Diets high in fat, sugar may reduce cognitive functioning by altering gut bacteria

A Diet high in fat or sugar may do more than expand our waistlines. A new study by researchers from Oregon State University finds such diets may lead to reduced cognitive functioning, with a high-sugar diet named as the biggest culprit.

The team found diets high in sugar or fat triggered alterations to the gut microbiome linked to reduced cognitive functioning.

Published in the journal Neuroscience, the study reveals that high-fat and high-sugar diets trigger changes in gut bacteria that are largely associated with loss of "cognitive flexibility" - the ability to adapt to changing situations.

In addition, the high-sugar diet was associated with poorer short- and long-term memory.

Principal investigator Prof. Kathy Magnusson, of the College of Veterinary Medicine and the Linus Pauling Institute at Oregon State, notes there is an increasing amount of evidence emerging that gut bacteria can communicate with the brain.

"Bacteria can release compounds that act as neurotransmitters, stimulate sensory nerves or the immune system, and affect a wide range of biological functions," Prof. Magnusson explains. "We're not sure just what messages are being sent, but we are tracking down the pathways and the effects."

One example of how gut bacteria may interact with the brain was revealed in a study published in the journal Cell in April, in which researchers from the California Institute of Technology (Caltech) found that gut bacteria influence the production of serotonin - a neurotransmitter responsible for maintaining mood balance.

Reduced cognitive flexibility with high-fat, high-sugar diets

Prof. Magnusson and colleagues reached their findings using 2-month-old male mice, which were randomized to be fed either a high-fat diet (42% fat, 43% carbohydrate), a high-sugar diet (12% fat, 70% carbohydrate - mainly from sugars) or normal chow.

Prior to dietary intervention and 2 weeks after, the researchers analyzed the feces of the mice in order to establish the composition of their gut bacteria.

The short- and long-term memory and cognitive flexibility of the mice were assessed before and after dietary intervention via water maze testing and novel object and location tasks.

Compared with mice fed normal chow, mice fed the high-fat or high-sugar diets experienced a significant reduction in cognitive functioning - particularly in cognitive flexibility.

Explaining what cognitive flexibility is, Prof. Magnusson asks us to imagine driving home using a route that is very familiar. One day, the road is closed, meaning we need to find a different route.

An individual with a high level of cognitive flexibility would adapt to the situation straight away, immediately seeking out an alternative route. But a person with impaired cognitive flexibility may find the unexpected change in situation very stressful, causing them to become flustered and take longer getting home.

Reduction in cognitive flexibility was strongest for mice fed the high-sugar diet, according to the researchers, and this diet was also found to reduce short- and long-term memory.

Diets altered gut microbiome of mice

The team believes the reduction in cognitive functioning following diets high in fat or sugar was driven by alterations to the composition of gut bacteria, or the gut microbiome.

Both diets were linked to an increase in bacteria called Clostridiales and a reduction in bacteria known asBacteroidales, with such changes associated with reduced cognitive flexibility.

Mice fed the high-sugar diet experienced the highest increases in Clostridiales and the biggest reductions in Bacteroidales, consistent with the largest reductions in cognitive flexibility.

The team says their findings are consistent with some previous studies suggesting that a Western diet - typically high in fat and sugar - may negatively impact cognitive functioning. Past research has associated a Western diet with greater risk of Alzheimer's disease, for example. Their study indicates that such a diet may affect cognitive functioning via alteration of the gut microbiome.

Prof. Magnusson says:

"We've known for a while that too much fat and sugar are not good for you. This work suggests that fat and sugar are altering your healthy bacterial systems, and that's one of the reasons those foods aren't good for you. It's not just the food that could be influencing your brain, but an interaction between the food and microbial changes."

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Crows count on 'number neurons'

Neurobiologists have discovered cells in the crow brain that respond to a specific number of items. The study provides valuable insights into the biological roots of counting capabilities. What makes this finding even more interesting is that a long evolutionary history separates us from birds; as a consequence, the brains of crows and humans are designed very differently.

