your food
and exercise
brain rule
MIND your meals
and get moving
Those who think they have not time for bodily exercise
will sooner or later have to find time for illness.
—Edward Stanley (Earl of Derby), 1873
Life expectancy would grow by leaps and bounds
if green vegetables smelled as good as bacon.
—Doug Larson, newspaper columnist
PATTY GILL RIS, EIGHTY-SEVEN, was eating her favourite meal at the Hyde Park senior facility in New York when she began choking on a piece of meat; it was suddenly and lethally lodged in her windpipe. Her dinner companion saw immediately what was wrong and, alert as a mousetrap, sprang into action. He turned the victim around, thrust his arms under her armpits, placed one fist below her rib cage but above her belly button, and pumped upward three times. He was obviously doing a classic Heimlich maneuver. Out flew the offending protein. But only part. Two more times he performed this legendary medical move to get all the meat out.
The age of Ris’s award-winning rescuer? Ninety-six years. His identity? Famed thoracic surgeon Dr. Henry Heimlich. Yep, that Dr. Heimlich.
Why do I bring up this interesting coincidence in a chapter on ageing, exercise, and food? It’s less to comment on Ris’s choice of meal than to point out why Heimlich was able to save her. Doing the Heimlich at any age is physically demanding. But doing it at ninety-six years of age—thrice—is almost science fiction. Perry Gaines, maître d’ at Hyde, said: “At his age, that’s a very physical type of activity. To see him do it is a fascinating thing.” Another employee confirmed that Heimlich, a resident of the senior facility for about six years, “is very active for his age. He swims and exercises regularly.”
Heimlich was obviously in shape, a fact that would become quite clear if you viewed an interview with him. (He looked like an elderly James Taylor.) But that’s not the only thing that would catch your eye. There was a light in Heimlich’s countenance, coupled with a gentle attentiveness that is almost startling. His mind appeared as alert as his body. He was deliberate, observant, and possessed with an air of quiet decisiveness. You can see how he could have spent a lifetime successfully navigating tense surgical suites. And you could see how he’d still be able save a life at an age when most people are dead. Though he’d long since retired by the time he rescued Ris, his mind did not get the memo. He died in 2016.
These two ideas, mental attentiveness and physical exercise, run through this chapter like the marbling in Ris’s piece of beef. We start with a fact that is, if you’ll forgive me, a bit hard to swallow: mental attentiveness naturally erodes over time. But we won’t dwell on this decline for long. There are powerful ways to elevate brain functioning that have to do partly with exercise and partly with food. Both were exemplified in the lifestyle of a famous ninety-six-year-old physician who gave more than one person a new lease on life.
Calm, cool, collected
We begin, like a Calvinist sermon, with the tough stuff. We’re going to spend most of our time here together on a certain category of mental attentiveness: a complex suite of behaviours in your brain termed executive function. I’ve mentioned executive function several times in this book. Each time, I’ve promised to elaborate on the cognitive gadget later. That later is now. I start with one of the clearest expressions of executive function I’ve seen in my lifetime.
I remember vividly the day Osama bin Laden was killed. Not because I was watching the news, but because I was watching snippets of the 2011 White House Correspondents’ Dinner, which had occurred the night before. President Obama was on the lectern that evening, cracking jokes at the expense of his guests with ease, smiling, seemingly relaxed. He had a few zingers for Donald Trump, praising him for putting the matter of Obama’s birth certificate to rest, saying that no one was happier than the future forty-fifth president because “he can finally get back to focusing on the issues that matter—like did we fake the moon landing? What really happened in Roswell? And where are Biggie and Tupac?”
No one could guess that the day before President Obama had authorised US Army Special Forces to execute Operation Neptune Spear, the secret operation that would kill Osama bin Laden. The strike took place on Sunday, the morning after the dinner. But there was no telltale clue that evening. I saw no “night before” tension on the president’s face, no distracting fifty-mile stare, no fidgeting, no uncalled-for sweat. Even when host Seth Meyers cracked a joke about bin Laden, all you could see was Obama’s broad smile and easy countenance. Yet he was about to kill the man the assembled might of the American military had been seeking for almost a decade. He looked as if he were watching a sitcom.
That, folks, in a nutshell, is executive function.
