Most people are aware by now that foods that offer dietary fiber and probiotics have a long list of health benefits, but nonetheless prebiotic foods are still mostly underappreciated. By and large, Americans don’t consume enough prebiotics every day—and, sadly, the result can cause indigestion, higher levels of inflammation, lower immune function, higher likelihood of weight gain, and a raised risk for various chronic diseases.
While probiotic foods are essential for gut health and overall well-being, prebiotics help “feed” probiotics. By pairing them them together, you can achieve an even better result.
What are prebiotics?
By definition, prebiotics are a type of non-digestible fiber compound. Just like other high-fiber foods, prebiotic compounds—including the kind found in foods like garlic, Jerusalem artichokes, jicama, dandelion greens, and onions—pass through the upper part of the gastrointestinal tract and remain undigested, since the human body can’t fully break them down. Once they pass through the small intestine, they reach the colon, where they’re fermented by the gut microflora.
Prebiotics are best known as a type of fiber called “oligosaccharides.” Today, when researchers refer to “fiber,” they’re speaking about not just one substance, but a whole group of different chemical compounds found in foods, including fructo-oligosaccharides, other oligosaccharides (prebiotics), inulin, and polysaccharides.
Originally, prebiotics weren’t classified as fiber compounds, but recently research has shown that these compounds behave the same way as other forms of fiber. Today, prebiotic carbohydrates that have been evaluated in humans largely consist of fructans or galactans, both of which are fermented by anaerobic bacteria in the large intestine.
How Prebiotics Work Together with Probiotics to Improve Health
While probiotic benefits have become more widely known in recent years, especially with the growing popularity of fermented foods like sauerkraut, kombucha, and kimchi, prebiotics still remain under the radar. All types of fiber that we get from eating whole, plant foods play a major role in nutrient absorption, gut, and digestive health. Prebiotics, together with probiotics, open the door for heightened levels of health in general, so nearly everyone can afford to include them in their diets more often.
As prebiotics make their way through the stomach without being broken down by either gastric acids or digestive enzymes, they bring about positive changes in the digestive tract and organs. Essentially, prebiotic compounds become nutrient sources, or “fuel,” for the beneficial bacteria that live within your gut.
Prebiotics work together with probiotics (selectively fermented ingredients that produce beneficial bacteria) to allow specific changes to take place, both in the composition and activity of the gastrointestinal system. They play a fundamental role in preserving health by maintaining balance and diversity of intestinal bacteria, especially increasing the presence of “good bacteria” called lactobacilli and bifidobacteria.
Because the health of our gut is closely tied to many other bodily functions, prebiotics and probiotics together are important for battling inflammation and lowering overall disease risk.
Higher intakes of prebiotics are linked to benefits, including:
- lower risk for cardiovascular disease
- healthier cholesterol levels
- better gut health
- improved digestion
- lower stress response
- better hormonal balance
- higher immune function
- lower risk for obesity and weight gain
- lower inflammation and autoimmune reactions
7 Benefits of Prebiotics
1. Better Gut Health and Improved Digestion
Prebiotics wind up stimulating the growth of beneficial bacteria (often called “probiotics”) that colonize our gut microflora. Since they act like food for probiotics, prebiotic compounds help balance harmful bacteria and toxins living in the digestive tract, which has numerous health implications, including improving digestion. Research has shown that higher intakes of prebiotic foods can increase numerous probiotic microorganisms, including Lactobacillus rhamnosus GG, L. reuteri, bifidobacteria, and certain strains of L. casei or the L. acidophilus-group.
One of the benefits of having good bacteria in the gut is that they’re able to use fiber from the foods that we eat, which would otherwise be non-digestible, as a source for their own survival. As our gut bacteria metabolize otherwise non-digestible fibers from foods, they produce those short-chain fatty acids that help us in many ways.
One of these beneficial fatty acids is called butyric acid, which improves the health of the intestinal lining. Short-chain fatty acids also help regulate electrolyte levels in the body, including sodium, magnesium, calcium, and water, that are also important for proper digestion, producing bowel movements, preventing diarrhea, and so on.
