still, eating 30+ different plants per week requires you to be intentional about the variety you incorporate throughout your meals, and really, 30 should be the minimum.

3. Eat slowly.

Proper digestion starts in your mouth. It is, after all, the first portion of the digestive tract, and a great start can help facilitate a great ending!

Chewing your food thoroughly can be essential to proper digestion. Quickly scarfing down food usually leads you to also inhale quite a bit of air between bites, which can lead to bloating and discomfort afterward.

Chewing foods until the bite is smooth and no longer chunky can help the rest of the downstream digestion and absorption that will happen in the stomach, small intestine, and large intestine, helping you absorb more nutrients and feel your best after the meal.

If you’re seeing large pieces of undigested food in your stool, that can be a sign of digestive distress and improper chewing.

When we eat carbohydrates, our saliva contains digestive enzymes that help us better breakdown and digest them. This can even matter when consuming carbs that don’t need chewing, like smoothies.

Chewing them a bit in your mouth can help slow down how quickly you finish them and can help reduce bloat you may experience when drinking them.

Suggestive research shows that the better a person chews the more likely they are to stimulate gut hormones that help regulate satiety.

4. Consciously choose your cookware and cleaning products.

What you cook and store your food in will ultimately make its way into your gut. We suggest swapping out plastic, aluminum, and other known endocrine disruptors with materials including glass, ceramic, stainless steel, and cast iron.

One study found that endocrine disruptors have interactions with food and the gut microbiota. The products and byproducts released following the microbial metabolism of endocrine disruptors can be taken up by the host, changing the composition of microbiota.

5. Avoid antibiotics, unless necessary.

We are so fortunate to be alive in a time when medicine is pretty accessible to most people in developed nations. This easy accessibility has caused excess use in both humans and animals raised for consumption in the past few decades, which leads to antibiotic resistance in humans and contamination of water sources from animal run-off.

In your gut, antibiotic resistance creates bad gut bugs that are resistant to antibiotics (Superbugs) that can drive up inflammation if they over-populate the body.

Antibiotics can be truly lifesaving if taken when necessary, but they can also off-set the delicate balance in the gut. One study showed that a single course of antibiotics can have effects lasting up to two years on the balance in the gut microbiome.

Speak with your care team to take antibiotics when it’s warranted, try to avoid them if lifestyle and other preventive measures can be used instead.

6. Exercise consistently.

The USDA Healthy People 2022 Guidelines recommend at least 150 minutes of moderate to intense activity per week. We recommend as much as possible!

An hour of conscious movement and exercise makes its way into each day of our lives and helps support our gut movement AKA gut motility. Studies show that moderate exercise can decrease constipation and bloating.

And no, couch surfing doesn’t count! Sorry.

7. Reduce stress (as best as possible).

Stress of any kind – physical, mental & emotional, or chemical – can take a toll on your good gut bugs. Addressing stressors and finding outlets for them can be key to helping your gut feel its absolute best.

Studies show that 40-60% of those diagnosed with Irritable Bowel Syndrome (IBS) have also been diagnosed with anxiety. What stresses your mind or body can definitely stress your gut.

Remember, we are more microbial DNA than human DNA, and they’re sensitive too!

8. Incorporate evidence-based nutrients.

Even with a diverse plant-centered diet, increasing the intake of certain vitamins and minerals can have a rapid and dramatic impact on improving your gut.

Remember Danny, the plant-based chef we introduced earlier?

After identifying a few deficiencies in her blood work, we had her supplement with additional:

Pre-activated B vitamins, including B1, B5, and B6, which are all essential for motility and optimal brain function. Suggestive research shows that B-vitamins are required for different immune responses related to gut health.
Molybdenum to help metabolize/ break-down sulfur, to reduce the amount of hydrogen sulfide gas produced. This type of gas can not only cause malodorous gas strong enough to clear a room, it can significantly slow down motility, causing uncomfortable bloat.
Ginger to help support motility and a healthy gut rhythm.
Peppermint to also support motility. We like recommending drinking strong peppermint tea between meals to help get the food moving through the digestive tract.

That helped restore her gut motility and gut balance which in return reduced her discomfort and bloating.

In addition to those we recommended to Danny, nutrient additions that can typically lead to improved gut health are:

Horse Chestnut, a potent antioxidant to help balance the gut microbiome and support the gut-immune connection.
A low FODMAP, less fermentable prebiotic fiber to feed the anti-inflammatory gut flora, which can help bring down blood sugar, cholesterol, appetite, and more.
A post-biotic- a potent end-product of fermentation of prebiotic fibers by probiotics and other microbes.
Licorice root to help soothe any irritations felt in the gut and support the integrity of the lining of the gut to potentially decrease inflammation in and around the gut.

Should You Take a Probiotic?

Probiotics were all the rage for a while, with companies and influencers telling you that they would solve every belch, bloat, and bump in your body.

That started in part because for a long time, healthcare practitioners were told to recommend probiotics after each course of antibiotics taken to restore good bacteria which may have been wiped out.

But a thorough 2018 study out of Isreal discovered probiotic support may not be in our best interest after all. The study showed those taking non-specific probiotics after a course of antibiotics took the longest to recover their original gut microbiome and the good bugs that live in it.

So what do we recommend instead? Eating plenty of prebiotic fiber-rich foods after taking antibiotics to naturally feed and restore the healthy gut bugs we want back.

Now, to be clear, probiotics aren’t always bad for you. In fact, a 2017 study published in the European Review for Medical and Pharmacological Scienceses has found that a specific strain of probiotic, Lactobacillus Reuteri, can reduce methane gas in the digestive tract by as much as 30%. This can help reduce bloat and gas as methane gas is known to slow down the digestive tract. Therefore, L. Reuteri results in reducing the gut methanogenic flora, then increasing bowel movements helping with constipation.

What we don’t recommend is unnecessarily taking expensive probiotics that you likely don’t need if you consume a diverse diet.

Research suggests that it is ideal to look at the origin of the microbes, species and strains, testing, and potency when choosing a probiotic supplement. Not all probiotics will have what the label says it has, not all strains will have a benefit, not all supplements will make it past your stomach acid and bile, and there can be some negative side effects along the way.

Don’t Flush your Gut Health Down the Toilet

Gut health is all the rage right now not because it’s difficult to achieve — as we mentioned before, if you eat a plant-based diet, you’re already doing the hardest part.

It’s on everyone’s mind because it’s so important, with countless new studies driving that point home and hopefully, onto your plate!

So quit thinking about your gut as just a place to process food and produce waste, and instead treat it like the delicate ecosystem that it is…

One that if kept balanced, will lead you towards a stronger immune system, better metabolism, lower mortality rate, improved sleep and energy, lower anxiety, and day-to-day abdominal comfort. We hope we’ve given you encouragement to continue your journey toward optimizing your gut health, even beyond the ways your plant-based lifestyle has!

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