Loosely stated, executive function (EF) is the behaviour that allows you to get tasks done—and to be calm and civil while doing them. It is vital in many aspects of life, including running the free world.
Many diverse cognitive processes make up executive function, and all scientists agree on which neural acreage belongs to Club EF. Researchers agree that executive behaviours can be subdivided into two simple fiefdoms: emotional regulation and cognitive control.
Emotional regulation includes impulse control, which incorporates the ability to delay gratification. You might want to eat that artery-petrifying cheeseburger in a sports bar, but you choose the healthy kale salad instead. Emotional regulation also involves emotional control: the capacity to edit your emotions in a socially appropriate manner (not laughing at funerals, for example). These two regulatory components often work together. You ache to punch your boss in the nose after he has given you a bad performance review. Proper emotional regulation, and perhaps threat of a lawsuit, ensures that you don’t.
Cognitive control is a flowing conduit of good sense. Its hallmarks include the ability to plan (creating steps in the pursuit of some goal), to adapt flexibly to changing circumstances, and to organise seemingly disparate inputs into manageable, organised rubrics. Add to that the capacity to shift attentional focus from one task to another, prioritising inputs while avoiding distractions. Another card-carrying member of Club EF is working memory. That’s our temporary storage feature that used to be called short-term memory (remember, from our memory chapter, Pixar’s Dory?).
Given its importance to human cognition, you might expect that scientists have spent a long time looking at the neurobiology behind executive function. And they have. One of the clearest findings is that EF is developmentally regulated: specific, observable changes occur over time. Teenagers supposedly don’t have much of it, for example—or they ignore the EF they do possess.
Remember being a teenager, or your kids being teenagers? Then you’ll appreciate this snarky post floating about online: “TEENAGERS: Tired of being harassed by your stupid parents? ACT NOW!!! Move out, get a job, pay your bills … while you still know everything.”
Teenagers, not surprisingly, have a different take on the dumb things they do. One mini manifesto online: “We’re teenagers. We’re still learning … We cheat, we lie, we criticise, we fight over stupid things. We fall in love and end up getting hurt. We party till dawn, we drink till we pass out … One day that’s going to all pass. You can waste your time focusing on all the bad things, but one day you’re gonna wish you were still a teenager. So make the most of what you have now, forget all the … drama and live your … life with a sexy smile on your face.”
Just about everything in that quote is related to executive function: planning, decision making, navigating social relationships, preserving aspects of personality, maintaining self-control.
And the part of the brain responsible for all this is the prefrontal cortex, or PFC, that important bundle of nerves we talked about in chapter 3. The PFC is involved in nearly every aspect of executive function. That’s not because it sits there isolated behind our foreheads being smart. It mediates executive function because it has befriended many other brain regions, reaching out via complex networks of neurons.
Vast systems of neurons connect the regions of the brain, as you know. They work something like interstate freeways, connecting one city with another. The PFC is a terrific example of a “city” with many neural highways connecting it to other regions. Technically, we would say the PFC has high “structural connectivity” to other regions.
Neuroscientists also think in terms of functional connectivity, which has to do with task rather than structure, and this occurs because the brain does not use all of its highways all the time. Some neural pathways are used in selective combination with others, connected to specific locations, to allow specific functions (hence the term). This is how the PFC mediates executive function.
These specific locations are familiar to you by now. The amygdala, working like a well-written romance novel, helps generate the experience of emotions. The neurological freeways connecting the PFC to the amygdala assist in the emotional regulatory components of executive function. Connections to the hippocampus, a region associated with long-term memory, assist in cognitive control. The PFC even has internal connections, as if the PFC befriended itself, involved in the formation of working memory.
There’s dramatic growth in executive function during our toddler years, followed by a rest, followed by even more dramatic growth at puberty. Things don’t actually settle down until we’re in our midtwenties. And then, in old age, executive function begins to slide. To help me explain, here’s a thought experiment regarding the city where I live.
Cracks, leaks, and potholes
I live in Seattle, Washington, a relatively small urban emerald (population 686,800) housing the world headquarters of a ridiculous number of corporations. From Amazon to Zillow, Nordstrom to Starbucks, many multinationals call Seattle home. Microsoft does, too, in a town just across the lake. And Boeing is everywhere.
