Tag: dementia

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Probiotics for dementia: What’s the evidence?

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A review asks no matter whether probiotics could boost cognitive purpose for men and women with dementia or moderate cognitive impairment. Nikola Nastasic/Getty Images
  • Alzheimer’s disorder is the most common variety of dementia in the United States, impacting far more than 6 million men and women.
  • The success of a meta-analysis propose that probiotic supplementation may make improvements to cognitive function in people today with delicate cognitive impairment.
  • The review provides more information and facts about the correlations in between intestine health and fitness and mind health and fitness.

Some research hint that probiotics and prebiotics may well sluggish the progression of some neurodegenerative disorders.

Having said that, there are restricted facts on their outcomes in humans with Alzheimer’s ailment or mild cognitive impairment (MCI).

Researchers from Jiangnan College in China collaborated to assessment the proof to day. Their systematic overview and meta-assessment seems in the journal Meals.

General, the authors report: “Consistently, our conclusions recommend that probiotic intervention at early stages of Alzheimer’s ailment, these as MCI, could boost cognitive functionality and delay ailment progression.”

The team explored quite a few databases for research released involving 1984 and early 2021 involving subjects with Alzheimer’s or MCI.

Zhu and colleagues sifted as a result of 294 reports, ultimately including just eight article content for the systematic critique and seven for the meta-evaluation.

Cognitive function was the major end result of all the studies, measured by Mini-Psychological Point out Evaluation (MMSE) scoring. Secondary outcomes incorporated nutritional status, irritation biomarkers, metabolic profiles, and oxidative tension.

The review’s authors identified that probiotic health supplements improved cognitive purpose in individuals with MCI. Having said that, the effects ended up less impressive for individuals with Alzheimer’s ailment. Over-all, the authors conclude:

“Compared with placebo or handle interventions, probiotic supplementation significantly improved cognitive operate in the participants with MCI, but it only brought on a modest cognitive improvement in people with Alzheimer’s sickness.”

The range of probiotic strains administered, their dosage, and the duration of procedure performed a purpose in the extent of cognitive advancement.

Probiotic supplementation also altered the composition and composition of fecal microbiota in persons with Alzheimer’s.

The co-authors cite experiments that clearly show a lowered fecal microbial range in Alzheimer’s. Nevertheless, only 1 analyze in the overview showed that probiotic supplementation altered the framework and composition of fecal microbiota in men and women with Alzheimer’s.

Dr. David A. Merrill, Ph.D., is an adult and geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health and fitness Middle at Providence Saint John’s Overall health Middle in Santa Monica, CA. He was not included with this assessment.

In an job interview with Health care News Now, Dr. Merrill discussed:

“This meta-evaluation — a examine of scientific tests — supplies an important update about latest evidence demonstrating that gut health may perhaps assist mind function in more mature grown ups, in particular those with moderate cognitive impairment […] This is an significant update on a subject matter which reveals that our gut overall health impacts not only our systemic wellness but our emotional and cognitive well-staying, as effectively.”

Dr. Merrill was intrigued by the review’s locating that prebiotics may perhaps greatly enhance the output of brain-derived neurotrophic factor (BDNF):

“We know that BDNF levels decrease in the brain of Alzheimer’s clients, and this decline of BDNF is believed to play a part in the enhanced dying of neurons in the mind. So, maybe indirectly, prebiotics may perhaps support the circulating levels of BDNF in the system, leading to larger cell survival in the brain.”

Zhu and fellow scientists mentioned quite a few limits to their meta-examination. For starters, some of the trials applied modest sample dimensions.

Also, the chosen studies did not contemplate how other dietary dietary supplements and lifestyles may perhaps have impacted the gut microbiota and metabolic profiles.

The research provided in the examination also employed distinct score scales for cognitive impairment to evaluate cognitive function. Only four of the integrated studies referenced the typically applied NINCDS-ADRDA standards for dementia.

Four of the scientific studies unsuccessful to report any adverse effects of probiotic supplementation. Even though probiotics have been usually safe and sound, more mature individuals are extra susceptible to serious gastrointestinal, skin, and systemic aspect consequences.

Zhu and the group also expressed worry that experimental layout flaws and industrial funding may well have skewed some benefits.

