By Simon J. Evans, PhD

What does the word ‘fitness’ mean to you? Do you think of a body builder or a marathon runner? Do you think an Olympic swimmer? How about an old person reading a map? Huh? Where’d that last one come from?

A new study published in the January 2009 edition of Hippocampus finds that older adults (59 to 81 years) who were more fit had increased spatial memory compared to less fit adults of the same age. They also had a bigger part of the brain, called the hippocampus, which is involved in learning and memory. The hippocampus is also a part of the brain that is particularly targeted in Alzheimer’s disease. Currently science assumes that when it comes to the hippocampus, bigger is better.

Larger hippocampi (plural form) are also associated with better ability to handle stress. In fact, some studies show that war veterans with a larger hippocampus have less intense post-traumatic stress disorder. This may be because their bigger hippocampi protect them from stress better. It may also be that stress itself, shrinks the hippocampus. In fact, the data suggest that both are probably true.

Having a genetically endowed hippocampus probably puts you at somewhat of an advantage when it comes to handling stress. But learning to manage stress can probably also protect your hippocampus and help you age with a little more cognitive grace.

In this new study, researchers recruited 109 older adults and tested their level of physical fitness using a treadmill, measuring aerobic fitness, heart rate and blood pressure. After that, the participants all had their brains scanned in an MRI machine, allowing researchers to measure the size of their hippocampus.

When they compared the two types of measures, low and behold, increased aerobic fitness correlated with increased hippocampal volume, a bigger hippocampus. But the researchers didn’t stop there. They also tested all the participants on spatial memory tasks.

Using a computer, dots were flashed on the screen and the subjects had to remember where those dots came up, monitoring one, two or three dots at the same time. Again, the older adults with better fitness measures performed better on this test.

The researchers believe that the reason they do better on the tests is because they have bigger hippocampi, and the reason they have bigger hippocampi is because they are more fit.

This all make sense, knowing what we know about how exercise boosts brain function. However, we still have to point out that this is a retrospective study. This means you can’t say for sure that increased fitness caused increased hippocampal size and increased performance on memory tests. There may be other factors.

Still, when you look at this new study in the context of all the other studies showing that exercise is good for the brain, it sure seems to be true. This is one more piece in the mind-body connection puzzle. Every day research comes out making it clearer and clearer that the health of your body influences the health of your brain. So if you want to stay sharp in those older years don’t just rely on crossword puzzles in the daily paper to get you there – unless you’re taking a brisk walk down to the corner store to pick it up.

Reference:
Hippocampus. 2009 Jan 2. [Epub ahead of print]

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By Paul R. Burghardt

A recent report by Xu and colleagues in the journal Diabetes, addresses one of the “modifiable risk-factors” for developing dementia. In other words, it tried to identify those things we do and control on a day-to-day basis that ultimately reduce or increase the likelihood of developing disease. These modifiable risk-factors include things like weight-management, blood pressure control, managing diabetes, and exercise. This study focused on how diabetes can influence the chances that we develop dementia depending upon genetic traits and when in the lifespan a person develops diabetes.

Since diabetes increases the risk of developing Alzheimer’s disease, as well as vascular dementia (yep, unfortunately there are a couple of ways to develop substantial cognitive decline), understanding how genetics and lifestyle choices interact during the development of disease will provide a lot of information that can be used for both prevention and treatment. We already know that avoiding diabetes, or managing diabetes effectively, is of the utmost importance.

To address the issue of how the development of diabetes relates to the risk for dementia, Xu and colleagues utilized the Swedish Twin Registry. This is a national survey in Sweden that tracks health information about twins, which is pretty cool for research purposes. Plus, it’s good to know the Doublemint girls are keeping busy, right?

Their general findings weren’t too surprising: diabetes increases the risk for developing dementia whether it be, vascular dementia or Alzheimer’s disease. However, there were some distinct findings in this study emphasizing that timing is everything.

A particularly interesting finding was that the risk for dementia (vascular or Alzheimer’s disease) increased if a person developed diabetes before they turned 65. By the way, the most common time for Alzheimer’s disease diagnoses is in people 65 years of age or older. Remember, this disease takes a number of years to develop, so what you do now may have a substantial impact on how your brain ages.

