Tag Archives: Influencing

The Gut Microbiome: Influencing Our Personality Traits

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Fecal bacteria observed through an electron microscope

Science Photo Library / Alamy Stock Photo

Rats that received gut microbiomes from energetic human infants seem more inclined to explore their surroundings. This research suggests that the bacteria present in our guts during childhood may influence our personalities.

“This indicates that our microbes play an active role in emotional development, rather than merely being passive presence,” explains Harriet Scherekens from University College Cork, Ireland, who was not involved in the study.

Increasing research identifies a link between the microbial communities in our guts and various aspects of our well-being, emotions, and mood. For instance, individuals lacking certain gut bacteria types seem to face a higher risk of depression and anxiety.

While it remains uncertain whether bacteria are the cause of these emotional shifts or if the microbial communities alter in response to user actions, some evidence suggests that changes in the microbiome can influence an individual’s mood. For example, fecal transplants from depressed individuals to rats appear to induce depressive behavior. Conversely, depressed rodents receiving fecal transplants have shown improved symptoms upon preliminary examination.

To delve deeper into how the gut microbiome relates to temperament, Anna Artshinki and colleagues at the University of Turku in Finland conducted fecal transplants from infants into young rats.

Initially, the team evaluated the personalities of 27 toddlers aged 2.5 years using standard temperament assessments and an activity that encouraged play with bubble guns.

“Although we couldn’t study anxiety in 2-year-olds directly, we anticipated assessing behavioral differences, such as levels of inhibition versus sociability,” notes Artosinki.

From their evaluations, researchers classified 10 infants as energetic and 8 as inhibited and withdrawn. They then selected four energetic and four restrained infants (split evenly between genders) for fecal sample collection.

Fecal samples spiked with glycerol, alongside control samples, were transplanted into 53 22- or 23-day-old rats whose intestines had been pre-cleaned.

Artshinki’s team then subjected the rats to a variety of behavioral tests. They discovered that rats with microbiomes from energetic infants displayed a greater exploratory tendency compared to those receiving control implants or feces from inhibited infants.

To investigate how gut bacteria might influence the brain, the researchers also examined rat brain tissues for gene activity changes. This analysis indicated that rats receiving microbiomes from inhibited infants showed reduced activity in dopamine-producing neurons, a neurotransmitter linked to rewarding risk-taking behavior.

“This study effectively illustrates how the early childhood gut microbiome contributes to shaping behavioral tendencies,” Scherekens remarks. “By transferring microbiomes from children to rodents, researchers have created a valuable translation between microbes, human temperament, and brain function.”

This indicates a gut-brain pathway that impacts curiosity, reward, and motivation through the dopamine system, Scherekens adds.

Nonetheless, Artshinki cautions against overstating the implications. “Overall, adult temperament traits are strongly correlated with genetics, yet environmental factors—potentially including the microbiome—may play a role in certain behavioral distinctions.”

Artosinki emphasizes that whether microbes drive the differences in children’s behaviors remains an open question. It’s possible that children exhibiting more active traits interact with their environment and new foods in unique ways, thereby developing distinct microbiomes as a result.

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Source: www.newscientist.com

This Cat-Related Parasite Might Be Influencing Your Poor Choices: Here’s How

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Parasites transmitted by cats may influence the behavior of nearly half of the global population, leading to riskier behaviors and increased aggression.

A recent review article aggregated various studies to emphasize the significance of considering both mental health and the physical consequences of parasite infections.

Reviews published in Frontiers of Psychiatry focus on the most prevalent parasitic infections affecting humans, particularly Toxoplasma gondii.

These parasites can enhance the production of dopamine, a hormone associated with feelings of pleasure, in the brain.

While increased dopamine may seem beneficial, it actually promotes detrimental behaviors, resulting in poor impulse control, heightened aggression, and an increase in risky sexual practices.

“The societal implications of these findings are significant,” the study notes. “The potential for behavioral modifications due to widespread infections of parasites like T. gondii highlights that such infectious diseases can lead to psychological and social challenges in addition to medical ones.”

“Particularly, the likelihood that these infections can intensify aggressive and impulsive behaviors raises vital considerations for understanding and preventing violence and behavioral disorders.”

