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.