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Lack Of Exercise May Mean Smaller Brain Size

If you want to keep your brain from shrinking as you age, your best bet may be to keep your body physically fit. New research from Boston University School of Medicine found that poor physical fitness in midlife was linked to smaller brain size (a sign of accelerated brain aging) 20 years later. Researchers used treadmill tests to assess the physical fitness of 1,583 people whose average age was 40. All were participants in the long-running Framingham (MA) Heart Study, and none had heart disease when they took their first treadmill test. They were re-evaluated with treadmill tests two decades later and also underwent MRI scans of their brains. Results showed that the poorer the participants performed on their original treadmill tests, the more volume their brains had lost over the 20 years. The researchers also reported that the higher an individual’s blood pressure and heart rate rose during the first treadmill test - changes that could mean lack of fitness - the smaller their brains were likely to be on the MRI scans 20 years later. The study doesn’t prove that poor physical fitness caused the brain shrinkage observed, but does suggest an association.

Why It’s So Hard To Give Up Sugar

Blame it on the brain. Researchers at Yale have found that our brains respond differently to sweet tastes and to calories. The brain is hardwired to seek out sugar to provide itself calories, but it considers sweetness separately, and it will go for the calories - energy - every time. "It turns out the brain actually has two segregated sets of neurons to process sweetness and energy signals," the Yale study’s senior author explained in a press release. "If the brain is given the choice between pleasant taste and no energy, or unpleasant taste and energy, the brain picks energy." The study found that both sweet taste and nutrient value register in an ancient brain region called the striatum, which is involved in processing rewards. In studies with mice and sugar, the researchers found that signals for taste and nutrients are processed in two separate areas of the striatum. One, the ventral striatum processes taste signals while the other, the dorsal striatum responds to energy signals. As far as eating behavior is concerned, the study showed that the brain chose signals that sugar (even sugar made to taste very bad) was delivering calories every time. The bottom line: Our human sweet tooth evolved to ensure that we eat enough to provide our brains with the calories it needs to operate at peak efficiency, but it is our brains desire for calories - not sweetness - that dominates our strong cravings for sugar, the researchers reported. 

Your Diet, Your Brain and Your Microbiome

What you eat can affect your ability to adapt and adjust to changing situations in your day-to-day environment, at least if you’re a mouse. New research from Oregon State University suggests that diets high in fat and sugar have an undesirable effect on the microbiome, the 100 trillion or so microorganisms that populate our digestive system. And that influence seems to impact the brain’s ability to adapt and adjust to new problems, a trait known as cognitive flexibility. Although this study was done in mice (which the researchers said are a “good model” for humans on a variety of topics), it suggests that these particular diets can affect the way we respond to unexpected changes. The real-world example lead investigator Kathy Magnusson gave was how quickly you would adapt if you were driving home and your usual route was closed. No problem plotting an alternate course as a solution if you have normal cognitive flexibility. If not, your trip home could be pretty stressful. With the mice, four weeks on a high sugar or high fat diet affected the way they performed on a variety of challenging tests compared to animals on a normal mouse diet. One of the most pronounced changes seen was in cognitive flexibility. The study was done with young mice. Dr. Magnusson said the effect of the high sugar or high fat diet might be more dramatic in older animals (or humans).

 

My take: These new findings mirror the results of other studies about the impact of fat and sugar on cognitive function and behavior, suggesting that some of these problems may be linked to dietary influences on the microbiome. We’re just beginning to understand the health consequences of our microbiomes, but based on what we know so far, they are becoming increasingly unbalanced in this country compared to other populations that eat traditional diets. This is likely due to growing reliance on processed products in addition to regular exposure to antibiotics from medical treatment and residues in foods. These changes in the microbiome may underlie an increased incidence of a wide range of diseases and conditions including psychological and behavioral disorders. 

Brain Chemistry and Obesity

Differences in brain chemistry between people who are obese and those who are not may help explain what triggers overeating in response to food cues such as the aroma of popcorn at the movies. To arrive at this conclusion, researchers at the National Institutes of Health (NIH) looked at 43 men and women with varying amounts of body fat. The investigators found that, compared to the study’s lean participants, those who were obese tended to have more dopamine activity in the brain’s habit-forming region and less activity in the brain area controlling rewards. (Dopamine is a chemical messenger in the brain that influences reward motivation and habit formation.) The finding suggested that the brain differences observed might result in obese people being more susceptible to environmental food cues than those who are lean. At the same time, the action of dopamine in other areas of the brain may make food less rewarding to the obese. During the study, all participants were on the same eating, sleeping and activity schedule. The researchers determined the tendency to overeat from the participants’ responses to detailed questions and to PET (positron emission tomography) scans that looked at sites in the brain where dopamine action can occur. The study didn’t prove cause and effect but did reveal a link between dopamine activity and the urge to overeat.