Here’s my thought experiment. These behemoths require massive numbers of people not only to run them but also to maintain and repair their infrastructure. What would happen to all of the companies’ glittering progress if the repair and maintenance personnel in the greater Seattle area began to disappear? What would it look like to have things break and never get fixed?
When power failed, there would be no electricity. When pipes broke, no one would plug leaks, replace conduits, or mop up. Windows would remain broken, roofs would leak, building structures would eventually fall. The corporations would stagger, then fall to their urban knees. The roads connecting one giant to another would get pockmarked, crumble, and ultimately fail. It wouldn’t take long for things to look positively postapocalyptic.
This type of erosion is exactly what happens to executive function. In our youth, the structures and connections get hobbled, but our repair mechanisms are active. Somewhere around age sixty, those maintenance mechanisms start retiring. “A man loves meat in his youth that he cannot endure in his age,” Shakespeare once said. Normal wear and tear, increasingly, is not repaired.
Failure occurs at two levels. First, the highways that connect the PFC to those distant regions mediating executive function begin deteriorating. One study showed that 82 per cent of executive function loss is directly attributed to a degeneration in the neural freeways the PFC used to stay in touch with its far-flung friends. Second, the brain structures linked together by those freeways—the cities in our metaphor—also begin to fail, buckling like abandoned towns. Research reveals that the hippocampus shrinks in an age-dependent manner. The PFC also loses volume.
These are critical losses. PFC neurons that support working memory do so by maintaining electrical activity through what are called excitatory networks. (This stimulation is sustained in the absence of any outside prompting.) When so many neurons are lost that one can observe structural shrinkage, maintaining internal network integrity becomes increasingly impossible.
So that’s the bad news. We obviously need a helping or two of that good news discussed earlier. Look no further than iconic television producer Norman Lear. His life is an emblem showing us just how good the news can be.
Get your brain off the couch
For those of us watching sitcoms in the 1970s, Norman Lear was as constant a presence in our lives as oxygen. He was the driving force behind such shows as All in the Family, Good Times, The Jeffersons, and Maude. He never retired. In 2016, at the tender age of ninety-three, he embarked on a new TV show, a Latino reboot of another hit show of his, One Day at a Time.
His brain is still lightsaber sharp. In 2016 he appeared on the NPR quiz show Wait Wait … Don’t Tell Me! Host Peter Sagal asked him, “So do you have any tips for those of us who would like to arrive at ninety-three as spry and as successful and happy as you are?” Lear responded, “What occurred to me first is two simple words. Maybe as simple as any two words in the English language: over and next. We don’t pay enough attention to them. When something is over, it is over, and we are on to next. And if there were … a hammock in the middle, between over and next, that would be what is meant by living in the moment. I live in this moment.” Lear was really on to something neurological, though he may not have known it. Remember our discussion about mindfulness? Living in the moment is one of its signature attitudes.
The panel and host, usually quick to pull out their satirical rapiers, were disarmed. “That’s brilliant,” one of them said, twice.
Lear is fit not only mentally but physically. Even in his nineties, he walks in an easy, almost athletic cadence. Exercise is a consistent part of his life, a fact he once demonstrated on The Dr. Oz Show. The good physician led Lear over to a yoga mat to demonstrate part of his physical routine. Lear stretched out his ninety-two-year-old body and reached down to his toes. “A three-finger touch!” the host exclaimed. “I used to be able to get my fists down,” Lear declared, smiling, “but son of a gun.”
In terms of the slowing effects of ageing, Lear doesn’t have a lot to worry about. And on average, neither do you, if you imitate his lifestyle. The key illustration here is the link between intellectual vitality and physical exercise. One of the most astonishing revelations of recent geroscience is this: greater physical activity means greater intellectual vigor, regardless of age.
Researchers noticed years ago that fit seniors seemed smarter than sedentary seniors, even when wading into the deep end of the statistical pool. Especially powerful were results linking aerobic exercise to changes in executive function. If you survey a large number of studies (called a meta-analysis) looking at aerobics and EF, you see really impressive numbers. Elderly individuals who regularly exercised scored higher, sometimes stratospherically higher, on executive function tests than sedentary controls (effect sizes, which are measures of correlation, were almost seven times greater with exercisers than with couch potatoes). It is quite rare you get such clear numbers in work of this kind.