The review’s authors hope that foreseeable future research will explore the adverse results of probiotic nutritional supplements. They also want to see scientific trials that group and evaluate individuals with Alzheimer’s disease and MCI in accordance to disease severity.

Further more, Dr. Merrill mentioned: “Knowing the most productive dose of specific probiotic strains for various condition situations like memory decline remains a obstacle.”

The psychiatrist cautions that this meta-assessment does not demonstrate that probiotics will support all people with MCI. On the other hand, he said:

“If you’ve had a overall health anxiety to your gut like having surgical procedure or needing to just take antibiotics, a person may take into account having probiotics for a time to improve the diversity of the good micro organism in the gut and return the intestine to its healthiest achievable state.”

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Does diet influence dementia risk? What we know

Dementia is a leading cause of disability and death worldwide. There is no cure. Recent research has focused on whether diet might influence the risk and progress of dementia. In this Special Feature, Medical News Today assesses the evidence and looks at how you might help reduce your risk of dementia.

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What does the latest research say about the link between diet and dementia risk? We investigate. Image credit: Luis Manuel Matias/Addictive Creative/Offset

According to the World Health Organization (WHO), dementia affects more than 55 million people worldwide, with 10 million people receiving a diagnosis each year. About 60-70{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} of people globally with dementia have Alzheimer’s disease, which affects almost 6 million people in the United States.

It may be the third leading cause of death after cancer and heart disease in certain age groups.

With an aging global population, the WHO predicts that the number of people with dementia will rise to 78 million by 2030 and 139 million by 2050.

According to existing research, diabetes, obesity, and heart disease, which can increase the risk of developing dementia, are all rising in number.

The main symptoms of dementia are memory problems, loss of cognitive function and coordination, and personality changes. The most significant risk factor for dementia is aging — more than 90{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} of people with dementia are over 65 — but other factors are also involved.

There is currently no cure for dementia, and most treatments alleviate symptoms without slowing the progress of the disease. So are there ways reduce to reduce this risk?

Keeping fit and healthy can reduce the risk of dementia — and diet is a large part of keeping fit.

In a comment for MNT, Dr. Christopher Weber, director of global science initiatives at the Alzheimer’s Association, noted that:

“Research looking at the relationship between diet and cognition is well-established. There is strong evidence to suggest that what is good for the heart is good for the head, and we know a healthy diet is good for the heart.”

Some studies have suggested that a Mediterranean diet can improve cognitive function. This diet includes plenty of fruit and vegetables, nuts and seeds, olive oil and fish, with small amounts of dairy, eggs, and red meat, together with a moderate amount of red wine.

Recent research showed that a Mediterranean diet has associations with improved cognitive functioning and slowed the progression from mild cognitive impairment to dementia.

An alternative to the Mediterranean diet is the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay). The diet is similar but focuses on green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine.

This diet highlights the importance of foods and nutrients that have an association with dementia prevention.

A problem with diet studies is that they are observational, and people usually assess their diet through self-reported questionnaires. However, researchers have demonstrated an association between these diets and improved cognitive function.

One study showed a substantially slower cognitive decline in those following the MIND diet. A 2021 study found a positive correlation between MIND diet score, cognitive resilience, and cognitive function.

Interestingly, the researchers found that improved cognitive function was independent of brain pathologies that post-mortems identified in participants.

Dr. Weber commented: “The Mediterranean diet and the MIND diet have been shown in clinical studies to be beneficial to brain and heart health. The Alzheimer’s Association encourages everyone to eat a healthy and balanced diet as a way to help reduce the risk of cognitive decline.”

Processed food is one of the current bad guys. Experts tell us to eat a balanced and varied diet containing plenty of fresh food to stay healthy. But could a diet high in processed food increase your dementia risk?

“There is […] strong evidence linking poor diet (for example, eating a diet high in unhealthy fats and sugar) and increased risk for dementia.”

– Dr. Christopher Weber

In animal models, a diet high in refined carbohydrates increases the risk of dementia and Alzheimer’s. A human study in France replicated this effect and confirmed that older participants who ate a daily snack high in refined carbohydrates were more likely to develop dementia.

