The "Chemical Factory" in the Gut Producing Health Benefits from Vegetables: What is the New Substance DNIC Created by Gut Bacteria?

"Eat your vegetables."

This phrase, often heard since childhood, indeed has scientific backing. Numerous studies have reported that a diet rich in vegetables is associated with a lower risk of cardiovascular and metabolic diseases.

Generally, vitamins, minerals, dietary fiber, and polyphenols found in vegetables are considered the main contributors to these health benefits.

However, a new player has been added to this explanation.

That player is "gut bacteria."

In August 2026, a research team led by the Karolinska Institute reported in the scientific journal "Cell" that gut bacteria utilize dietary nitrates and iron to produce a bioactive substance called "Dinitrosyl Iron Complexes (DNICs)."

This DNIC is not a substance that only works within the gut.

After being absorbed from the gut, it is transported to tissues throughout the body, such as the liver and kidneys, and may influence blood pressure, blood sugar, blood vessels, and fat metabolism.

In other words, the vegetables we eat are not just used as nutrients.

Some components may be "chemically transformed" by gut bacteria into different bioactive substances that were not present in the original food.

"Nitrates" Abundant in Beets and Leafy Vegetables

One of the key materials in this study was nitrate.

Nitrate is a substance widely present in nature, particularly abundant in vegetables like beets, spinach, arugula, and lettuce.

Another necessary component is "non-heme iron."

While many people associate iron with meat, plant-based foods like legumes, whole grains, and green vegetables also contain iron.

Most of the iron in plants is of the type known as non-heme iron.

The research team focused on what happens when this "nitrate" and "non-heme iron" meet in the gut.

This is where DNIC emerged.

Gut bacteria do not merely break down food remnants.

They perform various chemical reactions using the components we ingest, creating substances different from those directly produced by human cells.

The significance of this discovery lies in capturing one of the "chemical factory" functions of gut bacteria as a specific molecule.

DNIC Was Not Produced Without Gut Bacteria

The research team investigated where and how DNIC is produced using mice, cells, bacteria, and human-derived samples.

A particularly important comparison was between mice with normal gut bacteria and "germ-free mice" without gut bacteria.

In normal mice, DNIC was detected in multiple tissues.

However, in germ-free mice, DNIC was not observed.

This suggests that simply having nitrates and iron enter the body through diet is not sufficient, and gut bacteria are likely indispensable in the process of converting them into DNIC.

In nutritional research,

the focus has traditionally been on "what nutrients to eat and how much."

However, with advances in gut bacteria research, another important question is emerging.

That question is,

"What do your gut bacteria transform the food you eat into?"

Even if the same food is consumed, the types and activities of gut bacteria can lead to different substances being produced in the body.

This study further supports that perspective.

Substances Produced in the Gut Affect the Entire Body

An interesting aspect of DNIC is that it does not act solely within the gut.

The study confirmed that the formed DNIC is absorbed and moves to various tissues within the body.

Particularly high levels were observed in the liver and kidneys.

The liver is a central organ responsible for metabolizing sugars and lipids, while the kidneys are deeply involved in not only filtering blood but also regulating blood pressure.

Therefore, the discovery that DNIC is transported to these organs is intriguing when considering the connection between gut-produced molecules and systemic metabolism.

Recently, relationships between the gut environment and distant organs, such as the "gut-brain axis" and "gut-liver axis," have been actively researched.

This study can be seen as presenting a candidate for specific chemical substances that connect these inter-organ networks.

Changes in Blood Pressure, Blood Sugar, Blood Vessels, and Fatty Liver

So what actually happens when DNIC levels increase?

The research team conducted experiments to increase DNIC levels using animal models that replicate cardiovascular and metabolic diseases.

There were two main methods.

One method was to provide nitrates and iron as part of the diet, creating conditions for DNIC to be produced in the gut.

The other method was to administer synthetically produced DNIC.

As DNIC levels increased, improvements were observed in multiple health indicators.

Blood pressure decreased, vascular function improved, and positive changes in blood sugar control were noted.

Furthermore, the accumulation of fat in the liver was reduced.

Hypertension, blood sugar abnormalities, impaired vascular function, and fatty liver may seem like independent issues, but they are deeply interconnected through factors like obesity and insulin resistance.

The simultaneous changes observed in multiple indicators suggest that DNIC may be involved in the entire metabolic system rather than a single organ.

The Explanation for "Vegetable Health Benefits" May Change

What is particularly interesting about this study is that it adds a new explanation to the long-known phenomenon that "people who eat more vegetables have lower health risks."

Until now, the focus has tended to be on the nutrients contained in vegetables themselves.

However, in reality,

eating vegetables

↓

Nitrates and non-heme iron reach the gut
↓
Gut bacteria utilize them
↓
DNIC is formed
↓
DNIC is absorbed and moves throughout the body
↓
It affects blood vessels and metabolic functions

This suggests a more complex flow.

