[Shocking medical paper] Colon cancer is no longer just a disease of the elderly! Your diet determines the future of your children

Hello, I'm Miko, the manager of Kokaiko Shoten!

Today, I would like to share some important health information with you based on a National Geographic article I found in the Nikkei Newspaper.

Well then, let's get started!

table of contents

Colon cancer is occurring at younger ages worldwide
A silent abnormality occurring in the intestines of Japanese people
Colibactin toxin: The true nature of a genetic mutation frequently occurring in Japanese people
The collapse of the intestinal environment caused by the Westernization of food
Childhood eating habits determine your health 30 years later
A ray of hope: Scientific evidence from traditional Japanese foods
Japanese food culture has the world's highest health benefits
Preventive measures you can start practicing today
A "living cultural heritage" that Kogako Shoten continues to protect
Summary: Today's choices determine tomorrow's health

Colon cancer is occurring at younger ages worldwide

From an article by National Geographic published in the Nihon Keizai Shimbun

Until now, many people have thought of colorectal cancer as a disease of the elderly.

However, a large-scale study published in the world's leading medical journal, Lancet Oncology, on December 11, 2024, revealed a shocking fact that completely overturns this common sense.

The study involved detailed epidemiological surveys across 50 countries and regions and found that the incidence of colorectal cancer among younger people under the age of 50 is rising sharply in many parts of the world.

This is not a temporary phenomenon. A paper published in the prestigious academic journal Science in March 2023 revealed that since the 1990s, the incidence of colorectal cancer in people under the age of 50 has been steadily increasing by 2-4% per year in many countries, with the increase being particularly pronounced among younger people under the age of 30 .

In response to this serious situation, Andrew Chan, professor at Harvard Medical School and associate medical director of gastroenterology at Massachusetts General Hospital, has issued a strong warning, saying, "Colon cancer should no longer be thought of as a disease that only affects the elderly."

A silent abnormality occurring in the intestines of Japanese people

So, what is the situation for us Japanese?

Unfortunately, we have to say that the current situation in Japan is one of the most serious in the world.

According to cancer mortality statistics for 2023, colorectal cancer is the leading cause of death for women. It is also the second leading cause of death for men, after lung cancer. Even more shockingly, the colorectal cancer mortality rate in Japanese people has increased tenfold over the past 50 years, with a dramatic increase of 1.3 times in the last 17 years alone .

This abnormal increase in mortality rate is unique to Japan and not seen in other developed countries. What is particularly noteworthy is that the 1990s was a critical turning point when Japan's colorectal cancer mortality rate caught up with and then surpassed the levels of Western countries.

What's more, this period coincides exactly with the progress of the "Westernization of food" and the beginning of the abuse of "synthetic food additives."

It is no coincidence that this period, when fast food culture has rapidly spread, convenience stores have become widespread nationwide, and daily consumption of processed foods has become commonplace, has coincided with a sharp increase in colorectal cancer.

Colibactin toxin: The true nature of a genetic mutation frequently occurring in Japanese people

The scientific mechanism behind this serious situation shocked the scientific community in April 2025.

The findings of an international research team led by the National Cancer Center, published in Nature, the world's leading scientific journal, are truly a discovery that will go down in medical history.

The research team conducted a large-scale study using cutting-edge genetic analysis technology called whole genome sequencing on 981 colorectal cancer patients from 11 countries. As a result, they discovered that approximately 50% of Japanese patients had characteristic gene mutations caused by colibactin toxins produced by intestinal bacteria .

This figure was an astonishing 2.6 times higher than the global average of 19% .

Even more remarkable is the age distribution of this genetic mutation.

This mutation was detected 3.3 times more frequently in younger patients under 50 years of age than in older patients over 70 years of age .

This fact strongly suggests that colon cancer in young people is not merely a random phenomenon but is based on specific biological mechanisms.

Professor Ludmir Alexandrov of the University of California, San Diego, said of the discovery:

"Analysis of cancer DNA sequences indicates that the accumulation of intestinal conditions from childhood determines the risk of cancer several decades later," he said.

This represents an important concept in preventive medicine.

The collapse of the intestinal environment caused by the Westernization of food

So, let's review again. What has happened to the intestinal environment of Japanese people over the past 30 years?

