Glucose and The Brain: Improving Mental Performance

Glucose is a type of sugar which the brain depends on for fuel. Studies show that dips in glucose availability can have a negative impact on attention, memory and learning, and that administering glucose can enhance these aspects of cognitive function. The brain also uses up more glucose during challenging mental tasks. Therefore, it may be especially important to keep blood glucose levels at an optimum level for good cognitive function. Consuming regular meals may help to achieve this.

Glucose as fuel

Glucose is a type of sugar which comes predominantly from starchy foods (bread, rice, pasta and potatoes) as well as fruits, juices, honey, jams and table sugar. The body can break down the digestible carbohydrates in these foods into glucose, which is transported in the bloodstream to the brain and other organs for energy. The body tightly regulates blood glucose levels; this is known as glucose homeostasis. A process called gluconeogenesis allows the body to make its own glucose from the building blocks of protein and fat. Glucose can be stored in form of glycogen in the liver and to a somewhat lesser extent in the muscle. Glycogen forms an energy reserve that can be quickly mobilised to meet a sudden need for glucose (physical exercise), but also when glucose intake from food is insufficient (during fasting, for example), the body can get glucose by breaking down its glycogen stores. Liver glycogen is nearly depleted 12 to 18 hours after eating, overnight fasting, for example, after which the body relies more on energy from breaking down fats.

The energy needs of the brain

The human brain is made up of a dense network of neurons, or nerve cells, which are constantly active — even during sleep. To obtain the energy needed to sustain this activity, the brain depends on a continuous supply of glucose from the bloodstream. A healthy diet should provide 45-60% of total energy from carbohydrates.1 A normal weight adult requires 200 g of glucose per day, two-thirds of which (about 130 g) is specifically needed by the brain to cover its glucose needs.

The brain competes with the rest of the body for glucose when levels dip very low — such as during starvation. By tightly controlling its share of glucose under these conditions, the brain can maintain its high level of activity. It does this through two main mechanisms: first, by drawing glucose directly from the blood when its cells are low on energy; and second, by limiting the amount of glucose available to the rest of the body so that there is more available to the brain.2,3 These mechanisms are essential for survival. Unlike muscles (including the heart), and the liver, the brain cannot use fatty acids directly for fuel.

Glucose and the mental performance

Despite this sophisticated regulation, short-term dips in glucose availability do occur in certain brain areas. These may impair various cognitive functions such as attention, memory, and learning.4

Studies on glucose have demonstrated how administering this sugar can improve cognitive functioning — in particular, short-term memory and attention.4 Most of these studies give participants a set amount of glucose as a drink. A study by Sünram-Lea and colleagues found that a glucose drink significantly improved long-term verbal memory and long-term spatial memory in young adults. The effect was similar whether the drink was consumed after an overnight fast, a two-hour fast post-breakfast, or a two-hour fast post-lunch.5 Similarly, Riby and colleagues found glucose enhanced memory.6

The more demanding mental tasks appear to respond better to glucose than simpler tasks. This may be because the brain’s uptake of glucose increases under conditions of mild stress, which includes challenging mental tasks.4

Given that the brain is sensitive to short-term drops in blood glucose levels, and appears to respond positively to rises in these levels, it may be beneficial to maintain adequate blood sugar levels in order to maintain cognitive function.4 Eating regular meals may help to achieve this. In particular, studies in children and adolescents have shown that eating breakfast can help to improve mental performance by boosting ability in memory- and attention-related tasks.7

Conclusion

The brain is a highly active organ that relies on glucose for fuel. Glucose comes either directly from carbohydrate-containing foods and drinks, or is produced by the body from non-carbohydrate sources. Keeping blood sugar levels at an optimal level appears to be helpful for maintaining good cognitive function, particularly for more mentally demanding tasks. Consuming regular meals may be a useful way of achieving this.

Source: eufic


Today’s Comic

Advertisements

Keeping the Brain Active Help Preserve the Aging Brain?

Steven Reinberg wrote . . . . . . . . .

Keeping your brain active as you age, whether it be working on a computer, playing games or being socially involved, might ward off memory loss, a new study suggests.

Losing memory as you age is a sign of mild cognitive impairment, which can be a gateway to dementia or Alzheimer’s disease. But using your brain can help keep it sharp, and it’s never too late to start reaping the benefits, researchers say.

Why keeping mentally active has this effect isn’t known, but it might be that the brain responds positively to increased use, said senior researcher Dr. Yonas Geda, a psychiatrist at the Mayo Clinic in Scottsdale, Ariz.

“It’s like watering a flower,” he said.

It’s also possible that people who engage in mental activities also have other good behaviors, such as exercising and eating a healthy diet, which benefit brain health, Geda said.