Crows recognized the number of dots shown in computer displays. Tübingen researchers discovered ‘number neurons’ in the crow’s end-brain that responded to a specific number of items.

Credit: Andreas Nieder

An old story says that crows have the ability to count. Three hunters go into a blind situated near a field where watchful crows roam. They wait, but the crows refuse to move into shooting range. One hunter leaves the blind, but the crows won't appear. The second hunter leaves the blind, but the crows still won't budge. Only when the third hunter leaves, the crows realize that the coast is clear and resume their normal feeding activity.

Helen Ditz and Professor Andreas Nieder of the University of Tübingen found the neuronal basis of this numerical ability in crows. They trained crows to discriminate groups of dots. During performance, the team recorded the responses of individual neurons in an integrative area of the crow endbrain. This area also receives inputs from the visual system. The neurons ignore the dots' size, shape and arrangement and only extract their number. Each cell's response peaks at its respective preferred number.

The study published in PNAS provides valuable insights into the biological roots of counting capabilities. "When a crow looks at three dots, grains or hunters, single neurons recognize the groups' 'threeness' ," says Helen Ditz. "This discovery shows that the ability to deal with abstract numerical concepts can be traced back to individual nerve cells in corvids."

What makes this finding even more interesting is that a long evolutionary history separates us from birds. As a consequence, the brains of crows and humans are designed very differently.

"Surprisingly, we find the very same representation for numbers as we have previously discovered in the primate cortex," Prof. Andreas Nieder says. "It seems as if corvids and primates with independently und distinctively developed endbrains have found the same solution to process numbers." Even abstract behavior which we think of as sophisticated mental feats ultimately has biological roots.

---

Story Source:

The above story is based on materials provided by Universitaet Tübingen.Note: Materials may be edited for content and length.

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Stroke: not just an adult's condition

When you hear the word "stroke," the first picture that pops into your mind is likely to be of an elderly individual. It's true that older adults are at greater stroke risk; the chance of having a stroke doubles with each decade of life after the age of 55. But did you know that infants and children can also suffer stroke? It can even occur before birth.'

Stroke affects 6 in every 100,000 children in the US and is one of the 10 leading causes of death among children in the country.

According to the National Stroke Association, stroke affects 6 in every 100,000 children in the US. It is also one of the 10 leading causes of death among children in the country.

The rate of stroke is much higher in adults than children. Every year, more than 795,000 men and women suffer a stroke and around 130,000 die from the condition. However, studies have found stroke rates are on the rise in children in the US.

In 2011, a study published in the Annals of Neurology reported a 51% increase in ischemic stroke incidence among boys aged 5-14 from the period 1995-96 to 2007-08, while girls aged 5-14 saw a 3% rise in ischemic stroke in the same period.

In many ways, stroke in children - commonly referred to as pediatric stroke - can present more challenges than stroke in adults.

The early signs of stroke in children are much more subtle than in adults, meaning they often go unrecognized. According to the International Alliance for Pediatric Stroke (IAPS), newborns who suffer stroke may not even begin to show any symptoms until the age of 4-8 months.

What is more, because parents, caregivers and even health care professionals do not often associate stroke with children, it may be ruled out as a possibility. As a result, many children fail to receive adequate treatment.

A 2014 study conducted by Dr. Mark Mackay, director of the Children's Stroke Program at the Royal Children's Hospital and Murdoch Children's Research Institute in Melbourne, Australia, and colleagues found that only half of interviewed parents whose children suffered stroke thought their child's symptoms were serious enough to call 911, while 21% of parents adopted a "wait-and-see" approach. What is more, only 36% considered stroke as a possible cause of their child's symptoms.

As with most health conditions, early treatment for stroke is key. Unfortunately, around 20-40% of children die after a stroke, and of those who do survive, around 50-80% will have lifelong neurological problems, such a partial or total paralysis.

May is American Stroke Awareness Month. In this Spotlight, we investigate the risk factors for pediatric stroke, the signs and symptoms to look out for, as well as the treatment options for the condition.

Perinatal stroke and childhood stroke

There are two types of pediatric stroke: perinatal stroke and childhood stroke.

