Prebiotics and Probiotics: The Basics

Let’s talk about prebiotics and probiotics.

These words have been thrown around for a while now. Most people in the general public know that both prebiotics and probiotics have been associated with positive health effects, especially increased gastrointestinal (digestive) health. But, what exactly are prebiotics and probiotics anyhow?

Both pre- and probiotics help the body synthesize vitamins and nutrients while promoting overall well-being and GI (gastrointestinal) health.

Probiotics are live, beneficial bacteria found in the GI tract and certain types of foods. Prebiotics are indigestible carbohydrates (aka fiber) that are broken down by bacteria in the colon (the probiotics). In other words, the prebiotics feed the probiotics.

Both pre- and probiotics are important to consume on a regular basis. The prebiotics need to be ingested to feed the probiotics. The probiotics are important to have in your gut to balance out the 500 different species of bacteria in your digestive system—both good and bad. The number of probiotics in the gut can decrease when modern medicines like antibacterials are used to treat illnesses.

Probiotics have many scientifically established health benefits like:

  • Prevent or reduce diarrhea related to antibiotic use
  • Reduce the concentration of cancer-promoting enzymes in the gut
  • Prevent and relieves irregularities in the GI tracts in healthy individuals
  • Decrease inflammation in the gut
  • Regulate bowel movements and feces consistency for those with sever constipation or an irritable colon
  • Prevent or cure allergies in young children
  • Prevent illnesses such as the common cold and the flu

Although it hasn’t been firmly established, there’s evidence to suggest probiotics aid in cancer prevention, especially cancers of the intestinal tract (e.g. stomach and colon). Probiotics can help individuals with irritable bowel syndrome, Crohn’s disease and ulcers. Probiotics can also aid in maintaining sexual health in women. Probiotics help ensure that the female sexual reproductive system stays acidic enough to discourage vaginosis, yeast infections and UTIs.

While prebiotics have the inherent benefit of feeding the probiotics, they too have other indirect benefits such as:

  • Prevent diarrhea and constipation
  • Regulate the metabolism of gut bacteria
  • Prevent cancer
  • Regulate blood sugar
  • Stimulate nutrient absorption
  • Regulate the immune function

Probiotics are found naturally in fermented foods. Yogurt, cheese and milk are commonly known foods containing probiotics. However, many dairy foods on the market today don’t contain naturally-occurring probiotics that other non-dairy fermented foods have.

Most dairy products legally need to be pasteurized (cooked) in order to be sold on the market in many countries. Therefore, in order to keep the probiotic benefits, probiotics need to be added back into these products. Foods that can provide naturally-occurring probiotics are products like sauerkraut, tempeh, miso and rejuvelac. Foods with added or naturally-occurring probiotics shouldn’t cooked before consumption. Cooking the food (or drink) will kill all of the beneficial bacteria, thereby giving no probiotic benefits. Probiotic supplements can be purchased and breast milk also contains probiotics.

A glass of kefir water contains probiotics that are helpful to the digestive system

A glass of kefir water contains probiotics that are helpful to the digestive system

There’s nearly an infinite supply of prebiotics. Prebiotics are just fiber. Foods that contain more fiber will encourage healthier probiotics. Plant foods are the only foods that contain fiber. Whole grains and legumes are best known for being fibrous, so selections such as brown rice, rye and red lentils will ensure healthy and happy gut bacteria. Of course fruits and vegetables contain fiber, too.

Rye Cereal with Strawberries: fibrous and nutritious!

Rye Cereal with Strawberries: fibrous and nutritious!

Keep in mind that many of the benefits of probiotics are strain-specific. The benefits and effects that can be experienced depend upon the diversity and amount of prebiotics and probiotics that are ingested. Harvard Health also warns that there is a theoretical risk for people with impaired immune functions to eat probiotics. Individuals unaccustomed to eating probiotics and/or prebiotics sometimes complain about gassiness and bloating. This is healthy and will decrease or disappear over time as your gut becomes used to the new amount of fiber and probiotics in you GI tract.

In the end, prebiotics and probiotics are healthy and necessary to ensure a functional digestive system. Eating more fiber and more fermented products can create unwanted side effects at first (like gas), but don’t let this deter you from trying them. Humans have been eating pre- and probiotics for thousands of years. Feed yourself and your gut with a bowl of rye cereal and some kefir today!



Nutrition, Health and Lifestyle: Issues and Insights on Coursera lecture 4G

  • Updated 3 years ago
Sara Binde

Sara is a health and nutrition coach. She advocates for a whole foods plant-based lifestyle and teaches the world how to achieve weight loss.