<< Back

Prebiotics vs. Probiotics: What’s the Difference?

April 03, 2025

You’ve probably heard that probiotics are good for your gut — but what about prebiotics? And do you really need both? Understanding the role of prebiotics vs. probiotics in your gut health can help you make smarter choices for your digestion, immunity, and overall health.

We asked an expert to break down what each one does and where to get started. Here’s what he had to say.

Virtual care - when and where you need it

Download the app

Probiotics keep your gut healthy.

Brace yourself. Your digestive system has billions of live bacteria in it, which help keep your gut in balance. But things like antibiotics, illnesses or junk food binges can throw it off.

Enter: probiotics.

“Probiotics are like reinforcements for your gut,” says Raza Shariff, MD, a bariatric and general surgeon with the Hartford HealthCare Digestive Health Institute. “They work to replenish the good bacteria and maintain harmony in your digestive system.”

If yogurt and miso soup are staples in your diet, you’re probably eating plenty of probiotics without even knowing it. Foods rich in probiotics include:

  • Yogurt: Look for labels that say “live and active cultures” — that’s code for probiotics.
  • Kefir: A tangy, drinkable fermented milk, loaded with different strains of probiotics.
  • Sauerkraut: Is kielbasa a staple in your meal plan? Don’t forget to add sauerkraut – especially if it’s unpasteurized.
  • Kimchi: Spicy, fermented vegetables like cabbage and radish make this a probiotic gold mine.
  • Kombucha: A fizzy, fermented black tea with lots of health benefits.
  • Pickles: Choose pickles that are fermented in brine – not soaking in vinegar – and you’ve got a great source of probiotics.
  • Miso: This fermented soybean paste is the perfect addition to your next soup.

> Related: Does Kombucha Actually Help With Digestion? 

Here’s why you should get more probiotics in your diet.

If a happy digestive system isn’t reason enough to eat more foods rich in probiotics, there are plenty of other benefits, too. Here are a few:

  • Immune support: Probiotics help your body fight infections by stimulating immune cells like macrophages and T lymphocytes.
  • Mental health: Several studies have found that probiotics may have an effect similar to antidepressants, by improving the balance of serotonin in the brain.
  • Recovery after antibiotics: Antibiotics can reduce both good and bad bacteria in your gut – but probiotics can help restore that balance.
  • Heart health: Probiotics can improve cholesterol levels, blood pressure and inflammation.
  • Weight management: A balanced gut can regulate energy, appetite and fat storage. Probiotics might even improve insulin sensitivity, which can lower your risk of type 2 diabetes.

> Related: Can I Still Benefit From Probiotics If I’m Healthy? 

Are probiotics right for me?

Probiotics are generally safe, but there are a few exceptions.

“If you fall into any of these groups, check with your doctor before taking a probiotic supplement,” says Dr. Shariff.

These include people with:

  • Weakened immune systems: If you’re taking immune suppressants, going through chemotherapy or recently had a transplant, probiotics might not be for you.
  • Certain health conditions: Conditions like sepsis, pancreatitis or small intestinal bacterial overgrowth (SIBO) may be worsened by probiotics.
  • Allergies: If you have any allergies, double-check the ingredients in probiotic supplements before taking them.

Prebiotics vs. probiotics: what’s the difference?

If probiotics are your gut’s best friend, prebiotics are their favorite snack.

“Prebiotics are fibers that your body can’t digest, but your gut bacteria love them,” says Dr. Shariff. “Think of them as fertilizer for your gut garden. They help the good bacteria thrive and support overall gut health.”

When you eat prebiotics, they make their way to your colon where they are fermented by your gut bacteria. This turns prebiotics into energy for your gut, and also produces short-chain fatty acids.

“These are beneficial for gut health, reduce inflammation, and may even enhance the absorption of minerals like calcium and magnesium,” Dr. Shariff adds.

Find prebiotics in food like:

  • Fiber-rich food like whole grains, vegetables, fruit, nuts and seeds.
  • Resistant starches like potatoes, legumes and green bananas.
  • Foods containing inulin, a soluble fiber, like artichoke, asparagus, garlic, leeks and onions.

> Want more health news? Text StartHere to 85209 to sign up for text alerts

Bonus: A few foods to avoid.

You know how to get more probiotics and prebiotics in your system, but are there any foods you should avoid to keep your gut happy?

“Certain foods either feed the wrong gut bacteria, or limit good gut bacteria,” says Dr. Shariff.

Steer clear of foods like:

  • Refined sugars or artificial sweeteners
  • Highly processed foods or fast foods
  • Red and processed meats
  • White bread and other refined carbs
  • Excessive alcohol
  • High-fat, fried foods
  • Dairy – especially if you’re lactose intolerant
  • Artificial additives

Not sure where to start? Reach out to your primary care physician for guidance. Your gut will thank you for it!