Broadly speaking, there were two major changes : the Westernization of food and the overuse of synthetic food additives .

What these do to our bodies is fundamentally change our intestinal flora .

A comprehensive report published in 2007 by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) clearly identified consumption of red meat (beef, pork, and lamb) and processed meat as "definite risk factors" for colorectal cancer.

Following this assessment, in 2015 the International Agency for Research on Cancer (IARC) classified processed meat in the most severe category, "possibly carcinogenic to humans (Group 1)," and red meat in the most severe category, "probably carcinogenic to humans (Group 2A)."

As for specific risks, it has been scientifically proven that consuming 50g of processed meat (about two slices of ham) every day increases the risk of colon cancer by 18% . However, the problem is not limited to meat itself.

Other characteristics of the Western diet include refined white grains, soft drinks high in added sugars, and a crucial lack of dietary fiber.

These factors work together to disrupt the balance of the intestinal flora, creating an environment in the intestines that favors the proliferation of harmful bacteria that produce colibactin.

When you were little, didn't you often eat toast with ham and eggs, bacon and eggs, or sausages for breakfast?

Childhood eating habits determine your health 30 years later

Of most concern is the fact that this poor gut health begins in childhood .

Recent research has revealed a surprising mechanism that shows that mutations in the intestinal flora acquired by the age of 10 are directly linked to the development of colon cancer 30 to 40 years later . In Japan, it is said that the period up to the age of 3 is crucial for a child's intestinal environment.

This is not simply a statistical correlation or ethnicity. The gut microbiota gradually establishes itself from shortly after birth, and the basic composition is determined by around the age of 10. Therefore , if a person continues to eat a high-fat, low-fiber, processed food diet during this period, they will develop an intestinal environment dominated by harmful bacteria, which will continue to damage DNA for a long period of time.

This means that the dietary habits of children today will determine their health when they reach the prime of their working lives and become the core members of society.

This goes beyond an individual issue and is a serious challenge that concerns the future of society as a whole.

A ray of hope: Scientific evidence from traditional Japanese foods

However, there is a very interesting silver lining.

Let's take a closer look at why the results of the Multipurpose Cohort Study, a large-scale epidemiological study conducted by the National Cancer Center that followed approximately 140,000 Japanese people for 19 years, surprised the global medical community.

The research team scored the frequency of intake of traditional Japanese dietary patterns (rice, miso soup, seaweed, pickles, green and yellow vegetables, fish and shellfish, and green tea) in eight categories and then thoroughly analyzed the subsequent impact on health.The results showed that those with a high score on the Japanese dietary pattern had a 14% lower risk of all-cause mortality, a 19% lower risk of death from cardiovascular disease, and a 22% lower risk of death from cerebrovascular disease compared to those with a low score.

Looking at these figures alone, they may seem like small differences at first glance, but a 14% difference in the risk of all-cause mortality means a difference of 14 people out of 100 , which is a very large difference.From the perspective of medical statistics, this shows an extremely significant preventive effect.

Even more surprisingly, a follow-up study published in 2020 revealed that the group with the highest intake of fermented soy foods (miso and natto) (50.2g/day for men and 44.6g/day for women) had a 10% lower risk of total mortality in men and an 11% lower risk in women compared to the group with the lowest intake . In particular, natto intake reduced the risk of death from cardiovascular disease by 24% , demonstrating a preventive effect that cannot be fully explained by Western medicine.

These data scientifically support the reason why Japan has the longest life expectancy in the world, and prove that washoku, registered as a UNESCO Intangible Cultural Heritage, goes beyond mere cultural value to be a practical example of the idea that food is medicine and contributes to human health.

As you can see from this, if I had eaten Japanese food for breakfast from a young age, I may have been able to reduce the risks in the future...

Japanese food culture has the world's highest health benefits

Further detailed analysis reveals the scientific health benefits of each food group that makes up the Japanese diet:

Why is the Japanese diet so effective? The secret lies in its ideal nutritional balance of "one soup and three side dishes" and the unparalleled health benefits of each food group . Detailed analysis has revealed the scientific health benefits of each food group that makes up the Japanese diet:

① Seaweed

A 6% reduction in the risk of death was confirmed.

