Prebiotics are not to be confused with probiotics. Probiotics make up the “good” bacteria (such as bifidobacteria and lactobacilli) that normally colonize in your colon and can be found in fermented foods like kimchi, sauerkraut, and yogurt. Prebiotics, on the other hand, are a type of soluble fiber only your gut can digest. The fiber passes through the upper portion of your gastrointestinal tract undigested and serves as nourishment for the healthy bacteria in your colon. Think of it this way: Prebiotics feed probiotics.
Why you need them:
You want prebiotic foods in your diet because boosting probiotic groups like bifidobacteria can help reduce the amount of potentially damaging bacteria in your colon by improving your gut’s pH (it’s less hospitable for “bad” bacteria), help make your bowel movements more frequent, and actually boost your immune function. As probiotic bacteria thrive, they release beneficial digestive byproducts called short-chain fatty acids—the benefits of which range from preventing colon cancer to inducing remission in people with inflammatory bowel diseases.
Naturally, certain things we'd rather not deal with—like stress, a not-so-stellar diet, and antibiotics—can deplete our source of healthy gut bacteria, so you want to make sure you're taking care of the good stuff regularly. That’s not to say you should go on an all-out prebiotic frenzy; you’ll experience some not-so-nice side effects—gas, for one.
When looking for prebiotic foods, you’re essentially looking for foods with fermentable fibers, such as oligosaccharides, galactooligosaccharide, and inulin, since they can increase the population of bifidobacteria.
What defines a prebiotic food
1. Prebiotic foods can be fermented by the microbes inside your colon. 2. They can stimulate the beneficial bacteria in your gut. 3. The food must be resistant to stomach acid and other digestive processes so it can make it to your intestines.
Click through to get the lowdown on the foods that prove it's what's on the inside that counts.
Raw Chicory Root
Chicory root is one of the best sources of inulin (not to be confused with insulin). This may come as a surprise, but chicory root is part of the same plant that produces endive. Chicory is (as you could have guessed) the root, while endive is the leafy part of the vegetable.
Chicory root is usually processed to yield its inulin and add it to other food products, so you’ll find it in energy bars, low-calorie yogurts, and even cottage cheese to amp up the food’s fiber content and texture. You’ll also find chicory in coffee: The roots are baked, ground, and used as either a caffeine-free coffee additive or substitute.
Leeks are part of the Allium vegetable family (like garlic and onions), and though they’re often overlooked as a powerhouse vegetable, they pack some major health benefits. They’re full of vitamin B folate and a flavanoid called kaempferol, which helps reduce inflammation and oxidative stress, protects your blood vessels from damage, and defends against colorectal cancer. A natural source of inulin, leeks help your gut clean house and boost the presence of good bacteria.
Onions are an incredibly cheap and versatile way to add flavor to your diet and aid digestion. (Just, you know, think twice about gorging on them before a fancy date.) They’re an excellent source of cancer-fighting antioxidants and sulfur compounds. Eating onions raw—like in a salad or on a burger—can help protect against lung and prostate cancer.
Garlic is known for being a terrific antibacterial food. It naturally kills unfriendly bacteria in your gut, helping to detoxify and rebalance your gut bacteria. Maximize your benefits by eating it raw, which helps release its health-boosting enzymes that can help treat colds and prevent infection.
You’ll hear frisée used interchangeably with chicory and endive, but they’re a bit different. Frisée is a curly, leafy vegetable often used in salads. It’s low in calories and has a healthy amount of fiber and inulin, which can help reduce poor cholesterol and glucose in people with diabetes and obese patients. Plus, frisée packs plenty of vitamin A, vitamin E, beta carotene, folic acid, manganese, copper, iron and potassium.
Whole grains have been found to lower the risk of cancer and heart disease, presumably because of their fiber, vitamins, and minerals. They’ve also been found to have a prebiotic effect on the gut. A study published in the British Journal of Nutrition found three weeks of whole grain cereal consumption boosted levels of beneficial bacteria.
Aside from being a great source of potassium, B vitamins, and Vitamin C, bananas naturally soothe your gut and contain natural fibers that promote good bacteria growth. Though they don’t provide you with a huge amount of inulin, raw green bananas have a prebiotic starch called resistant starch, which allows probiotic bacteria to survive the acid in your stomach, helping ferry the good bacteria into the small and large intestine.
This one’s probably unfamiliar, unless you have an abuela with a culinary streak. Commonly known as Mexican yam bean or Mexican turnip, jícama is a root vegetable composed of about 80-90 percent water. It’s high in carbohydrates (in the form of dietary fiber), but what’s special about jícama is that its fiber is infused with oligofructose inulin, which has zero calories and doesn't metabolize in the body. The inulin balances your immunity, helps increase the absorption of calcium from other foods, and has a prebiotic role in the intestine by promoting “good” bacteria growth. Because it has a very low glycemic index, jícama is a great food for weight loss, too.
Honey contains some unique oligosaccharides that have an important prebiotic activity. Since they can’t easily be digested within your gastrointestinal system, your colon’s bacteria feasts on it. Oligosaccharides are not as potent as oligofructose inulin (the kind in jicama), but they do have many healthy enzymes, are typically easier on your stomach.
Dandelion greens may seem like a modest vegetable, but they are loaded with antioxidants, and vitamins C and A. And more importantly, they’re a rich, natural source of inulin. They’re an easy, low-calorie way to boost your immune function, get your bowel movements more regular, and reduce the population of potentially harmful bacteria from your colon.
Radicchio is quickly becoming more popular. The red-colored leafy vegetable comes from the Mediterranean, and is part of the chicory family (cousins to lettuces and dandelions). Radicchio's tightly bound leaves are bitter, so when you eat them, it increases your bile salts, which can aid digestion. In a continuing theme on this list, radicchio is a great natural source of inulin. It also provides 212 percent of your daily recommended value of vitamin K—said to strengthen bones, limit brain damage, and even help treat Alzheimer’s.
As we mentioned earlier, endive (the Belgian variety) comes from the same plant as chicory. It’s incredibly low in calories but high in inulin and fiber, which helps reduce glucose and bad cholesterol levels. You’ll get a healthy does of vitamin A and beta carotene, important vitamins for maintaining good eye and skin health; plus the veggie is high in manganese, copper, iron, and potassium, which are all essential in regulating blood sugar, metabolizing carbs, and absorbing calcium, among other functions. Plus, they make a really fancy-looking salad, so they’re an easy win on date night.
Asparagus is a natural diurectic, so it helps prevent and eliminate bloating. It’s also a great source of fiber, folate, B vitamins and—get this—only 8 stalks provide you with 4g of protein. Not bad for a veg.
Raw Jerusalem Artichoke - 14 Prebiotic Foods You Should Be Eating
Don’t confuse these with your typical artichoke; they’re very different. Unlike standard artichokes, Jerusalem artichokes come from the root of the plant (as do potatoes, yams and carrots). They’re small to medium in size and look a lot like ginger. Jerusalem artichokes are low in carbs (and have low glycemic index)—plus, they’re a great source of oligofructose inulin. Eat them raw or cooked; cooking won't destroy the prebiotic effect.