It is estimated that 30-60% of the global population may be infected with T. gondii, though rates in the U.S. are significantly lower, around 10%.

Most healthy adults do not exhibit obvious physical symptoms, resulting in many infections going unnoticed.

The ultimate target for T. gondii – the cat’s digestive system. Image source: Getty Images/Artmarie

Cats are primary hosts for these parasites as they reproduce within the cat’s digestive system, forming egg-like structures known as oocysts.

Once cats excrete waste, these oocysts can contaminate the environment, infiltrating soil, water, and vegetation. Other animals, including the prey of cats like birds and rodents, may ingest them.

In a bid to return to a cat’s digestive tract, T. gondii has adapted to manipulate the brain chemistry of these prey species, making them less likely to escape and more likely to be consumed.

Humans primarily contract T. gondii through handling cat feces or consuming undercooked foods. Fortunately, there are simple measures to reduce the risk of infection.

  • Thoroughly wash your hands, knives, and cutting boards after handling raw food, especially meat.
  • Ensure that lamb, pork, venison, and other meats are cooked thoroughly.
  • Thoroughly rinse fruits and vegetables under running water.
  • Avoid unpasteurized milk and dairy products, especially goat milk.
  • Wear gloves while gardening.
  • Exercise caution and wash hands after cleaning the cat’s litter box.

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Source: www.sciencefocus.com

Research shows that consuming citrus fruit can help protect against depression by influencing the gut microbiome

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New research reveals a potential protective role for citrus fruits in preventing depression. Faecalibacterium prausnitzii, a type of bacteria found in the human intestine, and its metabolic activity, may influence the impact of citrus fruits and their flavonoids on mood.

Samuthpontorn et al. We report that citrus intake and its ingredients are positively associated with changes in abundance of 15 intestinal microbial species, including reduced risk of depression and enrichment Faecalibacterium prausnitzii. Image credit: Hans.

Depression is a widespread and debilitating condition that affects more than 280 million individuals around the world.

The exact cause of depression is unknown, and treatment is often ineffective.

70% of patients with depression are unable to respond to initial antidepressant treatment and experience unbearable side effects of the drug.

Diet may be a promising tool for preventing and managing depression.

Mediterranean diets are associated with a nearly 35% reduction in the risk of depression, and similar diets show a reduction in mood symptoms.

While the specific food groups underlying these findings remain unknown, recent studies have linked citrus fruits, such as oranges and grapefruits, with a reduced risk of depression.

However, the mechanisms explaining the relationship between diet and depression prevention remain unclear.

In a recent study, Dr. Raaj Mehta, a medical instructor at Harvard Medical School and a physician at Massachusetts General Hospital, along with colleagues, analyzed the interactions between citrus consumption, gut microbiome, and risk of depression in over 32,427 participants.

They prospectively examined the long-term effects of citrus intake on depression, the abundance of gut microbial species, and the potential metabolic pathways related to depression.

“I was collaborating with a talented postdoc named Chatpol Samuthpontorn. He came across a paper from 2016 suggesting that citrus fruits could reduce the risk of depression,” explained Dr. Mehta.

“This finding intrigued us, as we had access to extensive datasets that could help us investigate further.”

“One of these datasets was the Nurse Health Study II (NHS2), which began in 1989 to identify risk factors for major chronic diseases in women.”

“We found evidence in this dataset that nurses who consumed higher amounts of citrus fruits had a lower incidence of depression in the future.”

The authors found that consuming one medium orange per day could reduce the risk of developing depression by about 20%.

“When examining total fruit and vegetable consumption, or other individual fruits like apples and bananas, we did not observe a significant relationship with depression risk,” Dr. Mehta noted.

A unique aspect of this study was that a subset of NHS2 participants provided stool samples over a year for researchers to analyze.

“We used DNA sequencing results from these stool samples to identify links between citrus intake and specific bacterial species in the gut microbiota,” said Dr. Mehta.

“One bacterial species, Faecalibacterium prausnitzii, stood out.”

“People who were not depressed had higher levels of this bacterium, and consuming more citrus was also linked to increased levels of Faecalibacterium prausnitzii.”

