The Healthiest Agers Had This One Thing In Common by mindbodygreen

 Ask your competent? doctor how they ARE ENSURING YOU AGE HEALTHILY!

That requires EXACT PROTOCOLS! Don't let them fob off guidelines as useful, THEY'RE NOT!

The Healthiest Agers Had This One Thing In Common

Gut microbiome shifts may begin before Alzheimer’s symptoms appear

 Then have your competent? doctor test for this so THOSE EXACT PREVENTION PROTOCOLS CAN BE INITIATED! Don't have any, do they? PURE INCOMPETENCE! 

Why you need them;

1. A documented 33% dementia chance post-stroke from an Australian study?   May 2012.

2. Then this study came out and seems to have a range from 17-66%. December 2013.`    

3. A 20% chance in this research.   July 2013.

4. Dementia Risk Doubled in Patients Following Stroke September 2018 

Gut microbiome shifts may begin before Alzheimer’s symptoms appear

A new review traces how diet, gut bacteria, and their metabolites may intersect with the silent biological changes that precede cognitive decline.

Want to read later? Download your PDF copy by clicking here.

In a recent narrative review published in the journal Nutrients, researchers across Australia summarized evidence on the gut microbiota, microbial metabolites, and dietary patterns in relation to early Alzheimer’s disease (AD). The review did not generate or analyze new data.

AD has a long preclinical stage when metabolic alterations, amyloid accumulation, and neuroinflammation develop while people remain cognitively unimpaired (CU). Understanding these biological changes can help elucidate mechanisms pertinent to early prevention. Recent findings suggest that early AD pathology may be accompanied by alterations in the gut microbiota and other systemic changes. Diet plays an important role in gut microbiota composition and metabolic output.

Diet-induced changes in the microbiota may influence gut–brain communication relevant to metabolic and neuroinflammatory regulation. Research also links long-term dietary patterns to the risk of cognitive impairment and AD. Nevertheless, the relevance of microbiome–diet interactions to microbial functional pathways in preclinical AD remains poorly defined. In this narrative review, researchers summarized evidence linking the gut microbiota, microbial metabolites, and diet to early AD.

AD: Diagnosis and Therapeutic Context

Research advances have enabled AD detection based on biological markers without relying solely on clinical symptoms. Cerebrospinal fluid (CSF) biomarkers and amyloid positron emission tomography (PET) imaging enable the detection of pathology in CU individuals. Standardized amyloid PET quantification, such as the Centiloid scale, can help stratify people along the preclinical continuum and facilitate comparisons across studies.

Current AD treatments offer limited benefit once cognitive decline is established. Common symptomatic treatments, including memantine, donepezil, galantamine, and rivastigmine, provide modest cognitive and functional improvements. Further, while disease-modifying therapies, for example, lecanemab, have been developed for early-stage AD, they are restricted to select populations and have limited clinical benefit.

As such, most available treatments are initiated only after substantial damage has occurred, thereby reducing their capacity to meaningfully modify disease progression. This therapeutic limitation constitutes a substantial challenge in AD treatment, underscoring the need for further research and attention toward earlier AD stages.

Gut–Brain Communication

The gut–brain axis (GBA) is the bidirectional communication network between the central nervous system (CNS) and the gastrointestinal system. It plays an important role in regulating physiological processes, including brain function, metabolism, and immune activity. Alterations in the microbiota composition can modify metabolic and inflammatory conditions in ways that may increase vulnerability to neurodegenerative processes.

Microbial metabolites are an important component of gut–brain communication. Short-chain fatty acids (SCFAs), the most studied metabolites, regulate immune cell differentiation, metabolic pathways, epithelial barrier integrity, and cytokine production. SCFAs can modulate neuronal function and neuroinflammatory processes through these actions. Emerging evidence suggests that GBA disruptions may contribute to the metabolic and inflammatory disturbances seen in early AD. However, direct human evidence in preclinical AD remains limited, and SCFA effects may depend on their concentration and biological context.

