Scientists investigating the explosive rise in colon cancer in young people say they have made “profound” discoveries about the role that dietary differences play.
The researchers compared and contrasted 176 previous scientific studies to dig deeper into the specific ways six popular diets affect the gut microbiomes in people — and which diets lead to increases in gut bacteria linked to tumor growth.
Based on these nearly two hundred studies, their extensive analysis concluded that a Western diet high in sugar, saturated fat and processed foods carried the greatest risks.
But the team found that a high-fiber diet, used to control blood sugar levels in diabetics, had a protective effect against changes linked to cancer.
The study also found that there is a lot of skepticism about the health benefits of high-protein and ketogenic diets, which are often popular among health-conscious athletes.
A microbiologist who worked on the new review study called it “an important milestone” that provides “tangible data” about the relevance of the microbiome to health.
The Western diet appeared to reduce the diversity of bacteria in the gut, leading to an explosion of Bacteria species associated with obesity.
These foods also left behind a flood of additives and preservatives, which the researchers linked to an “increase in chronic inflammation” in the gut.
A Western diet, low in fiber, fruits and vegetables, also made it harder for the digestive system to break down healthy fibers after they were eaten, the team found.
According to the researchers, people in the West who ate a normal diet also had fewer types of bacteria that produce short-chain fatty acids, which can help reduce inflammation in the gut.
Chronic or long-term inflammation in the gut is a concern because it can lead to harmful mutations in cells, increasing the likelihood that they will become cancerous.
Ultra-processed foods, such as donuts, pizza and chips, have previously been linked to a higher risk of inflammation and associated health risks.
The graph above shows the increase in colorectal cancer in young Americans from 1999 to 2020
On the other hand, those who followed a green Mediterranean diet – rich in fruits, vegetables and olive oil, as well as green tea and protein-rich aquatic plants, such as Mankai (duckweed) – had the best health outcomes overall.
According to the researchers, it increased ‘health-promoting bacteria’ in the gut and reduced the amount of bacteria responsible for cell damage.
Many of the 176 studies reviewed for the new analysis, published this week in the journal Nature Reviews Microbiologyturned to a bacterial genetic identification technique called metagenomic sequencing to map the gut microbiome.
Ecologists also use this method to study the hidden microbial world in the wild and to assess the health of the environment in polluted, post-industrial sites.
Just now one of those studies aloneFor example, followed the changes in the intestinal bacteria of 307 male participants, in addition to their eating behavior, over a period of six months.
All in all, the scientific reviewers divided this mountain of research into studies of six different broad categories of diets: the Western diet and the Mediterranean diet, as well as fiber-, protein-, plant-based, and ketogenic diets.
A diet high in fiber or whole grains is popular among people with chronic constipation or those wanting to lose weight.
The study found that it had a protective effect against colon cancer, type 2 diabetes and inflammation, specifically because it changed the mix of bacteria in the gut microbiome.
It was found that the high-fiber plant material consumed led to a ‘substantial increase’ in populations Lactic acid bacteria And Bifidobacteria bacteria — which release beneficial substances, such as short-chain fatty acids, which can reduce inflammation.
Researchers in Ireland compared and contrasted 176 previous scientific studies to gain a better understanding of the specific ways six popular diets affect the gut microbiome in humans – and which diets lead to increases in gut bacteria linked to tumor growth (stock image, above)
A plant-based, or vegetarian, diet has also been found to reduce the risk of colon cancer because the polyphenols in the plants stimulate the growth of other beneficial bacteria.
The plant-based diet in particular showed an increase in one particular group of bacteria, the genus Akkermansiathat help fight bacterial diseases, the researcher wrote.
Researchers called for more research into the ketogenic diet, or high-fat diet, warning of a history of previous studies showing it can cause sudden declines in the populations of 19 different types of beneficial bacteria, called Bifidobacteria.
Like it Akkermansiathis Bifidobacteria also play a crucial role in “regulating the immune system,” the researchers say, by inhibiting the growth of infectious bacteria.
But the team also had concerns about high-protein diets, with lots of red meat.
In their review, they noted that the breakdown of meat in the gut can lead to the release of hydrogen sulfide, which can cause harmful mutations in nearby cells.
“Our research highlights the profound impact of different diets on the gut microbiome,” the study’s lead author, Dr. Catherine Stanton, said in a statement.
“This insight is crucial for developing nutritional advice that promotes health and prevents disease,” said Dr Stanton, who works for Teagasc, an Irish public-private government organisation that conducts research into food and agriculture.
“It is fascinating to see how dietary choices can influence the balance of microorganisms in our gut and their metabolic functions,” she added.
Liberty “Libbie” Ashworth was diagnosed with stage 4 colon cancer at age 14 after a hospital visit with severe abdominal pain. She is from Panora, Iowa
Evan White is pictured above with his fiancée Katie Briggs and their dog Lola. The couple were dating when Evan was diagnosed with cancer and became engaged when his condition stabilized. However, he passed away after battling the disease for four years
The study comes as researchers race to understand the explosive increase in colon cancer cases among people under 50.
About 17,000 people under 50 now develop the disease each year. In just two decades, the number of cases has increased by almost 50 percent, compared with 12,000 cases per year in 1999.
The number of cases of colon cancer among people in their late 20s and early 30s has increased by an estimated 70 percent over the same period.
Other forms of cancer are also becoming more common in young people, including cancers of the bile ducts, intestines, breasts and appendix.
Kate Middleton, 42, was one of the younger celebrities to bravely reveal she had cancer this year, while actress Olivia Munn, 43, revealed she was suffering from breast cancer last year.
Scientists are baffled by the cause of the rise in cancer in young people. So far, they have blamed everything from rising obesity rates to eating processed foods.
Another study found that an additive in Red Bull and other energy drinks could fuel the growth of cancer cells.
A team of government-funded researchers launched a $25 million study in March of this year to determine the cause of the increase.
Colon cancer is particularly worrying because the disease often only causes symptoms at a later stage, when the disease is more advanced and more difficult to treat.
Current guidelines require all Americans over the age of 45 to be screened for cancer, but some doctors are calling for the age limit to be lowered further.