Forgetting is the new normal
Memory researcher Dr Scott Small would like to reassure you that you’re not losing your wits. Visit him in his lab at Columbia University Medical Centre, tell him how the last time you went to a party, you couldn’t put names to faces, how telephone numbers slip your mind, and he’ll walk to his blackboard, pick up a piece of chalk and draw two lines. One, he will tell you, represents age. The other is memory. “As age goes up, memory goes down,” he says. “Memory decline occurs in everyone.”
Anecdotally, that’s no surprise. Approach middle age, and it’s hard not to notice that your recall is flickering. This, we’re assured, is perfectly normal – all your friends are complaining about the same thing, aren’t they? – and yet it doesn’t feel normal. You don’t just have your mind, after all; you are your mind, and nothing threatens your well-being so much as the feeling that it’s at risk. What’s more, while most memory loss is normal, at least some people must be part of the unlucky minority that develops Alzheimer’s disease or other forms of dementia. Why not you?
Alzheimer’s is expected to strike 34 million people globally by 2025 and 14 million in the U.S. alone over the next 40 years. Half of all people who reach age 85 will exhibit symptoms of the disease. That, however, means that the other half won’t. And since average U.S. life expectancy currently tops out at 80.4 for women and only 75.24 men, by the time the average American’s 85th birthday rolls around, he or she is not likely to be troubled by Alzheimer’s disease – or anything else.
Still, that doesn’t make it any easier when you forget to pick up the dry cleaning or fumble to recall familiar addresses. The good news is, science is as interested in what’s going on as you are. With better scanning equipment and knowledge of brain structure and chemistry, investigators are steadily improving their understanding of how memory works, what makes it fail, how the problems can be fixed – and when they can’t.
Until a decade ago, the common assumption was that we were born with a fixed number of brain cells that die off as we age, making us, well, dummer. That, however, is not the case. A decade ago, when neuroscientist Fred Gage of the Salk Institute made the discovery that the adult brain continues to regenerate, the brains in question belonged to mice. Some of the mice had been sedentary, others had been exercising, and the ones that lodge the greatest distance on their wheels produced many more new neurons than did the sedentary ones.
Now it turns out that the same appears to be true for humans. In a paper published last spring, a team led by Gage, Small and Richard Sloan, a psychologist at Columbia University, revealed that after pounding the treadmill four times a week for an hour for 12 weeks, a group of previously inactive men and women, age is 21 to 45, showed substantial increases in cerebral blood volume (CBV) – a proxy for neurogenesis because where there are more cells, there are more blood vessels.
Not only did the CBV profile of the human exercisers mirror that of the mice, but the people who exercised more did better on a slew of memory tests. Other evidence backs this up. In a study of “previously sedentary” older subjects by psychologist Arthur Kramer at the University of Illinois and others at Israel’s Bar-Ilan University, investigators found that those who engaged in aerobic exercise did better cognitively than those who stretched and toned but never got their heart rate pumping. What’s more, subsequent imaging showed that aerobic exercise “increased brain volume in regions associated with age-related decline in both structure and cognition.“
Meanwhile, researchers from the Karolinska Institute in Stockholm who have been following over 1,500 people for more than 35 years found a significantly lower rate of dementia, including Alzheimer’s, in those who exercised. Another study, this one of 2,000 elderly men living in Hawaii, so that those who walked about three kilometres or more a day were half as likely to develop dementia as those who walked half a kilometre or less.
But physical activity isn’t all there is to improving your memory. There’s also what you eat. Take blueberries. According to Jim Joseph, a neuroscientist with the US Department of Agriculture in Boston, blueberries seem to have nearly magical powers: they zap free radicals (highly reactive atoms that can damage tissue), reverse ageing, enhance cognition – and this is the kicker – cause new neurons to grow. If you’re a rat.
In one of his animal studies, Joseph and his associates developed a series of motor-skills tests that they called the Rat Olympics. Rats had to walk balance beams and stay upright during a log-rolling task. Those raised on special blueberry rat chow did significantly better than those that were not, leading Joseph to conclude that “blueberries were actually able to reverse motor deficits in these ageing animals.” More remarkably, when mice that had been genetically altered to express Alzheimer’s were put on the blueberry diet, they did not experience memory loss. Joseph’s research has shown some similar benefits from walnuts, which contain alpha – linolenic acid, and essential omega-3 fatty acid.
No matter what you eat, if you want to keep your memory sharp you should strive for a diet that keeps your belly fat down. A study of more than 6,500 people published in the March 26 edition of the journal Neurology showed that people who were overweight and had a large belly were 2.3 times as likely to develop dementia as those with normal weight and belly size, while those who were obese and had a large belly were 3.6 times as likely. As scientists have long known, as belly fat – which disrupts body chemistry more than less reactive fat elsewhere on the body – increases, blood glucose rises along with it. That doesn’t draw a straight and conclusive line between waistline and memory, but it does suggest one. “It’s possible,” Small says, “that blood glucose, which tends to drift apart as we get older, is one of the main contributors to age related memory decline in all of us.”
None of these insights, of course, make your sputtering memory less frustrating. When you’ve misplaced your keys for the third time this month, it does you little good to be reminded that it all may be just too much glucose and too few blueberries. And nothing entirely removes the spectre of true dementia and the horrors it implies. Still, figuring out how memory works is the most important step in figuring out how it can be fixed. When you can make some of the fixes yourself, the news is even better. If you needed one more reason to get your exercise and watch your diet, the memory scientists are providing you with one – even if you have to write it down.
