By Simon J. Evans, PhD

The title question may be a bit of a stretch, but you only need to connect a couple of research dots to get from childhood obesity to reduced brain fitness in older age.

Belly Fat and Brain Fitness are Related

First, a recent meta-analysis from researchers at Johns Hopkins University verified that the odds of getting Alzheimer’s and other types of dementia increase as you gain weight. A meta analysis takes all previous studies on a particular topic and looks at them together to improve the statistical power over any one study by itself. This particular meta analysis looked at all studies that evaluated whether or not risk for Alzheimer’s or other types of dementia is increased in obese individuals.

Some studies evaluated obesity status of people in their mid-forties, others looked at people in their mid-sixties or seventies. In any case, obesity in mid-life or late life increased odds of getting Alzheimer’s disease or other dementias anywhere from 10 to 30 years later. Importantly, researchers controlled for socio-economic status, lifestyle choices, genetic factors and other illnesses so that the condition of obesity itself, seemed to be the culprit.

Adolescent Weight Problems Lead to Adult Weight Problems

The second dot to connect is that being overweight in childhood dramatically increases the odds of battling a weight problem throughout adulthood. So giving in to your kids’ demands for cakes, cookies and sugared cereals now, is not doing them any favors down the road.

There are really two ways to pack on the pounds. One is to make more fat cells, and the second is to store more fat in the fat cells you already have. An important study from the Karolinska Institute in Sweden, discovered that the number of fat cells you will carry throughout your adult life is really set during your adolescent years. After the age of 20, your number of fat cells will stay about constant.

Obviously, this doesn’t mean that your weight is set after age 20. You can still lose weight or dramatically gain weight. It’s not uncommon to gain weight in your 30s and 40s, as your activity level and metabolism slow down, especially if your food intake doesn’t change. You can always lose or gain fat in the cells that you already have. However, if you gain too much weight in adolescence, when you are actively making more fat cells, you are going to set yourself up for a tough battle for the rest of your life. So as parents, we should do everything possible to regulate our kids weight while it’s still somewhat in our control.

If you connect these two lines of research, you can see that increased weight gain in childhood predicts increased obesity in adulthood; and increased obesity in adulthood boosts your odds of Alzheimer’s and dementia in your 70s and 80s. There have not been any research studies following kids all the way from adolescence to old age to look directly at the relationship between childhood weight and dementia, but they will come eventually. Personally, I won’t be surprised if these studies find increased odds of dementia with childhood obesity.

It’s difficult to think of our kids as old people, but that is who they will become. We must think proactively and do everything we can to boost their odds of life-long cognitive success. If you have concerns about your own children’s weight, work with your pediatrician to design a diet and exercise program and get it under control while you still can. If you struggle with a weight problem yourself, don’t give up. The more effort you put in to bringing your weight under control, the better your odds of a fit brain down the road. Even if you only drop some of the weight you want to lose, every little bit helps boost those odds.

References:

Nature (2008) Jun, 453(7196):783-7

Obesity Reviews (2008) May, 9(3):204-18

By Simon J. Evans, PhD

Does your job have anything to do with your odds of getting Alzheimer’s disease down the road? Studies have come out recently linking intellectually challenging careers to reduced risk of dementia. Other studies link education level to cognitive health in later years. Overall, people with more education have lower rates of Alzheimer’s disease than those with less education.

This really isn’t that surprising if you think about it. We know that the more you use your brain, the stronger it gets. Just like muscles in your arms and legs, the brain gets more fit when you work it out. Higher education usually means more mentally stimulating jobs and that keeps your brain fit.

But that doesn’t mean that you have to go to graduate school to stay mentally active. Big studies look at large groups of people. On average, when you look at lots of people those with higher levels of education have more intellectually challenging jobs. So overall, they have lower rates of dementia. However, you can be a high-school drop out and still do what’s necessary to keep your brain fit. Just don’t be average.

You can maintain an active mind by committing yourself to life-long learning. It doesn’t take a formal education to teach yourself new skills, read new books and continually challenge your mind – it ain’t rocket science.