Perinatal stroke, also referred to as fetal or prenatal stroke, occurs between the last 18 weeks of pregnancy and the first 30 days of birth. In the US, perinatal stroke occurs in about 1 in every 2,800 live births.

Most cases of perinatal stroke are ischemic, caused by blood clots breaking off from the placenta and becoming lodged in the child's brain.

Childhood stroke occurs between the ages of 1 month and 18 years. Unlike adults, in whom ischemic stroke is most common, children are equally as likely to have ischemic stroke as they are hemorrhagic stroke - caused by a brain bleed from a ruptured blood vessel.

Around 60% of all pediatric strokes occur in boys, and African-American children are at greater stroke risk than Caucasian and Asian children.

The risk factors for pediatric stroke

Among adults, high blood pressure, irregular heartbeat and atherosclerosis - hardening of the arteries - are some of the most common risk factors for stroke. These factors rarely cause stroke in children, however.

According to the American Stroke Association, around half of all pediatric strokes are triggered by an underlying condition, most commonly sickle cell disease - an inherited blood disorder - and congenital heart disease.

Other underlying conditions that may raise a child's stroke risk include head and neck infections, abnormal blood clotting, head trauma and systemic conditions, such as autoimmune disorders.

Maternal history of infertility, premature rupture of membranes during pregnancy, maternal preeclampsia and chorioamnionitis - inflammation of the fetal membranes due to a bacterial infection - may also increase a child's stroke risk.

Though cardiovascular-related risk factors for stroke in adults are rare in children, recent studies have indicated an increase in these risk factors among the younger population. This is down to a rise in high blood pressure, obesity, diabetes, high cholesterol and tobacco and alcohol use among youth.

A 2014 study published in the journal Neurology also suggested colds and other minor infections in childhood may temporarily raise a child's stroke risk.

"We've seen this increase in stroke risk from infection in adults, but until now, an association has not been studied in children," commented study author Dr. Heather Fullerton, director of the University of California-San Francisco Pediatric Stroke and Cerebrovascular Disease Center.

"It is possible that inflammatory conditions contribute more to the stroke risk in children, however, further research is needed to explore this possible association."

It is important to note, however, that in around half of all childhood stroke cases, no previous risk factor can be determined.

What are the signs and symptoms to look out for?

As mentioned previously, it can be very hard to spot stroke symptoms among very young children. Around 40% of infants do not show symptoms of early stroke; a parent may not know their baby has suffered stroke until months later when they show reduced movement or weakness on one side of their face.

As well as weakness or numbness on one side of the body, other signs of stroke in children may include severe headache, dizziness and vomiting.

Repetitive twitching of the face, arm or leg can be an indicator of stroke in newborns, as can a pause in breathing alongside prolonged staring and extreme fatigue.

As children develop, the signs of symptoms of stroke are very similar to those in adults. Weakness or numbness on one side of the body and problems speaking or understanding language - such as slurred speech or problems understanding simple instructions - may be signs of stroke.

Other signs of stroke among children may include severe headache, vomiting, fatigue, severe dizziness and appearance of seizures.

The American Stroke Association stress that the F.A.S.T. acronym is an easy way to remember the sudden signs of stroke in both children and adults:

• Face drooping. Is one side of the face numb or drooping? Is the individual able to smile?
• Arm weakness. Is one arm numb or weak? Ask the individual to lift both arms. Does one arm drift downward?
• Speech difficulty. Is the individual's speech slurred? Do they find it hard to speak or are they hard to understand? Can they correctly repeat a simple sentence, such as "the sky is blue?"
• Time to call 911. If the individual shows any of these symptoms, call 911 immediately, even if the symptoms disappear. Check the time at which first symptoms appear.

"Think stroke, act fast and call 911. That message applies to adults and children," says Dr. MacKay. "Getting to the hospital quickly is an essential first step to develop strategies to improve access to emergency treatment in children."

