Posts tagged alcohol
Articles and news from the latest research reports.
Monday’s medical myth: alcohol kills brain cells
Do you ever wake up with a raging hangover and picture the row of brain cells that you suspect have have started to decay? Or wonder whether that final glass of wine was too much for those tiny cells, and pushed you over the line?
Well, it’s true that alcohol can indeed harm the brain in many ways. But directly killing off brain cells isn’t one of them.
The brain is made up of nerve cells (neurons) and glial cells. These cells communicate with each other, sending signals from one part of the brain to the other, telling your body what to do. Brain cells enable us to learn, imagine, experience sensation, feel emotion and control our body’s movement.
Alcohol’s effects can be seen on our brain even after a few drinks, causing us to feel tipsy. But these symptoms are temporary and reversible. The available evidence suggests alcohol doesn’t kill brain cells directly.
There is some evidence that moderate drinking is linked to improved mental function. A 2005 Australian study of 7,500 people in three age cohorts (early 20s, early 40s and early 60s) found moderate drinkers (up to 14 drinks for men and seven drinks for women per week) had better cognitive functioning than non-drinkers, occasional drinkers and heavy drinkers.
But there is also evidence that even moderate drinking may impair brain plasticity and cell production. Researchers in the United States gave rats alcohol over a two-week period, to raise their alcohol blood concentration to about 0.08. While this level did not impair the rats’ motor skills or short-term learning, it impacted the brain’s ability to produce and retain new cells, reducing new brain cell production by almost 40%. Therefore, we need to protect our brains as best we can.
Excessive alcohol undoubtedly damages brain cells and brain function. Heavy consumption over long periods can damage the connections between brain cells, even if the cells are not killed. It can also affect the way your body functions. Long-term drinking can cause brain atrophy or shrinkage, as seen in brain diseases such as stroke and Alzheimer’s disease.
There is debate about whether permanent brain damage is caused directly or indirectly.
We know, for example, that severe alcoholic liver disease has an indirect effect on the brain. When the liver is damaged, it’s no longer effective at processing toxins to make them harmless. As a result, poisonous toxins reach the brain, and may cause hepatic encephalopathy (decline in brain function). This can result in changes to cognition and personality, sleep disruption and even coma and death.
Alcoholism is also associated with nutritional and absorptive deficiencies. A lack of Vitamin B1 (thiamine) causes brain disorders called Wernicke’s ncephalopathy (which manifests in confusion, unsteadiness, paralysis of eye movements) and Korsakoff’s syndrome (where patients lose their short-term memory and coordination).
So, how much alcohol is okay?
To reduce the lifetime risk of harm from alcohol-related disease or injury, the National Health and Medical Research Council recommends healthy adults drink no more than two standard drinks on any day. Drinking less frequently (such as weekly rather than daily) and drinking less on each occasion will reduce your lifetime risk.
To avoid alcohol-related injuries, adults shouldn’t drink more than four standard drinks on a single occasion. This applies to both sexes because while women become intoxicated with less alcohol, men tend to take more risks and experience more harmful effects.
For pregnant women and young people under the age of 18, the guidelines say not drinking is the safest option.
So while alcohol may not kill brain cells, if this myth encourages us to rethink that third beer or glass of wine, I won’t mind if it hangs around.
Excessive Alcohol Use When You’re Young Could Have Lasting Impacts on Your Brain
Excessive alcohol use accounts for 4% of the global burden of disease, and binge drinking particularly is becoming an increasing health issue. A new review article published in Cortex highlights the significant changes in brain function and structure that can be caused by alcohol misuse in young people.
Functional signs of brain damage from alcohol misuse in young people mainly include deficits in visual learning and memory as well as executive functions. These functions are controlled by the hippocampus and frontal structures of the brain, which are not fully mature until around 25 years of age. Structural signs of alcohol misuse in young people include shrinking of the brain and significant changes to white matter tracts.
Age of first use may be considered to trigger alcohol misuse. According to the researchers however, changing the legal drinking age is not the answer. In Australia the legal drinking age is 18, three years earlier than in the US. Despite the difference in legal drinking age, the age of first use (and associated problems) is the same between the two countries.
Instead, the authors stressed the need for early intervention, by identifying markers and thresholds of risky drinking behaviour at an early stage, while individuals are in vulnerable stages of brain development.
