BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: gut microbes

Can Microbes Create Healthier Food?

A specific human gut microbe is making processed foods healthier. 

Researchers at Washington University School of Medicine in St. Louis wanted to find the chemicals in processed foods that correlate to diabetes and heart disease. In their study, the scientists used a bacteria called Collinsella intestinal (bacteria that contains an enzyme to break down Fructoselysine), which breaks down fructoselysine into small, harmless parts. According to Ashley R. Wolf, a researcher in the lab, “Fructoselysine is common in processed food, including ultra-pasteurized milk, pasta, chocolate and cereals.” This chemical has been linked to the cause of many diseases of aging.

When Wolf and her team tested the effects of feeding fructoselysine to mice that had Collinsella intestinalis, they not only discovered an increase in the amount of microbes in the stomach, but also found that the mice’s gut microbes had a stronger ability to break down fructoselysine.

“The new tools and knowledge gained from this initial study could be used to develop healthier, more nutritious foods as well as design potential strategies to identify and harness certain types of gut bacteria shown to process potentially harmful chemicals into innocuous ones,” says Jeffrey I. Gordon, a researcher of the lab.

Picture of human gut microbes

(“Courtesy of Pacific Northwest National Laboratory”)

Another study by Harvard University and the University of San Francisco, discovered that raw food was healthier than cooked food. They found that “cooked food allows the host to soak up more calories in the small intestine, leaving less for hungry microbes further down the gut; on the other hand, many raw foods contain potent antimicrobial compounds that appear to directly damage certain microbes.”

Although more research still has to be done to determine the effectiveness of the microbe, these discoveries help lead people into a healthier lifestyle. 

Babies Born via C-Sections Have Different Gut Microbiota

A study reported to the Journal Nature, found evidence that infants born by C-sections have different microbiota than babies born vaginally. The study found that method of delivery plays a factor in which bacteroids colonizes the intestines of infants immediately after birth. 

The study was conducted in the United Kingdom. Researchers took stool samples from 596 babies in total– 282 born via cesarean section and 314 born vaginally. Scientist took samples four, seven and 21 days after birth and samples a couple of months later after birth. They also took stool samples from 175 mothers took help determine the origin of the gut microbiota. 

Research found that babies born through cesarean section have less “good” bacteria from their mothers and more bacteria from the environment in which they are born. The infants born by c-sections contained pathogens such as enterococcus, enterobacter and klebsiella, which have been found in hospitals. Via natural birth, infants’ intestines contained gut microbiota from their mother as well as the environment in which they were born. Later on in infancy, researchers found that babies born by c-sections showed more similar gut microorganisms as their naturally-birthed counterparts. 

Scientists found that in the gut microbiota found in infants born via c-section, some pathogens contained antimicrobial resistance and bacterial virulence factors. This could potentially make infants born by cesarean sections more susceptible to infections and weaken their immune systems. 

Researchers concluded that the environment in which babies are born factor into how gut microbiota will be composed from birth to infancy. But it still remains unclear if the initial difference in gut microbiota will have any health effects later on in life. 

Regardless of this study, c-sections are still important to the health of millions of babies and mothers worldwide. In no way should this study discourage women from having c-sections; especially, if they are a necessity. Caesarean sections have saved millions of lives and will continue to do so.

The Secret of Human Gut Microbiomes in Athletes

Recently, scientists have tried to identify a correlation between the foods we eat and the microbes found in our gut. Although they were not successful in finding an answer, what they did find could be even more important in our understanding of the human gut microbiome. Two studies were conducted, one where microbes were compared between normal people, and another where microbes were compared between normal people and elite runners – all of these people ate the foods they would normally eat. Both of these studies were important in revealing the ways our diet does not impact the microbes found in our gut.

The study between regular individuals revealed that “each person has that unique mixture [of microbes] that’s special to only them” and that the same food can have drastically different effects in different individuals. Even people that consistently ate the same foods experienced changes in their microbiome. The study comparing elite runners to regular individuals found that the runners had a greater amount of microbes from the genus Veillonella after doing extreme exercise. Veillonella feast on lactate and make propionate which was found to raise heart rate and oxygen use in mice, as well as boost human metabolism. Mice given the Veillonella atypica from the runners were found to run for 13 percent longer than the mice in the control group. This study showed that it was the exercise, rather than diet, which contributed to the Veillonella in the gut microbiome, although lactate allowed the microbes to grow. Both studies concluded that they would need a larger sample to make any concrete conclusions, but they both show that diet does not determine the human gut microbiome as many thought.

