Advance Rutgers Podcast: Eating for a Healthier Gut

Published June 9, 2022

A healthy gut microbiome lowers our risk for disease and helps maintain overall health. So, it’s critical for all of us to nurture our distinct microbiota. This episode of the Advance Rutgers podcast is the second in a two-part microbiome mini-series. In it, Professor Liping Zhao, Eveleigh-Fenton chair of applied microbiology at Rutgers University–New Brunswick, explains why not all sources of dietary fiber are created equal. He also shares how feeding the microbes in his own gut helped him overcome obesity, the simple steps we all can take to improve the health of our microbiome, and how the Rutgers University Microbiome Program will help transform the lives of generations to come.

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Podcast Transcript

Christine Fennessy

Welcome to Advance Rutgers, a podcast about the many ways that Rutgers, The State University of New Jersey, is addressing the critical issues of our day.

At Rutgers, we believe a better tomorrow starts with bigger thinking today. And our talented and driven community is improving the human condition with transformative, multidisciplinary projects. This podcast will explore those groundbreaking initiatives: what they are, why they matter, and who they benefit.

Today’s episode is part two in a two-part series about the Rutgers University Microbiome Program. It features professor Liping Zhao. He’s the Eveleigh-Fenton chair of applied microbiology in the department of biochemistry and microbiology at Rutgers and director of the Center for Microbiome, Nutrition, and Health at the New Jersey Institute for Food, Nutrition, and Health.

In this episode, he talks about how feeding the microbes in his gut helped him overcome obesity, why dietary fiber is so critical to our health, the simple steps we can all take to improve the health of our own microbiome, and why he plans to do this work until he is 120.

Thanks for joining us.

Christine Fennessy

Professor Liping Zhao is a trim, fit-looking guy. But in the early 2000s, he was in pretty bad shape.

Professor Liping Zhao

I was about 45 pounds heavier. BMI over 30.

Christine Fennessy

He also had metabolic syndrome, which includes things like high blood pressure and excess belly fat. And it can lead to heart disease and Type 2 diabetes. But professor Zhao was also a microbiologist who studied gut health.

Professor Liping Zhao

And then in 2004, Professor Jeff Gordon at the University of Washington, St. Louis published a seminal paper in mice models to show that gut bacteria can actually regulate fat storage.

Christine Fennessy

That paper? It got him thinking …

Professor Liping Zhao

My gut microbiome may somehow be related with my own obesity problem.

Christine Fennessy

For two years, he experimented with different foods. He believed that if he improved his gut health, his overall health would get better.

Professor Liping Zhao

I used myself as a guinea pig to try this diet. And eventually it worked.

Christine Fennessy

He ate fermented foods like Chinese yam and bitter melon. And just to clarify, fermentation is the controlled growth of good bacteria, and it can give food and beverages a range of health benefits. So fermented foods would be things like kombucha, kimchi, sauerkraut, sourdough bread.

So anyway, professor Zhao combined fermented foods with a diet based on whole grains. After making these changes to his diet, he lost 45 pounds over two years and lowered his blood pressure, cholesterol, and heart rate.

Professor Liping Zhao

I eventually developed a dietary scheme. I call it the “Feed me, feed my microbiome” diet.

Christine Fennessy

“Feed me, feed my microbiome.” When it comes to maintaining our health and lowering our risk for disease, we’re all, in a sense, eating for two. But, says Professor Zhao…

Professor Liping Zhao

We need to make the distinction between human nutrition and microbiome nutrition.

Christine Fennessy

But why does our microbiome need its own nutrition? He says our gut microbiota co-evolved with us. And for thousands of years, we humans ate a lot of fiber.

Professor Liping Zhao

Our ancestors had a much higher fiber intake. On average, 200 to 400 grams of fiber…

Christine Fennessy

Every day. But now …

Professor Liping Zhao

On average, American people now take 15 grams of dietary fiber every day.

Christine Fennessy

He says this shift from a high-fiber diet to a low-fiber diet has disrupted our gut microbiota. And that disruption can lead to the inflammation that causes disease.

