That was the provocative headline in last week’s New York Times! We just may have to get T-shirts made. (If you’re blocked by the paywall, click here for a pdf.)

The NYTimes was reporting on a new study published in the prestigious BMJ (formerly the British Medical Journal.)

The news about the benefits of eating natto on heart health has been circulating widely since the study came out last week. It showed strong evidence that eating fermented soy foods like natto and miso significantly lowers risk of early death from disease. In particular, natto intake was singled out as the most significant factor in lowering risk of cardiovascular disease and death.

This is the month of hearts, so we’re going to break down the results of this study for you.

Fermented Soy Intake and Mortality: the BMJ Study

This massive cohort study measured mortality rates over a 15 year period, looking at 93,000 Japanese men and women aged 45-74. It was a prospective observational study, which means that the researchers decided in advance what they would measure – no cherry-picking results after the fact!

Key Findings of the BMJ Study

People who ate more fermented soy had lower death rates.
- People who ate high amounts of fermented soy (natto and miso) had a 13-14% lower death rate in the 15 year period.
  - This group ate about 45 grams per day of fermented soy.
  - The higher mortality group in the comparison ate about 9 grams per day.
- The effect persisted after adjusting for a wide range of demographic, lifestyle, and dietary factors; after adjustment, the statisticians found a 10-11% lower death rate.
The effect was strongest for natto, especially in women.
- Women who ate at least 1 serving per week had a 23% lower death rate than non-natto eaters (19% after adjusting for other factors).
The effect is due to fermentation.
- Consumption of non-fermented soy like tofu and soy milk had no effect.

What’s striking about the study results here is that although fermented soy foods, in general, appear to be linked to better cardiovascular and longevity outcomes, natto really outshined other fermented soy products. In terms of both heart-related and all-cause mortality risk, study data showed that the protective effects of natto were significantly greater.

Why Natto is the Most Beneficial Form of Fermented Soy

What are the possible reasons why natto is different and more beneficial from other fermented soy products like miso and tempeh? Here are just three potential reasons, more are possible and even likely:

Fermentation of natto produces vast amounts of Vitamin K2 (MK-7); while miso and tempeh do not. Vitamin K2 can only be produced by certain species of bacteria, most prolifically by the natto-fermenting bacterial species Bacillus subtilis. Miso and tempeh fermentations are mediated by fungi (Aspergillus & Rhizopus genuses, respectively) that do not generate Vitamin K2.
Natto contains the natural blood-thinning enzyme nattokinase (named after the food it comes from). This enzyme, more commonly seen in the West in an isolated supplement form, has been shown to prevent and dissolve blood clots in vitro and in vivo. Clinical studies also show oral nattokinase can lower blood pressure and risk of stroke.
Bacillus subtilis is a probiotic species of microbe, a well-established human gut microbiome member with demonstrated beneficial effects on inflammation and immunity in human health – factors that may plausibly affect cardiovascular health. In contrast, there is little current evidence that the fungal species that dominate in miso & tempeh fermentations act as probiotics.

Cardiovascular disease is the leading cause of death in the United States. Eating a heart-healthy diet is a key part of daily preventative care, and evidence suggests that consuming fresh fermented natto may be one of the single best choices you can make.

Take Home Message:

Fermented Soy food may help you & your heart live longer & better!

Especially Natto.

Disclaimer: Statements in this article are the summary of our evaluation of scientific literature and have not been evaluated by the FDA. This product is not intended to diagnose, treat or cure disease.

Here’s A Different Kind of Great News for Your Heart

Valentine’s Day Sale on Natto Chocolate Bars

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A perfect little gift of longevity-promoting natto embedded in rich Valrhona chocolate for your special someone or self!

New York Natto - Milk Chocolate Bar (1.4 oz)

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New York Natto Black - Dark Chocolate Bar (1.4 oz)

Freeze-dried New York Natto Black and premium dark chocolate.

Learn More About Miso & Tempeh and Other Soy Fermented Foods Here!

Our soft spot is for natto, but we also love other soy ferments like Miso & Tempeh too! If you’re curious about these other fermented foods and want to learn how to make them yourself at home . . . check out this book: Miso • Tempeh • Natto & Other Tasty Ferments by our friends and fermentation gurus Kirsten & Christopher Shockey.

We’re honored to have our natto featured and founder profiled in the Natto section! This beautiful photo-rich book is full of background history, science, fun facts & recipes too. You can get it here from us ($19) to ship together with your natto!

NYrture New York Natto is produced by hand in NYC, fresh and never frozen, to deliver the best quality natto with maximum potential health benefits to you.

We welcome your feedback! Please share your questions & comments below!

“Eat Natto, Live Longer?”