Treatment options for pediatric stroke

For adults suffering ischemic stroke, the first port of call in terms of treatment is the medication tissue plasminogen activator (tPA), which works by dissolving any blood clots that are blocking the arteries, restoring blood flow to the brain. Such treatment must be administered within 3 hours of symptom onset - 4.5 hours for some patients.

The use of tPA among young children with ischemic stroke, however, is controversial. Since children and adults have physiological differences, health care professionals are concerned about the drug's safety and efficacy among children - something that is currently being investigated.

As such, stroke treatment for children tends to vary depending on the cause of their stroke and any underlying medical conditions they may have. A child whose stroke was caused by a heart defect, for example, may be treated with blood-thinning medication, such as warfarin or aspirin.

Children who suffer stroke have around a 15-18% chance of suffering another stroke. Therefore, many children may receive treatment to prevent stroke recurrence, such as antithrombotic therapy - medication that stops blood clots from forming or growing.

One crucial treatment for the majority children who suffer stroke is rehabilitation therapy, which can involve physiotherapy, occupational therapy and speech therapy.

Sixty percent of children experience neurological problems, such as hemiplegia or hemiparesis cerebral palsy, following stroke. Rehabilitation therapy can really help reduce the neurological effects of stroke, and the earlier treatment is started, the more likely it is to succeed.

Severe delays in diagnosis of pediatric stroke

But as Dr. MacKay's study showed, many parents either do not consider the possibility that their child is suffering a stroke or are unable to recognize the signs, which can severely delay treatment.

Dr. MacKay's findings revealed that the average time from symptom onset of pediatric stroke to arrival at the emergency room was 1.8 hours, with some arrivals taking up to 4 hours.

And it is not only parents who may overlook the signs and symptoms of pediatric stroke - doctors can too. Studies have found that in the US, it can often take longer than 24 hours to diagnose stroke in children.

A report from ABC News in 2011 provides evidence of this, revealing how it took more than 25 hours for doctors to diagnose a 15-year-old boy from Ohio with stroke.

Because of the delay in diagnosis, the boy had to have a part of his skull removed to ease pressure from the build up of blood in his brain.

In a 2008 interview, Dr. Fullerton said she believes a delay in diagnosis of pediatric stroke has fallen into a gap in clinical care. "It is a rare disorder in general, and so most child neurologists will not be very comfortable in caring for children with stroke," she said, adding:

"Stroke is considered more a disease of adults, but then adult stroke neurologists aren't familiar of the etiologies of stroke in children or how to manage stroke in children, and so they're often uncomfortable with caring for a stroke in a child.

It can be difficult to diagnose the etiology of their strokes. It often takes sophisticated imaging studies and studies that are done by very experienced practitioners. It really often does take a team approach to figure out why a child has had a stroke and figure out what is the best way to prevent more strokes in that child."

While stroke is much rarer in children than adults, it is important that parents, caregivers and health care professionals are aware that children can be affected by the condition and take note of the signs and symptoms that may arise.

Not only is May American Stroke Awareness Month, 2nd-8th May is dedicated to World Pediatric Stroke Awareness Week. Set up by the IAPS and not-for-profit organization Brendon's Smile last year, the campaign aims to raise awareness of pediatric stroke around the globe and educate communities about how the condition can impact children's lives.

Visit the IAPS website to find out more about pediatric stroke and how you can help raise awareness of the condition.

Continue to Read more ...

Stroke: not just an adult's condition

When you hear the word "stroke," the first picture that pops into your mind is likely to be of an elderly individual. It's true that older adults are at greater stroke risk; the chance of having a stroke doubles with each decade of life after the age of 55. But did you know that infants and children can also suffer stroke? It can even occur before birth.

Stroke affects 6 in every 100,000 children in the US and is one of the 10 leading causes of death among children in the country.

According to the National Stroke Association, stroke affects 6 in every 100,000 children in the US. It is also one of the 10 leading causes of death among children in the country.

The rate of stroke is much higher in adults than children. Every year, more than 795,000 men and women suffer a stroke and around 130,000 die from the condition. However, studies have found stroke rates are on the rise in children in the US.