Professor Liping Zhao

So that is why dietary fiber is so important. If you look at the literature, almost the only nutrient which has consistent results on its beneficial effects is dietary fiber.

Christine Fennessy

And by beneficial effects, he means dietary fiber cannot only help prevent disease; it can help alleviate the symptoms of disease.

Professor Liping Zhao

That means it’s a fundamentally important nutrition to humans. But it’s actually targeting the gut microbiome.

Christine Fennessy

We’ll talk about sources of dietary fiber in a minute. But first, how exactly does fiber nourish our gut? Professor Zhao says we all have a huge number of bacteria and other microbes living in our guts, but we lose a massive number of them every time we have a bowel movement. So, to make up for that loss, microbes have to grow constantly. And all that growth requires a lot of food.

Professor Liping Zhao

And so the nutrition that our bacteria need to grow can come from two primary sources. One is anything non-digestible or undigested in our diet.

Christine Fennessy

Our bodies can’t digest dietary fiber, and that makes it the best energy source for certain bacteria: the bacteria that tend to be health-promoting. The more fiber these beneficial microbes get, the faster they grow. The faster they grow, the more they take over the ecosystem. And a gut dominated by beneficial microbes is a healthy gut.

He says the second source of nutrition comes from the gut itself—from mucus and dead cells. But the microbes that rely on this energy source …

Professor Liping Zhao

They tend to be pathogenic or detrimental. And so that’s why dietary fiber can be very important for microbiome nutrition.

Christine Fennessy

But what makes beneficial gut bacteria so beneficial? When these microbes eat dietary fiber, they release short-chain fatty acids.

Professor Liping Zhao

These short-chain fatty acids, they are not in our diet. Vinegar is an exception. And also, we cannot synthesize or produce [these fatty acids] by ourselves. But they are very, very important.

Christine Fennessy

They’re important because short-chain fatty acids help maintain a healthy gut surface, regulate our appetite, and reduce inflammation.

Professor Liping Zhao

We know inflammation is damaging to our healthy organs and cells.

Christine Fennessy

So, reducing inflammation is critical in preventing or alleviating disease—but like he says, [short-chain fatty acids] don’t exist in our food and we can’t synthesize them. And that’s why we need to feed the bacteria that can.

Professor Liping Zhao

This would be the best example for the so-called the symbiotic relationship—the mutual beneficial relationship between humans and some important gut bacteria. I think this is the most well understood, well studied, and also one of the most important mutual relationships between humans and gut bacteria.

Christine Fennessy

But in general, we humans aren’t doing a great job of holding up our end of this relationship. Among other things, we don’t eat nearly enough dietary fiber to keep these good microbes at high enough population levels.

Professor Liping Zhao

And most people, when I talk about the importance of high-fiber and how they nurture gut bacteria, say, “Oh, it’s fiber, okay. Have more fruits and vegetables. Problem solved.”

Christine Fennessy

He says it’s not that simple—because there’s fermentable fiber and there’s non-fermentable fiber. Beneficial bacteria can only digest fermentable fiber.

Professor Liping Zhao

Surprisingly, if you look at fibers in fruits and vegetables, they are mostly non-fermentable.

Christine Fennessy

Now, he does not mean that fruits and veggies aren’t important. Far from it. They have loads of vitamins, minerals, antioxidants, and they are good sources of dietary fiber.

Although, as he says, most of that is non-fermentable fiber. But that non-fermentable fiber is important. It absorbs water, which makes our gut content bulkier. And that bulk increases the gut pressure that helps with transit and alleviates constipation.

Professor Liping Zhao

But that’s it. That’s the physical benefits. In order to get the physiological, immunological, and psychological benefits that we talk about from short-chain fatty acids, dietary fiber should be fermentable.

Christine Fennessy

Because the bacteria that produces these short-chain fatty acids needs fermentable fiber. And that comes in large part from whole grains.

Professor Liping Zhao

The general advice is whole grains contain much more fermentable fiber than vegetable and the fruits.