This probably occurs by the amount of ‘wear-and-tear’ your brain is able to handle under diabetic conditions, particularly if you are genetically predisposed to developing dementia. The concept of cumulative wear-and-tear has a fancy name, “allostatic load.” This idea is important for all aspects of our health as it accounts for the interactions between our genes and environment in a time-dependent manner. But that is for another post….

In general, this study reiterates a couple of issues. First, it highlights the importance of the mind-body link. Although many people think that diabetes is a problem for blood sugar control, it influences a lot of other organs in our bodies, including our brains. Second, if you have a family history of diabetes the longer you avoid developing the disease the better this will be for your brain (and rest of your body).

Unfortunately in this study the authors weren’t able to look at individual’s ability to control/manage their diabetes. But I’d like to be optimistic and believe that better management of a disease like diabetes would help decrease its negative influence on other aspects of our biology. In line with this, please see our blog post for this Thursday!

Reference:
Diabetes. 2009 Jan;58(1):71-7. Epub 2008 Oct 24.

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By Simon J. Evans, PhD

Remember the ‘monster cereals’? Frankenberry, Booberry and Count Chocula? I liked the little marshmallows in Frankenberry the best, though the chocolate milk left behind by Count Chocula was hard to beat. But can eating these types of breakfast cereals be setting us up for future memory problems?

We’ve learned a lot over the past couple of decades about how the foods we choose to eat as kids and young adults, control our risks for chronic illness as older adults. More recently we are beginning to understand that many chronic diseases are related to each other. Now, a new study published the February 2009 issue of The Proceedings of the National Academy of Sciences (USA), adds a very interesting chapter, linking blood sugar control to memory decline.

Specifically the study examines the role of insulin in countering Alzheimer’s disease progression. But before we get into that, let’s connect a few dots.

We know that high sugar foods, if eaten on a regular basis, increase our risk for insulin resistance and diabetes. What does this mean? When you eat high sugar foods your blood sugar rises quickly and your body brings it back down by releasing insulin. However, if you continue to do this on a regular basis, your body will become less sensitive to its own insulin and require more and more of an insulin release to do the job. This is called insulin resistance and is a step toward diabetes.

In recent years, we have learned that insulin acts in the brain as well. Brain cells rely on this hormone to keep a regular supply of energy so you can think clearly, remember where you parked your car and why you went into the store in the first place. Insulin resistance in the brain may lead to mood and cognitive problems. While this is a young area of research we know that diabetes increases your risk for both depression and Alzheimer’s disease.

The new study gives us some insight into why this might be true. One feature of Alzheimer’s disease is an accumulation ‘tangles’ from a protein called amyloid-beta. It turns out that small pieces of this protein can attack certain cells in your brain that are responsible for making and storing memories. If these attacks get bad enough – boom, Alzheimer’s disease.

What the new study shows us is that insulin helps protect these ‘memory’ cells from attack by amyloid-beta, but only if the cells remain sensitive to insulin. This sheds light on why diabetes puts you at increased risk for Alzheimer’s disease. If you have lost sensitivity to insulin (become insulin resistant) then you may be more susceptible to attack by amyloid-beta proteins and the development of Alzheimer’s disease.

In their study, the researchers were able to ‘help’ insulin out using a diabetic drug that increases insulin sensitivity, and this is promising news for development of therapies to help people going down the Alzheimer’s road. But are there other ways to increase our insulin sensitivity. The answer is emphatically, yes!

First of all, exercise is known to boost insulin sensitivity, even if you are already diabetic. Getting your muscles working helps them regain their sensitivity to insulin and do a better job of maintaining blood sugar. Second, eating a low-glycemic diet, with high fiber and low sugar, help regulate blood sugar and boost insulin sensitivity. Third, sleep is an emerging factor in improving insulin sensitivity and blood sugar control.

Again, this returns to the fundamentals. Exercise more, eat better and get enough sleep. Understanding all the cool neuroscience on why these things help is great, and hopefully provides you with a little extra motivation. Sometimes connecting a behavior to a real change that you can put your finger on can give you that extra sticking power, which is why we write these summaries. But the decision is yours. You know what to do, now can you do what you know?

