Parts of Mediterranean diet shown to prevent colorectal cancer

mediterranean diet components

New research singles out a few key elements of the Mediterranean diet that are most important for colorectal health.
The benefits of the so-called Mediterranean diet have been hailed in the news over recent years. Now, new research looks closely at the elements of the diet that could help to prevent the risk of colorectal cancer.

Among many other benefits, the Mediterranean diet has been shown to lower the risk of colorectal cancer. But the specifics of this beneficial role have not been studied in depth.

New research – presented at the ESMO 19th World Congress on Gastrointestinal Cancer, held in Barcelona, Spain – singles out the few components of the Mediterranean diet key for preventing colorectal cancer. The first author of the study is Naomi Fliss Isakov, Ph.D., of the Tel-Aviv Medical Center in Israel.

More specifically, the research looks at the link between the components of the diet taken both separately and in combination, as well as the risk of developing advanced colorectal polyps.

Colorectal cancer tends to develop from advanced polyps, or adenoma. However, the chances of polyps becoming malignant depend on various factors, including size, structure, and location.

Zooming in on the Mediterranean diet

Dr. Isakov and team examined 808 people who were undergoing either screening or diagnostic colonoscopies.

The participants were aged between 40 and 70 years old and were not at a high risk of colorectal cancer. The researchers took anthropometric measurements – such as body mass index (BMI) and height – of the participants, and they asked them to fill in a food frequency questionnaire. They also took part in a medical and lifestyle interview.

The researchers defined adherence to the Mediterranean diet as an above-average consumption of fruit, vegetables, nuts, seeds, and whole grains, as well as fish and poultry.

A below-median intake of red meat, alcohol, and soft drinks was also considered to be a key component of the diet. A Mediterranean diet was also described as having “a high ratio of monounsaturated to saturated fatty acids.”

For the purposes of the study, the researchers defined advanced polyps as adenomas larger than 10 millimeters in size, with a “high-grade dysplasia or villous histology.”

As the American Cancer Society (ACS) explain, the term “dysplasia” refers to the abnormal aspect of the polyps. “High-grade dysplasia” is a term used to describe polyps that appear abnormal or cancer-like. The ACS also note that larger adenomas tend to have a villous growth pattern and are more likely to lead to cancer.

Dr. Isakov and colleagues also examined healthy controls who did not have any polyps, either in the past or at the time of the study.

More fish, fruit reduces risk

Having compared individuals with polyp-free colonoscopies and those whose colonoscopy showed advanced polyps, the authors found a clear association between components of the Mediterranean diet and the risk of colorectal cancer.

People with advanced polyps reported consuming fewer elements of the Mediterranean diet. More specifically, the average was 1.9 Mediterranean diet components in the advanced polyps group, compared with 4.5 components in the polyp-free group.

Surprisingly, even two or three elements of the diet correlated with a 50 percent reduction in the risk of advanced polyps, compared with consuming no key components at all.

Additionally, the risk further decreased as the number of Mediterranean elements increased. The more elements of the Mediterranean diet people consumed, the lower were the chances of advanced polyps showing up in their colonoscopies.

The researchers adjusted for other risk factors associated with colorectal cancer and found that increased fish and fruit consumption, together with a low intake of soft drinks, was most likely to reduce the risk of advanced polyps.

We found that each one of these three choices was associated with a little more than 30 percent reduced odds of a person having an advanced, pre-cancerous colorectal lesion, compared to people who did not eat any of the MD [Mediterranean diet] components.”

Naomi Fliss Isakov, Ph.D.

She concluded, “Among people who made all three healthy choices the benefit was compounded to almost 86 percent reduced odds.”

ESMO spokesperson Dr. Dirk Arnold, of the Instituto CUF de Oncologia in Lisbon, Portugal, also comments on the findings, saying, “This large population-based cohort-control study impressively confirms the hypothesis of an association of colorectal polyps with diets and other lifestyle factors.”

“This stands in line with other very recent findings on nutritive effects, such as the potential protective effects of nut consumption and vitamin D supplementation which have been shown earlier this year.”