Gut Microbiome Dysregulation in AD

A growing body of research suggests that AD is associated with changes in gut microbiota function and composition. In particular, reduced abundance of SCFA-producing genera, such as Eubacterium, Roseburia, and Faecalibacterium, has been commonly reported in AD and cognitive impairment. Meanwhile, some studies report an increased relative abundance of Escherichia/Shigella and other Proteobacteria, which are associated with inflammatory signaling, metabolic imbalance, and oxidative stress.

Microbiota functional alterations in AD include disruptions in fermentation pathways, changes in lipid and amino acid metabolism, and decreases in SCFA biosynthesis. Early changes in microbial metabolic pathways and SCFA-producing taxa have been reported in a small number of studies involving CU individuals with biomarker evidence of amyloid pathology. Although studies have reported inconsistent findings, they suggest that the earliest stages of AD may be characterized by gut microbial dysregulation.

Dietary Patterns Associated With AD

Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean diet (MD) are associated with improved cognitive, cardiovascular, and metabolic outcomes in aging populations. Both emphasize increased intake of plant-based foods, while limiting processed and red meats, added sugars, and saturated fats. Higher adherence to these diets is linked to reduced cerebral amyloid burden, slower cognitive decline, and improved vascular function in older individuals.

The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, which combines elements from DASH and MD, has similarly been associated with slower accumulation of AD-related pathology. Further, the prudent dietary pattern has been associated with improved inflammatory and metabolic profiles in aging populations. It is characterized by high intake of fruits, whole grains, vegetables, fish, low-fat dairy, and legumes. The prudent dietary pattern has been associated with higher microbial diversity and enrichment of SCFA-producing taxa.

Concluding Remarks

Collectively, available research suggests that alterations in the composition and metabolic activity of the gut microbiota may be associated with early AD pathology. Reductions in SCFA-producing taxa and alterations in microbial metabolic pathways have been observed in a limited number of studies involving CU populations with amyloid pathology.

However, the current evidence base has important limitations. Most studies have involved populations with AD or mild cognitive impairment rather than biomarker-confirmed preclinical AD, and much of the available evidence is cross-sectional, preventing conclusions about the direction of the relationship. Sequencing has generally been limited to the genus level, while few studies have jointly assessed diet, gut microbiota, microbial functional pathways, SCFAs, and amyloid pathology. As a narrative review, this work also focused primarily on SCFAs rather than other potentially relevant microbial metabolites.

Future studies should prioritize longitudinal, species-level metagenomic analyses in CU individuals grouped by amyloid status. These studies should assess microbial functional pathways, SCFAs, and diet within the same cohort. Researchers should also investigate fecal microbiota transplantation as a potential intervention in experimental AD models.

Journal reference:

• Dissanayaka DMS, Rainey-Smith SR, Sohrabi HR, et al. (2026). Gut Microbiome Changes in Preclinical Alzheimer’s Disease. Nutrients, 18(15):2469. DOI: 10.3390/nu18152469. https://www.mdpi.com/2072-6643/18/15/2469

Coffee linked to significant new side effect, says massive study

 Benefits of coffee have been out there for years! And your incompetent? doctor and hospital still haven't installed a 24 hour coffee station!

• coffee (415 posts to February 2012) 

Coffee linked to significant new side effect, says massive study

Your morning cup of coffee might be doing you more good than just waking you up—according to a new study, coffee also has a positive impact on the a person’s microbiome, improving the health of the gut-brain axis.

Researchers from the University College Cork in Ireland examined how regular consumption of coffee—both caffeinated and decaffeinated—affects the gut microbiome.

The study showed that coffee notably increased the presence of good bacteria like Eggertella sp and Cryptobacterium curtum in coffee drinkers. Both bacteria are thought to play a role in eliminating unhealthy bacteria and stomach infections.

Decaffeinated coffee drinkers, meanwhile, showed improvements in learning and memory, which may have been a result of components like polyphenols that provide cognitive benefits.

Caffeinated coffee, meanwhile, was linked to reduced feelings of anxiety, as well as improved attention.

‘Only part of the story’

“Coffee is one of the richest sources of dietary polyphenols, yet most research has focused almost entirely on caffeine,” corresponding author of the study John Cryan told Newsweek in an email.

