By the numbers, we are just as much – if not more – bacteria as we are human. (1) Inside and on our bodies, we are covered in trillions of bacteria. Sounds crazy, huh?

Interest in and research on the microbiome and gut health has increased drastically over the last several years. Many nutrition professionals are excited to use this increased interest in intestinal health to teach individuals how to incorporate gut-friendly foods into their diets. Two major players in building and maintaining optimal digestive health are probiotics and prebiotics. Learning about the difference between prebiotic and probiotic foods can help you make dietary choices that support your long-term health.

What are probiotics?

Let’s start by defining probiotics.

“live strains of strictly selected microorganisms which, when administered in adequate amounts, confer a health benefit on the host”

Food and Agriculture Organization (FAO) and World Health Organization (WHO) (2)

If it’s easier to think about probiotics in simpler terms, Chef V and Lexi had a professor at TCU that called probiotics “little critters.” Calling these beneficial microbes “little critters” is also a good way to teach kids from a young age about gut health – not all critters are bad!

In order to be classified as a probiotic, the bacteria must have documented pro-health effects. (2) The type, amount, and delivery of probiotics influence the potency of their health benefits. 

Some of the most common probiotic strains include those in the Lactobacillus and Bifidobacterium families, as well as Streptococcus thermophilus and E. coli strain Nissle 1917. (3) The next time you pick up a container of yogurt or kefir, look for these words on the ingredients list!

Probiotics have numerous health benefits, which may include the following:

• Reduce risk or development of chronic diseases such as obesity, type 2 diabetes, non-alcoholic fatty liver disease 
• Manage gastrointestinal disorders
• Reduce allergic reactions
• Counteract pathogenic bacteria
• Produce B-vitamins
• Enhance vitamin and mineral absorption
• Improve immunity
• Reduce chronic inflammation
• Aid in cancer cell elimination
• Decrease urinary tract infections
• Reduce constipation
• Prevent antibiotic associated diarrhea 

… and potentially more! (4)

Consuming a variety of probiotic strains will enhance these beneficial effects. (2)

Food Sources of Probiotics

Dietary sources of probiotics are most commonly found in fermented foods.

Here are some examples of probiotic foods:

• Yogurt 
• Kefir
• Kombucha
• Tempeh
• Miso
• Sauerkraut
• Kimchi

When purchasing fermented dairy products, look for “live and active cultures”. This will ensure that the beneficial bacteria are alive after processing and pasteurization. (5)

Many food manufacturers are jumping on the trending popularity of probiotic foods and are adding them to otherwise non-fermented foods. Proceed with caution when purchasing these foods. Advertising these foods as probiotic-containing foods can give them a health halo effect that makes them appear healthier than they probably are. Generally, if a company has to market and advertise the health benefits of a food, there’s probably a better choice out there. Probiotic cereal, anyone?

What are prebiotics?

Now let’s define prebiotics.

“a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food”

The International Scientific Association for Probiotics and Prebiotics (6)

More simply, prebiotics are non-digestible parts of foods (i.e. fibers and polyphenols) that feed the existing bacteria in our digestive tracts. Feeding these microorganisms keeps them alive and therefore promotes the health benefits of probiotics!

If you need some imagery to keep all of these concepts straight, think of your colon as soil, probiotics as seeds, and prebiotics as fertilizer that helps those seeds grow. Just as fertilizer helps seeds grow, so too do prebiotics help probiotics grow! And just as too much fertilizer would hurt the seeds and soil, excessive prebiotic consumption could hurt you by causing intestinal discomfort such as bloating, gas, or diarrhea.

Prebiotics have numerous health benefits, which may include the following:

• Reduce cancer risk
• Decrease LDL cholesterol
• Improve immunity
• Increase calcium absorption
• Alleviate peptic ulcers
• Maintain intestinal pH
• Reduce triglycerides 

… and potentially more! Consuming a variety of prebiotic-containing foods can promote an array of benefits. (2)

Food Sources of Prebiotics

Prebiotics are found in fiber-rich foods. All prebiotics are fiber, but not all fibers are prebiotics. Consuming a variety of fruits, vegetables, and whole grains will provide the necessary food for your healthy gut bacteria.

Here are some common examples of prebiotic foods:

• Artichokes
• Asparagus
• Apples
• Bananas
• Barley
• Beans
• Berries
• Cocoa
• Garlic
• Leeks
• Legumes
• Oats
• Onions
• Wheat Bran

Food manufacturers may also add artificially-produced prebiotic fibers to foods such as granola bars, protein powders, gluten-free breads, high-fiber breakfast cereals, and even ice cream!

