Probiotics vs. Prebiotics

What’s the difference, and do you need both for a healthy gut biome?

Lara McGlashan MFA CPT | February 02, 2017


Deep inside your belly there are bugs. Millions and billions and trillions 
of bugs. But this is not a setup for a horror movie: These probiotics are the good bugs that keep your digestive system healthy by controlling the growth of harmful bacteria and enhancing the absorption of nutrients in your gut.

Probiotics are living organisms that hitchhike to your GI tract in the foods you eat, such as yogurt, miso soup and sourdough bread, and they work to improve immune system function, lower blood pressure and cholesterol, and keep you regular.


Just like you need food to live, so do your little gut bugs. This is where prebiotics come in. A prebiotic is a non-digestible plant fiber that nourishes the existing bacteria in your gut, helping them grow and improving the good-to-bad bacterial ratio. Prebiotics are found naturally in foods such as onions, beans, asparagus, oat- meal, artichokes and edible fruit skins, and they are not affected by heat, cold, acid or time.

The Winner? Both

Eating certain foods in combination makes for the ideal gut-vironment. For example, having a yogurt with an apple delivers prebiotics and probiotics into your system, while a chicken sandwich on sourdough bread with a spinach salad will make your belly bugs jump for joy.

This is because leafy green vegetables contain sulfoquinose (SQ), a sugar that is essential for nourishing your good bacteria, allowing them to proliferate and in turn limiting the ability of bad bacteria to colonize, according to a study published in Nature Chemical Biology. Interestingly, SQ is the only sugar molecule that contains sulfur, and when SQ is digested by the bacteria, the sulfur gets released back into the environment. Explains a lot about broccoli!

Fun Facts:

College students suffering from colds who took a probiotic of Lactobacillus recovered two days earlier and had symptoms that were 34 percent less severe than those who did not take the probiotics.

A new study of 1,900 adults published in the International Journal
of Food Sciences and Nutrition found that taking probiotics resulted in a greater reduction in overall body mass index, with the greatest weight loss occurring in people taking more than one type of probiotic.

About the Author

Lara McGlashan MFA CPT

Oxygen Fitness Editor Lara McGlashan has more than 15 years of experience as a writer and editor, who specializes in health, fitness, and nutrition. 

Lara is an ACE-certified personal trainer and fitness consultant. Her sports background includes skiing, snowboarding, flying trapeze, yoga, competitive beach volleyball, dance, mountain biking, hiking and running, to name a few endeavors. She is currently exploring the world of CrossFit in her home base of Connecticut, where she lives with her 2-year-old son, Alex.

You can follow her on Facebook at LaraFitnessEditor.