What are probiotics and what do they do?


Q: I keep hearing about probiotics.  What are they?  What do they do? 

A: According to the World Health Organization, probiotics are “live microorganisms which confer a health benefit on the host”.  Our gastrointestinal tract normally contains many different types of bacteria, yeast and viruses, collectively known as our “gut flora.”  The theory behind probiotics is that certain illnesses or medications can knock that flora out of balance – which causes all kinds of other problems – and probiotics help restore it.   

Probiotics exist naturally in such foods as yogurts, cultured milks (buttermilk, kefir) and fermented foods such as fresh sauerkraut, kimchi, tempeh, and miso.  They also can be found in certain nutritional supplements, and are added to many commercial foods including:

  • Yogurt (Activia, DanActiv Dairy Drink, YoPlus, store brands)
  • LiveActive Cottage Cheese
  • Kashi Vive Cereal
  • LiveActive Drink Mix
  • Goodbelly Juices
  • Attune Probiotic Bars

So do they work? 

Hard to say.  It’s like comparing billions of apples and oranges and trying to find an exact match.  We each have our own unique gut flora made up of countless groups of microorganisms; within a given group, there are multiple species of microorganisms; and within a given species there are multiple strains of microorganisms.  Studies have shown that some probiotics may be helpful in the following conditions:

  • Acute gastroenteritis (“stomach flu” or “traveler’s diarrhea”)
  • Diarrhea associated with antibiotics
  • Atopic eczema in infants
  • Lactose intolerance
  • Inflammatory bowel disease
  • Irritable bowel disease
  • Childhood respiratory infections
  • Dental caries (cavities)
  • Clostridium Difficile diarrhea
  • Urinary tract infections in females

But there are some very important things to remember:

  • Like other products marketed as supplements (as opposed to medications), probiotics are not regulated by the FDA, so there’s no way to know if the product in the bottle actually contains what the label says.  ConsumerLab.com is an independent laboratory that analyzes dietary supplements and their report on probiotics showed several common brands did not have the ingredients they claimed.
  • Consuming foods that naturally contain probiotics is a healthier way to get them than taking a supplement.  Eating real food is not only more enjoyable, but you get the benefit of other nutrients as well.
  • No matter how you get your probiotic, they need help to work.  It is important to choose meals and snacks that contain fruits, vegetables, and whole grains.  The healthy non-digestible substances in these foods (call prebiotics) help the bacteria to survive and flourish once they enter your gastrointestinal tract.

To learn more about probiotics, click here or make an appointment to talk with one of our nutritionists

Cheryl Czapla, Med IV
College of Medicine
The Ohio State University

Greg Avellana RD, LD, CDE
Student Health Services
The Ohio State University