“However,” adds Dr. Arnold, “it remains to be seen whether these results are associated with reduced mortality, and it is also unclear if, and when a dietary change would be beneficial.”

Next, the authors plan to investigate the effects of the Mediterranean diet in a group at high risk of developing colorectal cancer.

[“Source-medicalnewstoday”]

Scientists sequence genome of worm that can regrow body parts, seeking stem cell insights


Adult flatworm M. lignano and diagrammatic key are shown. The tiny worm intrigues scientists because it can regenerate almost its whole body following an injury. Hence, their effort to sequence its genome.
Credit: Cold Spring Harbor Laboratory

Tourists spending a recuperative holiday on the Italian coast may be envious of the regenerative abilities of locally found flatworm Macrostomum lignano. Named for its discovery near the Italian beach town of Lignano Sabbiadoro, this tiny worm can regenerate almost its whole body following an injury, and researchers have long been trying to understand how it’s able to pull off this trick.

In work published in PNAS, a team of researchers has for the first time characterized the flatworm’s genome, paving the way for a host of new studies of the worm and its regenerative capabilities. The team was led by Cold Spring Harbor Laboratory (CSHL) Professor and HHMI Investigator Gregory Hannon, also a Professor and Senior Group Leader at the CRUK Cambridge Institute at the University of Cambridge, and CSHL Associate Professor Michael Schatz.

“This flatworm can regenerate every part of its body except the brain,” says Hannon. He was studying an important pathway in mammalian reproductive tissues when he became interested in Macrostomum. “This and other regenerating flatworms have the same kind of pathway operating in stem cells that is responsible for their remarkable regenerative capabilities. As we started to try to understand the biology of these stem cells, it very quickly became clear that we needed information about the genetic content of these organisms.”

M. lignano turned out to have an unusually complex genome filled with repetitive elements that made it challenging to assemble and analyze, says Schatz. “At the genomic level it has almost no relationship to anything else that’s ever been sequenced. It’s very strange and unique in that sense.” To overcome the extreme genomic complexity, the team used new long-read sequencing technology that boosted the quality of the genome sequence obtained by more than one hundred fold over standard short-read approaches.

The researchers used the worm’s genomic information to study how gene expression changed during regeneration. “It’s a very powerful tool to be able to see the genes that get activated that are responsible for regeneration of the animal,” Schatz explains. “We think this is going to be a very important species for stem cell research.”

The flatworm is ideal for studying stem cells, says lead author Kaja Wasik, who conducted the work as a PhD student in Hannon’s lab along with co-lead author James Gurtowski from Schatz’s lab. “The worms are just like floating sacks full of stem cells, so they’re very easily accessible,” says Wasik. “From what we looked at, it looks like many of the developmental pathways that are present in humans are also present in the worms, and we can now study whether they potentially could be involved in regeneration.”

According to co-author Peter Ladurner, an assistant professor at the University of Innsbruck, the worm has many properties that make it a good model system: “M. lignano is small, has simple tissues and organs, is transparent, and has sexual reproduction.” Well before its genome was available, M. lignano was already being studied for its insights into stem cells and tissue differentiation. The availability of the genome now enables researchers to do a lot of things they couldn’t previously, such as search within the genome, have a list of genes in hand, and gain insights into the worm’s genome organization.

Hannon says detailed analyses will be needed to figure out how the flatworm’s stem cells are able to develop into a variety of different cell types. He is also planning to examine how the pathways he has studied in other organisms operate in the worms. “The goal of this project was to enable ourselves and others to do new biology. The hope is that as these tools become more available, the community will grow.”

About 15 international research groups on three continents are actively working on Macrostomum flatworms, says co-author Lukas Schärer from the University of Basel. Schärer says he and Ladurner played a major role in helping to develop a broader Macrostomum research community. “The worm was initially used as a model to study embryology and neurobiology, and starting in the late 1990s research expanded into stem cell biology, tissue homeostasis, and regeneration, topics that are still very actively studied today,” he says. “We fully expect that the publication of the genome will lead to a surge in interest in this versatile model organism.”
[“source-gsmarena”]