BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: gut microbiota

Fermented and Fabulous: The Key to Gut Health

Fermented foods are truly underestimated. Yes, I’m talking kombucha, kefir, yogurt, sauerkraut, kimchi, etc. You might be thinking, how much can consuming a bitter tasting food really do for me? The truth is, a lot. Fermented foods may just be the answer to combating the rise in chronic inflammatory diseases. This is due to the fact that a diet with an abundance of fermented foods enhances gut microbe diversity. Gut microbiota, the human body’s largest population of microorganisms set in the intestine, are essential to the multifaceted nature of human health because they have impacts on immune, metabolic, and neurobehavioral traits.

Improving Human Intestinal Health

 In a trial run by Stanford School of Medicine, 36 healthy adults were assigned to a 10 week diet of either fermented or high-fiber foods to test the effects on gut microbiome and the immune system as a whole. The study discovered that those who consumed a diet rich in fermented foods had an increase in microbial diversity, four types of immune cells showed less activation, and the levels of 19 inflammatory proteins measured in blood samples decreased. Proteins, as we learned in AP Bio, have many different functions and structures and just one changed amino acid in the structure can cause diseases or viruses because its characteristics (hydrophobic vs. hydrophilic, non-polar vs. polar) are altered. One of these inflammatory proteins decreased by fermented food consumption, interleukin 6, has been linked to conditions such as rheumatoid arthritis, Type 2 diabetes and chronic stress. The success and promise that these results provided were immeasurable, for gut microbes have the potential to defend against harmful microorganisms, digest certain foods, produce important molecules like short-chain fatty acids, facilitate the absorption of dietary minerals, synthesize essential vitamins and amino acids, and even shape mood/behavior. Along with that, research suggests that low microbiome diversity has been linked to obesity, diabetes, arthritis, eczema, and even types of cancer, so any chance to increase microbial diversity is an opportunity to leap to. 

On the contrary, in the study, those adults assigned to a high-fiber diet saw no inflammatory protein decrease and the diversity of their gut microbes remained on average the same. Through a final step of analyzing blood and stool samples collected throughout the trial, the scientists confirmed that short term dietary changes involving a diet rich in fermented foods/drinks can rapidly increase microbial diversity, resulting in a series of health benefits that ultimately aid in protection against serious health issues and in general just keep you healthy and happy! 

So next time you’re at the grocery store, pick up that bottle of kombucha. It may look questionable, but tastes pretty good and has so many health benefits!

We Didn’t Start the Fire…Gut Microbes Did.

Many scientists have hypothesized that infants’ gut microbiota could influence the development of their immune system. Recently, a test led by Drs. Christine C. Johnson at the Henry Ford Health System in Detroit and Susan Lynch at the University of California, San Francisco, but this theory to test. Specifically, they set out to examine the relationship between an infant’s gut microbiota and their relative risk of atopy and asthma. The researchers inspected the composition of gut microbes in stool samples from almost 300 infants—all part of a diverse study group born in and around Detroit between 2003 and 2007—by means of examining sequence variation within ribosomal RNA. Ultimately, the team found that the infants could be divided into 3 separate groups, each with distinct bacterial and fungal gut microbiota.

When blood samples obtained from the infants at 2 years of age were tested for sensitivity to allergens, the 3 microbiota groups had significantly different risks for allergen sensitivity. The “high-risk” microbiota group had a relatively lower abundance of certain bacteria and a higher level of some fungi, and was more likely to be diagnosed with asthma at 4 years of age. This seeming link between gut microbiota and allergy and asthma was also manifested when other factors associated with allergic disease—such as breastfeeding—were controlled. Moreover, the researchers found that the high-risk group had a distinct set of metabolites that lacked anti-inflammatory fatty acids and breast milk-derived oligosaccharides that were found in children in the low-risk microbiota group, increasing vulnerability to inflammation.

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Neonatal gut microbiota play a huge role in health and disease (Credit: Eric Atkins)

The researchers also mixed immune cells from healthy adult donors in solutions containing metabolites extracted from the infant’s stool samples. The high-risk group’s metabolite samples increased the amount of allergy-promoting immune cells interleukin-4, a cell-signaling protein associated with allergies, and also reduced T-regulatory cells, an essential group of immune cells that suppress allergic responses. This reduction in T-regulatory cells was also spurred by a lipid that the team identified, called 12,13-DiHOME, that was found at high levels in the high-risk group. Discussing this finding, Lynch expressed to The Scientist, “That for me is incredibly exciting as it suggests that microbial-associated metabolites in the neonatal gut may represent an important driver of early-life immune cell phenotypes associated with disease development in childhood.”

The team plans to conduct a similar study that will focus on environmental factors and how they may affect the development of the gut microbiota. According to Lynch, “Understanding the basis of human-microbial development may prove critical to unraveling the basis of allergy and asthma and to developing preventative therapeutic strategies.”

Can Bacteria in Your Gut Cause Obesity?

Bacteria in your gut, aka gut microbiota, is made up of tens of trillions of microorganism, including 1000 different species of known bacteria. Although scientists are currently not incredibly knowledgeable on gut microbiota, an increasing amount of research has shown that it is plays a significant role in our health.

https://pixabay.com/en/anatomy-bacteria-bacterium-bowels-160524/

In a recent study at Lund University in Sweden, researchers have found correlation between gut bacteria and obesity. The purpose of the study was to identify metabolites in the blood that can be linked to obesity and see if they affect the composition of the gut microbiota in stool samples. The researchers studied blood plasma and stool samples from 674 participants and found 19 different metabolites that could be linked to the person’s BMI. Their data showed that Glutamine and BCAA (branched-chain and aromatic amino acids) had the strongest connection to obesity and that four different intestinal bacteria, Blautia, Dorea, Ruminococcus, and SHA98, were linked to the obesity related metabolites. Glutamine, “the strongest risk factor in the study”, has been linked with obesity in previous studies as well. Marju Orho-Melander, professor of genetic epidemiology at Lund University, summed up the study by stating, “The differences in BMI were largely explained by the differences in the levels of glutamate and BCAA. This indicates that the metabolites and gut bacteria interact, rather than being independent of each other.” Therefore, the metabolites they found are potential mediators between gut microbiota and obesity, and may be consequential in ultimately preventing obesity.

Our Intestines Cure Cancer??

There are over one hundred trillion organisms- most are bacteria- living in our intestine today. These are referred to as the gut microbiota.

While trillions of bacteria sounds scary, they can actually be very helpful. Research has been done worldwide and the discovery has been that gut microbes actually can kill cancer cells all over the body. (Not just in the intestines) But how? Gut microbes and cancer actually cross paths. Gut microbes can manipulate the immune system and can either increase inflammation or lower it as needed. This means the bacteria can actually work with cancer treatments, boost T-cells, and control other factors that help cancer grow such as fungi, or viruses.

However, this is not all. While some cells help against cancer growth, others do the opposite. It varies cancer to cancer, and all have different results. As said by microbiologist and immunologist Patrick Schloss “What we really need is to have a much better understanding of which species, which type of bug, is doing what and try to change the balance.” So more research is still being done to decide how to control the microbiota, but a possible theory is that because it’s in the intestine it is related to our metabolisms and so what we eat controls the bacterium- this can also then effect the colon, thus effecting more cancer: colon cancer.

 

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