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Natto
The calcium hardening your arteries and the calcium leaving your bones are one problem, running silently from your thirties, invisible on any check-up. One food moves both, and Western diets barely contain the thing that makes it work. It's natto: sticky, ammonia-smelling fermented soybeans, a pack a day. The people who eat it die of heart disease about a quarter less often and break fewer bones past 70. Cheap, and years ahead of your next stress test.
Do ยท Daily Evidence Moderate Chapter Food

Two things ride in one pack. The first is vitamin K2 as MK-7, the long-acting form your leafy greens barely supply. It's the signal that routes calcium into bone and keeps it out of artery walls; run short, as most Western adults do, and calcium goes the wrong way.

The second is nattokinase, an enzyme the fermenting bacteria leave behind. It dissolves forming clots; your blood's clot-clearing activity rises for about twelve hours per pack 1. Supplements sell each alone; only the food carries both.

The signal lines up across populations. In 29,079 Japanese adults tracked 16 years, the heaviest natto eaters died of cardiovascular disease about 25% less often; tofu, soy milk, and edamame showed nothing equivalent 2. In nearly 5,000 Dutch adults, the most dietary K2 meant 41% lower heart-disease incidence; K1, nothing 3.

The mechanism trials agree. Two years of MK-7 slowed coronary calcium buildup about 29% 4; three years in postmenopausal women reduced arterial stiffness and bone loss 56; natto eaters broke fewer bones over 15 years 7. The enzyme alone dropped systolic pressure about 5.5 mmHg in eight weeks 8. The honest ceiling: no whole-food trial in a Western population yet.

One pack a day, and the trick is not cooking it to death.

Give the taste a week; most daily eaters stop noticing the smell. If it stays impossible, an 180 ยตg/day MK-7 supplement covers the K2 half but skips the enzyme and the habit.

Little of this is anything you feel.

  • Weeks: if your blood pressure ran high, the cuff reads a few points lower 8.
  • A year: the blood marker for artery calcium handling drops by about half 5; a coronary calcium score climbs more slowly.
  • A decade: this is where the cohort data lives. The heart attack that doesn't come at 62, the fracture that doesn't come at 73 2.
The fine print โ€” when to skip it, and what people get wrong

On warfarin (Coumadin, Jantoven), do not eat natto: one pack swings your INR within days. On newer thinners, before surgery, or with a bleeding disorder, ask your prescriber; the enzyme adds bleeding risk. Soy allergy rules it out.

"All vitamin K is the same." No: kale's K1 lasts an hour, MK-7 three days 3. "Tofu is the same." The mortality signal was natto-specific 2. "Pills replace it." Half the benefit, and no blood thinner.

References
  1. 1Sumi H, Hamada H, Nakanishi K, Hiratani H (1990). Enhancement of the fibrinolytic activity in plasma by oral administration of nattokinase. Acta Haematologica. link
  2. 2Nagata C, Wada K, Tamura T, Konishi K, Goto Y, Koda S, Kawachi T, Tsuji M, Nakamura K (2017). Dietary soy and natto intake and cardiovascular disease mortality in Japanese adults: the Takayama study. American Journal of Clinical Nutrition. link
  3. 3Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MHJ, van der Meer IM, Hofman A, Witteman JCM (2004). Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. Journal of Nutrition. link
  4. 4Vermeer C, Knapen MHJ, et al. (2025). VitaK-CAC trial: menaquinone-7 supplementation slows coronary artery calcification progression in patients with coronary artery disease. link
  5. 5Knapen MHJ, Braam LAJLM, Drummen NE, Bekers O, Hoeks APG, Vermeer C (2015). Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women: a double-blind randomised clinical trial. Thrombosis and Haemostasis. link
  6. 6Knapen MHJ, Drummen NE, Smit E, Vermeer C, Theuwissen E (2013). Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporosis International. link
  7. 7Kojima A, Ikehara S, Kamiya K, Kajita E, Sato Y, Kouda K, Tamaki J, Kagamimori S, Iki M (2020). Natto intake is inversely associated with osteoporotic fracture risk in postmenopausal Japanese women. Journal of Nutrition. link
  8. 8Kim JY, Gum SN, Paik JK, Lim HH, Kim KC, Ogasawara K, Inoue K, Park S, Jang Y, Lee JH (2008). Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertension Research. link
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