Heart Doc VIP with Dr. Joel Kahn Episode 485: What's the Hoopla About Nattokinase?
Mar 10, 2026
They dig into the hype around nattokinase supplements and scrutinize the quality of the trials behind the claims. Risks of combining nattokinase with blood thinners and reported bleeding cases get discussed. Sleep apnea paired with insomnia and how sleep duration ties to insulin sensitivity are explored. Possible cancer concerns with spermidine and mood benefits from flavonoid-rich foods are also covered.
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Spermidine Supplements May Carry Cancer Risks
- Spermidine, a popular antiaging supplement, may stimulate cancer cell growth in lab studies.
- Recent Journal of Biochemistry experiments showed polyamines increase protein synthesis in cancer tissues, raising safety questions for high-dose supplements.
Social Media Hype Outpaces Nattokinase Evidence
- Nattokinase hype exceeds supporting randomized evidence.
- Systematic review pooled only 546 participants and showed small changes in lipids and ~3/2 mmHg BP reductions, not robust clinical outcomes.
Randomized Trial Found No Plaque Regression
- The only sizeable randomized nattokinase RCT (265 people) showed no carotid plaque benefit after three years.
- That trial used 2,000 FU daily and found no significant changes in carotid intima or labs versus placebo.