Study lead author Janina Krell-Roesch, a research fellow at the Mayo Clinic, cautioned that this study can’t prove that mental activity keeps mild cognitive impairment at bay.

“Our study was an observational study, so we can only say that there is an association between mental activities and the risk of mild cognitive impairment,” she explained.

But Geda added that the good news is that even people over 70 can benefit from mental activity.

“Our study shows that it’s never too late to engage in mental activities,” he said. “These activities don’t need to be expensive, they’re accessible and simple and reduce the risk for mild cognitive impairment.”

For the study, Geda and his colleagues followed 2,000 men and women, average age 78, who didn’t suffer from mild cognitive impairment. The participants answered questions about mentally stimulating activities they engaged in when they were 50 and when they were 66 and older.

Participants also took thinking and memory tests every 15 months over the five years of the study. During that time, 532 people developed mild cognitive impairment.

The researchers found that those who used a computer during middle age had a 48% lower risk of developing mild cognitive impairment. Using a computer after age 66 was linked to a 30% lower risk.

Computer use during middle and old age reduced the risk of thinking and memory problems by 37%, the study found.

Involvement in social activities (being with friends, going to the movies, etc.) and playing games were both tied to a 20% lower risk for mild cognitive impairment. Doing crafts in later life was linked to a 42% lower risk for mild cognitive impairment.

Also, the more activities people had, the less likely they were to develop mild cognitive impairment. For example, doing two activities was associated with a 28% lower risk of developing memory and thinking problems, compared with those who didn’t do any activities.

Those who did three activities lowered the risk by 45% and doing four activities reduced the risk 56%. For five activities, the risk was lowered by 43%.

“This study aligns with a growing body of evidence that there are steps you can take today to help keep your brain healthier as you age, and perhaps also reduce your risk of cognitive decline,” said Heather Snyder, senior director for medical and scientific operations at the Alzheimer’s Association. She wasn’t involved with the study.

“Keeping your brain healthy is a lifelong pursuit and staying engaged in a variety of mentally and socially stimulating activities is important throughout one’s life,” Snyder said.

The report was published online in the journal Neurology.

Source : HealthDay


Today’s Comic

Insulin Resistance Linked to Memory Decline

Rick Nauert wrote . . . . . . . . .

A study adds to the growing evidence that insulin resistance, a common occurrence among people who are obese, pre-diabetic, or have type II diabetes, may lead to memory loss and even Alzheimer’s disease.

Iowa State University researchers believe the word should go out that obesity not only increases the risk of cardiovascular disease and some cancers, but also influences memory loss.

The study appears in the Journal of the American Medical Association Neurology.

Researchers found a strong association between insulin resistance and memory function decline, increasing the risk for Alzheimer’s disease. Auriel Willette, Ph.D., a research scientist in the Department of Food Science and Human Nutrition at Iowa State, said insulin resistance is common in people who are obese, pre-diabetic or have type II diabetes.

Researchers examined brain scans in 150 late middle-aged adults, who were at risk for Alzheimer’s disease, but showed no sign of memory loss.

The scans detected if people with higher levels of insulin resistance used less blood sugar in areas of the brain most susceptible to Alzheimer’s. When that happens, the brain has less energy to relay information and function, Willette said.

“If you don’t have as much fuel, you’re not going to be as adept at remembering something or doing something,” he said.

“This is important with Alzheimer’s disease, because over the course of the disease there is a progressive decrease in the amount of blood sugar used in certain brain regions. Those regions end up using less and less.”

Willette’s work focused on an area of the brain — the medial temporal lobe and specifically the hippocampus — that is critical for learning new things and sending information to long-term memory. This region is also one of the areas of the brain that first show massive atrophy or shrinkage due to Alzheimer’s disease, Willette said.

Researchers say that this is the first study to look at insulin resistance in late middle-aged people (average age was 60), identify a pattern of decreased blood sugar use related to Alzheimer’s, and link that to memory decline.

Participants were recruited through the University of Wisconsin-Madison and Wisconsin Registry for Alzheimer’s Prevention study, an ongoing study that examines genetic, biological and lifestyle factors that contribute to dementia.

Experts explain that the link between insulin resistance and Alzheimer’s disease is important for prevention, but the risk is much more immediate. Problems regulating blood sugar may impact cognitive function at any age.

Testing for insulin resistance in obese patients and taking corrective action, through improved nutrition and moderate exercise, is a crucial first step, said Willette.

“We are terrible at adjusting our behavior based on what might happen in the future.”

“That’s why people need to know that insulin resistance or related problems with metabolism can have an effect in the here and now on how they think, and it’s important to treat.

