Share this page:
Prebiotics vs. Probiotics

Prebiotics vs. Probiotics – Understanding the Difference



No matter where you're reading this, you are not alone! You – like everyone else in the world – are host to 100 trillion microbes.

The gut, skin, vagina, inside of the mouth, and other parts of our bodies are all home to colonies of microorganisms, including bacteria, fungi, viruses, protists, and archaea. Scientists call this microscopic community the microbiota. Influenced by your diet, lifestyle, and history of taking antibiotics, your microbiotia is unique to you.

The word "microbiota" only refers to the microorganisms themselves, but what interests researchers more is your microbiome – the genetic makeup of the various organisms that make up the microbiota. These genes have an impact on your general health – so much so that some scientists view the microbiome as "an organ in its own right."

How the Microbiome Affects Your Health

Most research into the microbiome focuses on the gut. While there is still a lot we don't know, we do understand some of the benefits our intestinal fauna can have for our health.

  • Digestion. Anyone who cares about their health understands the importance of fiber in a healthy diet. However, you can't naturally produce enough enzymes to break down all those fruits and veggies you eat without help from the "good" bacteria living in your gut. This symbiotic relationship begins at birth. Newborns cannot break down the sugars in human breast milk on their own but microbes in the baby's gut metabolize the sugar babies need to grow.
  • Metabolism. Research on the relationship between gut bacteria and obesity is ongoing. Certain organisms influence intestinal absorption of fat, glucose, and cholesterol. Understanding that relationship could help researchers find new ways to address and treat obesity and type 2 diabetes.
  • Vitamin production. Bacteria in your gut turn the carbohydrates you eat into enzymes and vitamins your body needs, such as thiamine, folate, biotin, riboflavin, panthothenic acid, and vitamin K.
  • Protection against disease. Certain gut bacteria produce substances that can kill dangerous pathogens and stimulate the intestines to churn out antibodies. Some gut bacteria form short-chain fatty acids, the main nutrient source of the cells lining the colon. These acids strengthen the gut barrier to keep out harmful substances, viruses, and bacteria, reduce inflammation, and possibly lower the risk of colon cancer.
  • Immune system health. Scientists are studying how a diet high in whole grains affects bacteria that aid digestion, protect against pathogens, and boost the immune system. Studies are being conducted to see whether modulating the microbiome with dietary changes or antibiotics to kill specific bacteria can improve the effectiveness of immunotherapy in the treatment of certain cancers.
  • Mood and mental health. We don’t yet understand the connection between the gut and mental illness, but research is ongoing. Many people with irritable bowel syndrome also suffer from depression. Individuals with autism often have digestive problems, while those suffering from Parkinson’s Disease often suffer from constipation. Microbiome research may lead to the discovery of new mental health therapies, or "psychobiotics."

Prebiotics vs. Probiotics

Many doctors, dieticians, and nutrition experts promote the concept of "food as medicine." As we learn more about the beneficial bugs in our bodies, it makes sense to look at food as a way to support a healthy microbiome. Processed foods, chemical residues and food additives, and excess use of antibiotics can all have a negative impact on the microbiome. That's why more people are supplementing their diets with probiotics and prebiotics:

  • Probiotics are beneficial bacteria found in certain foods and supplements. Probiotic foods contain living bacteria that can help balance your intestinal fauna.
  • Prebiotics are fiber-rich foods that nourish beneficial bacteria. Some of these foods contain carbohydrates that the human gut cannot digest without help from our microscopic occupants.

Probiotic Foods

The regular consumption of probiotic foods has been linked to better digestion, more energy, clearer skin, and even a stronger immune system. Studies indicate that regular consumption of probiotic foods may reduce incidence of vaginal yeast infections, eczema, and gestational diabetes. One study found that taking probiotics while using antibiotics reduced the risk of antibiotic-related diarrhea by 60%. When you eat probiotic foods, you are transferring healthful microorganisms directly to their new home – your digestive system. Try adding a few of these to your diet for better nutrition:

