Streptococcus thermophilus

Studies in people

• Open question

  Gut survival of probiotics³

  Scientists often can't tell whether Streptococcus thermophilus found in stool was the probiotic or a look-alike germ.

• Benefit

  Diarrhea severity in infants⁴

  Infants fed formula fermented with Streptococcus thermophilus had less severe diarrhea, though how often it happened was the same.

Animal and lab studies only

• Benefit

  Gut bacteria growth⁷

  Streptococcus thermophilus makes folate, which helped certain gut bacteria grow.

• Benefit

  Gut survival and germ-killing⁸

  In lab studies, Streptococcus thermophilus from dahi survived acidic conditions and bile salts and killed some food-borne germs.

• Benefit

  Immune system response⁹

  Streptococcus thermophilus made human immune cells release a signal that calms inflammation.

• Benefit

  Gut tumours in mice¹⁰

  In mice, Streptococcus thermophilus reduced tumor formation, though it is unclear if it works the same way in people.

• Benefit

  Liver health¹¹

  In animal studies, Streptococcus thermophilus helped keep liver blood markers normal in mice exposed to air pollution particles.

• Benefit

  Gut infection defence¹²

  In lab studies, one Streptococcus thermophilus strain kept Listeria, Staphylococcus and Salmonella germs from sticking to gut cells better than another strain.

• Benefit

  Alcohol-related liver damage¹³

  In animal studies, Streptococcus thermophilus improved liver tests and reduced liver fat and inflammation in mice with alcohol-related liver damage.

How it’s made and used

• Gut bacteria after eating⁵

  Streptococcus thermophilus showed up in people's stool during and after eating yogurt or a supplement, then faded away.

• Gut bacteria survival⁶

  Streptococcus thermophilus was found in the guts of many healthy adults and can stay there for days.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.