In 2011, a study published in the Annals of Neurologyreported a 51% increase in ischemic stroke incidence among boys aged 5-14 from the period 1995-96 to 2007-08, while girls aged 5-14 saw a 3% rise in ischemic stroke in the same period.

In many ways, stroke in children - commonly referred to as pediatric stroke - can present more challenges than stroke in adults.

The early signs of stroke in children are much more subtle than in adults, meaning they often go unrecognized. According to the International Alliance for Pediatric Stroke (IAPS), newborns who suffer stroke may not even begin to show any symptoms until the age of 4-8 months.

What is more, because parents, caregivers and even health care professionals do not often associate stroke with children, it may be ruled out as a possibility. As a result, many children fail to receive adequate treatment.

A 2014 study conducted by Dr. Mark Mackay, director of the Children's Stroke Program at the Royal Children's Hospital and Murdoch Children's Research Institute in Melbourne, Australia, and colleagues found that only half of interviewed parents whose children suffered stroke thought their child's symptoms were serious enough to call 911, while 21% of parents adopted a "wait-and-see" approach. What is more, only 36% considered stroke as a possible cause of their child's symptoms.

As with most health conditions, early treatment for stroke is key. Unfortunately, around 20-40% of children die after a stroke, and of those who do survive, around 50-80% will have lifelong neurological problems, such a partial or total paralysis.

May is American Stroke Awareness Month. In this Spotlight, we investigate the risk factors for pediatric stroke, the signs and symptoms to look out for, as well as the treatment options for the condition.

Perinatal stroke and childhood stroke

There are two types of pediatric stroke: perinatal stroke and childhood stroke.

Perinatal stroke, also referred to as fetal or prenatal stroke, occurs between the last 18 weeks of pregnancy and the first 30 days of birth. In the US, perinatal stroke occurs in about 1 in every 2,800 live births.

Most cases of perinatal stroke are ischemic, caused by blood clots breaking off from the placenta and becoming lodged in the child's brain.

Childhood stroke occurs between the ages of 1 month and 18 years. Unlike adults, in whom ischemic stroke is most common, children are equally as likely to have ischemic stroke as they are hemorrhagic stroke - caused by a brain bleed from a ruptured blood vessel.

Around 60% of all pediatric strokes occur in boys, and African-American children are at greater stroke risk than Caucasian and Asian children.

The risk factors for pediatric stroke

Among adults, high blood pressure, irregular heartbeat and atherosclerosis - hardening of the arteries - are some of the most common risk factors for stroke. These factors rarely cause stroke in children, however.

According to the American Stroke Association, around half of all pediatric strokes are triggered by an underlying condition, most commonly sickle cell disease - an inherited blood disorder - and congenital heart disease.

Other underlying conditions that may raise a child's stroke risk include head and neck infections, abnormal blood clotting, head trauma and systemic conditions, such as autoimmune disorders.

Maternal history of infertility, premature rupture of membranes during pregnancy, maternal preeclampsia and chorioamnionitis - inflammation of the fetal membranes due to a bacterial infection - may also increase a child's stroke risk.

Though cardiovascular-related risk factors for stroke in adults are rare in children, recent studies have indicated an increase in these risk factors among the younger population. This is down to a rise in high blood pressure, obesity,diabetes, high cholesterol and tobacco and alcohol use among youth.

A 2014 study published in the journal Neurology also suggested colds and other minor infections in childhood may temporarily raise a child's stroke risk.

"We've seen this increase in stroke risk from infection in adults, but until now, an association has not been studied in children," commented study author Dr. Heather Fullerton, director of the University of California-San Francisco Pediatric Stroke and Cerebrovascular Disease Center.

"It is possible that inflammatory conditions contribute more to the stroke risk in children, however, further research is needed to explore this possible association."

It is important to note, however, that in around half of all childhood stroke cases, no previous risk factor can be determined.

What are the signs and symptoms to look out for?

As mentioned previously, it can be very hard to spot stroke symptoms among very young children. Around 40% of infants do not show symptoms of early stroke; a parent may not know their baby has suffered stroke until months later when they show reduced movement or weakness on one side of their face.