(Source: alphagalileo.org)
A brain protein called vimentin can indicate damage to the hippocampus following binge drinking
Chronic drinking is known to have detrimental health effects such as cardiac and liver problems, cognitive impairments, and brain damage. Binge drinking in particular is known to increase the risk of developing dementia and/or brain damage, yet little is known about an exact threshold for the damaging effects of alcohol. A study using rodents to examine various markers of neurodegeneration has found that brain damage can occur with as little as 24 hours of binge-like alcohol exposure.
Results will be published in the March 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"We know that the extent of damage following alcohol exposure depends heavily on the manner in which it is consumed," said Kimberly Nixon, associate professor of pharmaceutical sciences at The University of Kentucky as well as corresponding author for the study. "Human studies suggest that binge-pattern drinking is more closely associated with brain damage. One study, for example, reported that binge drinking at least once per month in adulthood significantly increases the risk of developing dementia later in life. Animal models help provide the critical information that binge drinking, which produces high blood alcohol levels, directly causes damage."
"The exact threshold for the damaging effects of alcohol on the brain is unclear," commented Fulton T. Crews, John Andrews Distinguished Professor and director of the Center for Alcohol Studies at the University of North Carolina. "It is likely that the higher the blood alcohol level the greater the damage, however, this manuscript only studies binge drinking, using vimentin and flurojade B as markers of neurotoxicity."
"People hear from multiple sources that low-moderate alcohol consumption can be beneficial, and then we come along and say that heavy alcohol use leads to detrimental outcomes," said Nixon. "People then want to know what the line is between beneficial and detrimental Unfortunately, we don’t know exactly. However, our study suggests that it may be even less than previously thought."
Nixon and her colleagues administered a nutritionally complete liquid diet to adult male Sprague-Dawley rats that additionally contained either alcohol (25% w/v) or isocaloric dextrose every eight hours for either one or two days. The rodents were sacrificed immediately following, two days after, or seven days after alcohol exposure and their brain tissues were examined.
"This was really a simple study that took advantage of some new ‘tools’ to look for evidence of brain damage," explained Nixon. "In other words, we didn’t look for dying cells themselves, but we looked at more indirect indices of damage by looking at what happens to astroglia, one of the ‘supporting’ cells for neurons. Astroglia react to brain damage by expressing several proteins that they do not normally express under healthy, happy conditions, one of which is an intermediate filament protein called vimentin. We saw a remarkable number of cells expressing this marker It is one of those ‘here is your brain, here is your brain on drugs’ kind of findings where the expression was obvious to the naked eye in many brains with as little as 24 hours of high blood alcohol levels."
Nixon added that, because rodents metabolize alcohol significantly faster than humans do, it is important to look at the actual concentration of alcohol in the blood in order to translate this to the human condition. “These rats had blood alcohol levels that were more than four times the legal driving limit, which for humans would require excessive drinking in the nature of a 12-pack of beer, a couple bottles of wine, or half of fifth of whisky. Unfortunately, drinking self-reports and blood alcohol level data from emergency rooms confirm that this level of drinking is common in those with alcohol use disorders.”
"Rodent brain damage can model human damage," noted Crews. "Vimentin seems to be a good marker of glial activation that shows that one day of binge drinking can cause some brain damage that persists and grows after a week of abstinence. However, both rodent and human brain damage generally require long-term alcohol consumption that models alcoholism and not the acute responses studied in this manuscript."
Nixon agreed. “The lack of overt neuronal deterioration suggests that a single, short-term, high-level binge probably does not result in functional changes and/or cognitive deficits,” she said. “However, since alcoholics experience multiple binges throughout their lifetime, it is important to consider that each successive binge, starting with the very first one, affords some level of damage to the brain. Therefore, theoretically, with multiple binges comes a cumulative detrimental effect where pronounced cognitive, behavioral, and structural effects are observed.”
Nixon said this study demonstrates that new discoveries are always possible. “You have to know where and when to look for some of these effects,” she said. “The reason why this discovery wasn’t made previously is merely due to groups, ourselves included, not taking the time to thoroughly investigate these lower threshold doses with some pretty specific time points. Chasing down a threshold is not a sexy topic and it was actually fairly risky in that it was possible that we would have had all negative effects. Nonetheless, the take-home message of our data is that even one short-duration binge-alcohol experience – which is unfortunately similar to what young adults may experience during spring break or weekend partying - may start a cascade that leads to brain damage.”