Japanese people have been eating seaweed such as kelp, wakame, nori, and mozuku for thousands of years as "sea vegetables," and their intake is unparalleled anywhere in the world.

It has been elucidated at the molecular level that the polysaccharide fucoidan contained in these foods improves immune function and has anti-cancer properties. In particular, it has been discovered in recent years that the intestines of Japanese people contain intestinal bacteria that possess special enzymes that break down the polysaccharides found in seaweed, a phenomenon that can be said to be proof of the genetic adaptation of the Japanese people.

② Green and yellow vegetables

It also reduces risk by 6% .

Antioxidants such as carotenoids, vitamin C, and folic acid found in seasonal Japanese produce such as chrysanthemum, komatsuna, spinach, carrots, and pumpkins prevent DNA damage and maintain normal cell function.

Japan's unique food culture of "eating seasonal foods in season" has made it possible to maintain optimal health in line with natural cycles by consuming vegetables at their most nutritious.

3. Root vegetables

Root vegetables such as radish, carrots, and burdock root dramatically improve the intestinal environment thanks to their high dietary fiber content and unique phytochemicals .

In particular, the inulin contained in Jerusalem artichoke and burdock promotes the growth of beneficial bacteria such as bifidobacteria and effectively expels harmful substances from the intestines. The cooking methods of root vegetables that have been familiar to Japanese people since ancient times as "kinpira" and "nimono" are also a way to maximize the benefits of these active ingredients.

④ Fish and shellfish

This showed a 3% risk reduction .

In addition to the omega-3 fatty acids EPA and DHA found in fish, the zinc and taurine found in abundance in shellfish are known to suppress chronic inflammation in the intestines and inhibit the growth of cancer cells.

Shellfish such as clams, clams, and oysters, which Japanese people have collected from the seashore since ancient times, are a true gift from the sea, providing high-quality protein and essential fatty acids without relying on meat. They are a symbol of Japan's food culture, which we can be proud of around the world, making the most of the geographical characteristics of an island nation.

⑤ Green tea

The most significant effect was an 11% reduction in the risk of death .

As Zen Master Eisai wrote, "Tea is an elixir for health," the health benefits of green tea, which has been enjoyed daily by Japanese people for over 800 years, have now been proven by modern science.

The powerful antioxidant and anti-cancer properties of catechins , including epigallocatechin gallate (EGCG), are thought to be the main factors behind this amazing effect.

Currently, "MATCHA" and "GREEN TEA" are experiencing an incredible boom in health foods in the West, with Silicon Valley entrepreneurs drinking matcha first thing in the morning and Hollywood celebrities relying on matcha lattes.

Because matcha is selling well, mass production in China has recently become popular, but there are still issues with pesticides, so "organically grown Japanese matcha" has become a premium among the intellectually wealthy overseas. However, the true way to maximize its health benefits is to brew each cup carefully and with care, along with the "ichigo ichie" spirit of the tea ceremony.

⑥ Fermented foods (miso soup, pickled vegetables, natto, pickled plums)

Another thing I would like to add is fermented foods, which are the essence of Japanese cuisine.

Fermented foods, which have been around in Japan since ancient times, are the most important factor that has made the intestinal bacterial flora of the Japanese people so diverse .

Miso is a prime example of a nutritious fermented food, as evidenced by many proverbs, such as "Pay the miso maker, not the doctor," "A cup of miso soup a day keeps the doctor away," and "A cup of miso soup is worth three miles." The lactic acid bacteria and koji bacteria contained in miso increase the number of beneficial bacteria in the intestines and contain a balanced amount of minerals that the body needs. In addition, the plant-based lactic acid bacteria in bran pickles are resistant to stomach acid and are known to reach the intestines alive.

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Nattokinase, contained in natto, has a thrombolytic effect that thins the blood and significantly reduces the risk of cardiovascular disease. The aforementioned study also confirmed the astonishing effect of reducing the risk of death from cardiovascular disease by 24%.

Another advantage of fermented foods is that they are often rich in dietary fiber and have high enzyme activity.

All of these benefits are the result of fermentation techniques passed down since ancient times, born from the symbiosis of Japan's climate and microorganisms, making it a true "living cultural heritage."

