When it comes to digestive health, you may have heard of “prebiotics” and “probiotics.” Both are important in supporting the health of your digestive system – particularly that of the microorganisms that live in your gut, also known as the microbiome.

In simple terms, probiotics are the “good” bacteria that keep your body healthy, while prebiotics are the foods that promote their growth.

Before we dive into the benefits of both, it helps to understand why these friendly microbes are so important.

How the Gut Microbiome Supports Your Health

Did you know that your digestive system does so much more than simply process and extract nutrients in your foods? In fact, your gastrointestinal tract has been called the “second brain” – a complex system that sends and receives all kinds of information to and from your “first” brain.

The “brain” in your gut has a variety of receptors that gather information about conditions in your digestive tract. It then sends signals to your “first” brain, which uses that information to control digestive function.

But signals travel in the other direction, too, and this is something you’ve probably experienced in the form of a “gut reaction.” When stress or anxiety strikes, your brain sends a signal to your gut – and the next thing you know, you’ve got a churning stomach.

For this reason, it’s important to promote the growth of “good” bacteria in your gut. The microbiome is an entire ecosystem comprising trillions of diverse organisms, including bacteria, fungi, and viruses. They weigh between two and six pounds and can have profound effects on your physical health and may even affect your mood.

One of the primary functions of the microbiome is to break down dietary fiber since the human body lacks the mechanism to get the job done.

In addition, the microbiome:

With so many important roles that it has in protecting your health, there is increasing attention to the role that diet plays in maintaining the health of your microbiome. While we don’t know exactly what the ideal composition of the microbiome should be, we do know that the more diverse the population of inhabitants in your gut, the better.

The foods you put into your system have a big influence on maintaining a healthy balance of the microbes in your gut, which, in turn, helps your two “brains” to work optimally together.

What Are Prebiotics?

Broadly speaking, prebiotics are the compounds in many of the high-fiber foods that you eat. While humans lack the ability to break down the certain carbohydrates and fiber that we consume in foods like fruits, vegetables, beans, and whole grains, the microbes in your gut are more than happy to do the job for you in a process referred to as fermentation. In fact, probiotics stimulate the growth and activity of the good bacteria in your digestive tract and can improve health.

Of the two general types of fiber – soluble and insoluble – it’s the soluble fibers (found in foods like oats, barley, and beans) that are considered to be prebiotic. Not only do they tend to thicken and swell when they come in contact with liquid, making foods tend to be filling, but soluble fibers also encourage the growth of the good bacteria in your digestive tract.

More specifically, you may hear about specific prebiotic compounds – such as resistant starches in underripe bananas – or compounds called fructooligosaccharides (found naturally in onions, garlic, asparagus, and artichokes) that are known to stimulate bacterial production in the lower digestive tract.

What are the benefits of prebiotics?

Prebiotics serve as food for probiotics, but they potentially can affect other organs and systems in the body. Soluble fibers not only help to fill you up, but they also slow the absorption of sugar into the bloodstream, so they can help to keep blood sugar levels even throughout the day in normal, healthy people. These same fibers can also help keep blood cholesterol levels within a normal range.

In addition, prebiotics:

What are foods rich in prebiotics?

Prebiotic fiber compounds are particularly abundant in plant foods, particularly bananas, onions, garlic, leeks, asparagus, artichokes, tomatoes, plums, apples, nuts, soybeans, and whole-wheat foods. But rather than focusing on a short list of fruits and vegetables, it’s wise to consume a wide variety of vegetables, fruits, beans, and whole grains to reap the many nutritional benefits they provide.

What Are Probiotics?

The word “probiotic” derives from Greek, meaning “promoting life.” And probiotics certainly do just that in your digestive tract. Probiotics are the “good” bacteria (sometimes called live cultures) that you can consume from foods or supplements. Probiotics are the same bacteria that reside in your gut. Taking in probiotics can help to balance the populations of the various types of bacteria in your gut, which, in turn, promotes gut health.

While the idea of consuming bacteria may not sound appealing, it’s likely that you already consume them without realizing it. Probiotics are found in many fermented foods. Fermentation is a natural process in which bacteria convert sugars and other carbohydrates in foods into acids. That’s why many naturally fermented foods have a tangy taste.

