Good Gut Bacteria

Researchers of synthetic biology based at the Massachusetts Institute of Technology (MIT) in the US have devised a system to protect the gut microbiome from the effects of antibiotics.

The new study, published in Nature Biomedical Engineering, reports on the successful use in mice of a “live biotherapeutic” – a genetically engineered bacterium that produces an enzyme which breaks down antibiotics in the gut.

“This work shows that synthetic biology can be harnessed to create a new class of engineered therapeutics for reducing the adverse effects of antibiotics,” says MIT professor James Collins, the paper’s senior author.
The dark side of antibiotics

Antibiotics – substances that kill or inhibit the growth of bacteria – are hugely important in fighting bacterial infections.

But there’s a dark side to antibiotics too. Increasing human use of antibiotics has contributed to the rise of antibiotic resistance, which has made many bacterial diseases increasingly difficult to successfully treat.

Antibiotic treatment can also kill off bacteria in our resident healthy gut microbiome – the trillions of microbes that live in our gastrointestinal tract and assist with food digestion, immune development and vitamin synthesis.

This causes two problems: firstly, we can lose the benefits provided by our good bacteria; and secondly, this disruption can tip the balance of the microbial ecosystem towards species that cause harm.

In some cases, these indiscriminate effects of antibiotics can have life-threatening consequences. In the US, about 15,000 deaths each year are attributed to diarrhoea and colitis (inflammation of the colon) caused by overgrowth of the bacterium Clostridium difficile following antibiotic overuse.

So, while antibiotics are an important and necessary tool to fight bacterial infections, working to limit antibiotic resistance and damage to the gut microbiome are key priorities for research.  READ MORE...

Gut Bacteria

Flavonoid-rich foods, including berries, apples, pears and wine, appear to have a positive effect on blood pressure levels, an association that is partially explained by characteristics of the gut microbiome, according to new research published today in Hypertension, an American Heart Association journal.

"Our gut microbiome plays a key role in metabolizing flavonoids to enhance their cardioprotective effects, and this study provides evidence to suggest these blood pressure-lowering effects are achievable with simple changes to the daily diet," said lead investigator of the study Aedín Cassidy, Ph.D., chair and professor in nutrition and preventive medicine at the Institute for Global Food Security at Queen's University in Belfast, Northern Ireland.

Flavonoids are compounds found naturally in fruits, vegetables and plant-based foods such as tea, chocolate and wine, and have been shown in previous research to offer a variety of health benefits to the body. Flavonoids are broken down by the body's gut microbiome—the bacteria found in the digestive tract. 

Recent studies found a link between gut microbiota, the microorganisms in the human digestive tract, and cardiovascular disease (CVD), which is the leading cause of death worldwide. Gut microbiota is highly variable between individuals, and there are reported differences in gut microbial compositions among people with and without CVD.

With increased research suggesting flavonoids may reduce heart disease risk, this study assessed the role of the gut microbiome on the process. Researchers examined the association between eating flavonoid-rich foods with blood pressure and gut microbiome diversity. The study also investigated how much variance within the gut microbiome could explain the association between intake of flavonoid-rich foods and blood pressure.  READ MORE

Gut Bacteria

People who live to age 100 and beyond may have special gut bacteria that help ward off infections, according to a new study from Japan.

The results suggest that these bacteria, and the specific compounds they produce — known as "secondary bile acids" — could contribute to a healthy gut and, in turn, healthy aging.

Still, much more research is needed to know whether these bacteria promote exceptionally long life spans. The current findings, published Thursday (July 29) in the journal Nature, only show an association between these gut bacteria and living past 100; they don't prove that these bacteria caused people to live longer, said study senior author Dr. Kenya Honda, a professor in the Department of Microbiology and Immunology at the Keio University School of Medicine in Tokyo.

"Although it might suggest that these bile-acid-producing bacteria may contribute to longer life spans, we do not have any data showing the cause-and-effect relationship between them," Honda told Live Science.

The community of bacteria and other microorganisms that live in the gut, known as the gut microbiome, is known to play a role in our health and changes as we age. For example, having less diversity in the types of gut bacteria has been linked with frailty in older adults. But researchers suspected that people who reach age 100 may have special gut bacteria that contribute to good health. 

Indeed, centenarians tend to be at lower risk of chronic diseases and infections compared with older adults who don't reach this milestone.  READ MORE

Our Gut & Diet

YOUR GUT IS A THRIVING UNIVERSE UNTO ITSELF. This tiny cosmos is inhabited by thousands on thousands of microorganisms, which together make up your gut microbiome.

Among other things, this internal ecosystem contains bacteria that we rely on to help us break down and process the foods that we’re not readily equipped to digest. But a slew of recent scientific studies shows that our gut also connects more broadly to our holistic health, even to things that are seemingly unrelated, like our brains.

The science is preliminary, but there is compelling evidence that what you eat — and in turn, that changes the gut microbiome — has an outsized influence on your health. But not in the way you’d think.

WHAT’S NEW — A new study published on Friday in the journal Science Advances looks at how diet could alter multiple sclerosis (MS) symptoms via the gut microbiome. By feeding mice with an MS-like condition a specific diet, scientists were able to reprogram their gut bacteria — and reduce their symptoms.

The study started with the observation that the gut microbiomes of people with MS lack a kind of bacteria that, in most folks’ gut, breakdowns a nutrient called isoflavones. This nutrient is commonly found in everyday staple foods, like soy and beans.

So, the team hypothesized that MS might be related to the absence of these bacteria — and in turn, eating more foods with isoflavones in them could alleviate the symptoms.

From there, they were able to demonstrate the critical difference that the bacteria’s presence or absence can make in this disease.

WHY IT MATTERS — This study is so intriguing because it identifies a clear relationship between the gut, the food we eat, and our brain and body health.

In the new study, the researchers go further than past work by not only establishing a clear link between gut bacteria and diet, but also the mechanisms driving the relationship — and how to potentially game it to our advantage.

“The hypothesis has always been that bacterial composition is tightly linked to diet,” says Sergio Baranzini, a neurology professor at the University of California, San Francisco who was not involved in the research. While other studies have investigated this relationship, “what those studies fell short of is showing what could be the potential mechanism.”