“This bacterium may play a key role in connecting citrus consumption with good mental health.”

“We also investigated similar studies involving men, as NHS2 only included women, and found an inverse correlation between Faecalibacterium prausnitzii and depression risk scores in this group,” Dr. Mehta added.

“This raises the question: Does Faecalibacterium prausnitzii contribute to positive mood?”

“One possible explanation is that these bacteria use metabolic pathways, such as the S-adenosyl-L-methionine cycle I pathway, to influence the production of neurotransmitters like serotonin and dopamine in the intestine,” Dr. Mehta explained.

“These neurotransmitters not only influence digestion but can also travel to the brain, where they affect mood.”

“We hope our findings encourage further research into the link between diet and mental health,” Dr. Mehta stated.

“People generally understand that food can impact mood, but researchers are just starting to unravel the specifics.”

A paper detailing these findings was published in the journal Microbiome.

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C. Samuthpontorn et al. 2024. F. Prausnitzii Potentially modulates the association between citrus intake and depression. Microbiome 12, 237; doi:10.1186/s40168-024-01961-3

Source: www.sci.news

Recent study provides insights into the factors influencing human evolution in East Africa

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East Africa contains the world’s most complete record of human evolution, yet scientists know little about how long-term biogeographic dynamics in the region have influenced human diversity and distribution.

An artist’s depiction of early human habitation in Tanzania 1.8 million years ago. Image courtesy of M. Lopez-Herrera / Enrique Baquedano / Olduvai Paleoanthropology and Paleoecology Project.

In the new study, Dr. Ignacio Razaga-Baster from the National Center for Research on Human Evolution (CENIEH) and his colleagues focused on the mammal fossil record of the East African Rift Valley.

“The Late Cenozoic fossil beds of the East African Rift Valley provide the world’s richest, longest and most continuous record of human evolution and its environmental context,” the authors explained.

“As such, the human and faunal records of East Africa have been central to understanding the factors that shaped human evolutionary history.”

“Our study provides a new perspective on how climatic and environmental changes over the past six million years have influenced mammal and human evolution,” Dr Razaghabastar said.

“This study particularly highlights how biotic homogenization – the process by which the faunas of different regions become more similar in composition – has been an important factor in the evolution of ecosystems and the species that live in them.”

“Beta diversity analysis, which shows the relationships between regional and local biodiversity, allows us to trace how changes in vegetation and climate have driven patterns of dispersal and extinction over time.”

The team found that faunas from the Late Miocene and Pliocene (approximately 3 million to 6 million years ago) were primarily made up of endemic species.

The shift towards biotic homogenization, or faunal homogenization, began around 3 million years ago with the loss of endemic species within functional groups and an increase in the number of grazing species shared between regions.

This important biogeographic transition coincides closely with the regional expansion of ecosystems dominated by grasses and C4 grasslands that thrive better in warmer, drier climates.

These environmental changes directly affected the feeding and migration patterns of humans and animals that shared the habitat.

“We are certain that hominoids, like other East African mammals, were influenced by many factors. This study offers a new perspective on the link between environmental and human evolutionary change and, through an integrated approach, provides a framework for future research and to test the hypothesis that hominoids adapted to their environment,” Dr Razaghabastar said.

of study Published in the journal on July 15, 2024 Natural Ecology and Evolution.

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J. Rowan othersLong-term biotic homogenization in the East African Rift Valley during the past 6 million years of human evolution. Nat Ecol EvolPublished online July 15, 2024; doi: 10.1038/s41559-024-02462-0

Source: www.sci.news

New research reveals deeper insights into the genetic factors influencing coffee consumption

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Coffee is one of the most widely consumed beverages. In a new study, scientists from the University of California, San Diego and others conducted a genome-wide association study (GWAS) of coffee intake among US-based 23andMe participants. They investigated genetic correlations and conducted a phenotype-wide association study across hundreds of biomarkers, health, and lifestyle traits, and compared their results with the largest GWAS of coffee intake from UK Biobank.

Coffee drinking is an inherited habit and carries a certain amount of genetic load. Image courtesy of Sci.News.