What are the benefits of probiotics?

There are many, many different microbes that live in your gut, and gut health relies on the right balance of the different types. The typical modern diet, with an abundance of sugar and highly processed foods, promotes the growth of certain bacteria that can lead to digestive discomfort – often in the form of bloating or irregularity.

But a diet rich in prebiotic fibers helps to promote the right balance in the digestive system. And, when you consume fermented foods that contain live bacteria, you are introducing beneficial bacteria directly into your digestive tract.

While the benefits of probiotics to digestive function are well-documented, the list of additional health benefits of probiotics continues to grow and is supported by scientific evidence. Aside from effects on intestinal health, probiotics appear to enhance the body’s immune response, reduce blood cholesterol levels, and may also play a role in cancer prevention. Evidence also suggests that probiotics may help with blood pressure control and may also have positive effects on mood.

Some benefits of probiotics include:

What are foods rich in probiotics?

For many people, the most common source of probiotics is fermented dairy products such as yogurt, kefir, and certain aged cheeses. In fact, one of the most common strains of probiotic bacteria that reside in your intestines is Lactobacillus acidophilus, which is found in yogurt.

Beneficial probiotics can also be found in:

Should You Take Prebiotic and Probiotic Supplements?

Let me address some frequently asked questions related to prebiotic and probiotic supplements.

1) Why should someone consider taking prebiotic and probiotic supplements?

Adults should be eating in the neighborhood of 30 grams of fiber a day, but the average grownup only eats about a third of that. Our busy lifestyles contribute to the problem — when we’re on the go, we’re less likely to eat the high-fiber fruits, vegetables, and whole grains that are more typically found at home. So, many of us are lacking when it comes to good sources of prebiotics. And, unless you are a regular consumer of fermented vegetables or dairy products, you might not be getting good sources of probiotics on a daily basis. Fiber supplements that contain both soluble and insoluble fibers, along with probiotic supplements, can help to fill in gaps.

2) How long does it take to notice changes in the body?

When adding fiber supplements to your diet, you may notice changes in your bowel function in just a couple of days. With probiotic supplements, a lot depends on the strain of the probiotic, the quality of the supplement and the dose, or simply to support general health – in which case it may be weeks to months before effects may be felt.

3) How often should you take these supplements? Should I worry about taking too much?

Supplements should be taken in amounts recommended on the product label and can be used daily. However, when starting a fiber supplement, it’s often a good idea to start with a bit less than recommended and gradually increase the daily dose. That way, your digestive system has a chance to adjust.

4) When is the best time to take prebiotics? When is the best time to take probiotics?

The most important factor in taking supplements is taking them consistently. So choose a time of day when you will remember to take your supplements. You can take your prebiotics at any time – with food or without –, but probiotics might be better taken on an empty stomach. That’s because stomach acid can degrade the probiotic bacteria, which means they may not survive the trip to the intestine. But an empty stomach provides less acidic conditions, which might be more favorable.

5) Can I take these supplements together?

While it’s not necessary that you take your prebiotic and probiotic supplements at the same time, it might make it easier to get into the habit if you do. And there’s certainly no reason why you can’t take them at the same time – the combination is known as a symbiotic – since one acts as a food source for the other.

Susan Bowerman

Susan BowermanM.S., R.D., CSSD, CSOWM, FAND – Sr. Director, Worldwide Nutrition Education and Training

Susan Bowerman is the senior director of Worldwide Nutrition Education and Training at Herbalife Nutrition. She also serves as a chairwoman of the Dietetic Advisory Board (DAB). As a registered dietitian, she educates distributors about our global nutrition philosophy and is responsible for developing nutrition education and training materials.

Bowerman earned a B.S. in Biology with distinction from the University of Colorado and an M.S. in Food Science and Nutrition from Colorado State University. She is a fellow of the Academy of Nutrition and Dietetics and holds two board certifications as a specialist in Sports Dietetics and in Obesity and Weight Management. When she is not busy teaching and writing, Susan enjoys spending time with her family, cooking and gardening. Her favorite Herbalife Nutrition products include Simply Probiotic and Herbalife Nutrition Formula 1 Healthy Meal Nutritional Shake Mix Banana Caramel.