In fact, Jen Messer, president of the New Hampshire Academy of Nutrition and Dietetics, explains the importance of dietary fiber by saying, "Dietary fiber shortens the time it takes for stool to pass through the large intestine, reducing exposure to carcinogens." It's no wonder that many cancer patients have a "low body temperature and a tendency to constipation."

Traditional Japanese food has been practicing the theory that condenses all of these problems for over 1,000 years.

Preventive measures you can start practicing today

From the perspective of preventive medicine, I highly recommend the following practices!

① Appropriate intake of red meat

As the song goes, "Eating fish makes you smarter," and the Japanese have had a diet centered on fish and shellfish since ancient times. Modern research has shown that limiting red meat (beef, pork, lamb) intake to less than 500g per week (cooked weight) can minimize the risk of colon cancer. The wisdom of our ancestors to "eat fish rather than meat" was indeed a sensible choice.

② Restrictions on processed meat

The modern perception that "food full of additives is poisonous to the body" is correct, and processed meats such as ham, sausage, and bacon have been recognized as carcinogenic by the International Agency for Research on Cancer. It is important to return to the Japanese food philosophy of "eat natural things as they are" and limit your intake of these foods as much as possible .

3. Active intake of dietary fiber

As the saying goes, "food is medicine," the idea that food can be medicine has existed in Japan since ancient times. Intake of 30g or more of dietary fiber per day can dramatically improve the intestinal environment , and traditional Japanese foods such as seaweed, root vegetables, beans, and brown rice are truly natural intestinal health foods. The ancient teaching that "food is better than medicine" has now been proven by modern science.

④ Daily intake of fermented foods

As old proverbs like "Pay the miso maker, not the doctor," "A cup of miso soup a day keeps the doctor away," and "A cup of miso soup is worth three miles" suggest, miso soup is a representative Japanese dish made from nutritious fermented foods. It has also been shown that incorporating other traditional fermented foods such as natto, pickles, amazake (sweet sake), and umeboshi (pickled plums) into your daily diet can effectively increase beneficial bacteria.

⑤ Switching from refined grains

During the Edo period, samurai who traveled to Edo for work fell ill with a disease known as "Edo disease." The actual name of the disease was "beriberi," and it is well known that this was caused by a lack of B vitamins, due to the fact that people ate brown rice in the countryside but regularly ate white rice in Edo. Therefore, if you are currently eating white rice, we recommend that you immediately switch to brown rice or mixed grain rice . This alone will significantly increase not only your vitamin intake, but also your dietary fiber and minerals.

A "living cultural heritage" that Kogako Shoten continues to protect

So, what do you think?

At Kogaoka Shoten, we deliver authentic ingredients made using traditional methods that have been passed down for generations by artisans from all over Japan. These products are more than just food; they are "living cultural heritage" with scientifically proven health benefits.

Naturally brewed miso and soy sauce

We don't use any artificial seasonings or preservatives, and the abundant enzymes and lactic acid bacteria produced during the natural fermentation process fundamentally improve your intestinal environment. Miso sold at supermarkets is full of additives. Ours is made with simple ingredients and can be stored at room temperature. This is the real deal!

Osawa's Three-Year Aged Brown Rice Miso, 300g, by Suya Shigeru, Naturally Brewed, Raw Miso

Osawa's brown rice miso is carefully aged for three years in wooden barrels in Suyamo, Shinshu. It features the deep richness of natural fermentation and the fragrant aroma of brown rice koji. This miso is alcohol-free and unheated. For premium, additive-free seasonings, visit Kokako Shoten. Free shipping on orders over 9,000 yen (tax included). [Authorized Retailer]

Umi no Sei Barley Miso, 1kg, Wooden Barley Miso, Authorized Retailer | Kogaiko Shoten

This fragrant barley miso is made with specially cultivated domestic barley and soybeans, and traditional sea salt "Umi no Sei." It's made in traditional wooden barrels and is additive-free. The unique sweetness and mellow aroma of barley add depth to dishes. For premium additive-free seasonings, visit Kokako Shoten. Free shipping on orders over 9,000 yen (tax included).

We also have a variety of soy sauces!