Cellular Roadblocks for Immigrants: The Loss of Gut Microbe Diversity

Recent evidence from the University of Minnesota in conjunction with the Somali, Latino, and Hmong Partnership for Health and Wellness suggested that immigrants and refugees moving to the United States were likely to experience a rapid change in their gut microbes. Described as “westernizing” to their environment, immigrants tended to lose their diverse, native microbes in favor of microbes that are common to European Americans.

The participants of this study originated from Southeast Asia, specifically the ethnic minorities of Hmong and Karen from China, Burma, and Thailand. The study used ethnic minority communities from both Southeast Asia as well as those living in Minnesota as a comparison, analyzing the gut microbes in these participants and using Caucasian American people as controls. The researchers also looked into the first generation children of these immigrants. Additionally, the study was able to follow a group of nineteen Karen refugees, tracking the changes in their gut microbes as they traveled to the United States.

The study discovered that the gut microbes in these participants changed rapidly. Particularly, in the group of Karen refugees, the Western strain of Bacteriodes replaced the non-Western strain of Prevotella in the matter of less than a year. Furthermore, the overall gut microbe diversity continued to decrease in all participants in the United States in relation to the length of their stay. Likewise, the children of immigrants had a more profound decrease in diversity. Researchers in this study suggested that this decrease in microbe diversity may have been a result of a Western diet, or for the children, growing up in the United States.

Image result for bacteroides

Closeup of Bacteroides biacutis(Image Credit: CDC/Dr. V.R. Dowell)

 

So why does this matter? Well, the study established a correlation: the greater the “westernization” of gut microbes, the greater obesity in immigrants. This obesity problem appeared to be more prevalent in immigrants, and the study had discovered a key piece of evidence for why.

“When you move to a new country, you pick up a new microbiome.” Dan Knights, one of the key authors of the study as well as a quantitative biologist at the University of Minnesota, says. “…What enzymes they carry…may affect the kinds of food you can digest and how your diet affects your health. This may not be a bad thing, but we do see that Westernization of the microbiome is associated with obesity in immigrants.”

 

I Can’t Sleep Because of… My Gut?

The Issue at Hand:

Unfortunately, the following scenario is all too common for some of us: We lie in bed, eyes closed, pacing our breath, all in a failed attempt to fall asleep. We periodically check our alarm clock, only to see the time get later and later. 2:30 a.m.? How could it be?! Well fellow reader, as Kate Leaver points out in her article ‘Could it be your gut keeping you awake at night?,’ there is a potential (and perhaps surprising) explanation to such restlessness… microbes.

So What Exactly Are Microbes?

In essence, microbes are microorganisms, such as bacteria. There are trillions in the small intestine alone. Despite their microscopic size, they have the ability to impact mood, digestion, and, as previously mentioned, sleep.

Above is an image of gut microbes. (Credit: Rocky Mountain Laboratories)

Ongoing Studies:

As Matt Walker, the director of the Center of Human Sleep Science at the University of California, Berkeley, points out: “…we don’t fully understand yet…the role of the microbiome in sleep.” However, various studies are currently exploring this phenomenon. Among these include a study conducted by scientists at the University of Colorado, which links microbes and quality of sleep by utilizing both probiotics (i.e. live bacteria) and prebiotics (i.e. carbohydrates such as fiber). Essentially, probiotics and prebiotics supplement the ‘good’ bacteria/microbes in our guts. In fact, after taking supplements for five days, insomniac Dr. Michael Mosley calculated that his time awake in bed decreased drastically from 21% to a mere 8%. Other sleep experts, such as clinical psychologist Dr. Michael Breus, attest to the link between sleep and microbes. Dr. Beus believes that, “…the microbial ecosystem may affect sleep and sleep-related physiological functions in a number of different ways: shifting circadian rhythms, altering the body’s sleep-wake cycle, affecting hormones that regulate sleep and wakefulness.” Finally, Tim Spector, professor of genetic epidemiology at King’s College London, points out how people with depression and people with poor sleeping schedules often have, “…abnormal microbes in the gut.”

What to Do Going Forward?