“We wanted to understand how coffee as a whole affects the microbiome, metabolism, mood and cognition. One of the biggest surprises was that decaffeinated coffee produced many of the same effects as regular coffee. 

(Really? You incompetently missed this earlier research?

How Coffee May Protect Brain Health: A New Study Suggests The Benefits Aren't Just From Caffeine December 2018 )

“That suggests caffeine is only part of the story, and that other coffee compounds, particularly polyphenols, may play a major role in shaping the gut–brain axis.”

Coffee’s Health Benefits

Coffee has previously been shown to have health benefits.

One 30-year study of women over the age of 70 found that they were significantly more likely to be living well if they consumed coffee during middle age.

Another study found that drinking black coffee reduced the risk of death from all causes.

(I have to add whole milk to get the dairy fat benefits)

The study from the University College Cork, meanwhile, showed that coffee has a positive impact on gut health, a major topic of interest.

Prebiotic sodas are gaining popularity, and gut health is increasingly linked to a number of health outcomes, including mental health.

Coffee’s Potential to be ‘Harnessed’

Gastrointestinal cancers are on the rise as well, particularly in American adults, which has drawn more attention to how people should take care of their gut microbiome.

“Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome,” Cryan said in a press release.

“Coffee may modify what microbes do collectively and what metabolites they use.

“As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy balanced diet.”

‘More biologically complex’

Cryan added that “like many dietary factors,” coffee is best in moderation.

“We also found that habitual coffee drinkers showed higher impulsivity and emotional reactivity than non-drinkers, which highlights that the effects are not universally positive,” he told Newsweek.

According to Cryan, he is hopeful that as research progresses, they might be able to use diet and microbiome to “more precisely” support overall health and well-being.

“The main takeaway is that coffee is much more biologically complex than we tend to think,” Cyan said.

“It’s not simply a stimulant; it interacts with the gut microbiome, immune system, metabolism and brain simultaneously.”

This Probiotic Combination Was Linked To Better Mood & Higher BDNF Levels by mindbodygreen

 Of course your competent? doctor already has EXACT PROTOCOLS that deliver all the BDNF you need. And has been for over a decade, right? But your doctor incompetently knew nothing and did nothing, right? Which means your board of directors is so incompetent they can't recognize incompetence in their staff!

• BDNF (208 posts to April 2011)

This Probiotic Combination Was Linked To Better Mood & Higher BDNF Levels

The best vegetable for metabolic health, according to an endocrinologist

 Of course your incompetent? doctor hasn't had the dietician create any form of diet protocol for you, right? So this won't show up in your hospital food or your suggested diet at home!

The best vegetable for metabolic health, according to an endocrinologist

One vegetable that checks all the boxes for metabolic health is broccoli.

Reviewed by Dietitian Jane Leverich, M.S., RDN

Key Points

• Metabolic health consists of how well our cells are process glucose and inflammatory compounds.
• According to an endocrinologist, broccoli is the best vegetable to support metabolic health.
• Broccoli delivers antioxidants that help combat inflammation and fiber that supports gut health.

Unlike heart health or gut health, metabolic health can feel a bit more abstract. “When we talk about metabolic health, we’re really talking about how efficiently our body’s cellular engines are functioning,” says Chhaya Makhija, M.D., DipABLM, a triple-board certified endocrinologist.  Another way to think about it, she says, is how well our cells process glucose, fats, cholesterol and inflammatory compounds and carry out the many functions required to maintain energy and overall health.

One of the best ways to support those cellular engines is by eating more vegetables. “Different vegetables provide different fibers, antioxidants, phytonutrients, vitamins and minerals that work together to support our health,” says Makhija. But one vegetable that may be particularly beneficial for metabolic health is broccoli. Read on to learn why broccoli earned an endocrinologist’s top pick.

Related: I Test Kitchen Gear for a Living—These Are the Amazon Deals I’d Never Pass Up, and You Have Hours to Grab Them

Why Broccoli Tops the List for Metabolic Health

It Contains Compounds That Fight Inflammation

Oxidative stress and chronic inflammation are two factors that can interfere with metabolic health. Though inflammation progresses quietly, it is linked to various chronic diseases and can make it more difficult for the body to regulate blood sugar, cholesterol and blood pressure. The good news is that eating broccoli may help keep inflammation in check. 