The important point is that it's not just "vegetable components" or "gut bacteria" alone, but the combination of both.

The effect of food is not determined the moment it enters the body.

As it passes through the digestive tract, it encounters the vast ecosystem of gut bacteria and is chemically processed.

Without considering the "post-processed substances," we may not fully understand the health benefits of diet.

Attention on SNS: The Surprise of "Vegetable → Gut → Whole Body"

This paper was published online in "Cell" on August 19, 2026, and was subsequently introduced by the Karolinska Institute and scientific media.

On social media, the official Cell account announced the publication, and shares and reactions were observed on X. The official Cell account also introduced the paper on Bluesky.

On Mastodon, an article from ScienceDaily introducing the research was shared with tags like "#nutrition," "#plantbased," "#vegetables," "#gut," "#GutHealth," and "#bacteria," indicating interest from multiple communities beyond just cardiovascular research.

However, as of August 27, 2026, it is still early days since the paper's publication.

Thus, large-scale discussions or personal experiences like "I've tried it myself" have not yet accumulated.

The current spread on social media suggests that the unexpected nature of "not the nutrients in vegetables themselves, but substances produced by gut bacteria mediate health benefits" is a major point when introducing the research.

This aligns well with the popular theme of "gut health" in recent years.

However, caution is needed against oversimplifying and spreading the study as "eating certain vegetables lowers blood pressure and blood sugar."

"Beet + Iron Supplements" Cannot Reproduce the Effect

This is the most important caution when understanding this study.

While promising results were obtained in animal models, it has not yet been proven that humans can achieve the same effects by consuming specific foods or supplements.

Although human-derived samples were used in the research, the main evidence for improvements in blood pressure, blood sugar, and fatty liver comes from experimental models.

Therefore,

"Eating a lot of beets lowers blood pressure,"

"Taking nitrate and iron supplements together increases DNIC,"

"Increasing DNIC can prevent lifestyle diseases,"

cannot be concluded.

The human gut microbiome varies greatly from person to person and is influenced by many factors, including diet, age, medication use, and lifestyle.

It is also quite possible that the gut environment conducive to DNIC production differs among individuals.

The Next Step is Measuring "Human DNIC"

The next challenge identified by the research team is establishing the technology to accurately measure DNIC present in the human body.

How much DNIC is produced in humans?

What kind of diet increases it?

Which gut bacteria are important?

Do people with higher DNIC levels have lower cardiovascular and metabolic disease risks?

Can dietary changes increase or decrease DNIC?

These questions are not yet fully understood.

If these questions are clarified in the future, it may lead to personalized nutrition that considers "what metabolites your gut bacteria produce," moving beyond simple nutritional guidance like "eat a certain amount of vegetables per day."

Furthermore, it may develop into research to control DNIC production by increasing specific gut bacteria or adjusting their functions.

However, this is merely a possibility to be verified in the future and is not an established treatment at this stage.

Our Diets Are Not Digested by "Humans Alone"

The most intriguing message from this study lies beyond individual nutrients.

Humans do not process food alone.

An enormous number of microorganisms exist in the gut, breaking down, combining, and transforming components delivered from food into new substances.

Some of these products work within the gut, while others enter the bloodstream and reach distant organs like the liver and kidneys.

Thus, diet is not a "two-way relationship between food and the human body,"

but an interaction of "Food × Gut Bacteria × Human Body."

This may require us to consider it as a tripartite interaction.

Beets, spinach, arugula, lettuce, legumes, whole grains.

Behind these familiar foods long considered healthy, chemical reactions we were unaware of are occurring.

The discovery of DNIC may only visualize a part of that vast and complex gut world.

Gut bacteria research is beginning to add new answers to the age-old question of "why are vegetables good for the body?"

In the future, if the relationship between DNIC and health status is confirmed in humans, the day may come when "what your gut bacteria transform it into" becomes an important indicator in nutrition science, not just "what to eat."

SciTechDaily:

"A Hidden Gut Reaction May Explain Why Vegetables Are So Good for You"

https://scitechdaily.com/a-hidden-gut-reaction-may-explain-why-vegetables-are-so-good-for-you/

Cell: Original Research Paper "Gut microbiota generate dinitrosyl iron complexes with cardiometabolic benefits." Reports on DNIC formation, verification in germ-free mice, and effects on cardiovascular and metabolic indicators

https://www.sciencedirect.com/science/article/pii/S0092867426009244

DOI of the Paper: Permanent Identifier of the Paper Published in Cell

https://doi.org/10.1016/j.cell.2026.07.055

Karolinska Institutet: Official Announcement by the Karolinska Institute, which conducted the research. Includes research overview, future verification tasks in humans, research funding, etc.

https://news.ki.se/gut-bacteria-convert-dietary-nitrate-and-iron-into-protective-molecules

ScienceDaily: Research Introduction Based