There is, however, a flip-side to this coin. Even though higher education predicts lower odds of getting Alzheimer’s disease, those with higher education who do get Alzheimer’s, decline much more rapidly and die sooner than those with less education. Remember, again, this is based on big number averages and is not necessarily predictive for any one person. Still, on average if you have an intellectually challenging career, your odds of getting dementia are lower, but if you do get it, your odds of rapid decline are greater.

At first, this might seem paradoxical. But I think there is a likely explanation for these seemingly odd data. It all relates back to the cognitive reserve theory, which we have discussed in the past.

Essentially, cognitive reserve is something you create throughout your life. The more you learn and the more you experience, the more you create cognitive reserve. This is like ‘extra’ brain circuits to accomplish intellectual tasks.

Think of it like a city building multiple bridges across a river. If you only have one bridge to cross the river and it gets knocked out by a freak storm, you can’t get traffic to the other side. If, however, you’ve created reserve routes to cross the river with multiple bridges and one gets knocked out, you can divert traffic across the other bridges.

This is the same with brain circuits. If you’ve created multiple circuits through a variety of experiences you have different ways to accomplish the same task. If one takes a hit due to age-related damage, you can divert thoughts through different circuits and not really notice a problem.

So people with higher education and more challenging jobs may have reserve brain circuits. That means that even though we may all experience the same age-related damage, someone with more cognitive reserve will show less cognitive decline. There are also ways to minimize the age-related damage through healthy living, but that’s another topic.

So why would people with more reserve show more rapid decline once dementia sets in? Again, this makes sense if you think about it. People with high levels of reserve who get dementia must have experienced severe damage that took out all their bridges. Damage of this severity will take them down quickly.

However, it’s an illusion. Since studies only compare people diagnosed with dementia, they may be comparing apples to oranges. On average, the people with high reserve (mentally challenging careers in these studies) who have Alzheimer’s disease have likely experienced a lot more damage than, on average, the people with low reserve who have Alzheimer’s.

This would explain why people with more challenging careers would have fewer cases of Alzheimer’s; and also why people with higher levels of education who do get Alzheimer’s, decline much more quickly.

Overall, it’s better to boost your odds of not getting dementia in the first place by doing what’s necessary to challenge your mind on a daily basis. Commit yourself to life-long learning and stay mentally active to build more bridges. Couple this with quality nutrition, plenty of exercise and enough sleep, and you will also minimize the storms that create the damage that can damage your bridges.

By Simon J. Evans, PhD

Many of us have a sweet tooth. It’s hardwired into our brains. Several thousand years ago, when we went long periods of time between meals, we needed to get all the calories we could whenever we had the chance. Sweet and fatty foods are high in calories, so our brains made them taste good to get us to eat them. It was a survival instinct back then that made for fit brains. It doesn’t work so well for us now.

Taste Isn’t Everything

We’ve known this for some time. We know that when you eat something sweet you light up pleasure centers, driven by dopamine, in your brain. New research shows it’s not just the sweet flavor that pleasures us. We will light up pleasure centers even if we can’t taste the sweet foods. The high sugar content of sweet foods cranks up our insulin. It turns out that the insulin spike is enough to activate our pleasure centers.

In a recent study, researchers knocked out the ability of mice to taste sweetness. They proved it by allowing mice to choose between plain water and water spiked with sucralose (a non-digestible sugar with no available calories). Normal mice will prefer the sucrolose water because it’s sweet, but these mice couldn’t tell the difference. Next, the researchers gave the un-sweetened mice a choice between plain water and sugar water, and they those the sugar water, even though they couldn’t taste the difference.

In the same studies, the researchers looked at the pleasure centers in the brains of the mice. Sucralose water (sweet but no calories) had no affect, but sucrose water (regular sugar) cranked up the dopamine in please circuits, whereas in regular mice, both sucrolose and sucrose activate pleasure. This showed that the high calorie content alone was enough to activate pleasure, even in the absence of taste.

Sweet Pleasures, or Not

So what does this mean for us sweet-toothed humans? First, since our pleasure circuitry is similar, it’s likely that the same thing happens in our brains (although this remains to be tested directly). Second, we’ve discussed in the past how high glycemic foods (simple carbohydrate, high sugar) spike your blood sugar and insulin levels. This is likely tickling your pleasure centers and reinforcing high glycemic eating. The problem is that this type of eating is gaining more and more data on increasing your risk for metabolic and cognitive diseases, like diabetes and dementia.