Another study has linked processed meat products, such as sausages, salami, and bacon, with dementia. Regular consumption of processed meat increased the relative risk of all dementias by 44{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} and Alzheimer’s disease by 52{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809}.

However, like all the other dietary studies, this was observational and the risks reported are relative rather than absolute. One expert commented that the results “would not persuade me to give up my breakfast bacon.”

Proponents of vitamin and mineral supplements often tout them as a way of compensating for a less than optimal diet, but is there any evidence that they might help combat dementia?

A recent study gave older male rats a processed food diet high in refined carbohydrates and found that their learning and memory skills suffered. Another group of rats on the same diet but with omega-3 supplements showed no memory problems.

The authors of the study explained their findings in terms of the inflammatory response provoked by processed foods. Scientists know that omega-3 resolves inflammation, which might explain the effect in the rats who received it.

However, there is little other evidence to suggest that supplements affect dementia. The WHO advises that a healthy diet and regular exercise will likely have more significant effects.

The link between alcohol and dementia is not entirely clear. While heavy alcohol consumption has strong associations with the development of dementia, the effect of moderate alcohol intake is still open to question.

The majority of studies show an association between low to moderate alcohol use and reduced risk of dementia, particularly for red wine drinkers.

Two systematic reviews, one of which analyzed results from 26 studies, concluded that reducing heavy alcohol use could be an effective dementia prevention strategy.

However, they also noted that those who abstained from alcohol entirely had a higher dementia risk than those who drank in moderation.

Therefore, it is possible that drinking in moderation may have some protective effect, but no observational study can exclude all other factors. It may be that those who drink moderately have a better diet, do more exercise, or are generally in better health.

One study into the effects of moderate drinking in older adults in New Zealand controlled for socioeconomic status but found no evidence for a link between moderate drinking and better health.

So perhaps that protective effect is just wishful thinking from those of us who enjoy an occasional drink!

Research has linked memory decline with inflammation, and this is an area that is attracting a lot of interest.

According to Prof. Tim Spector, Professor of Genetic Epidemiology, King’s College London and Zoe Study lead, “This fits with the ‘inflammaging’ theory that is gaining a lot of traction.”

There are links between inflammation and the gut microbiome. Several clinical studies have seen an association between the gut microbiome and dementia.

One cross-sectional study in Japan found a significant difference between the microbiome of people with dementia and those without the disease.

Those with dementia had a much lower number of Bacteroides, a species known to reduce inflammation. They also had much higher numbers of microbes (enterotype III) that have associations with dementia.

Two other studies back up these findings. One analyzed gut microbiome metabolites, finding that people with dementia had significantly different metabolites from those without the disease.

A second stressed the links between the gut microbiota and dementia development, observing effects on the microglia and cytokine release, which have implications in inflammation and dementia.

“There are large numbers of studies that are pointing in the same direction. People with dementia have sub-optimal microbiomes. The picture is of not only reduced numbers of species but also increased numbers of inflammatory species.”

– Prof. Tim Spector

The gut microbiome and diet have links, and this could be why the Mediterranean and MIND diets have shown positive effects in reducing dementia risk and progression.

“Reduced [microbiome] diversity and [more] inflammatory species are related to poor diet, generally low in fiber and diversity of plants,” Prof. Spector told us. “With elderly people, there’s often a tipping point, such as losing a partner. The diet reduces in quality and diversity. That can accelerate cognitive decline.”

He did, however, stress that there may be a reverse causality. People in the early stages of cognitive decline might reduce the quality of their diet and thereby accelerate the process.

“Studies of centenarians have found that they generally live in areas with a good food culture and lots of socializing,” he added. “It’s not about fats. It’s not about carbohydrates or calories, but can you get fresh, varied food? You need your gut microbes to keep your immune system suppressing inflammation?”

The short answer is probably; that diet may well play a part. Evidence is growing that a varied diet rich in plants will support a varied gut microbiome. And a varied gut microbiome helps to reduce the inflammation implicated in dementia.

“Poor diet harms microbes, which harms the immune system with these knock-on effects of cognitive decline. In dementia, inflammatory aging is the current theory. It’s partly triggered by the immune system which involves the microbes and diet.”