Broccoli contains a variety of bioactive compounds—including sulforaphane, quercetin and flavonoids—that have been associated with antioxidant and anti-inflammatory benefits, says Lauren Harris-Pincus, M.S., RDN. This mighty green veggie is also a surprisingly rich source of vitamin C, another potent antioxidant. In fact, a ½-cup serving of cooked broccoli provides more than half of the Daily Value for vitamin C.,

It Supports a Healthy Gut Microbiome

“The gut microbiome plays a much larger role in metabolism than many people realize, influencing everything from glucose regulation to inflammation and overall health,” says Makhija.

Eating more veggies like broccoli is one of the best ways to support gut health. For starters, broccoli is a good source of fiber, which supports digestive health and helps maintain a healthy gut microbiome—creating a more favorable metabolic environment, according to Makhija.

In fact, 1 cup of cooked broccoli provides an impressive 5 grams of fiber. What’s more, research suggests that eating broccoli may positively influence the composition of the gut microbiome. Because broccoli contains prebiotic fiber, it may help support the growth of beneficial gut bacteria.

It’s a Great Choice for Heart Health

When metabolic health is impaired, it can create a domino effect that increases the likelihood of high blood pressure, low HDL (“good”) cholesterol, high triglycerides and elevated blood sugar levels, all of which are associated with a greater risk of heart disease. Broccoli provides several nutrients and compounds that may help support these aspects of cardiometabolic health.

For starters, the fiber in broccoli may help lower cholesterol and support healthy blood sugar levels. The glucosinolates and polyphenols in broccoli also have antioxidant and anti-inflammatory properties, which may help protect blood vessels from oxidative stress. Finally, this cruciferous vegetable naturally contains nitrates, compounds that can help support healthy blood flow and blood pressure. In other words, adding broccoli to your plate may offer multiple benefits for heart health.

It Supports a Balanced Plate

Another reason to add broccoli to your plate is that it can help create a more balanced eating pattern. “I frequently encourage patients to build their plates around vegetables first, because doing so naturally helps reduce reliance on highly processed foods, refined carbohydrates and foods with hidden sugars,” says Makhija. 

One helpful rule of thumb is to fill at least half of your plate with nonstarchy vegetables like broccoli. “In many ways, vegetables are foundational to metabolic health because they nourish both our cells and our gut while supporting healthier eating patterns overall,” she adds. 

Ways to Enjoy Broccoli

Ready to add more broccoli to your plate? Here are some delicious ways to enjoy it: 

• Toss it into a salad. Broccoli makes a sturdy, fiber-rich base for salads and holds up well in the fridge without getting soggy. Pair it with a creamy or savory dressing and plenty of toppings, like nuts and cheese. 
• Mix it into pasta or casseroles. If broccoli’s strong flavor has been holding you back, try adding it to mixed dishes like pasta or casseroles instead of serving it as a stand-alone side.
• Roast it. Toss raw broccoli florets with olive oil and seasonings, then roast until tender with crispy edges and deeper flavor. For an easy dinner, roast broccoli on the same sheet pan as potatoes and your protein of choice.
• Blend it into soups. Steam broccoli until soft and blend it into soups and stews. You can also blitz it in a food processor to make a higher-fiber broccoli pesto for pasta.

Other Tips for Supporting Metabolic Health

Eating more broccoli—and more vegetables in general—is a great first step toward supporting metabolic health. Here are a few other habits that may help:

• Focus on fiber. “Approximately 95% of Americans miss the mark on fiber intake, which is an important factor in gut health and the prevention of lifestyle diseases like heart disease, diabetes and cancer. Focus on fiber-rich plant foods, including produce, whole grains, beans/pulses, nuts and seeds,” says Harris-Pincus.
• Prioritize sleep. Diet isn’t the only factor that influences metabolic health—sleep matters too. “Sleep disruption affects multiple hormonal pathways and can contribute to insulin resistance, higher cortisol spikes, increased appetite, blood pressure changes and greater glucose variability,” says Makhija. She recommends maintaining a consistent sleep schedule with regular bedtimes and wake-up times to help support adequate rest.
• Manage stress. Don’t overlook the negative health effects of chronic stress. Like inadequate sleep, ongoing stress can affect many of the same hormonal pathways involved in metabolism, says Makhija. “This doesn’t mean eliminating stress—which is impossible—but rather building tools to manage it more effectively.”