(Source: eurekalert.org)
Reviewing alcohol’s effects on normal sleep
Sleep is supported by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. Typically, people begin the sleep cycle with NREM sleep followed by a very short period of REM sleep, then continue with more NREM sleep and more REM sleep, this 90 minute cycle continuing through the night. A review of all known scientific studies on the impact of drinking on nocturnal sleep has clarified that alcohol shortens the time it takes to fall asleep, increases deep sleep, and reduces REM sleep.
Results will be published in the April 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"This review has for the first time consolidated all the available literature on the immediate effects of alcohol on the sleep of healthy individuals," said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study.
"Certainly a mythology seems to have developed around the impact of alcohol on sleep," added Chris Idzikowski, director of the Edinburgh Sleep Centre. "It is a good time to review the research as the mythology seems to be flourishing more rapidly than the research itself. Also, our understanding of sleep has accelerated in the past 30 years, which has meant that some of the initial interpretations need to be revisited."
Some of the review’s key themes are:
- At all dosages, alcohol causes a reduction in sleep onset latency, a more consolidated first half sleep, and an increase in sleep disruption in the second half of sleep.
"This review confirms that the immediate and short-term impact of alcohol is to reduce the time it takes to fall asleep," said Ebrahim. "In addition, the higher the dose, the greater the impact on increasing deep sleep. This effect on the first half of sleep may be partly the reason some people with insomnia use alcohol as a sleep aid. However, the effect of consolidating sleep in the first half of the night is offset by having more disrupted sleep in the second half of the night."
- The majority of studies, across alcohol dose, age, and gender, confirm an increase in slow-wave sleep (SWS) in the first half of the night. SWS, often referred to as deep sleep, consists of stages 3 and 4 of NREM. During SWS, the body repairs and regenerates tissues, builds bone and muscle, and appears to strengthen the immune system. Alcohol’s impact on SWS in the first half of the night appears to be more robust than its effect on REM sleep.
"SWS or deep sleep generally promotes rest and restoration," said Ebrahim. "However, when alcohol increases SWS, this may also increase vulnerability to certain sleep problems such as sleepwalking or sleep apnoea in those who are predisposed."
- Alcohol’s effects on REM sleep in the first half of sleep appear to be dose related. Low and moderate doses show no clear effects on REM sleep in the first half of the night, whereas at high doses, REM sleep reduction in the first part of sleep is significant. Total night REM sleep percent is decreased in the majority of studies at moderate and high doses.
"Dreams generally occur in the REM stage of sleep," said Ebrahim. "During REM sleep the brain is more active, and may be regarded as ‘defragmenting the drive.’ REM sleep is also important because it can influence memory and serve restorative functions. Conversely, lack of REM sleep can have a detrimental effect on concentration, motor skills, and memory. REM sleep typically accounts for 20 to 25 percent of the sleep period."
- The onset of the first REM sleep period is significantly delayed at all doses and appears to be the most recognizable effect of alcohol on REM sleep, followed by a reduction in total night REM sleep.
"One consequence of a delayed onset of the first REM sleep would be less restful sleep," said Idzikowski. "The first REM episode is often delayed in stressful environments. There is also a linkage with depression."
Excessive alcohol when you’re young could have lasting impacts on your brain
Alcohol misuse in young people causes significant changes in their brain function and structure. This and other findings were recently reviewed by Dr Daniel Hermens from the University of Sydney’s Brain and Mind Research Institute in the journal Cortex.
"Young people are particularly vulnerable to the damaging effects of alcohol misuse," said Dr Hermens.
Most people have their first alcoholic drink during adolescence and while they drink less frequently than adults, they tend to drink more on each occasion - binge drinking.
The early functional signs of brain damage from alcohol misuse are visual, learning, memory and executive function impairments. These functions are controlled by the hippocampus and frontal structures of the brain, which are not fully mature until around 25 years of age.
Structural signs of alcohol misuse include shrinking of the brain and significant changes to white matter.
In his review, Dr Hermens notes that changes in a young person’s brain caused by alcohol misuse could either represent a predisposition (genetic or environmental) to alcohol misuse, or a marker for future risk of ongoing misuse. Whichever it is, there is no doubt that the more frequent the alcohol misuse, the greater the damage and the less likely the brain is to recover from that damage.