“To create the GWAS, we collected genetic data and self-reported coffee consumption,” said lead author Dr. Hayley Thorpe, a researcher at Western University and the University of Guelph.

“Our goal was to identify associations between genes known to be associated with coffee consumption and health-related traits and conditions.”

“We used these data to identify regions in the genome that are associated with a higher or lower likelihood of drinking coffee.”

“And then we identify the genetics and biology that underlie coffee consumption.”

“Many people are surprised that coffee consumption has genetic effects,” said co-author Abraham Palmer, PhD, a research scientist at the University of California, San Diego.

“From previous papers, we had good reason to suspect that there was a gene that influenced coffee intake.”

“So it wasn’t a surprise to us that in both cohorts we looked at, there was statistical evidence that this is a genetic trait.”

“In other words, the specific genetic variants we inherit from our parents influence how much coffee we drink.”

“The genetic influence on coffee consumption was the first of two questions we wanted to answer,” said Sandra Sanchez Loij, PhD, a research scientist at the University of California, San Diego and senior author of the paper.

“The second thing is what coffee lovers really want to know: Is drinking coffee good or bad? Does drinking coffee have positive health consequences or not?”

The group’s genome-wide association study of 130,153 US-based 23andMe study participants, compared with a similar UK Biobank database (334,649 British individuals), found consistent positive genetic associations between coffee consumption and adverse health outcomes such as obesity and drug use.

A positive genetic association is a link between a particular gene variant (genotype) and a particular condition (phenotype).

Conversely, a negative genetic association would be a clear protective trait that would thwart the onset of the disease.

When it comes to mental illness, the findings are more mixed.

“For example, if you look at the genetics of anxiety disorders, bipolar disorder and depression, in the 23andMe data, they tend to be positively correlated with the genetics of coffee consumption,” Dr. Thorpe said.

“However, in UK Biobank we see the opposite pattern of negative genetic correlation, which is not what we expected.”

“There were other instances where the 23andMe sets did not match the UK Biobank, but the biggest discrepancies were for psychiatric disorders.”

“It’s common in this field to combine similar datasets to increase research power. This information tells us pretty clearly that combining these two datasets was not a smart idea. And we ended up not doing so.”

“Mixing databases can mask effects, leading researchers to erroneous conclusions, or even cancel each other out.”

“There are a few ideas as to how the differences in results could have arisen. First, the studies were comparing apples with oranges,” Dr. Sánchez Loisi said.

“For example, the 23andMe survey asks, ‘How many 5-ounce (cup-sized) cups of caffeinated coffee do you drink per day?’ Compare this to UK Biobank’s, ‘How many cups of coffee do you drink per day (including decaffeinated coffee)?'”

“The study did not take into account the variety of ways coffee is presented, beyond serving size and whether it’s caffeinated or decaffeinated.”

“We know that in the UK instant coffee is generally preferred, whereas in the US ground coffee is more commonly preferred,” Dr Thorpe said.

“And then there’s the Frappuccino, the American fad of drinking coffee loaded with added sugar,” Dr. Sánchez Loij added.

“There are other caffeinated drinks out there and, particularly in the UK Biobank context, tea was not included in the GWAS that looked solely at coffee,” Dr Palmer said.

“GWAS shows that the genotype-phenotype relationship is more different than that between coffee and tea.”

“Genetics influences a lot of things. For example, it influences your height.”

“And these things would probably play out in the same way whether you lived in the US or the UK. But coffee is a decision people make.”

“Coffee comes in many forms, from instant to Frappuccino, and is consumed within different cultural norms in different places,” Dr Sánchez Loij said.

“Someone with one genotype may end up with a completely different phenotype if they live in the UK and the US.”

“And that’s exactly what the data tells us, because in the case of height, behavior doesn’t really matter, but behavior and selection in the environment affect it in different ways. So genotype-environment interactions complicate the picture.”

Team paper Published in the journal Neuropsychopharmacology.

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HHA Soap othersGenome-wide association study of coffee consumption in UK/US participants of European descent revealed cohort-specific genetic associations. NeuropsychopharmacologyPublished online April 17, 2024, doi: 10.1038/s41386-024-01870-x

Source: www.sci.news