Changes in the gut microbiota composition are classically considered as one of the many factors involved in the development of either inflammatory bowel disease or irritable bowel syndrome. A 2012 report published in The Journal of Nutrition states that prebiotics, along with probiotics, can help treat many digestive problems, including:
- diarrhea (especially after taking antibiotics)
- certain intestinal infections and chronic disorders like Crohn’s disease and ulcerative colitis
- symptoms of irritable bowel syndrome (IBS)
- inflammatory bowel disease
- leaky gut syndrome
- Candida virus
2. Enhanced Immune Function and Cancer Protection
A large number of human intervention studies have demonstrated that dietary consumption of certain prebiotic-containing food products can result in statistically significant changes in the composition of the gut microbiota that help improve immunity. The “prebiotic effect” has been associated with modulation of biomarkers and activities of the immune system, including a reduction of the concentration of cancer-promoting enzymes and putrefactive (bacterial) metabolites in the gut.
Prebiotics help “improve stool quality (frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being, and reduces the incidence of allergic symptoms,” according to a report in The British Journal of Nutrition. Prebiotics and probiotics boost immunity because they enhance our ability to absorb important nutrients and trace minerals from the foods we eat. They also effectively help lower the pH in the gut, which inhibits the growth of potential pathogens or damaging bacteria. Research has shown a lot of promise for the immune system–boosting benefits of prebiotics and probiotics consumed together.
Some of the ways these can enhance immunity include offering prevention or treatment of urinary tract infections, vaginal yeast infections, digestive disorders, colds and the flu, cognitive disorders, and even cancers, including colon cancer. Often associated with toxic load, colon cancer is an example of a pathology for which a possible role of gut microbiota composition has been hypothesised. Many studies show a reduction in the incidence of tumors and cancer cells after consuming specific food products with a prebiotic effect.
3. Lower Inflammation
Prebiotics can help lower inflammation, which is one of the root causes of diseases, including our nation’s number one killer: heart disease. People consuming more prebiotics, and in general eating a high-fiber diet, tend to have healthier cholesterol levels and lower risk markers for cardiovascular diseases.
It’s believed that prebiotics and probiotics contribute to improvements in metabolic processes that are tied to both obesity and type-2 diabetes. It also appears that a healthier gut environment turns off autoimmune reactions, helps the body metabolize nutrients including fats, and modulates hormonal and immune functions that control how and where the body stores fats (including in the arteries).
4. Reduced Risk for Heart Disease
Consuming foods high in prebiotics can reduce glycation, which increases free radicals, triggers inflammation, and lowers insulin resistance.
Prebiotics have a so-called hypo-cholesterolemic effect, improving the body’s ability to prevent ischemic heart diseases and autoimmune diseases (like arthritis, for example). Another benefit is that they balance the body’s electrolyte and mineral levels, including potassium and sodium, which are responsible for controlling blood pressure.
5. Help with Weight Loss or Maintenance
Recent data from both human and animal studies support the beneficial effects of particular prebiotic food products with better energy homaeostasis, satiety regulation, and lower body weight gain. Higher intakes of all types of fiber are, in fact, linked to lower body weight and protection against obesity.
A 2002 study published in The British Journal of Nutrition states that prebiotic foods promote a sense of fullness or satiety, prevent obesity, and spur weight loss. Their effects on hormone levels are related to appetite regulation, with studies showing that animals given prebiotics produce less ghrelin, the body’s signal to the brain that it’s time to eat.
6. Protection of Bone Health
A 2007 study published in The Journal of Nutrition found that prebiotics enhance the absorption of minerals in the body, including magnesium, calcium, and possible iron. All of these are crucial for retaining strong bone bones and preventing fractures or osteoporosis. In one study, just eight grams of prebiotics a day was shown to have a big effect on the uptake of calcium in the body that led to an increase in bone density.
7. Hormone Regulation and Improved Moods
Research regarding the “gut-brain connection” is still in its infancy, but it’s becoming clear that mood-related disorders like anxiety or depression are highly tied to gut health. Research suggests that your mood and hormonal balance are affected by a combination of factors that most definitely includes the state of the bacterial inhabitants living inside of your body. Your gut helps to absorb and metabolize nutrients from the foods you eat that ultimately are used to support neurotransmitter functions that create the hormones (like serotonin) that control your mood and help bust stress.
The final straw in triggering a mood-related disorder might be a series of misfiring neurotransmitters in parts of the brain that control fear and other emotions. These transmissions partly depend on the health of the microbiome, so when the balance of gut bacteria isn’t working right, other biological pathways including hormonal, immunological, or neuronal won’t work right either.