"When the toxicity of alcohol stops your brain from laying down new memories, you experience a blackout," said Dr Hermens. Young people who binge drink may only drink once a week, but on a massive night out they may have three to four blackouts, which begins to cause serious damage to their brain.
One of the best predictors of a person having problems with alcohol is their earliest age of first use. But changing the legal drinking age is not the answer. In Australia the legal drinking age is 18, three years earlier than in the US. Despite the difference in legal drinking age, the age of first use is the same between the two countries.
Another key factor affecting young people who drink is mental health, “poor mental health more than doubles a young person’s risk of alcohol and other substance misuse” says Dr Hermens.
The solution lies in education, treatment and prevention. Dr Hermens and his team have been working with NSW Health to prepare a set of guidelines for health carers to identify and respond to early stages of brain impairment in young people resulting from alcohol misuse. They are currently working on a set of educational charts that inform young people of the risks of irresponsible drinking.
It may be possible to use cognitive remediation to change the drinking habits of young drinkers and prevent relapse. At the same time, vitamin supplements or other medicines may effectively treat some of the structural changes, and it may be possible to develop protective agents that can prevent young brains from the damaging effects of alcohol.
"More work needs to be done in this area. Excessive alcohol use accounts for 4 percent of the global burden of disease. We would save a lot of money and improve the quality of life for millions of people if we could prevent the mental and physical problems associated with alcohol misuse" said Dr Hermens.
Research reveals why some teenagers more prone to binge drinking
New research helps explain why some teenagers are more prone to drinking alcohol than others.
The study, led by King’s College London’s Institute of Psychiatry (IoP) and published in Proceedings of National Academy of Sciences (PNAS)* provides the most detailed understanding yet of the brain processes involved in teenage alcohol abuse.
Alcohol and other addictive drugs activate the dopamine system in the brain which is responsible for feelings of pleasure and reward. Recent studies from King’s IoP found that the RASGRF2 gene is a risk gene for alcohol abuse, however, the exact mechanism involved in this process has, until now, remained unknown.
Professor Gunter Schumann, from the Department of Social, Genetic and Developmental Psychiatry (SGDP) at King’s Institute of Psychiatry and lead author of the study says: “People seek out situations which fulfill their sense of reward and make them happy, so if your brain is wired to find alcohol rewarding, you will seek it out. We now understand the chain of action: how our genes shape this function in our brains and how that, in turn, leads to human behaviour. We found that the RASGRF-2 gene plays a crucial role in controlling how alcohol stimulates the brain to release dopamine, and hence trigger the feeling of reward. So, if people have a genetic variation of the RASGRF-2 gene, alcohol gives them a stronger sense of reward, making them more likely to be heavy drinkers.”
*Paper reference: Stacey, D. et al. ‘RASGRF-2 regulates alcohol-induced reinforcement by influencing mesolimbic dopamine neurone activity and dopamine release’ Proceedings of the National Academy of Sciences (PNAS) 2012
Alcoholic fly larvae need fix for learning
Fly larvae fed on alcohol-spiked food for a period of days grow dependent on those spirits for learning. The findings, reported in Current Biology, a Cell Press publication, on November 29th, show how overuse of alcohol can produce lasting changes in the brain, even after alcohol abuse stops.
The report also provides evidence that the very human experience of alcoholism can be explored in part with studies conducted in fruit flies and other animals, the researchers say.
"Our evidence supports the long-ago proposed idea that functional ethanol tolerance is produced by adaptations that counter the effects of ethanol, and that these adaptations help the nervous system function more normally when ethanol is present," says Brooks Robinson of The University of Texas at Austin. "However, when ethanol is withheld, the adaptations persist to give the nervous system abnormal properties that manifest themselves as symptoms of withdrawal."
Robinson and his colleagues found that alcohol consumption, at a level equivalent to mild intoxication in humans, at first impeded learning by fly larvae. More specifically, those larvae had some trouble in associating an unpleasant heat pulse with an otherwise attractive odor in comparison to larvae that had not been drinking alcohol.
After a six-day drinking binge, however, those larvae adapted and could learn as well as normal larvae could. In fact, the alcohol-adapted animals learned poorly when their ethanol was taken away from them. And, when given alcohol back, their learning deficit was erased.
