The Claim

Supplementation with Streptococcus salivarius M18 for 14 days has no effect on systolic, diastolic, or mean arterial blood pressure in healthy normotensive adult males, despite increasing plasma nitrite levels, indicating that elevated plasma nitrite does not result in reduced blood pressure in this population.

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 for 14 days increases plasma nitrite levels but does not lower blood pressure in healthy adult men with normal blood pressure.

See the scientific wording

Supplementation with Streptococcus salivarius M18 for 14 days does not reduce systolic, diastolic, or mean arterial blood pressure in healthy normotensive adult males, despite a significant increase in plasma nitrite, suggesting that nitric oxide bioavailability alone is insufficient to lower blood pressure in this population.

Why this might work

A probiotic bacteria in the mouth converts dietary nitrate into nitrite, which enters the bloodstream and raises nitrite levels, but this does not cause blood vessels to widen or lower blood pressure in healthy men with normal blood pressure.

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 for two weeks made a blood marker related to blood vessel relaxation go up, but it didn’t lower blood pressure in healthy men. So, just boosting that marker isn’t enough to change blood pressure in people who already have normal levels.

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.