As well as weakness or numbness on one side of the body, other signs of stroke in children may include severe headache, dizziness and vomiting.

Repetitive twitching of the face, arm or leg can be an indicator of stroke in newborns, as can a pause in breathing alongside prolonged staring and extreme fatigue.

As children develop, the signs of symptoms of stroke are very similar to those in adults. Weakness or numbness on one side of the body and problems speaking or understanding language - such as slurred speech or problems understanding simple instructions - may be signs of stroke.

Other signs of stroke among children may include severe headache, vomiting, fatigue, severe dizziness and appearance of seizures.

The American Stroke Association stress that the F.A.S.T. acronym is an easy way to remember the sudden signs of stroke in both children and adults:

• Face drooping. Is one side of the face numb or drooping? Is the individual able to smile?
• Arm weakness. Is one arm numb or weak? Ask the individual to lift both arms. Does one arm drift downward?
• Speech difficulty. Is the individual's speech slurred? Do they find it hard to speak or are they hard to understand? Can they correctly repeat a simple sentence, such as "the sky is blue?"
• Time to call 911. If the individual shows any of these symptoms, call 911 immediately, even if the symptoms disappear. Check the time at which first symptoms appear.

"Think stroke, act fast and call 911. That message applies to adults and children," says Dr. MacKay. "Getting to the hospital quickly is an essential first step to develop strategies to improve access to emergency treatment in children."

Treatment options for pediatric stroke

For adults suffering ischemic stroke, the first port of call in terms of treatment is the medication tissue plasminogen activator (tPA), which works by dissolving any blood clots that are blocking the arteries, restoring blood flow to the brain. Such treatment must be administered within 3 hours of symptom onset - 4.5 hours for some patients.

The use of tPA among young children with ischemic stroke, however, is controversial. Since children and adults have physiological differences, health care professionals are concerned about the drug's safety and efficacy among children - something that is currently being investigated.

As such, stroke treatment for children tends to vary depending on the cause of their stroke and any underlying medical conditions they may have. A child whose stroke was caused by a heart defect, for example, may be treated with blood-thinning medication, such as warfarin or aspirin.

Children who suffer stroke have around a 15-18% chance of suffering another stroke. Therefore, many children may receive treatment to prevent stroke recurrence, such as antithrombotic therapy - medication that stops blood clots from forming or growing.

One crucial treatment for the majority children who suffer stroke is rehabilitation therapy, which can involve physiotherapy, occupational therapy and speech therapy.

Sixty percent of children experience neurological problems, such as hemiplegia or hemiparesis cerebral palsy, following stroke. Rehabilitation therapy can really help reduce the neurological effects of stroke, and the earlier treatment is started, the more likely it is to succeed.

Severe delays in diagnosis of pediatric stroke

But as Dr. MacKay's study showed, many parents either do not consider the possibility that their child is suffering a stroke or are unable to recognize the signs, which can severely delay treatment.

Dr. MacKay's findings revealed that the average time from symptom onset of pediatric stroke to arrival at the emergency room was 1.8 hours, with some arrivals taking up to 4 hours.

And it is not only parents who may overlook the signs and symptoms of pediatric stroke - doctors can too. Studies have found that in the US, it can often take longer than 24 hours to diagnose stroke in children.

A report from ABC News in 2011 provides evidence of this, revealing how it took more than 25 hours for doctors to diagnose a 15-year-old boy from Ohio with stroke.

Because of the delay in diagnosis, the boy had to have a part of his skull removed to ease pressure from the build up of blood in his brain.

In a 2008 interview, Dr. Fullerton said she believes a delay in diagnosis of pediatric stroke has fallen into a gap in clinical care. "It is a rare disorder in general, and so most child neurologists will not be very comfortable in caring for children with stroke," she said, adding:

"Stroke is considered more a disease of adults, but then adult stroke neurologists aren't familiar of the etiologies of stroke in children or how to manage stroke in children, and so they're often uncomfortable with caring for a stroke in a child.

