Nattokinase for Blood Pressure: Does It Work?

observational-study PMID: 18971533

Quick Summary: Research suggests that taking nattokinase, a natural enzyme, may help lower blood pressure in people with slightly high blood pressure. A study found that it reduced both systolic and diastolic blood pressure over 8 weeks.

Nattokinase and Blood Pressure: What The Research Found

This study looked at whether nattokinase could help people with pre-hypertension or stage 1 hypertension (slightly high blood pressure). The results showed that taking nattokinase for 8 weeks led to:

A decrease in systolic blood pressure (the top number) by about 5.5 mmHg.

A decrease in diastolic blood pressure (the bottom number) by about 2.8 mmHg.

This means nattokinase might help lower blood pressure.

Study Details

Who was studied: 86 adults (ages 20-80) with slightly high blood pressure.

How long: The study lasted for 8 weeks.

What they took: Participants took either 2,000 FU (fibrinolytic units) of nattokinase in a capsule or a placebo (a dummy pill) daily.

What This Means For You

If you have slightly high blood pressure, nattokinase might be worth discussing with your doctor. It could be a helpful addition to lifestyle changes like diet and exercise. However:

Don't stop taking any blood pressure medication without talking to your doctor first.

This study shows a potential benefit, but more research is needed.

Always talk to your doctor before starting any new supplement.

Study Limitations

It's important to know that this study has some limitations:

Short-term: The study only lasted 8 weeks, so we don't know the long-term effects.

Small group: The study involved a relatively small number of people.

No major health outcomes: The study only measured blood pressure, not things like heart attacks or strokes.

Age range: The study included people of different ages, which might affect the results.

Key Findings

Nattokinase supplementation (2,000 FU/day) significantly reduced systolic blood pressure (SBP) by -5.55 mmHg and diastolic blood pressure (DBP) by -2.84 mmHg over 8 weeks compared to placebo in adults with pre-hypertension or stage 1 hypertension. Renin activity also decreased by -1.17 ng/mL/h in the nattokinase group (p<0.05 for all). The authors conclude that nattokinase may aid in preventing and managing hypertension.

Study Design

This was a randomized, double-blind, placebo-controlled trial (RCT) conducted over 8 weeks. The study included 86 participants (ages 20–80) with untreated SBP of 130–159 mmHg, of which 73 completed the protocol. Participants were divided into nattokinase and placebo groups, with blood pressure and renin activity measured pre- and post-intervention.

Dosage & Administration

Participants received 2,000 fibrinolytic units (FU)/capsule of nattokinase or a placebo capsule daily for 8 weeks. The supplement was administered orally in capsule form.

Results & Efficacy

After 8 weeks:
- SBP: Nattokinase group showed a net reduction of -5.55 mmHg (95% CI: -10.5 to -0.57 mmHg; p<0.05).
- DBP: Nattokinase group had a net reduction of -2.84 mmHg (95% CI: -5.33 to -0.33 mmHg; p<0.05).
- Renin activity: Decreased by -1.17 ng/mL/h in the nattokinase group versus placebo (p<0.05).
Effect sizes suggest clinically meaningful reductions in blood pressure, though the wide confidence intervals indicate variability in individual responses.

Limitations

Short duration (8 weeks) limits conclusions about long-term efficacy or safety.
Moderate sample size (n=73 completers) reduces statistical power and generalizability.
Lack of cardiovascular outcome data (e.g., stroke, heart attack) prevents assessing clinical impact beyond BP reduction.
Broad age range (20–80) may mask age-specific effects.
Unclear baseline renin status; changes in renin activity require further mechanistic exploration.
Potential publication bias (only positive results reported; no details on adverse effects).

Clinical Relevance

For individuals with pre-hypertension or stage 1 hypertension, nattokinase supplementation (2,000 FU/day) may offer a modest but statistically significant BP-lowering effect. These findings support its potential use as an adjunct to lifestyle modifications, though it should not replace prescribed antihypertensive medications without medical supervision. Users should note the short-term nature of the evidence and consult healthcare providers for personalized plans. Larger, longer trials are needed to confirm these results and evaluate cardiovascular risk reduction.

Word count: 398