Does eating natto lower cholesterol? An evidence-based analysis

November 14, 2025 •

5 min read

According to a 16-year study of nearly 30,000 Japanese individuals, higher natto consumption was associated with a 43% lower risk of death from heart disease, raising the question: does eating natto lower cholesterol?. This fermented soy food contains unique compounds that scientists believe contribute to its powerful cardiovascular benefits.

Quick Summary

An examination of natto's effects on cholesterol. Key components like the enzyme nattokinase and dietary fiber influence lipid profiles and promote cardiovascular health. Some studies show promise, particularly at higher doses, though more research is needed to draw definitive conclusions.

Key Points

Natto contains nattokinase: A potent enzyme produced during fermentation that can break down fibrin, a protein involved in blood clotting.
Supports lipid metabolism: Animal studies have shown that natto can significantly lower total cholesterol, LDL-C, and triglycerides, while raising HDL-C.
Dosage matters: Clinical trials suggest that higher doses of nattokinase supplements (e.g., 10,800 FU/day) are associated with more significant reductions in cholesterol and arterial plaque.
Benefits go beyond lipids: In addition to cholesterol effects, natto and nattokinase are associated with lower blood pressure and reduced arterial plaque formation.
Fermentation enhances benefits: The fermentation process creates probiotics that support a healthy gut microbiome, which has been linked to improved lipid metabolism.
Exercise and diet are still key: Natto is a supplement to, not a replacement for, a healthy lifestyle that includes a balanced diet and regular physical activity for managing cholesterol.

The Key Players in Natto: Nattokinase and More

Natto's unique health-promoting properties stem from its fermentation process, which transforms soybeans into a superfood rich in key bioactive compounds. While soybeans themselves are nutritious, the fermentation by Bacillus subtilis bacteria supercharges natto with unique heart-healthy components.

Nattokinase: The Fibrin-Fighting Enzyme

One of the most-studied compounds in natto is nattokinase, a potent enzyme with fibrinolytic properties. This means it helps to dissolve fibrin, a protein that is essential for forming blood clots. By breaking down fibrin, nattokinase can help keep blood from getting too thick and sticky, which supports smoother blood flow and eases the burden on the cardiovascular system.

Fiber and Unsaturated Fats

Like other soy foods, natto is a source of fiber and healthy fats. The dietary fiber in natto can help reduce LDL, or "bad," cholesterol by binding to cholesterol in the digestive system and removing it from the body before it can be absorbed. The polyunsaturated fats also contribute to a healthy lipid profile.

Soy Isoflavones and Antioxidants

Natto contains soy isoflavones and other antioxidants that offer cardiovascular protection by reducing inflammation and preventing the oxidation of LDL cholesterol, a key step in the development of atherosclerosis (hardening of the arteries).

Probiotics and the Gut Microbiome

The probiotics in natto, specifically the Bacillus subtilis strain, contribute to a healthy gut microbiome. Research in mice has indicated that natto can regulate gut microbiota, which in turn influences lipid metabolism and helps prevent diet-induced hyperlipidemia. An increase in beneficial bacteria like Lactobacillus has been shown to boost the excretion of fecal lipids, aiding in cholesterol reduction.

How Natto Affects Lipid Levels: Evidence from Research

The evidence regarding natto's ability to lower cholesterol comes from various studies, including in-vitro research, animal models, and a growing number of human clinical trials. It is important to look at the findings in context to understand the potential benefits and limitations.

Findings from Human Trials

Some human trials have shown positive effects, particularly with nattokinase supplements. One large clinical study of over 1,000 participants with atherosclerotic plaque and hyperlipidemia found that a high dose of nattokinase (10,800 FU/day) for 12 months significantly reduced total cholesterol, LDL-C, and triglycerides while increasing HDL-C. Notably, a lower dose (3,600 FU/day) was less effective. However, some shorter-term and smaller studies have found inconsistent or statistically insignificant results, particularly when nattokinase was used alone or at lower doses.

Animal and In-Vitro Studies

Animal research has consistently demonstrated natto's lipid-lowering potential. Studies using high-fat diet-fed mice showed that natto treatment effectively reduced total cholesterol, LDL-C, and triglycerides while increasing HDL-C. These effects are attributed to the regulation of gut microbiota and related metabolic processes. In-vitro studies also confirm that natto fractions can inhibit LDL oxidation, a mechanism that helps prevent atherosclerosis.

Natto vs. Other Natural Approaches: A Comparative Look

Natto offers a multi-faceted approach to cardiovascular health. Here is how it compares to other common natural strategies for managing cholesterol.


