Nutrition Diet: Uncovering the Truth: Is there vitamin K2 in IDLI?

October 29, 2025 •

2 min read

While fermentation is known to produce beneficial vitamins and probiotics, the popular South Indian staple, idli, contains only insignificant or undetectable amounts of vitamin K2. This is a crucial distinction for those relying on fermented foods as a primary source of this important nutrient. The answer to the question, "Is there vitamin K2 in IDLI?" lies in understanding the specific microorganisms involved in its traditional preparation.

Quick Summary

The traditional fermentation process for idli, which uses specific lactic acid bacteria, does not produce significant amounts of vitamin K2. Primary food sources of this essential nutrient include fermented products made with other bacteria, as well as certain animal products.

Key Points

Idli is not a reliable source of Vitamin K2: The fermentation process for this popular dish does not produce significant levels of menaquinones.
Not all fermented foods are equal: While some fermented foods like natto and aged cheeses are excellent sources of Vitamin K2, idli's fermentation process primarily focuses on probiotics and B-vitamins.
K2 supports bone and heart health: This fat-soluble vitamin plays a crucial role in directing calcium to your bones and teeth while preventing its buildup in arteries.
Look for alternative K2 sources: To increase intake, focus on animal products (grass-fed butter, egg yolks, liver) and specific bacterial-fermented foods like natto.
Idli provides other benefits: Despite lacking K2, idli remains a healthy meal choice, offering probiotics, improved digestibility, and B vitamins.
Consult a professional on supplements: If considering K2 supplements, especially with pre-existing conditions or medication, talk to a healthcare provider.

What is Vitamin K2 and Why Does it Matter?

Vitamin K is a fat-soluble nutrient essential for the body, known for its role in blood coagulation. It exists as Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone). K1 is found in leafy greens, while K2 is primarily synthesized by bacteria in fermented foods and found in animal products. Vitamin K2 is important for regulating calcium deposition, directing it to bones and teeth and preventing buildup in soft tissues like arteries, supporting bone and cardiovascular health.

The Fermentation Process of Idli vs. K2 Production

Idli is traditionally made from fermented rice and black gram batter using naturally occurring lactic acid bacteria. This fermentation improves digestibility and adds B vitamins and probiotics. However, the bacteria used in idli fermentation do not typically produce significant amounts of Vitamin K2. Studies on Indian foods, including idli, show undetectable levels of K2. This differs from other fermented foods where specific bacteria are used to produce high K2 content.

How Different Fermentations Create K2

K2-rich fermented foods include:

Natto: Fermented soybeans using Bacillus subtilis natto, a high producer of MK-7.
Cheese: Aged cheeses like Gouda use bacterial cultures that produce various menaquinones (MK-8, MK-9).
Sauerkraut: Fermented cabbage contains smaller amounts of K2 from lactic acid bacteria.

Comparing Vitamin K2 Sources: Idli vs. Alternatives


Food Source	Primary Vitamin K Form(s)	K2 Content (Approx. µg per 100g)	Notes
Idli (Fermented Rice & Lentil)	Mainly B-Vitamins, Probiotics	Negligible to Undetectable	Fermentation focuses on lactic acid, not K2 synthesis.
Natto (Fermented Soybeans)	MK-7	900–1000	Exceptionally high source due to Bacillus subtilis.
Aged Gouda Cheese	MK-8, MK-9	32	K2 content increases with aging.
Chicken (Thigh)	MK-4	8.9	Contains the MK-4 subtype.
Egg Yolk (Free-Range)	MK-4	Up to 192 (variable)	Content highly dependent on chicken's diet.
Beef Liver	MK-4	7–14 (variable)	Also rich in other nutrients.

Boosting Your Vitamin K2 Intake

To increase K2 intake, focus on known sources:

Include high-fat dairy from grass-fed cows, such as aged cheeses and butter.
Add grass-fed meats, organ meats, and egg yolks to your diet.
Consider natto for a concentrated MK-7 source.
Incorporate other fermented foods like sauerkraut.
Supplements are an option, but consult a healthcare provider, especially if on blood thinners.

Conclusion

Idli is a nutritious food but not a significant source of vitamin K2. Its fermentation offers other benefits, but for K2, focus on diverse K2-rich foods like natto, aged cheeses, and animal products to support bone and cardiovascular health. More information on Vitamin K is available from the NIH Office of Dietary Supplements.

Reference: For official dietary guidance on Vitamin K and other nutrients, see the NIH Office of Dietary Supplements fact sheet on Vitamin K.

Frequently Asked Questions

The bacteria used in the traditional fermentation of idli are not the types that produce significant quantities of menaquinones (Vitamin K2). While the process is beneficial for other nutrients, K2 synthesis is not a primary outcome.

The most well-known producer of high levels of Vitamin K2 (specifically MK-7) is Bacillus subtilis natto, used in making the Japanese fermented soybeans called natto. Other lactic acid bacteria used in some cheeses also produce menaquinones.

Excellent food sources of K2 include natto, aged hard cheeses (like Gouda), goose liver, chicken meat, egg yolks (especially from grass-fed hens), and grass-fed butter.

Both forms of Vitamin K are important for different bodily functions. K1 is vital for blood clotting, while K2 is critical for calcium metabolism and cardiovascular health. While some K1 can be converted to K2, consuming K2 directly from foods is more efficient.

Yes, idli fermentation is highly beneficial. It enhances the digestibility of rice and lentils, increases levels of B vitamins like riboflavin and folic acid, and introduces beneficial probiotics for gut health.

It is unlikely that home fermentation methods could be easily modified to produce a significant amount of vitamin K2. The specific bacterial strains and fermentation conditions required are specialized and distinct from the traditional idli process.

No, not all fermented foods are significant sources of Vitamin K2. The K2 content depends entirely on the type of bacteria used in the fermentation process. Foods fermented with specific high-producing bacteria, like natto, are reliable sources, but others like idli or yogurt may contain very little or none.