  • Sauerkraut, like all fermented, non-pasteurized foods, is a probiotic. During the fermentation process, bacteria convert the carbs in a food into alcohol or organic acids. Buy refrigerated as opposed to canned fermented foods. These have been processed to extend shelf life, which kills beneficial organisms.
  • Unsweetened yogurt is an excellent probiotic, but make sure it says "live active cultures" on the label. Greek yogurt is especially rich in these cultures.
  • Olives, especially the green ones, are a good source of probiotic bacteria. Some research indicates that they may help reduce inflammation.
  • Kombucha is a fermented tea packed with beneficial bacteria and vitamin B.
  • Apple cider vinegar contains probiotics, but don't drink it straight as the acid is bad for your teeth and esophagus. Instead, try using it in salad dressing.
  • Kimchi, a staple of Korean food, is a fermented cabbage condiment.
  • Pickles and other pickled veggies such as beets, carrots, tomatoes, or cauliflower are packed with probiotic strains such as Lactobacillus acidophilus and Lactobacillus plantarum.
  • Miso soup is made from probiotic-rich fermented soybeans and is a great accompaniment to a sushi meal.
  • Kefir, an Icelandic yogurt drink, is a great way to add protein, calcium, and probiotics to your morning smoothie.
  • Tempeh, a popular vegetarian meat alternative, contains plenty of probiotics plus an impressive 20 grams of protein per 3 ounce serving!
  • Sourdough, as many of us learned during the pandemic, is made by fermenting flour with wild yeast. In addition to providing a delicious dose of probiotics, the fermentation process facilitates the absorption of magnesium, iron, and zinc.
  • Green peas contain a potent probiotic named Leuconostoc mesenteroides.
  • Buttermilk is rich in probiotics like Lactococcus lactis and Streptococcus thermophilus.
  • Organic apples contain about 100 million diverse bacteria which could be beneficial to the gut microbiome.
  • Cottage cheese is sometimes made with live culture but be sure to read the label. Good Culture is a brand that offers probiotic rich cottage cheese.

Prebiotic Foods

Prebiotic foods provide nutrition for you AND your microscopic belly buddies. When you eat these foods, you're sustaining colonies of beneficial microbes that help keep you healthy. In addition, prebiotic foods appear to improve calcium absorption and slow the rate at which the body processes carbohydrates. Make these healthy foods a regular part of your diet:

  • Bananas, especially unripe ones, are packed with prebiotics.
  • Oatmeal is a fiber-rich prebiotic. Steel cut oats are the least processed, but they also take longer to cook.
  • Asparagus is a prebiotic that is also high in antioxidants and inulin fiber.
  • Sunchokes, also known as Jerusalem artichokes, are the tubers of a variety of sunflower. They are rich in inulin fiber, undigestible for humans but easily processed by our gut bacteria.
  • Leeks are a versatile and underappreciated vegetable that have a positive effect on the gut microbiota.
  • Garlic and Onions are prebiotics that have been shown to increase the growth of the probiotic L. acidophilus. They also add flavor to pretty much everything but dessert!
  • Chicory root, most often ground up and served like coffee, is an inulin-rich prebiotic and contains fibers known to help lower cholesterol.
  • Soybeans, an essential source of protein in a plant-based diet, are an excellent prebiotic. You won't get the same benefit from soy milk, in which the beans are soaked and drained during processing.


Because a balanced diet provides a varied supply of probiotics, it is not necessary to consume them in supplement form. Probiotic supplements are available as pills, powders, or liquids containing live beneficial bacteria or yeast. If you choose to take probiotic supplements, keep in mind the following:

  • The benefits of probiotic supplements vary widely, depending on the type of strain, product formula, the quality of the product, and storage.
  • It is not known whether the microbes you ingest will actually colonize, or which probiotic to consume for a specific health issue.
  • Some probiotic supplements are destroyed by stomach acid and never make it all the way to your large intestine, where they would do the most good.
  • The health benefits of currently available probiotic supplements have not been conclusively proven.
  • If you decide to take probiotic supplements, be sure to up your intake of prebiotic foods.
  • While side effects are rare, people with Crohn's Disease should not take probiotic supplements as they can worsen flair up symptoms.
  • If you would like to try taking probiotic supplements, start by discussing it with your doctor.


This article first appeared in the August 2023 edition of the HealthPerks newsletter.

Share this page:

Find a Blog