Like anything that stimulates your brain pleasure circuits, it becomes less intense over time. So the more you eat high glycemic foods, the less intensely your pleasure centers are likely to respond. This is also how drug addiction works, and is why people need more of a drug to get the same high over time. Not only that, but when you come off the drug your pleasure centers crash to really low activation and you feel horrible. Similarly, when you try to improve your diet to reduce low glycemic foods you are not getting that pleasure boost so you crave sugar.

Now, to be clear, drugs of abuse and high glycemic foods operate at completely different levels. In the words of Nigel from Spinal Tap, drugs turn your volume up to 11, while high glycemic foods probably crank it up to 3 or 4. But the principle is the same.

It’s Never Too Late to Change

The human brain is an amazingly adaptive thing. Even though it’s wired to enjoy sweet and fatty foods, we can modify and retrain those brain circuits to adapt to health in today’s environment. After all, our brains weren’t designed to be pleasured by sweet foods on a daily basis as is the case today.

Fortunately, you can reset your dopamine scale with a focus on low glycemic eating. It takes a week or two of strictly removing excess sugar from your diet, but you can reset the circuits and lose the bulk of your cravings for sweet foods. Furthermore, if you replace the pleasure activating foods with active healthy behaviors that you enjoy, like playing tennis or shooting hoops, you’ll have a much greater chance of success.

Reference: de Araujo, Neuron 57 (2008), 930–941.

By Simon J. Evans, PhD

If you talked to a person from the 1950s about all the modern marvels we have today they’d likely drool at the mouth. What? You don’t have to get up to change the TV channel? You can reheat leftovers in 1 minute? You can access any information at any time without leaving your house? No way!

Be Careful What You Ask For

But are our lives really getting any easier? Do all these time saving devices allow us to work less? Well, sort of. It certainly takes less work to do any specific task. When I was in graduate school writing my thesis, I thought of the poor slobs who had to do that without the aid of a computer or the internet. It must have taken people an entire day to go to the library to find references that I can now get in 10 minutes (God bless Google). The trade-off is that we are expected to do a lot more tasks as part of our normal day.

I was reading an interesting paper by Kelly Lambert recently that put some of this into perspective as it may relate to rates of depression in our modern society. Even with all our modern conveniences, high-end medical care and plethora of designer drugs, we have a huge mental health crisis. In fact, today mental health accounts for about 15% of disease burden worldwide. So why are we so unhappy?

The Thrill is in the Chase

Dr. Lambert argues that one factor in our overall societal unhappiness is the fact that we have it too easy, especially when it comes to feeding ourselves. Years gone by, dinner was more than a phone-call away. We actually had to track our food across the tundra and risk death by saber-toothed tigers or violent weather, in order to feed ourselves. Even if we were successful, we had to do it again the next day. As time drew on, we learned it was much easier to plant food in the ground. But this still required intensive labor and patience to bring our sowing efforts to the fruition of harvest.

All of this effort made the reward that much more enjoyable. The magnitude of the reward may actually depend on the magnitude of the effort required to achieve it. Meaning the harder we have to work for something, the more we enjoy it when we are successful. Since successfully finding food is a major factor in our survival, and we used to work very hard to stay fed, we had ample opportunity for regular high intensity rewards.

Appreciate What You Have

Today, however, we take for granted this major facet of our lives. Finding food does not require much effort at all, at least for most of the lucky people living in our society. Because we don’t need to put out effort, we don’t activate reward centers in our brains that our ancestors activated on a regular basis. We are essentially robbing ourselves of a major ‘happiness factor’, and this, argues Dr. Lambert, may be a problem. It may be that today’s lack of regular reward, due to lack of necessary effort, may be a factor in high rates of depression.

Whether or not she is right, I don’t know. She provides many examples and scientific studies to back up her argument and I thought it was a very interesting point worthy of a post. In fact, I have two cats that seem to agree with her. They are not content just eating their chow out of a dish. Instead, they enjoy scooping out one nugget at a time, batting it across the kitchen floor and then pouncing on their prey before eating it.