It can be difficult to diagnose the etiology of their strokes. It often takes sophisticated imaging studies and studies that are done by very experienced practitioners. It really often does take a team approach to figure out why a child has had a stroke and figure out what is the best way to prevent more strokes in that child."

While stroke is much rarer in children than adults, it is important that parents, caregivers and health care professionals are aware that children can be affected by the condition and take note of the signs and symptoms that may arise.

Not only is May American Stroke Awareness Month, 2nd-8th May is dedicated to World Pediatric Stroke Awareness Week. Set up by the IAPS and not-for-profit organization Brendon's Smile last year, the campaign aims to raise awareness of pediatric stroke around the globe and educate communities about how the condition can impact children's lives.

Visit the IAPS website to find out more about pediatric stroke and how you can help raise awareness of the condition.

Continue to Read more ...

Healthy diets make brighter brains

A study following nearly 28,000 people aged 55 and older at high cardiovascular risk, which monitored their diets for 5 years and tested declines against thinking and memory tests, found a smaller drop in brain power for those who ate well.

Fish was part of healthy eating while red meat was among the unhealthy foods.

The American Academy of Neurology has published the results in the journal Neurology. The healthy eating linked to the stronger cognitive health was a diet with not much red meat, moderate alcohol and lots of fruits and vegetable, nuts and fish.

The 27,860 over-55s included for the analysis, from across 40 countries, were studied over an average of around 5 years.

Certain health conditions were excluded at the start of the study of people at high risk of cardiovascular disease. None of the participants had diabetes or a history of heart disease, stroke or peripheral artery disease; nor had any recently experienced serious disease outcomes such as a stroke or congestive heart failure.

Participants who experienced heart disease or stroke during the study were no longer followed for diet and mental power.

To take a baseline measure of cognitive health and monitor any decline, thinking and memory skills were tested at the start of the study, then 2 years and about 5 years later.

A maximum of 30 points was possible against these thinking and memory tests and cognitive decline was noted when scores dropped by 3 points or more, which happened for 17% overall - a total of 4,699 participants.

Cognitive decline lowest among those who reported healthiest diets

The proportion registering a decline was lower for people reporting the healthiest diets - 14% of these showed a drop in thinking and memory, compared with 18% of the people eating the least healthy diets.

Measuring cognitive health

This new study linking brain power and diet involved a test of cognitive health that is used during dementia diagnosis. The mini mental state examination (MMSE) measures:

• Orientation to time and place
• Word recall
• Language abilities
• Attention and calculation
• Visuospatial skills.

For the measure of diet, the participants were asked at the start of the study to say how often they ate certain foods, including vegetables, nuts and soy proteins, whole grains and deep-fried foods. They also reported levels of alcohol intake and gave data to produce a ratio of fish to meat and eggs in their diets.

The measure of diet quality was a modified version of the healthy eating index used by the US government.

Among the 5,687 people with the healthiest diet, 782 made up the 13.8% having cognitive decline, while of the 5,459 people with the least healthy diets, 987 accounted for the 18.1%.

The relative difference from these figures produces a 24% lower likelihood of a drop in thinking and memory for people eating well.

The researchers accounted for factors that could have affected the results, such as physical activity, high blood pressure and history of cancer.

Study author Dr. Andrew Smyth, of McMaster University in Hamilton, Ontario, Canada, and the National University of Ireland in Galway, says diet in later life is only part of the picture:

"Adoption of a healthy diet probably begins early in life, and a healthy diet might also go along with adoption of other healthy behaviors."

For their data, the authors examined participants from randomized drug trials in cardiovascular disease supported by pharmaceutical company Boehringer Ingelheim.

In background to their work, the authors cite previous brain health links to healthy diet but point out that using the large multinational prospective cohort study allows observation of "more precise associations between diet (assessed using standardized methodology) and cognitive outcomes."

Explaining what biological explanations may lie behind the emerging evidence, the authors say: "Dietary intake may modify the risk of cognitive decline through multiple mechanisms, including increased risk of stroke (both overt and covert) and through deficiency of nutrients required for neuronal regeneration (for example, group B vitamins, and vitamin C)."