“For Alzheimer’s, it’s not just people with type II diabetes. Even people with mild or moderate insulin resistance who don’t have type II diabetes might have an increased risk for Alzheimer’s disease because they’re showing many of the same sorts of brain and memory relationships.”

Understanding the progression of cognitive decline will take additional research. Willette says following those who are at risk through the different stages of dementia and Alzheimer’s will offer insight as to what happens as their cognitive function declines.

Source: Psych Central


Today’s Comic

Chronic Cannabis Use by Youth May Lead to Poor Conflict Resolution Skills

The development of neural circuits in youth, at a particularly important time in their lives, can be heavily influenced by external factors—specifically the frequent and regular use of cannabis. A new study in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP), published by Elsevier, reports that alterations in cognitive control—an ensemble of processes by which the mind governs, regulates and guides behaviors, impulses, and decision-making based on goals are directly affected.

The researchers found that these brain alterations were less intense in individuals who recently stopped using cannabis, which may suggest that the effects of cannabis are more robust in recent users. Additional findings from the study also suggest greater and more persistent alterations in individuals who initiated cannabis use earlier, while the brain is still developing.

“Most adults with problematic substance use now were most likely having problems with drugs and alcohol in adolescence, a developmental period during which the neural circuits underlying cognitive control processes continue to mature,” said lead author Marilyn Cyr, PhD. “As such, the adolescent brain may be particularly vulnerable to the effects of substance use, particularly cannabis—the most commonly used recreational drug by teenagers worldwide,” added the postdoctoral scientist in the Division of Child and Adolescent Psychiatry at the New York State Psychiatric Institute, Vagelos College of Physicians & Surgeons, Columbia University, New York.

The findings are based on functional magnetic resonance imaging (fMRI) data acquired from 28 adolescents and young adults (aged 14-23 years) with significant cannabis use and 32 age and sex-matched non-using healthy controls. Participants were scanned during their performance of a Simon Spatial Incompatibility Task, a cognitive control task that requires resolving cognitive conflict to respond accurately.

Compared to their healthy counterparts, the adolescents and young adults with significant cannabis use showed reduced activation in the frontostriatal circuits that support cognitive control and conflict resolution.

The authors also examined the degree to which fluctuations in activity in relation to conflict resolution is synchronized across the different regions comprised in this frontostriatal circuit (that is, to what extent are regions functionally connected with each other). Although circuit connectivity did not differ between cannabis-using and non-using youth, the research team found an association between how early individuals began regularly using cannabis and the extent to which frontostriatal regions were disrupted, suggesting that earlier chronic use may have a larger impact on circuit development than use of later onset.

“The present findings support the mission of the Adolescent Brain and Cognitive Development study, a longitudinal study aimed at understanding the developmental trajectory of brain circuits in relation to cannabis use,” said Dr. Cyr. “In addition, these findings are a first step towards identifying brain-based targets for early interventions that reduce addiction behaviors by enhancing self-regulatory capacity.

“Given that substance use and relapse rates are associated with control processes, interventions based on neural stimulation, such as transcranial magnetic stimulation (TMS), and behavioral interventions, such as cognitive training, that specifically target the brain circuits underlying these control processes may be helpful as adjunct intervention strategies to complement standard treatment programs for cannabis use disorder.”

Source: ELSEVIER

The Best Exercises for Brain Health

Len Canter wrote . . . . . . . . .

There’s a lot you can learn from your elders, starting with the results of a multi-year study of exercise and brain health in seniors.

Researchers from Columbia University and the University of Miami compared results of two sets of brain scans and tests measuring memory and thinking skills in 876 seniors. The tests were done five years apart.

The investigators found a greater mental decline for those who reported low-activity exercises, such as light walking and yoga, compared to those with high-activity levels and exercises like running and cardio workouts.

The difference was equal to 10 years of brain aging, and that was after taking into account other factors that can influence brain health, such as excess weight, high blood pressure, smoking and drinking, according to the findings published in the journal Neurology.

Researchers are also learning about the brain benefits of cardio exercise from lab studies — those done on animals. One study found that sustained aerobic activity — such as daily jogging for several miles at a moderate pace — can encourage the growth of new brain cells, even later in life.

Research into which specific cardio activities are best for each of the sexes is ongoing, so there’s still more to learn. In the future, the goal is to learn more about how to individualize exercise for brain health.

This isn’t to say that other types of exercise aren’t important parts of an overall fitness regimen. Strength training helps you stay independent, while yoga, other flexibility exercises and balance work help prevent dangerous falls and keep you limber.

It may be hard to begin an exercise program if you’ve never been active, but it starts with your mindset: Don’t think of exercise as a necessary evil, but rather as something positive you do for yourself because of all the things it gives back.

Source: HealthDay


Today’s Comic