Recently, studies have demonstrated that prebiotics have significant neurobiological effects in the human brain, including lowering cortisol levels and the body’s stress response. A 2005 study published in The Journal of Psychopharmacology explored the effects of two prebiotics on the secretion of the stress hormone cortisol and emotional processing in healthy adult volunteers. After volunteers received one of two prebiotics or a placebo daily for three weeks, the group receiving prebiotics showed positive changes in levels of cortisol and decreased attentional vigilance to negative versus positive information on an emotional test.
Top Sources of Prebiotics
Prebiotics are primarily found in certain vegetables, some whole grains, sources of resistant starch (like under-ripe bananas), and even in honey. Some of the top probiotic sources, on the other hand (that use prebiotics to thrive), include cultured or fermented foods like yogurt, kefir from raw dairy, kimchi, kombucha, and cultured veggies.
The best natural sources of prebiotics include:
- acacia gum (or gum arabic)
- raw chicory root
- raw Jerusalem artichoke
- raw dandelion greens
- raw garlic
- raw leeks
- raw or cooked onions
- raw jicama
- raw asparagus
- under-ripe bananas
Some other sources include foods that contain isolated carbohydrates (galactooligosaccharides and transgalactooligosaccharides), such as raw honey, wheat dextrin, psyllium husk, whole-grain wheat, and whole-grain corn.
If you’re thinking that this list is short, and you’re worried about how to include these foods in your diet more often, here are some tips:
- One of the most realistic and delicious ways to prebiotics to your meals is by including nutrition-packed onions. Onions, both cooked or raw, give plenty of flavor to your food and also provide immune-enhancing antioxidants. They contain a natural source of inulin, one type of good bacteria that fights indigestion. Use onions in savory dishes like sauces, salads, dips, and soups, or grilled on the BBQ.
- Raw garlic is another easy prebiotic ingredient to use that offers loads of benefits. The benefits of garlic include: cancer prevention, along with antifungal, antioxidant, anti-inflammatory, and antiviral properties. Try using some in a tomato salad, dips, spreads, or homemade hummus.
- Nutrient-dense bananas that aren’t yet fully ripe have the most resistant starch and prebiotics. Look for bananas that are still greenish instead of bright yellow and spotted. While they won’t be as soft or sweet-tasting, they still work well in smoothies or even warmed up as a dessert.
- Dandelion greens are another food that can be found in most grocery stores and nearly all health food stores. These leafy greens are a great source of prebiotics in addition to antioxidants, vitamins, and minerals. Eat them raw by chopping them up finely and adding some to a salad or side dish.
- If eating asparagus raw doesn’t initially appeal to you, try fermenting them. You can easily make homemade fermented asparagus (and many other veggies too) with just some salt and a mason jar. The same goes for jicama—either slice them thinly and throw them in a salad for some crunch, or try bringing out their natural flavors and probiotics by making cultured jicama sticks.
- Jerusalem artichokes, often called sunchokes, are more similar to a root vegetable than the large green artichokes you’re probably familiar with. Try shredding them and sprinkling some on top of a salad, into a smoothie, or into a dip. They have a mild flavor and blend easily with other tastes.
- Chicory root is useful for baking since it binds ingredients together. It’s also a high-antioxidant food and great digestive cleanser. Some people use chicory when making homemade cultured veggies, like kimchi or sauerkraut. Chicory root is also used as a coffee substitute for those suffering from caffeine overdose or additive elsewhere in the world since its taste mimics that of coffee, without any of the caffeine or acidity.
- Acacia gum is used in a variety of products, including some supplements, powders, and even ice cream. In herbal medicine, the gum is used to bind pills and lozenges and to stabilize emulsions. It’s possible to find powder acacia to add to smoothies in certain health food stores or online.
Probiotics and prebiotics are also added to some foods artificially and available as dietary supplements. While many food manufacturers now produce foods that are “high in fiber,” many use isolated fiber sources that are difficult to digest; some might even have mild laxative effects.
Therefore, getting fiber and prebiotics from whole, real foods is always going to be your best option. Supplementing with a quality probiotic supplement that also includes prebiotics can be beneficial too, but this shouldn’t take priority over eating a balanced, healthy diet.