– Prof. Tim Spector

So until randomized control trials can prove how diet influences dementia, it is probably best to eat a diet that reduces the risk of heart disease and supports your microbiome, combining it with regular exercise.

The jury is still out on moderate alcohol consumption, but there is clear evidence that too much alcohol increases the risk of many health conditions, including dementia.

Dr. Weber concluded: “While we continue to learn more about lifestyle factors that have the greatest impact on our overall risk, there are things we can do today that may decrease our risk of cognitive decline as we age. Eating a heart-healthy diet, exercising regularly, and staying cognitively engaged are just a few.”

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Early-onset hypertension may increase dementia risk

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A new study looks at links between age of hypertension diagnosis and dementia risk. Laurent Hamels/Getty Images
  • Researchers recently investigated how age at hypertension diagnosis affects brain volume and dementia risk.
  • Their results suggest people with a high blood pressure (HBP) diagnosis between ages 35 and 44 are 61{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} more likely to develop dementia than those without HBP.
  • The team says doctors should help young adults manage HBP, given lower treatment rates in this age group.

According to the World Health Organization (WHO), around 1.28 billion people aged 30–79 worldwide have HBP, or hypertension.

HBP is the leading cause of cardiovascular disease and premature death worldwide. It is also a risk factor for diabetes, depression, and dementia.

Previous research has found that HBP before the age of 35 has associations with cognitive impairment in mid-life. Some studies also suggest hypertension in mid-life is a risk factor for dementia. However, the link between later-life hypertension and dementia is inconsistent.

While the link between hypertension, brain volume, and dementia is well-established, researchers are still not sure how the age of hypertension onset affects dementia risk.

In a recent study, researchers from China and Australia used public health data to investigate how the age of hypertension onset affects brain health and the risk of developing dementia.

“Many previous studies have demonstrated that midlife hypertension is associated with an increased risk of dementia, but whether the association of hypertension with brain volume and dementia is affected by age at diagnosis of hypertension is unclear, “ Dr. Xianwen Shang, lead author of the study, told Medical News Today.

“We found hypertension diagnosed in young adulthood or mid-life, but not late life, was associated with smaller brain volumes and an increased risk of dementia. The younger age at diagnosis of hypertension, the larger brain volume reduction was observed,” explained Dr. Shang, a research fellow at the Guangdong Provincial People’s Hospital in Guangzhou, China.

“Our findings indicate both early- and mid-life are critical periods for the prevention of dementia or brain damage via prevention and treatment of hypertension,” he added.

The authors published their study in the journal Hypertension.

The researchers used publicly available data from UK Biobank, a database that contains anonymous health records from around half a million people in the United Kingdom.

They included 11,399 individuals diagnosed with hypertension before receiving a brain MRI scan between 2014 and 2019. All participants entered the biobank between 2006 and 2010. The researchers split the participants into five groups according to the age they received a hypertension diagnosis:

  • under 35 years
  • 35–44
  • 45–54
  • 55–64
  • over 65

The researchers then matched each individual with hypertension with a control individual who had also undergone an MRI but did not have hypertension. The team matched controls for factors including age, sex, ethnicity, income, education, cholesterol, and body mass index.

By comparing MRIs of individuals with and without dementia, the researchers found that those diagnosed with hypertension between the ages of 35 and 54 had smaller brain volumes compared with those without hypertension.

They also discovered that those diagnosed with hypertension before the age of 35 had the largest reductions in brain volume, and this difference remained significant even if these individuals later normalized their blood pressure.

Next, to investigate dementia, the researchers analyzed health records of 124,053 individuals with HBP at baseline alongside matched individuals who did not have HBP. Over an average follow-up of 11.9 years, 4,626 people developed dementia of some type.

The researchers showed that individuals diagnosed with hypertension between ages 35 and 44 had a 61{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} higher risk of developing dementia than those without hypertension.

In particular, the risk of vascular dementia — a common form of dementia due to impaired blood flow to the brain — was generally higher the earlier individuals received an HBP diagnosis.