There’s not really much we can do about this unless you want to pull a Grizzly Adams and drop out of society, move to the hills and live off the land. Alternatively, you could do all your grocery shopping in full camouflage, crawling around on your belly through the frozen food aisle, stalking fish sticks. Or, maybe we can be more appreciative of what we have and not take all our modern conveniences for granted.

Reference: Lambert, K.G. Neuroscience and Biobehavioral Reviews 30 (2006) 497–510

By Dr. Simon Evans and Dr. Paul Burghardt

For some time now, we’ve been promoting the role of a healthy lifestyle in maintaining brain fitness. Another new study lends more support, but before we get into that we thought we’d focus on some common-sense topics as to why this is true.

One simple concept to understand that doesn’t require a PhD is the fact that any organ in your body, including your brain, needs a healthy blood supply to access nutrients and oxygen. This is one reason why heart disease and mental health problems, including dementia are so often related. If you tied a tourniquet around your leg to cut-off the blood supply, you shouldn’t be surprised when your foot stops working to well.

The same is true for your brain. If you continue to do things that are bad for your cardiovascular system, like sit around all day and eat chips, your vascular system will eventually have a problem, and this is not good news for your brain. In fact, your brain uses about 20% of the oxygen that you breathe and the calories that you eat. Your blood supply is responsible to get that stuff to the right place in order to keep your brain in good working operation.

The benefits of life-long learning and continually challenging your mind to keep it sharp are well established. But if you don’t couple that effort with doing what’s necessary to maintain a healthy neurovascular system, you cannot fully realize the benefit. You may have read a lot about neurogenesis and synaptogenesis, which is the constant rewiring of your brain that occurs when you stay mentally active and helps to keep your mind agile. However, this process can only work well if the blood vessels near all this rewiring are healthy enough to do their job. Otherwise, where is the energy, nutrients and oxygen necessary for the remodeling job going to come from?

Think of neurogenesis as a new housing subdivision going into an existing community and the roads as the blood supply to service the houses. If you were the builder constructing this new development you wouldn’t get very far if you didn’t first attend to the new roads. Not only are the roads needed for the new owners to get in and out of their homes; but they are needed for delivering all the lumber and concrete, enabling the different crews to come in and construct the new houses, and take all the trash away. Similarly, new brain cells or new brain cell connections need healthy roads (neurovascular system) to work right.

Related to this, a recent large study, just unveiled this month (April 2008) by Dr. Thomas Montine from the University of Washington, reports that 33% of the risk of dementia stems from disease of small blood-vessels in the brain. In this 12-year study, 3,400 men and women over age 65 volunteered for periodic cognitive testing and a brain autopsy upon their death. In the 221 autopsies performed, researchers discovered that small blood vessel disease accounted for about 1/3 of the risk for dementia. Importantly, this type of small blood vessel disease may go unnoticed for some time. We’re not talking about big events like a stroke or blood clot blocking a large vessel. However over time these small problems can add up, and result in cognitive impairment.

Admittedly, this study comes from the Pacific Northwest, the origin of grunge-rock and Starbucks coffee. We can’t be sure that all these people aren’t suffering from some kind of post-angst cognitive disorder, or a latent flannel shirt allergy! We also can’t rule out suffering from some sort of post-tramautic stress after invading the world with high-priced coffee, equivalent to about $18.00 per gallon; slightly more than we’re currently paying for gas. In fact, one of us (Evans) was raised in Seattle and may be showing some early symptomology.

However, with these potential confounds aside (unless Austin Powers was right, and during the time that Dr. Evil was cryogenically preserved his faithful cronies invested heavily in Starbucks), this study is an incredibly important step that illustrates the diversity of factors that can lead to dementia. Even more importantly, it suggests that you can substantially decrease your odds of developing dementia by attending to life-style factors that can protect against vascular disease.

The beauty is that we have a good idea of how to do this since blood vessels serve to supply active areas of the body with nutrients! So if your brain is active (which requires energy), and you’re maintaining your overall vascular health by eating right and exercising, odds are that you will be greatly reducing your risk of developing dementia from small vessel disease. Now it should be noted that research is ongoing on this subject, but common sense would suggest that this will hold true.