Source:
Kevin D. Hall et al  “Striatal dopamine D2-like receptor correlation patterns with human obesity and opportunistic eating behavior.” Molecular Psychiatry, 2014; DOI: 10.1038/mp.2014.102

This is Your Brain on Laughter

Seriously, research suggests that a good laugh can boost memory, lower stress, protect against heart disease and even burn calories. The latest news on the health benefits of laughter comes from a small study at California’s Loma Linda University, where researchers investigated the effects of humor on 20 seniors. First, they tested short-term recall among all the participants and took saliva samples from them to measure levels of the stress hormone cortisol. They then showed comic videos to half the participants while the others were asked to sit silently elsewhere without talking, reading or using their cell phones. After 20 minutes, the researchers again tested short-term recall in all the participants and took new saliva samples. They found that recall among those who watched the videos increased by 43.6 percent compared to 20.3 percent in the other group and that cortisol levels in the video-watching group were significantly lower than they were in the others. The researchers noted that studies elsewhere have demonstrated that a sense of humor helps protect against heart disease and that 10 to 15 minutes of laughter daily burns up to 40 calories.

My take? Laughter is infectious. When we see or hear people laugh, we tend to laugh ourselves, which makes them laugh more, and so on. This means that a group of people laughing constitutes a powerful collection of internal and external feedback loops of positive emotion. If you want to be happy, put yourself in joyful situations as often as you can. Or consider laughter yoga. According to the official Laughter Yoga website, there are more than 6,000 "social laughter clubs" in 60 countries. Studies have shown that laughter can influence health by easing pain, reducing stress and even helping protect against heart disease. Researchers in Japan have shown that participating in laughter yoga can help lower blood pressure among adults ages 40 to 74, and are now investigating whether the positive changes are long-lasting.

Sources:
G.S. Bains et al “The Effect of Humor on Short-term Memory in Older Adults: A New Component for Whole-Person Wellness,” Advances in Mind Body Medicine, Spring 2014, 28(2):16-24

What Sedentary Living Does to Your Brain

Being a couch potato can take a toll on your brain. We have long known that physical activity has positive effects on the body, and now a newly published study has shown that lack of exercise can reshape certain neurons in the brain, and not in a good way. Researchers at Wayne State University reported these findings from a study with rats that they said has implications for humans. They put one group of animals in cages with running wheels, and other rats in cages with no rodent gym equipment. The animals who had access to the running wheels took full advantage of them – they ran about three miles a day. After almost three months, the researchers checked the brains of all the rats. They saw no changes in the brains of the animals that received plenty of exercise but potentially dangerous alterations in neurons in the brains of the sedentary rats, including increased numbers of tentacle-like arms on neurons that could over-stimulate the sympathetic nervous system and lead to high blood pressure and the development of heart disease.

My take? These findings may give us new insight into how inactivity affects human health. Our bodies evolved in very demanding environments and are meant to be used. If they are not used, they deteriorate quickly. Many of the illnesses that plague our society result from underuse of bodies. Clearly, the prevalence of heart and artery disease correlates as much with lack of aerobic exercise as it does with unhealthy diets. Insufficient aerobic activity also predisposes us to musculoskeletal disorders, gastrointestinal problems, nervous and emotional illnesses, and a long list of other ailments.

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Source:
Patrick Mueller et al, “Physical (in)activity-dependent structural plasticity in bulbospinal catecholaminergic neurons of rat rostral ventrolateral medulla.” The Journal of Comparative Neurology, doi: 10.1002/cne.23464

What Are You Doing to Sharpen Your Brain? (Poll)

A recent Q&A discussed vitamin E and it's health benefits, especially on the brain: Does Vitamin E Halt Alzheimer's Disease? Check out the article and tell us what you do to sharpen your brain.