Our Expert Take

If there’s one vegetable that stands out for metabolic health, it’s broccoli. This tasty and versatile veggie delivers antioxidants that help combat inflammation, fiber that supports a healthy gut and key nutrients that promote heart health. Still, as much as broccoli has to offer, it’s important to keep in mind that no single food can transform your metabolic health on its own. “Metabolic health is not built through one food, one supplement or one exercise program. It is the result of daily habits that support our hormones, our metabolism and our overall well-being,” says Makhija.

Read the original article on EatingWell

What Berberine Does To The Gut Microbiome, According to a New Study by mindbodygreen

 Your competent? doctor has already told you of all the benefits of berberine, right? Oh NO; you got one of the incompetent ones, didn't you?

berberine (8 posts to November 2017)

What Berberine Does To The Gut Microbiome, According to a New Study

14 Foods That Protect Gut Health and Slow Biological Aging by Super Age

 Will your competent? doctor get the dietician to evaluate all the hospital meals for compliance? NO?  Which means your whole hospital is incompetent and needs to be reconstituted! 

14 Foods That Protect Gut Health and Slow Biological Aging

‘Smart Underwear’ Measures Gut Gas for Microbiome Science

 Does your competent? doctor have enough brains to start using this to monitor your gut micobiota? And does s/he have protocols to fix that microbiome?

• gut microbiota (48 posts to June 2016)
• gut microbiome (65 posts to March 2016)

‘Smart Underwear’ Measures Gut Gas for Microbiome Science

A “smart underwear” device, created by scientists at University of Maryland (UMD) in College Park, Maryland, monitors frequency of flatulence and hydrogen concentration in hopes of more accurately setting a baseline for what’s typical.

The device is about the size of three stacked nickels that can be snapped onto the exterior of any underwear near the perineal region. It uses electrochemical sensors and researchers receive the readings through an app around the clock.

It’s the “first wearable for monitoring gut microbiome activity via flatus hydrogen,” according to the researchers, led by first author Santiago Botasini, PhD, a UMD assistant research scientist with the Department of Cell Biology and Molecular Genetics. The team introduced the device in a study published in Biosensors and Bioelectronics: X.

Previous Tracking Methods Limited

Few flatulence studies have been conducted and much of the research had been done using rectal tubes, Brantley Hall, PhD, Department of Cell Biology and Molecular Genetics, UMD, told Medscape Medical News, “but rectal tubes aren’t a very comfortable, scalable approach. We think there’s an opportunity to build on that so we can understand flatulence patterns. You can ask people how much they fart, but it’s not very accurate. People’s perception is really off. Clinicians need better evidence.”

Article Key Points

Smart underwear developed by University of Maryland scientists tracks flatulence frequency and hydrogen levels, offering insights into gut microbiome activity. The device, not a medical tool, could aid clinicians in understanding gas patterns and tailoring treatments.

Asking people about frequency also misses accounting for the time a person is asleep, something the underwear device can automatically capture, he noted.

In a weeklong User Experience Study, participants who were asked to wear the device for at least 3 days reported high comfort and compliance. In a second study, the device accurately detected increased hydrogen production after inulin ingestion with 94.7% sensitivity in 38 healthy participants, demonstrating its ability to track changes in microbial metabolism with diet changes.

Individual Variation Extreme

The research also found that healthy adults expel gas about 32 times a day, about twice as often as the current literature states. Individual variation was extreme, researchers found.

Recently, one person’s device logged expulsions “more than 300 times a day,” Hall said. “We’ve shipped out about 100 devices so far and we’re starting to get some interesting results.” And though 300 was the highest number so far, some devices are showing 200-plus readings, he said.