Those diagnosed before age 35 were at an 80{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} higher risk, while those diagnosed between 45 and 54 were at a 45{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} higher risk. And those aged 65 years or older were at only a 2{cfdf3f5372635aeb15fd3e2aecc7cb5d7150695e02bd72e0a44f1581164ad809} higher risk.

However, the researchers found there was no relationship between hypertension diagnosed at any age and the risk of Alzheimer’s disease.

“There are several mechanisms for the effects of hypertension on the risk of dementia,” said Dr. Shang. “Firstly, hypertension is a well-known primary cause of stroke resulting in an increased risk of dementia, especially vascular dementia.”

“Secondly, a continuous supply of oxygen and glucose from blood to the brain is fundamental for brain and cognitive health. Increased motor stiffness and reduced compliance caused by long-term exposure to hypertension may reduce cerebral blood flow and increase cerebrovascular reactivity, thus resulting in brain damage or cognitive decline,” he added.

“The exact mechanism underlying the link between HBP and dementia risk is unknown and was not the focus of this study,” Dr. Simin Mahinrad, Ph.D., told MNT. Dr. Mahinrad is a research assistant professor at Northwestern University’s Feinberg School of Medicine in Chicago, IL, and was not involved in the study.

“However, it is generally believed that interactions between several pathologic factors are most likely responsible. Importantly, hypertension may result in structural and functional alterations in cerebral vessels, such as atherosclerosis, vascular stiffness, vascular remodeling, and impaired cerebral blood flow circulation and regulation.”

– Dr. Mahinrad

“Such alterations in cerebral vessels predispose the brain to several pathologies, such as white matter damage, brain volume loss, deposition of pathologic proteins, and stroke. All of these pathologies have been shown to affect cognitive function negatively and increase the risk for dementia,” Dr. Mahinrad continued.

MNT also spoke with Keenan Walker, Ph.D., from the Laboratory of Behavioral Neuroscience at the National Institute on Aging, who was not involved in the study. He said:

“Chronic hypertension, especially if untreated, may cause damage to the small vessels, which deliver blood to the brain, making them less efficient and reactive to systemic changes in blood pressure.”

“In this way, hypertension may lead to changes in cerebral blood flow, limiting the brain’s ability to deliver the necessary oxygen and nutrients. [The] age at which hypertension begins and the duration of hypertension seem to matter. Those who have hypertension begin earlier in life will likely have much more exposure to the adverse effects of HBP on end organs, such as the brain.” he added.

The researchers conclude that their findings highlight the importance of age during a hypertension diagnosis in the link between hypertension, brain volume, and dementia.

They say scientists should focus more on managing blood pressure among young adults given high levels of unawareness and lower treatment rates in this age group.

The researchers explain that their study cannot prove a causal relationship because of its observational design.

They also say that early dementia can begin decades before diagnosis and, therefore, before a hypertension diagnosis. With this in mind, scientists need to conduct more research to confirm the relationship between dementia and the age of hypertension diagnosis.

“Whether hypertension diagnosed at a younger age is associated with a larger decrease in brain volumes remains to be explored in studies with brain structure measured at multiple time points.”

– Dr. Shang

Another issue is that determining when healthcare professionals diagnosed hypertension relies on participant memory. As Dr. Walker explained:

“This is subject to inaccuracies, and a proportion of participants may have gone with undiagnosed hypertension for some time. Another limitation is the inability [to] differentiate Alzheimer’s dementia from vascular dementia with a high degree of accuracy. Biomarkers would have been helpful for this purpose,” he added.

Dr. Mahinrad explained another limitation: “The effect of antihypertensive treatment on the results has not been reported. This is important because antihypertensive drugs are known to affect neurocognitive measures, and their impact on brain volume within the context of [the] study is unknown.”

Dr. Mahinrad also explained that “the generalizability of these results to other populations with different ethnic backgrounds remains unknown.”

“This study has several strengths: a population-based study of a large number of individuals — around 20,000 participants — in the U.K., [the] inclusion of both males and females, rigorous statistical analyses to minimize sources of bias, and use of fully automated quantitative MRI data,” said Dr. Mahinrad.

Dr. Shang added, “Future longitudinal studies with longer follow-up duration are needed to examine whether hypertension diagnosed at a younger age was associated with a larger excessive relative risk of dementia over two or more decades.”