Look for these terms on nutrition labels to help you identify sources of artificially-produced prebiotics:

• Lactulose
• Galactooligosaccharides
• Fructooligosaccharides
• Cyclodextrins
• Inulin
• Oligofructose

Although these ingredients are not necessarily bad for you, aim to get the majority of your prebiotics through whole foods.

What are synbiotics?

For all of the multitaskers out there asking, “can you take prebiotics and probiotics together?”, the answer is yes! Synbiotics are the synergistic combination of both probiotics and prebiotics. Probiotic survivability in the GI tract increases when combined with prebiotics. 

Synbiotics have numerous health benefits which may include the following:

• Prevent osteoporosis
• Reduce blood sugar
• Reduce blood lipids 
• Improve immunity
• Improve liver function in patients with cirrhosis (2)

Food Sources of Synbiotics

Sauerkraut and kimchi are examples of natural synbiotic foods. Although there aren’t many food sources of synbiotics, combining prebiotic and probiotic foods into the same meal or dish can provide synbiotic benefits. 

There are nearly endless ways to combine these ingredients, but here are some of the best prebiotic and probiotic combinations:

• Kefir + unripe banana
• Kefir + oats
• Sauerkraut + whole wheat bread
• Kimchi + tempeh
• Miso + beans
• Yogurt + berries

What other delicious synbiotic combinations can you come up with?

Why are prebiotics and probiotics important?

By this point, it probably sounds like prebiotics, probiotics, and synbiotics are the magical cure for all diseases and ailments. While we cannot validate this claim – there are far too many other factors that influence health – gut health can play a huge role in improving overall health. 

When combined and as part of an overall healthful diet, prebiotics and probiotics may reduce the risk of chronic diseases, improve immunity, and regulate bowel function.

Research also suggests that altering the composition of the microbiome could help treat obesity. Positive dietary changes can beneficially affect gut bacteria in mere hours. Making dietary changes to improve gut health is a relatively non-invasive and cost-effective strategy to improve overall health. (7)

Although more research needs to be done, there is minimal risk or harm in incorporating prebiotic and probiotic-rich foods into your diet in order to populate your gut with healthy “critters”! (8)

How to Incorporate Prebiotics and Probiotics into Your Diet

Prebiotics and probiotics – you know what they are, what they do, where to find them…so now what?

Start by thinking about your current diet. Which of the foods on the prebiotic and probiotic lists do you currently consume? Which foods could you easily add to your diet? Are there any foods that you have never eaten but would like to try?

If you do not currently consume a lot of fiber-rich foods, we recommend making changes slowly at first. Incorporating too much fiber too fast can cause intestinal discomfort – gas, bloating, constipation, or diarrhea. Start by making one dietary change each week. For example, instead of starting your morning with sugary cereal, make a batch of overnight oats for an easy and healthy breakfast. Or instead of using protein powder in your smoothie, use Greek yogurt. 

For more personalized guidance on incorporating gut-friendly foods into your diet, visit a registered dietitian. A dietitian can help you make changes that will best suit your needs, preferences, and lifestyle.

Want some prebiotic and probiotic recipes? Check out these base recipes, then get creative customizing them to your taste!

Should I take probiotic supplements?

We promote a food-first approach to health and diet.

We recognize the attractiveness of buying supplements that promise major health benefits, especially when they give the illusion that you don’t have to change anything else in your diet!

However, if you’re following a diet rich in PopTarts, mac and cheese, and frozen dinners, these are probably the areas of your diet that you should improve first before purchasing supplements. 

Supplements are expensive, not proven to be 100% effective, and in need of more oversight and research. (9, 10, 11) Research is currently underway for many probiotic and prebiotic supplements, with some showing real promise. (12) But until those supplements are readily available, inexpensive, and proven effective, we recommend consuming more probiotic- and prebiotic-rich foods.

Instead of paying big pharmaceutical companies for non-essential supplements, support farmers by purchasing more fruits, vegetables, and whole grains!

Want to learn more about the gut microbiome? 

Check out these other helpful resources!

Digestible Books

Gut: The Inside Story of Our Body’s Most Underrated Organ by Giulia Enders

The Mind-Gut Connection by Emeran Mayer, MD

Fiber Fueled by Will Bulsiewicz, MD, MSCI

The Good Gut by Justin Sonnenburg and Erica Sonnenburg

Helpful Articles

Type 2 Diabetes and Probiotics: What does Science Say? – Laurel Ann Nutrition

Gut-Friendly Podcasts

That Gut Feeling – BBC Food Programme

Eat Fibre – The Doctor’s Kitchen

We’d love to hear how you are adding more probiotic and prebiotic foods to your diet. Let us know in the comments section below!

To YOUR Taste!

Lexi