“If clinicians learned in their medical textbook that 14 +/- 6 flatus a day is normal and someone says, ‘I’m farting 200 times a day’, that can cause anxiety for patients,” Hall said. “Flatus is the most noticeable thing your microbiome does,” he said. “And it’s insane to me that we’re not measuring it. For us to identify what’s abnormal, we first have to find out what’s normal.”Toward that end, Hall’s Lab launched the Human Flatus Atlas. The project will use smart underwear to track flatulence patterns and correlate those patterns with diet and microbiome composition for a diverse population. Devices are shipped to participants in the US.

Not a Medical Device

The tracker is not a medical device, Hall emphasized, “but I think it could help clinicians inform the directions of their treatment.”

“We hope to capture a baseline that is a trustworthy, scientifically validated number of flatus,” he said. “It will give a pretty unprecedented view of something that’s been invisible until now.”

He said he thought originally it might be hard to recruit people to sign up to use the device, but that wasn’t the case. “We’re completely overwhelmed with the demand” and currently offering only a waitlist. “We’ve made 850 devices and we’ve had more than 5000 people sign up to be part of the research,” Hall said.

Supriya Rao, MD, managing partner of Integrated Gastroenterology Consultants in Boston, said this work fills a gap.

“Until now we have relied on breath tests, invasive rectal tube studies, and symptom reporting which are really, limited snapshots,” she told Medscape Medical News. “This device can capture real time data over days and shows that people pass gas more frequently than we previously thought. It challenges some of our baseline assumptions about that normal physiology.”

Timing and Pattern Important

She said timing and pattern matter just as much as magnitude in medicine. “We care about whether fermentation occurs and when it begins, how frequent it is, and how it evolves throughout the day. Do we see hydrogen production increase after a meal, or is there a delay? Timing can tell us a lot,” she explained.

Gastroenterologists often see a disconnect between a patient’s perception of bloating and the actual volume of gas present. “This could help me figure out whether a patient’s symptoms are coming from excess gas production or from heightened sensitivity in the gut. This would allow us to tailor treatments more effectively,” she said.

She noted that the studies were small and done in healthy volunteers and characterized the device as “promising.”

“I would like to see a study done with those with gastrointestinal disorders. Hydrogen is only one part of the metabolic puzzle in our guts. Some microbes consume hydrogen and not all fermentation pathways produce it,” she noted.

Botasini reported having a relationship with Ventoscity LLC that included equity or stocks. Hall reported having a relationship with Ventoscity LLC that included board membership and equity or stocks. Botasini and Hall reported having a patent pending on Smart Underwear to Measure Volatile Metabolites Produced by the Human Gut Microbiota to Licensee from the UMD by Ventoscity LLC. Botasini and Hall reported having a patent on Method for Assessing the Likelihood of Malabsorption or SIBO via Measurements of Gut Microbial Gas Production Excreted in Flatus pending to Licensee from the UMD by Ventoscity LLC. Hall and Botasini reported having submitted two patent applications about the uses for the Smart Underwear device and cofounded a startup, Ventoscity LLC, to commercialize the technology and Ventoscity LLC has licensed the patents from the UMD. The other authors had no other conflicts to declare.

This work was supported by UMD Startup funds to Hall, the Maryland Technology Development Corporation through the Maryland Innovation Initiative, and the UM Ventures Medical Device Development Fund.

Rao reported having no relevant financial relationships.

Study Suggests Certain Olive Oil May Help Boost Brain Function and Cognitive Health

 Does your competent? doctor have enough functioning neurons to get the dietician to put this in your diet protocol? Oh, you incompetently DON'T HAVE A DIET PROTOCOL? Why not? But you also need daily EXACT AMOUNTS! To get mine I dip bread in a mixture of olive oil and balsamic vinegar, found from Italian restaurants.

Do you prefer your doctor, hospital and board of director's incompetence NOT KNOWING? OR NOT DOING? Your choice; let them be incompetent or demand action!

OH NO! your doctor KNOWS NOTHING AND DOES NOTHING! 

