Center for Research on Ingredient Safety

What are probiotics and prebiotics? 

Probiotics and prebiotics can be foods, ingredients, supplements, products, and more that contain or support microorganisms, most often beneficial that may impact our microbiome, impacting our overall health (1).

Typically, manufacturers design prebiotic and probiotic products to encourage beneficial bacterial growth that supports our microbiome.

What is the difference between a prebiotic and a probiotic?  

Prebiotics are food, ingredients, supplements, products, and more that support the wanted beneficial bacteria in our microbiome by providing an ideal nutritional source for the bacteria.
 
To support our gut microbiota, a prebiotic ingredient must (1,2):

• not be easily digested (or only partially digested);
• not be absorbed in the small intestine;
• be poorly fermented by bacteria in our mouth;
• be well fermented by seemingly beneficial intestinal bacteria;
• be poorly fermented by potential pathogens in the bowel.

The above requirements are met in foods containing high dietary fiber levels, such as fruits, vegetables, whole grains, legumes, and more (1,2).

Other prebiotic products designed to support microbiota on our skin have not undergone extensive studies to support their claims. However, there is limited evidence that prebiotic ingredients in skincare products may help support a healthy skin microbiota (1,2,3).

Probiotics are food, ingredients, supplements, products, and more that contain the wanted beneficial bacteria. 
 
To support our gut microbiota, as defined by regulatory agencies, a probiotic ingredient must be:

• Safe, meaning the ingredient should contain beneficial bacteria that don’t cause adverse reactions in the gut.
• Functional, meaning it needs to work as intended and be able to survive and thrive properly in the gut
• Technologically useful, meaning manufacturers can easily replicate, store, and continue to use the ingredients ongoing. 

The above requirements are met in fermented foods and beverages, such as yogurt, sauerkraut, kimchi, kombucha tea, kefir, and more.

We can also find probiotics in skincare products such as lotions, deodorants, and more that manufacturers design to support our skin microbiota.

Probiotics in skincare is an emerging research area, so there are limited but promising studies showing their efficacy to help treat acne, atopic dermatitis, and other skin conditions (1,2).
 
As research in this area evolves, we’ll continue to update the article. 

What types of ingredients are prebiotics? Where are they found? 

We can break prebiotic ingredients down into foods containing prebiotic ingredients and manufactured ingredients that we may encounter as additives in foods and beverages or dietary supplements. 

Foods that are prebiotic include (but are not limited to):

• artichokes
• asparagus
• bananas
• barley
• berries
• chicory
• garlic
• green vegetables
• legumes
• linseed
• oats
• onions
• tomatoes
• wheat

Manufactured prebiotics include (but are not limited to): 

• cyclodextrin 
• galactooligosaccharides
• lactulose
• maltooligosaccharides
• ructooligosaccharides

What types of ingredients are probiotics? Where are they found?

We typically find probiotics in fermented foods and dietary supplements. 
 
Fermented probiotic foods and beverages often include:

• kefir
• kimchi
• kombucha 
• miso
• pickles
• sauerkraut
• sourdough bread
• tempeh
• yogurt

The most common probiotic ingredients found in dietary supplements may include (but are not limited to) (1,2):

• Bacillus
• Bifidobacterium 
• Enterococcus 
• Escherichia (beneficial subtypes)
• Lactobacillus
• Streptococcus (beneficial subtypes)

Are prebiotic and probiotic foods and beverages healthy and safe?

As long as you are not allergic to foods rich in prebiotics and probiotics, they are healthy and safe for you to consume as part of a balanced diet.  While probiotic foods are safe for adults, children, especially infants, are vulnerable to potential pathogens found in unpasteurized fermented foods. So, it’s best to talk with your child’s doctor before serving young children unpasteurized fermented foods like homemade kombucha tea.

Are prebiotic and probiotic supplements healthy and safe to use?

As with all supplements, the quality of the supplement varies significantly between manufacturers. Additionally, prebiotic and probiotic supplements may be unnecessary unless recommended by a healthcare provider (1,2). 

Suppose you need to take prebiotic or probiotic supplements. In that case, it’s important to go with a third-party laboratory-verified supplement to ensure you’re getting a supplement free from contamination that contains the advertised ingredients. It’s especially important for infant and children supplements as they’re more vulnerable to variations in product quality (1,2).

Many laboratories verify supplements, including NSF International, US Pharmacopeia, Consumer Lab, and more. Verified products will contain a label on the product informing you of the laboratory. 

What else do I need to know?

A proper, well-balanced diet rich in fruits, vegetables, whole grains, legumes, as well as fermented foods such as yogurt, sauerkraut, kimchi, and more is your best bet at maintaining a healthy microbiome. 
 
Evidence suggests probiotic supplements may only yield short-term health results if people do not follow up with a diet rich in prebiotic foods (e.g., fruits, vegetables, whole grains, etc.). A healthy diet is imperative to maintaining our microbiome and our overall health (1).

The good news.

A balanced, healthy diet will provide the prebiotics and probiotics we need to maintain a healthy microbiome. Our next post will look at how you can safely ferment foods at home