Reference:
Proceedings of the National Academy of Sciences (USA). 2009, 106(6):1971-1976.

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By Simon J. Evans, PhD

The head bone connected to the neck bone, The neck bone connected to the back bone, The back bone connected to the thigh bone . . . Dem bones, dem bones gonna walk aroun’, Dem bones, dem bones, gonna walk aroun’. . . remember that song? It’s a basic principle. Your body systems are all connected up. So it should be no surprise that the health of your brain is connected to the health of your body and a new study revealed just how much.

We’ve known for some time that fit people feel better, and more recently discovered that they may also think better. Canadian researchers took this to the test by looking at how the physical fitness level 50 – 90 year old women predicted their cognitive abilities. Their research will be published in the March 2009 edition of the journal, Neurobiology of Aging.

The research team recruited 42 healthy post-menopausal women who were free of chronic illness and medication. They then evaluated their level of physical fitness using a standard exercise test and compared fitness levels to cerebral blood flow (blood supply to the brain) and a battery of cognitive performance tests.

Not surprisingly, women who reported getting regular exercise were more fit than women who were sedentary. But let’s explore for a minute what fitness actually means to these women. First, fitness significantly predicted the cerbrovascular health of these women, which is a fancy way to say that fit women had a better blood supply to their brains.

What does that mean? Basically, it means their brains can perform better and they proved it by doing better on all kinds of cognitive tests, including cognitive speed, perception, verbal ability and executive function. Even if you don’t know what all of these test measure, understand that the physically active women out-performed the sedentary women on every cognitive test the researchers through at them.

We all know that exercise helps our heart and arteries work better. For some people, that is motivation enough. However, only about 1-3 adults get any regular exercise so maybe we need a bigger motivator. Understanding that physical fitness will also make your brain work better might be the driver that many people need. While nobody wants diabetes and heart disease, people may work a little harder to stave off cognitive decline and Alzheimer’s disease and that’s what makes studies like this important.

Your brain uses up to 20% of the oxygen that you breathe. How does it get from your lungs to those brain circuits that remember where you put your keys? Answer: your blood supply and your neurovascular system. This new study shows that the more fit you are the more efficiently you will get blood to your brain and the smarter you will be.

Studies like this may not provide us with earth shattering revelations. The results are not surprising, but they give us evidence that how we choose to live effects how we think and feel. And evidence leads to recommendations, which lead to policy changes, which hopefully, someday will lead to health care systems that promote and reward you to stay fit. So next time you’re struggling with whether or not to get off the couch and go for a walk, think about your brain – while you still can.

Reference:
Brown et al. Neurobiology of Aging (2009) In Press

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By Simon J. Evans, PhD

For far too long, neuroscientists have considered the brain as somehow separate from the body. As a neuroscientist, I have been guilty of that myself. The brain is, after all an incredibly complex organ that really defines who you are. But it is still an organ that plays by physical rules of the body.

Your brain does have special treatment not enjoyed by other organs. It has a blood-brain barrier that keeps many unwanted toxins out and necessary nutrients in, giving it first dibs on much of the good stuff. But your brain still requires a healthy blood supply to deliver energy, in the form of oxygen and nutrients, and to remove metabolic waste products, even if this process is under tighter control than it is for other organs.

We’ve been touting the message for some time now that eating better and exercising more helps your brain fitness. But how exactly does that work? The answer to that question is currently a hot topic of investigation, but a couple of new reports shed some light – in my opinion, a fairly bright light related to your brain’s blood supply.

The first study, published in the December 2008 issue of Neuron, reported that brain cells that don’t get enough energy tend to increase markers of Alzheimer’s disease. Brain cells have the potential to produce a protein that accumulates during Alzheimer’s disease, called amyloid-beta. In the new study, researchers discovered a process that leads to production of this protein when the neurons don’t get enough glucose (blood sugar).

What can lead to a lack of blood sugar delivery? Answer: A poor brain blood supply, which can be a result of poor cardiovascular health. What can improve cardiovascular health, and improve energy delivery to the brain? Answer: A good diet and exercise.