Christine Fennessy

Whole grains include quinoa, oats, barley, brown rice. But he says you have to be careful how you cook them. Because if you cook whole grains too long, they become too digestible and can release a lot of glucose into your body, which can cause your blood sugar to spike. And over time, repeated blood sugar spikes can increase your risk for conditions like Type 2 diabetes and heart disease.

Professor Liping Zhao

So that’s why I’m very careful in giving across-the-board very general advice to people. It’s just because our microbiome nutrition research has advanced to a level where we can use a data-driven approach to help people.

Christine Fennessy

The research behind this data-driven approach began when Professor Zhao was obese and using himself as a guinea pig. He and his team learned that a diet high in fermentable fiber fed beneficial bacteria. But what they didn’t know was which of the hundreds of species of bacteria in our guts were the good ones.

They developed the WTP diet, which stands for whole grains, traditional Chinese medicinal foods, and prebiotics. And then they conducted numerous clinical trials giving the diet to those with adult obesity, childhood genetic obesity, and Type 2 diabetes.

Professor Liping Zhao

We identified a very specific group of bacteria. Before we gave the WTB diet, they were very low in numbers. And when we provide the WTB diet, after about four weeks they become predominant. And they regain their ecological dominance.

Christine Fennessy

This group of bacteria produces the short-chain fatty acids that nurture our guts, regulate our appetite, and reduce inflammation. His team also found that when it comes to Type 2 diabetes, these short-chain fatty acids stimulate production of a hormone that promotes the secretion of insulin. Professor Zhao says that after patients were on this high-fiber diet, they had much better glycemic control.

Professor Liping Zhao

So, this is one side of the story.

Christine Fennessy

The other side? This group of good bacteria lowers the pH of the gut. And that makes it a lot harder for disease-causing bacteria to grow. On top of that, these good microbes …

Professor Liping Zhao

They themselves actually are also antimicrobial. These short-chain fatty acids also can kill or inhibit other pathogenic bacteria. Eventually, disease-related pathogens are reduced and then beneficial bacteria promoted. You’ll have a much healthier gut ecosystem.

Christine Fennessy

Professor Zhao calls this group of good bacteria “the Foundation Guild”…

Professor Liping Zhao

Because they are not one species. They are actually many different species, but they work together as a guild. That’s why we call them instead of foundation species, we call them a Foundation Guild. And this is a very important finding.

Christine Fennessy

Very important, because the Foundation Guild is the key to a healthy gut. If the average American doesn’t get enough fiber and a lot of the fiber that we do eat isn’t the right kind, why can’t we all just eat some version of the WTP diet? The whole grains, traditional Chinese medicinal foods, and prebiotics dietary scheme.

Professor Zhao says that diet was designed to test the hypothesis that a high-fiber diet could promote good bacteria. It wasn’t meant to go mainstream for a lot of reasons.

Professor Liping Zhao

Because different ethnic groups, different geographic regions, different families, different individuals, they have their own dietary habits, preferences, and the local produce they prefer. So, we cannot provide a diet which across the board, everybody should [eat].

Christine Fennessy

But all of this research has led to where we are right now: at a point where he says we can use a data-driven approach to help people. For example, once they identified the Foundation Guild bacteria, they could sequence their genome to understand why the bacteria thrive on such a high-fiber diet.

Professor Liping Zhao

Then we look at their genome. Now we realize, ‘Okay, so they are very good at using several different kinds of plant fibers.’ And you know the chemical structure, properties of those fibers. And so now we no longer need the whole diet.

Christine Fennessy

Professor Zhao and his team at Rutgers have developed a high-fiber formula specifically designed to promote Foundation Guild bacteria. The FDA has granted the formula investigational new drug status. They used it in a recent feasibility study on a patient who had COVID-19 in 2020 and was suffering from Long COVID.

Professor Liping Zhao

She developed very severe GI symptoms, like nausea and bowel refluxes, and almost could not have a regular meal for over a year.

Christine Fennessy

She also had anxiety and palpitations and couldn’t work. Professor Zhao and his team gave the patient the high-fiber formula for two months, and…

Professor Liping Zhao

She recovered. Not completely, but she started to have regular meals.