Eating Chocolate May Keep You Slim and Sharpen Your Mind

Eating a moderate amount of chocolate is associated with lower body fat and less abdominal fatWe know that flavonols - the antioxidants in chocolate - have anti-inflammatory effects that can help prevent heart disease. Now Spanish researchers have discovered that eating a moderate amount of chocolate is associated with lower body fat and less abdominal fat, no matter how much (or little) you exercise and regardless of the rest of your diet. The investigators from the University of Granada looked at nearly 1,500 European adolescents (between ages 12 and 17) and found that the more chocolate they ate (without overindulging), the lower their body mass index and waist circumference. Meanwhile, a team of British and Australian researchers found that the more flavonols a cocoa drink contained, the faster their study subjects could perform on a timed mental test requiring them to count down by threes and sevens. The researchers described their findings as the first evidence of acute cognitive improvements following consumption of cocoa flavonols by healthy adults. Earlier studies have shown that consumption of flavonols can help relax blood vessels and increase blood flow in the brain.

Source:
Magdalena Cuenca-Garcia  “Association between chocolate consumption and fatness in European adolescents,” published online October 21, 2013

Crystal F. Haskell et al. “Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort”, Journal of Psychopharmacology  doi: 10.1177/0269881109106923

Early Learning Boosts Brain Resilience

Childhood music lessons pay off much later in life by speeding brain responses to speech soundsDid you take music lessons in your youth? Can you speak a second language? New research suggests that being bilingual can stave off dementia for more than four years, and that childhood music lessons pay off much later in life by speeding brain responses to speech sounds. Scottish and Indian researchers reviewed the case histories of 684 seniors with dementia. Of this group, 391 spoke more than one language. The investigators found that that being bilingual delayed the progression of dementia, even in study subjects who were illiterate, a finding that demonstrated for the first time that education levels alone don’t explain the delay. However, the study found no additional advantage to knowing three or more languages. Researchers at Northwestern University in Illinois found that taking music lessons for four to 14 years early in life paid off later by making possible recognition of a speech sound a millisecond faster than seniors who had no musical training. A millisecond may not seem like a big deal, but it is significant in terms of brain function. For the Northwestern study 44 healthy adults, ages 55-76, listened to a synthesized speech syllable (“da”) while researchers clocked electrical activity in the auditory brainstem, the brain region that processes sound. Childhood music lessons were related to faster brain responses, even in study participants who hadn’t played music in nearly 40 years, the researchers found.

My take? Mental exercise is vital to keeping sharp as we age. In general, the more education you have, the less likely you are to develop Alzheimer’s disease or to experience age-related cognitive decline; if you do experience them, they will appear later in life than in less educated people. Both of these new studies demonstrate again that using the brain is protective against age-related mental decline. The more learning you have had, the more connections you have in your brain, even if that learning took place during music lessons early in life or if you managed to master two languages, even without formal education or the ability to read.

Source:
Suvarna Alladi, et al, “Bilingualism delays age at onset of dementia, independent of education and immigration status.” Neurology, 10.1212/01.wnl.0000436620.33155.a4; published ahead of print November 6, 2013

Nina Kraus et al, “Older adults benefit from music training early in life: biological evidence for long-term training-driven plasticity,” Journal of Neuroscience, doi: 10.1523/JNEUROSCI.2560-13.2013

Teach Your Mind to Multitask

Video games may help you train your brain to be more flexible and to think more strategicallyNew research from Britain suggests that video games may help you train your brain to be more flexible and to think more strategically. This kind of “cognitive flexibility” can be advantageous in today’s knowledge economy, the researchers said. Investigators at Queen Mary University of London and University College London recruited 72 female volunteers and measured their baseline cognitive flexibility, which they described as the ability to adapt and switch between tasks while keeping in mind at the same time multiple ideas for problem solving. All the volunteers were women - primarily because the researchers couldn’t find enough men who played video games for fewer than two hours a week. The women were divided into three groups. The first two groups were trained to play different versions of StarCraft, which requires players to construct and organize armies for battle. The third group played The Sims, a game that doesn’t require much memory or tactical thinking. The investigators found that the women who played the most complex version of StarCraft performed best in psychological tests given at the end of the study. Next on the agenda is to determine whether the positive brain changes seen are permanent. If so, the researchers said, certain types of gaming could be a tool to help people with attention deficit hyperactivity disorder or traumatic brain injuries. The study was published in PLoS One on August 7, 2013.

Source:
Brian Glass and Brad Love et al, “Real-time strategy game training: emergence of a cognitive flexibility trait,” PLoS One. August 7, 2013;8(8): e70350. doi: 10.1371/journal.pone.0070350. eCollection 2013.