But there is another side of the coin. It’s not enough to deliver blood sugar to the brain efficiently, you have to get your brain cells to take it as well. If you have become insulin resistant then your brain cells may not be able to take up the glucose that’s delivered. Current estimates are that about 42% of American adults have at least early stages of insulin resistance, which if it gets bad enough can lead to type II diabetes.

A second report, published in the December 2008 issue of Annals of Neurology, bolsters that argument. In this study, researchers evaluated blood volume in the brains of diabetics. What they found was that specific parts of the brain in diabetic patients had less blood volume, which likely means less energy delivery. Based on the above study, this means a potential for production of more the Alzheimer’s related protein, amyloid-beta.

Furthermore, the part of the brain where researchers found less blood volume was a region of the hippocampus known to play a role in learning and memory and known to be one of the regions most affected by Alzheimer’s disease.

How do you improve insulin sensitivity? Answer: Eat better and exercise.

These were very cool studies because they can potentially lead to better treatments for people with early stages of Alzheimer’s or other types of cognitive decline. But in a way they are also proving the obvious. If we give our brain and body what we know we should give it, namely good food and exercise, we go a long way toward supplying ourselves with the tools we need to stay brainfit.

When you eat nutritious foods, like fruits, vegetables and whole grains you arm your brain with the tools to defend itself. When you exercise regularly you ensure those tools get where they need to go. It’s not rocket science. Do it for your brain.

References:
Neuron (2008) 60, 988-1009
Annals of Neurology (2008) 64, 698-706

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By Simon J. Evans, PhD

More and more studies continue to emerge on the brain fit benefits of some food and drinks. The best part is that some of these are foods and drinks that many of us enjoy. We all know that fruits and veggies help our general health, but what other goodies help the function of the brain and could be part of our brain fitness program?

A new study in the Journal of Nutrition evaluated the cognitive performance of over 2,000, seventy – seventy four year olds who regularly eat chocolate, drink tea, or drink wine. Researchers compared these adults performance on a battery of cognitive tests to same-age adults who did not partake in one or all of these culinary delights.

The study concluded that eating chocolate, drinking tea or drinking wine, was associated with improved performance on tests for learning, memory, word association and other types of intellectual function. What’s more is that eating and drinking all three was better than one or two. Now let’s get to a little of the nitty-gritty.

Chocolate – How Much and What Kind.

Chocolate eaters performed better than non-chocolate eaters, but don’t go out and stuff your face too much. First of all, the benefits are confined mostly to dark chocolate and the higher the concentration of cocoa, the better. This is where most of the beneficial flavonoids come from in this particular delicacy. As for the amount, about 10g per day did the trick, which is about one-third of an ounce for you non-metric types. Just a little square after dinner will do it.

Tea Time

Tea drinkers did better than those who didn’t drink tea on all the cognitive tests as well. The researchers in this study were not able to separate green tea from black tea drinkers. Both types of tea have about equal concentrations of flavonoids anyway, but green tea has been more strongly associated with cognitive performance in the past. This may be due to the fact that it has more of a specific ingredient called, catechins. However, most of the tea drinkers in this particular study population probably drank black tea – so pick your poison, or in this case, your antidote.

Wine and Dine

Wine had the strongest effect on cognitive performance in this study. However, it was a relatively modest amount that had the biggest effect, on the order of about half a glass per day. After that, there wasn’t really any added benefit. The study did not include heavy drinkers to evaluate how much is too much. However, past studies have indicated about one to two glasses a day may be OK. White and red wines were not separated for this study either and many previous studies have implicated red wine more strongly in overall health. But, several studies have also implicated any alcohol in moderation to improved cardiovascular tone, which probably translates into neurovascular health as well (the blood supply to the brain).

A big caveat to all of this is that these older adults had likely been eating dark chocolate and drinking tea and wine for a long time. It’s unclear how long is necessary to see beneficial effects for any of these, but like most things, it’s likely that the earlier the better, but it’s never too late to start. Of course, these studies are also associative, which means we can’t say for sure that chocolate, tea and wine cause better cognitive performance, but those who use them seem to do better.

So this holiday season, curl up by the fire with a nice glass of wine, cup of tea, or dark hot chocolate and think about thinking about stuff more clearly.

Reference:
Journal of Nutrition (2009) 139:120-127

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