Christine Fennessy

And he says her GI symptoms and anxiety improved significantly. It was the first study to show the potential of treating [Long COVID] by targeting the gut microbiota. The next step is a randomized, controlled, phase two trial. The formula that Professor Zhao developed is a product of a Rutgers startup.

Professor Liping Zhao

And so I’m the scientific co-founder of a microbiome company called Notitia Biotechnologies Company.

Christine Fennessy

The company has a clinical program for patients and a wellness program for the general public. If you’re wondering about the state of your gut, you can send in a fecal sample and they’ll analyze it to measure the level of your Foundation Guild bacteria. And if it’s low, they have a product that can help restore it.

Professor Liping Zhao

And this company is now producing a nutrition formula—our microbiome formula, which is high in fermentable fiber—for the general public.

Christine Fennessy

It’s a powder you can mix in water, add to smoothies or to muffin, pancake, or waffle mixes. And there’s a third step to the wellness program, too. Once your Foundation Guild is restored, you can send in another sample.

The company will isolate your bacteria and store it. And if you ever lose those good microbes completely, which can happen with certain infections or treatments, they’ll help you regain your original Foundation Guild.

Okay. But we all want to know: What can we do right now?

Professor Liping Zhao

In general, my advice would be not much different from what a nutritionist would give you: Have more fiber. But when it comes to using various fiber-rich ingredients, we know that you need to balance the intake between fruits and vegetable fiber and the green fiber and the whole grains fiber.

Christine Fennessy

But remember: Don’t overcook your whole grains.

Professor Liping Zhao

For the whole grains… I also roast it. So that means after you roast the seed, the starch inside the seeds become much less digestible, so you can get even more benefits. But there is a balance between how much you roast and how much you still keep the necessary “mouth feel” that you like. If it’s too dry, then nobody likes it.

Christine Fennessy

He says in general, ethnic foods tend to be more beneficial to their respective ethnic groups.

Professor Liping Zhao

That makes sense. Why? Because your ancestors and your ancient microbiome has been relying on those ingredients. And so if you want to nurture your Foundation Guild, the first place to turn to is your ethnic food.

Christine Fennessy

But a lot of us want to know about the supplements that we see on the shelves and all the foods that say they contain prebiotics or probiotics. He says they can be helpful.

And just a refresher, prebiotics are nutrients for beneficial bacteria, and probiotics are the beneficial bacteria themselves. But he says, you need to do your research. First, read the label. Professor Zhao says you’ll usually see two Latin words.

Professor Liping Zhao

The first word is the genus name. And the second word is a species name. That’s not enough.

Christine Fennessy

He says you also need the strain ID of the bacteria. So, whether you’re reaching for yogurt or a supplement, look for the bacterium that’s included on the label.

Professor Liping Zhao

By taking this name and putting it in Google search, you can pull out all the patent application, clinical trial papers, all centered on that strain. So if you see, ‘Okay, I can pull quite a number of clinical trial papers showing the benefits of this particular strain or products containing this particular strain,’ that might be a product worth trying.

Christine Fennessy

There’s another simple thing that you can do on a daily basis. And just a heads up here: We’re going to get very blunt about bowel movements.

Professor Liping Zhao

Well, I know in the West people don’t talk about bowel movement in public, right? Some people have never looked at their poop before. But you need to monitor the so-called stool quality, because that’s a very immediate sign of your gut health and then your overall health.

Christine Fennessy

So, what comprises stool quality? First: shape.

Professor Liping Zhao

And I actually have a chart on the wall beside every toilet in my home.

Christine Fennessy

He’s referring to the Bristol Stool Chart, which lists seven shapes ranging from too dry (constipation) to too loose (diarrhea).

Professor Liping Zhao

So even my three-year-old granddaughter, after each poop, she will look at the chart and say, “Okay, it’s type four. Normal, normal.”

Christine Fennessy

The second indicator is color.

Professor Liping Zhao

If you have a very dark color, that’s not a good sign. A yellow golden color, light color, usually is better than a very dark color.

Christine Fennessy

The third is odor. He says a strong odor usually means an unhealthy gut. And finally, stickiness. It’s exactly what you think.