Mechanism	Natto	High-Fiber Foods	Omega-3 Fats
LDL Reduction	Yes, through fiber, isoflavones, and potentially nattokinase	Yes, especially soluble fiber from oats, beans, and fruits	Yes, reduces triglycerides and can improve LDL
HDL Increase	Yes, shown in some higher-dose nattokinase studies	Modest effect, primarily focused on LDL	Yes, particularly from fatty fish
Triglyceride Reduction	Yes, significant reduction reported in human and animal studies	Limited, though often improved as part of overall healthy diet	Yes, significantly reduces triglyceride levels
Plaque Reduction	Yes, high doses of nattokinase were shown to reduce arterial plaque size	Indirectly, by lowering LDL and systemic inflammation	Indirectly, by reducing triglycerides and inflammation

Factors to Consider Before Adding Natto to Your Diet

While natto shows significant potential for heart health, it is not a magic bullet and comes with certain considerations. It should always be part of a broader, heart-healthy lifestyle, and anyone with existing health conditions should consult a doctor before making significant dietary changes.

Dosage and Form

For cholesterol-lowering effects, the dosage appears to be important. High-dose nattokinase supplementation has shown more significant results in studies than lower doses or simply eating the food. This suggests that a person would need to consume natto regularly to achieve therapeutic effects, but the exact amount is unclear and the potency can vary. Supplements offer a standardized dose, but always ensure quality and consult a healthcare provider.

Flavor and Consistency

Natto has a distinct, pungent smell and sticky, stringy texture that many in Western cultures find challenging. It is often mixed with other ingredients like rice, soy sauce, or mustard to improve palatability. Getting used to the flavor may take time.

Potential Side Effects and Drug Interactions

Blood Thinners: Nattokinase has potent anticoagulant effects. Individuals taking blood-thinning medications like warfarin should absolutely not take nattokinase supplements or consume large amounts of natto without strict medical supervision.
Vitamin K: Natto is very high in vitamin K2, which plays a role in blood clotting. This is another reason for caution if on anticoagulant therapy.
Digestive Issues: As with other fermented foods, some people may experience mild gastrointestinal discomfort, such as bloating, when first introducing natto to their diet.

Conclusion: The Bottom Line on Natto and Cholesterol

Research suggests that eating natto may help lower cholesterol and improve other markers of cardiovascular health, thanks to its unique enzyme nattokinase, fiber, healthy fats, and probiotics. However, the magnitude of the effect appears to be dose-dependent, with strong evidence from animal studies and some human trials, particularly at higher supplement concentrations. While incorporating natto into a balanced diet can be a heart-healthy choice, it is not a replacement for a doctor-prescribed treatment plan. For maximum benefits, a holistic approach that includes regular exercise, a diet rich in fruits, vegetables, and whole grains, and medical consultation is recommended.

Resources for Heart Health

American Heart Association: A leading resource for information on cardiovascular health, including diet and lifestyle recommendations to lower cholesterol. Visit their official website.

Note: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making any decisions related to your health or treatment.

Frequently Asked Questions

There is no definitive food-based dosage for lowering cholesterol established by research. Studies often use concentrated nattokinase supplements, sometimes at high doses. For general health benefits, incorporating a serving of natto (typically a small container, around 40-50g) into a balanced diet is a common approach in Japan.

Yes, nattokinase supplements are available and may offer a more concentrated, standardized dose of the enzyme responsible for many of natto's cardiovascular benefits. However, whole natto contains other beneficial compounds like fiber and soy isoflavones that are not in the isolated supplement.

The timeframe for seeing results is not standardized and depends on the individual and consumption method. Some studies have shown effects after a few months, while others required longer-term, high-dose supplementation. A single study on a high dose of nattokinase found significant lipid profile improvement after 12 months.

Yes. Individuals taking blood-thinning medications (anticoagulants) like warfarin should consult their doctor before consuming natto or taking nattokinase supplements, as the enzyme's anticoagulant properties and high vitamin K2 content could interfere with their medication.

The gut microbiome is regulated by the probiotics in natto, particularly Bacillus subtilis. Animal studies suggest these changes can influence lipid metabolism and reduce blood lipid levels.

Nattokinase, the key enzyme, is sensitive to heat and can be denatured by cooking. To preserve its potential cholesterol-lowering effects, it is best to consume natto raw, as it is traditionally eaten.

Nattokinase has been compared to statins in some studies, but it is not a direct replacement. Its lipid-lowering effect is generally less potent and slower acting than high-intensity statins, but it is often better tolerated and has multiple mechanisms of action.