Adapted from Forgetting is the New Normal by Sue Halpern. Time, May 19, 2008.
Anecdotally, that’s no surprise. Approach middle age, and it’s hard not to notice that your recall is flickering. This, we’re assured, is perfectly normal – all your friends are complaining about the same thing, aren’t they? – and yet it doesn’t feel normal. You don’t just have your mind, after all; you are your mind, and nothing threatens your well-being so much as the feeling that it’s at risk. What’s more, while most memory loss is normal, at least some people must be part of the unlucky minority that develops Alzheimer’s disease or other forms of dementia. Why not you?
Alzheimer’s is expected to strike 34 million people globally by 2025 and 14 million in the U.S. alone over the next 40 years. Half of all people who reach age 85 will exhibit symptoms of the disease. That, however, means that the other half won’t. And since average U.S. life expectancy currently tops out at 80.4 for women and only 75.24 men, by the time the average American’s 85th birthday rolls around, he or she is not likely to be troubled by Alzheimer’s disease – or anything else.
Still, that doesn’t make it any easier when you forget to pick up the dry cleaning or fumble to recall familiar addresses. The good news is, science is as interested in what’s going on as you are. With better scanning equipment and knowledge of brain structure and chemistry, investigators are steadily improving their understanding of how memory works, what makes it fail, how the problems can be fixed – and when they can’t.
Until a decade ago, the common assumption was that we were born with a fixed number of brain cells that die off as we age, making us, well, dummer. That, however, is not the case. A decade ago, when neuroscientist Fred Gage of the Salk Institute made the discovery that the adult brain continues to regenerate, the brains in question belonged to mice. Some of the mice had been sedentary, others had been exercising, and the ones that lodge the greatest distance on their wheels produced many more new neurons than did the sedentary ones.
Now it turns out that the same appears to be true for humans. In a paper published last spring, a team led by Gage, Small and Richard Sloan, a psychologist at Columbia University, revealed that after pounding the treadmill four times a week for an hour for 12 weeks, a group of previously inactive men and women, age is 21 to 45, showed substantial increases in cerebral blood volume (CBV) – a proxy for neurogenesis because where there are more cells, there are more blood vessels.
Not only did the CBV profile of the human exercisers mirror that of the mice, but the people who exercised more did better on a slew of memory tests. Other evidence backs this up. In a study of “previously sedentary” older subjects by psychologist Arthur Kramer at the University of Illinois and others at Israel’s Bar-Ilan University, investigators found that those who engaged in aerobic exercise did better cognitively than those who stretched and toned but never got their heart rate pumping. What’s more, subsequent imaging showed that aerobic exercise “increased brain volume in regions associated with age-related decline in both structure and cognition.“
Meanwhile, researchers from the Karolinska Institute in Stockholm who have been following over 1,500 people for more than 35 years found a significantly lower rate of dementia, including Alzheimer’s, in those who exercised. Another study, this one of 2,000 elderly men living in Hawaii, so that those who walked about three kilometres or more a day were half as likely to develop dementia as those who walked half a kilometre or less.
But physical activity isn’t all there is to improving your memory. There’s also what you eat. Take blueberries. According to Jim Joseph, a neuroscientist with the US Department of Agriculture in Boston, blueberries seem to have nearly magical powers: they zap free radicals (highly reactive atoms that can damage tissue), reverse ageing, enhance cognition – and this is the kicker – cause new neurons to grow. If you’re a rat.
In one of his animal studies, Joseph and his associates developed a series of motor-skills tests that they called the Rat Olympics. Rats had to walk balance beams and stay upright during a log-rolling task. Those raised on special blueberry rat chow did significantly better than those that were not, leading Joseph to conclude that “blueberries were actually able to reverse motor deficits in these ageing animals.” More remarkably, when mice that had been genetically altered to express Alzheimer’s were put on the blueberry diet, they did not experience memory loss. Joseph’s research has shown some similar benefits from walnuts, which contain alpha – linolenic acid, and essential omega-3 fatty acid.
No matter what you eat, if you want to keep your memory sharp you should strive for a diet that keeps your belly fat down. A study of more than 6,500 people published in the March 26 edition of the journal Neurology showed that people who were overweight and had a large belly were 2.3 times as likely to develop dementia as those with normal weight and belly size, while those who were obese and had a large belly were 3.6 times as likely. As scientists have long known, as belly fat – which disrupts body chemistry more than less reactive fat elsewhere on the body – increases, blood glucose rises along with it. That doesn’t draw a straight and conclusive line between waistline and memory, but it does suggest one. “It’s possible,” Small says, “that blood glucose, which tends to drift apart as we get older, is one of the main contributors to age related memory decline in all of us.”
None of these insights, of course, make your sputtering memory less frustrating. When you’ve misplaced your keys for the third time this month, it does you little good to be reminded that it all may be just too much glucose and too few blueberries. And nothing entirely removes the spectre of true dementia and the horrors it implies. Still, figuring out how memory works is the most important step in figuring out how it can be fixed. When you can make some of the fixes yourself, the news is even better. If you needed one more reason to get your exercise and watch your diet, the memory scientists are providing you with one – even if you have to write it down.
Adapted from Forgetting is the New Normal by Sue Halpern. Time, May 19, 2008.