So, while it may take some getting used to, monitoring your bowel movements can reveal a lot about your gut health. And if the indicators aren’t good, he says, fix your diet first.

Professor Liping Zhao

It’s just because there’s nothing more powerful than your own diet.

Christine Fennessy

Take a minute to look at your plate, and remember: You’re eating for two.

Professor Liping Zhao

Every time I look at my meal, I’ll have a very quick estimation of whether I have enough protein and fat for myself. And also how much microbiome nutrition I [have on the plate]. It almost becomes automatic.

Christine Fennessy

He’s not saying give up all those treats you love. Just don’t forget those microbes need a lot of love too.

Professor Liping Zhao

We indulge from time to time, right? We enjoy life. But then I would say, ‘Okay, next day,’ and the next two or three days I need to make it back. You know, to become balanced.

Christine Fennessy

Professor Zhao has been working in the fields of nutritional health and gut ecology for 30 years. And he plans to keep doing it for quite a few more.

Professor Liping Zhao

I joke that I’m going to retire at 120.

Christine Fennessy

And that’s because he’s got a lot to do.

Professor Liping Zhao

I actually have a goal: I hope at least 10 million people can either restore and recover or maintain their health by using what I found in my scientific research. And that will be very fulfilling.

Christine Fennessy

One way he plans to reach that goal is through the Rutgers University Microbiome Program. Professor Zhao is a co-founder and co-leader of the program. And as part of it, he’ll soon be launching the Family Microbiome Project.

Professor Liping Zhao

We know that the Foundation Guild bacteria are essential to human health—so that’s why we need to get them very early in our life.

Christine Fennessy

He says the Foundation Guild bacteria are transmitted from mother to baby through the reproductive tract and through breast milk.

Professor Liping Zhao

But they can also be picked up from interactions with other family members. From a father, from grandparents.

Christine Fennessy

He wants to recruit 1,000 families to identify the Foundation Guild bacteria unique to each one and to each family member. They’re hoping to learn more about how this essential bacteria is transmitted among families and among ethnic groups.

Professor Liping Zhao

New Jersey is the best place to start this project, because we have the highest ethnic diversity not only in the U.S., but also in the world.

Christine Fennessy

He says the goal is to better understand how modern-day practices are affecting the transfer of Foundation Guild bacteria—practices like scheduled C-sections, bottle feeding, and antibiotic use early in life. And if that transfer is severed, can it be restored?

Professor Liping Zhao

We need to identify and understand this. And hopefully we can find such bacteria, identify them, and isolate them so that we can have a bank. And then they can be used to develop drugs and to help those who have permanently lost them.

Christine Fennessy

The Family Microbiome Project will be a very long-term study, but he sees real change coming in the not-so-distant future.

Professor Liping Zhao

Probably the generation who’s going to be born 10 years from now will be the microbiome babies. Because their microbiome will be taken care of from even before they were born. Their [parents] will manage and test and optimize their microbiome to prepare for the new baby.

Christine Fennessy

But really, when it comes to making our microbiome healthier, we don’t have to wait that long. Professor Zhao says that’s the beauty of this research: so much of it can be applied today.

Professor Liping Zhao

Sometimes I joke that before you listen to my talk, you are you. After you listen to my talk, you are no longer you, but you and your microbiome, right?

When you realize there is a gut microbiome living inside your gut, you need to respect it. You need to nurture… it so that it can keep you healthy. This will fundamentally change your behavior in many ways.

Christine Fennessy

That’s it for today’s show. I’d like to thank Professor Zhao for being so generous with his time. And remember, this episode is part two in our two-part microbiome miniseries.

In part one, Dr. Martin Blazer and professor Maria Gloria Dominguez-Bello help us understand what our microbiome does for us, why it’s changing, and the impact that change is having on our health, specifically on the health of kids.

Music in this episode is by Epidemic Sound, and you can subscribe to the show wherever you get your podcasts. Multidisciplinary projects like the Rutgers University Microbiome Program embody the innovative drive of Rutgers, New Jersey’s academic, health, and research powerhouse.

I’m your host and producer, Christine Fennessy. Join us next time as we explore more initiatives that will better the world.