Walk down any grocery aisle and you will see “probiotic” on yogurt cups and “prebiotic” on sodas, snack bars and supplements. The words are only one letter apart, so it is no surprise people mix them up. Here is what each one actually means, and how to get both from ordinary food.
Your gut is home to trillions of microbes
Your digestive tract hosts a huge community of bacteria and other microorganisms, often called the gut microbiome. These microbes help break down food, produce certain compounds your body uses, and interact with your immune system. Researchers are still learning exactly how the microbiome affects health, but a diverse, well-fed community is generally considered a good sign.
Probiotics: the helpful microbes
Probiotics are living microorganisms, usually bacteria or yeast, that may support digestion or help with certain health issues when you consume them (Mayo Clinic). You find them naturally in fermented foods such as:
- Yogurt and kefir with live and active cultures
- Sauerkraut and kimchi (refrigerated, not shelf-stable)
- Miso and tempeh
- Some aged cheeses
Not all fermented foods contain live microbes at the time you eat them. Baking, canning and pasteurizing after fermentation can kill them, so look for “live and active cultures” on the label.
Prebiotics: food for those microbes
Prebiotics are parts of food your body cannot digest, but your gut bacteria can. They act as fuel for beneficial microbes and may encourage them to grow (Mayo Clinic). Most prebiotics are types of fiber. Good sources include:
- Onions, garlic and leeks
- Asparagus and artichokes
- Slightly green bananas
- Oats, barley and other whole grains
- Beans, lentils and chickpeas
The easy way to remember it
Probiotics are the gardeners. Prebiotics are the fertilizer. A healthy garden needs both.
Synbiotics: both together
Some products combine probiotics and prebiotics. These are called synbiotics. On a plate, you can create the same idea yourself: yogurt topped with oats and a sliced banana, or kimchi alongside a bean and vegetable bowl.
Do you need supplements?
For most healthy people, food is the best place to start. Supplements vary a lot in which strains they contain and how much, and research has not shown that they benefit everyone. Mayo Clinic advises talking with a healthcare professional before starting probiotic or prebiotic supplements, especially if you have a health condition or a weakened immune system.
If you do increase prebiotic fiber, go slowly. A sudden jump can cause gas and bloating while your gut adjusts. Adding a little more each week, and drinking enough water, makes the change more comfortable (Mayo Clinic).
A simple gut-friendly day
- Breakfast: plain yogurt with oats and banana slices
- Lunch: lentil soup with a side salad and onions
- Snack: a handful of nuts and an apple
- Dinner: grilled chicken or tofu, roasted asparagus and barley, with a spoon of sauerkraut
The bottom line
Probiotics are live microbes; prebiotics feed them. You can get both from a varied diet rich in fermented foods, vegetables, legumes and whole grains. Start with food, add fiber gradually, and check with your doctor before adding supplements.