Taken together this highlights some very important reasons as to why exercise and nutrition play such a crucial role in brain fitness. Attending to both of these lifestyle factors is necessary to maintain a healthy blood supply and the creation of new blood vessels, in order to feed new brain circuits established by learning and mental activity. If you neglect this aspect of brain fitness, you may literally limit your ability to benefit from neurogenesis and synaptogenesis induced by many of the ‘brain-training’ programs designed to keep your mind young.

Written by Paul R. Burghardt, PhD

A recent paper in the journal Neurobiology of Learning and Memory by Bernward Winter and colleagues investigated the effects of a single session of exercise of different intensities on individuals’ ability to learn and remember new words.

College students were asked to sit quietly for 15 minutes, walk at a moderate pace for 40 minutes, or sprint two times for three minutes per sprint. Fifteen minutes after finishing one of those intensities of exercise, they learned a pairing between a made up word and a picture (e.g. glump/ picture of a car). The subjects were rated on the speed at which they learned the new pairings, and their accuracy when recalling the pairings between pictures and novel words one week and eight months after the single exercise session.

For the record, my money was on the moderate intensity group to perform the best, but……the high-intensity group learned the pairings 20% faster than both the control and moderate intensity exercise groups. Translated that means that after two sprints of less than three minutes each increased peoples’ speed of learning by 20% compared to the other conditions. And that, folks, is the reason why I am not a gambler.

Another interesting finding was that after intense exercise, the students not only learned faster, but recalled those word-picture pairings more accurately after 1-week and 8-months. So do some sprints….you’ll learn it quicker, and remember it longer!

Along with the learning component, this group of researchers also examined levels of hormones in the blood for potential association with peoples’ ability to learn in the word-picture paring task.

Levels of the growth factor BDNF (Brain Derived Neurotrophic Factor) and other hormones involved in our flight-or-fight response were elevated after sprinting. Further, these hormones were associated with better short-term and long-term learning success. This indicates that enhanced learning after this intense, but brief, exercise may be modulated by these hormones.

One of the main questions to ask is whether this type of exercise would produce the same learning effects in non-athletes? Since the subjects of this study were athletic to begin with, their perception of intense exercise is likely to be much different than that of an individual who rarely or never exercises but decides to go out and does some sprints. In fact, this study showed a subtle association between increased mood after intense exercise and overall greater success in learning. What I’m trying to say is that these people probably felt pretty good, amped-up (so to speak) after the sprints. It’s possible that a positive emotional spin on the situation enhanced learning.

We know that the emotional value of a situation influences how strongly a memory is stored, and this happens at both ends of the spectrum. Very happy events often stick in our memories. Unfortunately very unhappy events also stick in our memories, and can cause a lot of problems, for example post-traumatic stress disorder (PTSD).

Now I don’t think that an out-of-shape individual would suffer PTSD from doing a couple of sprints (unless the sprints caused an asthma or heart attack). However, for someone that really enjoys exercise and is familiar with exercise this may have been just enough of a “rush” to make learning a little easier and more memorable.

Another important point to highlight is that this study was specifically looking at the effect of one session of exercise. There are numerous studies indicating that increasing moderate physical activity as a part of one’s daily life has positive benefits on learning and cognition. So don’t feel like you need to start incorporating sprint work into your daily routine to enhance learning. The intriguing thing about this current study is that it provides another way to try and enhance learning, and also starts to address issue of when to learn new things after you have exercised.

Although there is some obvious follow-up that needs to occur after this study, this is a very nice experiment that illustrates the critical issue of timing in maximizing one’s efforts.

The old cliché “timing is everything” should be looked upon as a tried-and-true adage. Much of our biology works on a daily rhythm. Along with that, our bodies respond to environmental ‘pressures’ (eating, exercise, temperature, interacting with other people, etc.) with a variety of finite behavioral, and biological responses. Basically, when our current state of living is interrupted by some environmental (outside) factor, we will respond until those factors are neutralized.

This paper illustrates how we could capitalize on some of that compensatory biology to do a little multitasking. Get some quick exercise in, and while you’re recovering teach yourself a new language. I’m not saying this approach will work for everyone, or for every type of learning, but the possibilities are there; and the combinations will be virtually endless.