Given that the aforementioned studies are ongoing, and thus lack solidity, it can be difficult to determine how to improve one’s sleeping schedule. However, Mr. Spector adamantly believes that a healthy diet is the key to eliminating sleep disturbances. More specifically, he proposes the consumption of ‘gut-friendly’ foods, which are unprocessed and high in fiber. These include, but are not limited to, berries, green tea, dark chocolate, nuts, and seeds. Hopefully, with these tips, along with future discoveries, you will find yourself fast asleep in no time!

Can Probiotics Cure Alzheimer’s?

 

 

Research on how gut microbiota affects Alzheimer’s Disease, also called AD, has been done, and promising data collected. The only problem is that all of this data comes solely from research done on mice. There has been minimal research up to the present that was tested on actual people.

The closest thing to real-life research in this field, however, would be the research done by Dr. Mahmoud Salami, as reviewed by Gut Microbiota Research and Practice. Dr. Salami has collected data from a trial he is conducting in Iran. This trial consists of 60 people between the age 60 and 95. Now since we know that there has been minimal research on how gut microbiota effects Alzheimer’s, this work done by Dr. Salami is impressive.

Dr. Salami has found that a daily dose of probiotic Lactobacillus and Bifidobacterium bacteria taken over 12 weeks may improve cognitive function in elderly Alzheimer’s patients. Although more research must be done to have more definitive answers, Dr. Salami’s research opens up even more of a reason to human testing to be done.

Countless research has been done on how where one lives can affect there health, so wouldn’t it be interesting to see if data, similar to Dr. Salami’s, collected in varying locations throughout the world may provide varying results due to the location the participant calls their home?

 

 

Gut Microbes and the Brain

Neuroscientists are studying the idea that intestinal microbiota might influence brain development and behavior.

Neuroscientist Knickmeyer is looking to study 30 newborns and how they have grown into inquisitive, curious one-year olds through a series of behavioral and temperament tests. She is eager to see their faecal microbiota, bacteria, viruses and other microbes that live in their guts.

Studies of animals raised in sterile, germ-free conditions showed that these microbes in the gut influence behavior and can alter brain neurochemistry and physiology. Some research has drawn links with gut bacteria and their interactions with the brain.

Escherichia coli, a species of bacteria present in the human gut https://en.wikipedia.org/wiki/Gut_flora#/media/File:EscherichiaColi_NIAID.jpg

Gut Reactions

Prior to recent research, microbes and the brain have rarely been known to interact, with the exception of when pathogens penetrate the blood brain barrier. When they do, there can be intense effects. For example, the virus causing rabies elicits aggression, agitation and a fear of water. The idea that gut microbes could influence neurobiology was not ever thought of, but this is changing.

One research study showed that IBS lead to issues such as depression and anxiety. This lead scientists to wonder if psychiatric symptoms are driven by inflammation or a whacky microbiome caused by infection.

One 2011 study showed that germ-free mice were less-anxious than mice with indigenous microbes. These studies also showed that many of these behaviors are formed during a critical period during which microbes have their strongest effects. Another problem is that “germ-free” is an unnatural situation. However, it allows for researchers to learn which microbial functions are important for development of organs or cell types.

Chemical Exploration

Recent studies have found that gut microbes directly alter neurotransmitter levels, enabling their communication with neurons.

Scientists are also studying whether or not altered serotonin levels in the gut trigger a cascade of molecular events, therefore affecting brain activity.

In 2015 research showed that myelination can also be influenced by gut microbes, at least in a specific part of the brain. Germ-free mice are protected from some conditions, for example multiple sclerosis, because it is characterized by demyelination of nerve fibers. These scientists wish to use these studies to help humans who suffer from MS.

A Move to Therapy

Tracy Bale, a neuroscientist, sought to study how microbes of pregnant mothers affect their offspring. Maria Dominguez-Bello, microbiologist, wants to see if babies born through Caesarean sections end up with microbiota similar to babies born vaginally if they are swabbed on the mouth and skin with gauze taken from their mothers’ vaginas.

For Knickmeyer, the amygdala and prefrontal cortex are the brain areas that interest her the most in her studies with the newborn infants. This is because both of these areas have been affected by microbiota manipulations in rodent models. Something she is worried might affect the study is the confounding factors such as diet, home lives and environmental exposure.

Source: http://www.nature.com/news/the-tantalizing-links-between-gut-microbes-and-the-brain-1.18557

For more information:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4228144/

https://www.sciencenews.org/article/microbes-can-play-games-mind

http://www.huffingtonpost.com/healthline-/gut-bacteria-and-the-brai_b_11898980.html

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