The Claim

Supplementation with Streptococcus salivarius M18 increases plasma nitrite levels without altering the abundance of oral bacterial taxa previously associated with nitrate reduction.

Source: The Probiotic Streptococcus salivarius M18 Increases Plasma Nitrite but Does Not Alter Blood Pressure: A Pilot Randomised Controlled Trial

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
74score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

Taking Streptococcus salivarius M18 raises plasma nitrite levels, but this change does not correspond to changes in the levels of oral bacteria known to reduce nitrate.

See the scientific wording

The increase in plasma nitrite following Streptococcus salivarius M18 supplementation is not associated with changes in the abundance of oral bacteria previously linked to nitrate reduction, suggesting the effect may be mediated by mechanisms other than altering the oral microbiome composition.

Why this might work

The probiotic bacteria live in the mouth and convert nitrate from food into nitrite, which then enters the bloodstream directly through the mouth lining, raising nitrite levels in the blood without changing the number of other mouth bacteria.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: The Probiotic Streptococcus salivarius M18 Increases Plasma Nitrite but Does Not Alter Blood Pressure: A Pilot Randomised Controlled Trial

    Taking this probiotic made more nitrite appear in the blood, but the types of bacteria in the mouth didn’t change—so the probiotic must be boosting nitrite in some other way, not by changing mouth bacteria.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.