Robinson says that the findings are the first proof of cognitive ethanol dependence in an invertebrate, suggesting that some of ethanol’s ability to change behavior must begin at the cellular level. After all, flies and humans share many of the same features at the level of individual neurons, and not so much in terms of the way those neurons are put together into working circuits.
Brain Tissue Damage Experienced By Children With Fetal Alcohol Exposure
Drinking during pregnancy can have a severe, adverse effect on the central nervous systems of children after birth, researchers from Poland have discovered.
The study, which was presented Sunday at the annual meeting of the Radiological Society of North America (RSNA), looked at 200 children who were exposed to alcohol during their fetal stage, as well as 30 other kids whose mothers did not drink while pregnant or during lactation.
The researchers used a trio of different MRI techniques in order to study the brain development of both groups of subjects. First, they used standard MRI scans to observe the size and shape of the corpus callosum, which is a group of nerve fibers that oversees communication between the two halves of the brain.
Fetal alcohol exposure is believed to be one of the primary causes of impaired development of the corpus callosum, and sure enough, the MRI scans revealed those who had been exposed to alcohol had “statistically significant thinning of the corpus callosum… compared with the other group,” the RSNA said in a statement.
They also used diffusion weighted imaging (DWI) to study six areas of the central nervous system in both groups. The DWI technique maps the diffusion of water in the brain and can be more successful in detecting tissue abnormalities than regular MRI scans, the researchers explained.
Again, children who had been exposed to alcohol “exhibited statistically significant increases in diffusion on DWI” than their counterparts — an indication there had been damage to the brain tissue, or the presence of neurological disorders, according to Dr Andrzej Urbanik, chair of the Department of Radiology at Jagiellonian University.
Finally, they used proton (hydrogen) magnetic resonance spectroscopy (HMRS) to study the metabolism in the youngsters’ brains. The results uncovered “a high degree of metabolic changes that were specific for particular locations within the brain,” according to Dr. Urbanik.
The RSNA, citing US Centers for Disease Control and Prevention (CDC) statistics, reports as many as 1.5 out of every 1,000 children born alive suffer from fetal alcohol syndrome, and the costs of treating those victims tops $4 billion annually in America alone.
(Source: redorbit.com)
Research shows binge drinking inhibits brain development
Teenagers who binge drink risk inhibiting part of their brain’s development and many are laying the groundwork for alcoholism down the track a Queensland University of Technology (QUT) researcher has found.
Professor Selena Bartlett, from QUT’s Institute for Health and Biomedical Innovation (IHBI), studied the effect excessive binge drinking during adolescence had on a particular receptor in the brain and discovered teen bingeing altered it irreversibly, keeping the brain in an adolescent state.
"The human brain doesn’t fully develop until around age 25 and bingeing during adolescence modifies its circuits, preventing the brain from reaching maturity," she said.
"During adolescence, the brain undergoes massive changes in the prefrontal cortex and areas linked to drug reward but alcohol disrupts this.
"The research, which was carried out on rats, suggests that during ageing, the brain’s delta opioid peptide receptor (DOP-R) activity turns down, but binge drinking causes the receptors to stay on, keeping it in an adolescent stage.
"The younger a child or teenager starts binge drinking and the more they drink, the worse the possible outcome for them."
Professor Bartlett said recent trends to mix high-caffeine drinks such as Red Bull with alcohol were making the binge drinking problem worse.
Rutgers Researchers Say Daily Drinking Can Be Risky
Study finds moderate consumption decreases number of new brain cells
Drinking a couple of glasses of wine each day has generally been considered a good way to promote cardiovascular and brain health. But a new Rutgers University study indicates that there is a fine line between moderate and binge drinking – a risky behavior that can decrease the making of adult brain cells by as much as 40 percent.
In a study posted online and scheduled to be published in the journal Neuroscience on November 8, lead author Megan Anderson, a graduate student working with Tracey J. Shors, Professor II in Behavioral and Systems Neuroscience in the Department of Psychology, reported that moderate to binge drinking – drinking less during the week and more on the weekends – significantly reduces the structural integrity of the adult brain.
“Moderate drinking can become binge drinking without the person realizing it,” said Anderson.“In the short term there may not be any noticeable motor skills or overall functioning problems, but in the long term this type of behavior could have an adverse effect on learning and memory.”
(Source: news.rutgers.edu)