The risk factors for dementia listed by the US National Institute of Neurological Disorders and Stroke includes a number that can be modified by dietary and lifestyle measures.

The new study ends by stating:

"In conclusion, we report that higher diet quality is associated with a reduced risk of cognitive decline. Improved diet quality represents an important potential target for reducing the global burden of cognitive decline."

Continue to Read more ...

Could high blood sugar be a cause of Alzheimer's disease?

While nobody knows exactly what causes the complex brain changes that lead to Alzheimer's disease, scientists suspect one of the drivers is the accumulation of plaques of a faulty protein called beta-amyloid. Now, a new study of mice shows how too much sugar in the blood can speed up the production of the protein.

The researchers suggest their findings will lead to new treatments that reduce the harmful effects of high blood sugar on the brain.

Earlier studies have pointed to diabetes - where the body fails to control high blood sugar naturally with insulin - as a possible contributor to Alzheimer's disease, but the new study links high blood sugar itself to beta-amyloid.

Researchers from the School of Medicine at Washington University in St. Louis (WUSTL) report their findings inThe Journal of Clinical Investigation.

Lead author and postdoctoral research scholar Dr. Shannon Macauley says:

"Our results suggest that diabetes, or other conditions that make it hard to control blood sugar levels, can have harmful effects on brain function and exacerbate neurological conditions such as Alzheimer's disease."

She and her colleagues suggest their finding could lead to new treatment targets to reduce the harmful effects of high blood sugar on the brain.

Doubling of blood glucose led to 20% higher levels of beta-amyloid

For their study, the team used mice bred to develop a condition that is like Alzheimer's in humans - as they age their brains accumulate amyloid plaques.

When they infused glucose into the bloodstream of young mice, they found their brains produced beta-amyloid faster. A doubling of blood glucose led to 20% higher levels of beta-amyloid compared with mice that had normal blood glucose levels.

When the team repeated the experiment in older mice that already had amyloid plaques in their brains, beta-amyloid levels rose by 40%.

Closer examination revealed that sudden elevation of blood sugar increased brain cell activity, which stimulates them to make more beta-amyloid.

The team found that openings called KATP channels were an important feature of increased beta-amyloid. These ATP-sensitive potassium channels sit on the surface of brain cells and close when glucose levels get too high. When the channels are closed, the neurons are more likely to fire.

Under normal conditions, neurons fire to encode and send information - a basic function essential for learning and memory. But too much firing in certain areas of the brain increases beta-amyloid, which makes it more likely that plaques will form and encourage the development of Alzheimer's, the authors suggest.

KATP channel 'directly links glucose, brain cell activity and beta-amyloid'

In a final set of experiments, the team injected diazoxide straight into the brains of mice (to bypass the blood brain barrier). Diazoxide is a glucose-elevating drug that is used to treat low blood sugar.

The drug forced the KATP channels to stay open as glucose levels rose. Under these conditions, the brain cells produced beta-amyloid at the normal rate - it did not speed up.

The team concludes this result shows that the KATP channel directly links glucose levels with brain cell activity and rate of beta-amyloid production.

The researchers are already exploring the link further using diabetes drugs in Alzheimer's-like mice.

KATP channels feature in all kinds of cells, not just brain cells. For example, they feature in the pancreatic cells that make insulin - the enzyme the body uses to control blood sugar.

Commenting on the contribution of their findings, Dr. Macauley says:

"This observation opens up a new avenue of exploration for how Alzheimer's disease develops in the brain as well as offers a new therapeutic target for the treatment of this devastating neurologic disorder."

She and her colleagues are also looking into how raised glucose levels may interfere with how different parts of the brain work together in cognitive functioning.

Funds for the study came from the National Institutes of Health, the National Science Foundation and the JPB Foundation.

Meanwhile, Medical News Today recently learned how scientists at Johns Hopkins University found a molecule that links high blood sugar to metabolic disease. Writing in the Proceedings of the National Academy of Sciences, the team says the discovery could lead to new ways to prevent and treat diabetes.

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