Study Suggests Certain Olive Oil May Help Boost Brain Function and Cognitive Health

3 Science-Backed Ways To Support Memory & Brain Health With Diet by mindbodygreen

 Don't let your incompetent? doctor give you guidelines like this! You need SPECIFICS, like an EXACT DIET PROTOCOL! 

3 Science-Backed Ways To Support Memory & Brain Health With Diet

Gut microbiome changes improve memory in early cognitive decline

 Will your competent? doctor ENSURE A PROTOCOL GETS WRITTEN ON THIS? To prevent cognitive decline from your stroke!

Do you prefer your doctor, hospital and board of director's incompetence NOT KNOWING? OR NOT DOING? Your choice; let them be incompetent or demand action!

OH NO! your doctor KNOWS NOTHING AND DOES NOTHING! 

Gut microbiome changes improve memory in early cognitive decline

From Mediterranean diets to probiotics, scientists reveal how reshaping the gut microbiome could help protect brain function, while highlighting why timing may be critical for slowing cognitive decline. 

Study: The association between gut microbiota and cognitive decline: A systematic review of the literature. Image credit: Toa55/Shutterstock.com

The gut-brain axis is gaining importance as a modulator of brain functional health. A recent paper in Nutrition Research synthesized evidence from the literature to show that multiple approaches to manipulating the gut microbiome share common biological pathways to improve cognitive performance in adults aged 45 years or older with cognitive impairment or at risk of dementia.

Aging gut microbiota shifts linked to dementia risk 

Multiple neurodegenerative disorders like Alzheimer’s disease (AD) are mediated in part by alterations in the gut-brain axis caused by aging-related shifts in the gut microbiota. Dementia is progressive and irreversible, causing neurological decline and a reduced life expectancy.

This is in contrast to the early stages of cognitive impairment, or mild cognitive impairment (MCI), when functional deficits can be detected but typically do not affect daily functioning.

Gut-brain mechanisms underlying cognitive decline

The gut-brain axis is a bidirectional communication system between the central nervous system and the gut. It involves signaling via nerves, hormones, and immunological mediators. Recent research has established its important role in regulating neurodevelopment, mood, and cognition.

However, age- and diet-related changes in the gut microbiota may induce dysbiosis, which is thought to contribute to the onset of neurodegeneration.

With gut dysbiosis, the gut epithelial barrier is compromised. This allows bacteria and microbial-associated molecular patterns to enter the bloodstream. The resulting systemic endotoxemia may trigger chronic low-grade inflammation. Gut dysbiosis also causes immune cell abnormalities, resulting in a systemic pro-inflammatory state.

Systemic inflammation may weaken the blood-brain barrier (BBB), exposing the brain to pro-inflammatory triggers and mediators. The resulting neuroinflammation is associated with the accumulation of abnormal proteins, such as amyloid-β and tau, the hallmark of AD. Neuronal synapses are damaged, and function is impaired. The eventual outcome is cognitive decline, whether as a part of aging or of AD.

The microbiome, immune system, and brain are engaged in a continuous dialogue, where perturbations in one component can reverberate throughout the system, creating a vicious cycle that promotes cognitive decline.

Microbiome research evolves from observation to intervention

The researchers outlined the progression of such studies. The earliest, purely descriptive, studies of gut microbial responses were followed by detailed microbiome characterizations driven by advances in DNA and RNA sequencing and metabolomics. This was followed by the current interventional studies with a stronger mechanistic focus.

Integrating evidence on dysbiosis and cognition

The authors aimed to pull together evidence from studies covering various microbiota-targeting interventions in isolation. They reviewed the literature on cognitive changes in adults aged 45 years or older with cognitive impairment or at risk of dementia who participated in experimental manipulations of the gut microbiota.

The interventions included probiotics, prebiotics, methyl donor nutrient supplementation, omega-3 fatty acid intake, synbiotics, fecal microbiota transplants (FMT), and diets like the Mediterranean or keto diets. The patients were evaluated for inflammatory and metabolic changes, as well as alterations in fecal microbiota.

Microbiota changes linked to cognitive improvement

The review included 15 studies covering a range of demographic characteristics. The study sample ranged from 5 to over 1,200 participants. Overall, there were 4,275 participants.