Kogaoka Shoten's miso lineup

Kogaoka Shoten's soy sauce lineup

Natto made from 100% domestic soybeans

Natto, made using only non-genetically modified, domestically grown soybeans and traditional methods, has nattokinase activity that is incomparable to commercially available products, protecting the health of blood vessels. Our store offers a selection of freeze-dried natto that is convenient to carry around . It has no unpleasant odor, so even those who dislike natto can enjoy it. Enjoy it as a snack with nuts.

Kawaguchi Natto Dried Natto 65g, Authorized Retailer, Freeze-Dried, Made in Japan, No Additives

We are an authorized retailer of Kawaguchi Natto. We use 100% domestically grown "Suzumaru" soybeans, cultivated over 75 years of tradition, and our unique freeze-drying method condenses the natto bacteria alive. No additives, salt, or oil are used. It's also perfect as baby food, pet food, or a snack. We deliver FDA-certified quality.

We also have a furikake seasoning made with freeze-dried Kawaguchi natto.

Nori seaweed from the Ariake Sea

Ariake nori is the finest type of seaweed, which has become rare due to global warming. Grown in the mineral-rich Ariake Sea, this seaweed contains high concentrations of active ingredients unique to seaweed, including fucoidan.

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We also have Okinawan mozuku seaweed!

Natural mozuku seaweed grown in the beautiful waters of Okinawa is a source of particularly high-quality fucoidan, and is expected to have cancer-preventing effects. Ours is a particularly thick, top-quality product! It's salted, so wash it for about a minute and eat it as is with ponzu sauce or millet vinegar. This is a seasonal product available only in the summer.

Limited seasonal item! Natural thick mozuku seaweed (salted) from Ishigaki Island, Okinawa Prefecture 500g

We also have many other domestically produced seaweeds.

Domestically produced organic matcha, green tea, and roasted green tea

When tea drinking culture was introduced to Japan from China, Zen Master Eisai wrote in his "Kissa Yojoki" (Record of Tea Ceremony) that tea is a "medicine for all ills," and now, 800 years later, those words have been scientifically proven. Matcha, green tea, and roasted green tea grown in Japan organically, without the use of chemical fertilizers or pesticides, are rich in natural catechins and theanine, which are produced through symbiosis with soil microorganisms, and as mentioned in the aforementioned study, have been shown to have the astonishing effect of reducing the risk of death by 11%.

Organic Matcha Green Tea, 30g, Kirishima, Organic JAS 7-Star Certified, Henta Tea, Authorized Retailer

We are an authorized retailer of Henta Tea. This 30g bottle of Gensen Kirishima organic matcha has been certified with the highest rating of "7 stars." This exceptional product is made in Kirishima, Japan's top tea producing region for three consecutive years, with meticulous attention to detail, right down to the soil. Certified organic by the JAS, it offers a rich, sweet flavor with minimal bitterness, and is delivered directly to you with the peace of mind you only get from an authorized retailer.

Suiho Matcha, 20g, Pesticide-Free, Shiga Asamiya Tea, 100% First-Flush Tea, Stone-Ground, Katagi Kokoen

This premium matcha is from Katagi Kokoen, a farm in Shiga Prefecture's Asamiya district, which has a 1,200-year history, and has been growing its tea without pesticides or chemical fertilizers since 1975. Made with 100% premium first-grade tea, it's carefully ground in a stone mill. It boasts a rich aroma with little bitterness. The 20g size is perfect for tea ceremonies and sweets.

We also have a selection of healthy, domestically produced organic teas and beverages.

Through these products, we do not simply sell food ingredients. We believe it is our mission to ensure that the scientifically proven wisdom of Japanese food is passed on to people around the world who wish to improve their health, and to future generations.

Summary: Today's choices determine tomorrow's health

Medical research has clearly shown that the current rapid increase in early-onset colorectal cancer is directly linked to changes in our diets, but at the same time, the preventative effects of traditional Japanese foods have also been scientifically proven.

The food you choose now will determine your health and that of your loved ones 30 years from now. If you have children or grandchildren, please keep in mind that their intestinal environment is being formed right now.

There is no better cure than prevention. Japan's food culture, which has a history of over 1,000 years, is packed with health wisdom that modern science is only beginning to unravel.

I believe that starting your intestinal health today and encountering authentic Japanese ingredients will create the health of you and your family tomorrow, and we will continue to deliver authentic Japanese ingredients to keep you healthy and happy.