Yet correlation, as you can hear your logic teacher intone, does not mean causation. To establish that exercise is the cause of the improvements, you have to take a group of elderly individuals with low EF scores, have them exercise for a period of time, and then reassess their EF. If there’s improvement, you can tentatively assign the luxurious word “causal” to the experiment.
I am happy to report that such experiments have been done—and the results are consistent and compelling. One study got a 30 per cent boost in executive function scores after a skimpy three-month exercise program consisting of an even skimpier “walking regimen.” Some studies show much greater improvements. And the boosts appear to be long-lasting. One lab showed that, after people in midlife exercised, their executive function boost was still apparent twenty-five years later. Strengthened in the gym of peer review, this idea has muscled its way into our thinking: exercise boosts cognition in the senior brain. No wonder researchers like Harvard’s Frank Hu have said: “The single thing that comes close to a magic bullet, in terms of its strong and universal benefits, is exercise.”
Naturally, there are the usual ifs-and-buts and what-abouts surrounding such findings. First, not all parts of executive function are susceptible to exercise. The ability to focus, for example, seems impervious to exercise. The effects of exercise on working memory are also mixed. Some studies show a boost if the workout is aerobic; others show no effect at all. The titans of peer review thus state that further research is needed. Not to lose hope, though. Researchers have indeed found something that affects working memory. It appears, however, to be more about the contents of the fork you put in your mouth than about the shoes you put on your feet. We’ll have more to say about that in our discussion of diet.
Right now, we need to get into some of the mechanics of why exercise works at all in the brain.
Bulking up your neural tissue
Remember the postapocalyptic Seattle urban metaphor from a few pages back, with brain regions likened to cities, their connectivity likened to highways? Both the structure of the brain’s cities and the functions of its neural highways are altered in seniors who exercise. The neural tissue involved in executive function is more active and more bulky, exhibiting a larger overall volume. Scientists readily observe the change in just the area where you really want it: the prefrontal cortex. One particularly sensitive subregion is the dorsolateral PFC, the most connected area in the entire PFC. It is involved in decision making and working memory.
Certain regions in the brain’s interior get a cognitive six-pack with exercise, too. Most sensitive is the medial temporal lobe, specifically its crown jewel, the hippocampus. You might recall that the hippocampus is involved in many functions related to clear thinking, including memory and navigation. People who do aerobics bulk up their hippocampal volume by a whopping 2 per cent. In contrast, people who just do stretching exercises show a decrease of 1.4 per cent. People who do nothing, just letting nature take its course, lose 2 per cent.
These regions don’t just get bigger in aerobicisers, they get denser. In the PFC, it’s likely that more connections are occurring within existing neural structures. The hippocampus, however, may be literally growing new neurons, a process called neurogenesis. The protein BDNF, short for brain-derived neurotrophic factor, is thought to be responsible for much of this growth. You want BDNF in your brain. Brain cells take to it like scientists to grant money.
It’s not just the cities that grow. Connectivity increases, enabled by the neural cell bodies in grey matter. One study showed an 8 per cent increase in global grey matter for seniors who exercised. And the effect was as durable as a tax increase. Nine years later, the exercising group still had more grey matter than sedentary controls. Astonishingly, this elevation reduced their risk for dementia twofold.
Given this activity, you might think these newly minted neural structures would need feeding—and need their waste removed—just as the old ones do. And you’d be right. Since both feeding and garbage control involve your blood system, you might predict an increase in blood flow to the new regions. And again, you’d be right. Cerebral blood volume increases dramatically in areas of the brain associated with the exercise-induced growth. The effect is especially pronounced in the hippocampus.
The molecular basis for the improvement in cerebral blood flow has begun to be uncovered, at least in rodents. Exercise stimulates a process called angiogenesis (literally “vessel creation”), and the protein responsible for it is called VEGF—pronounced “vedg-eff,” as in vegetables. It’s actually short for a tongue twister: vascular endothelial growth factor. It does for blood vessels what BDNF does for neurons. It makes them grow.
But here is what’s extraordinary about the data I just described. By exercising, you are not just slowing age-related decline. Your brain actually gets better at its job. And you don’t have to be an Olympian to reap the benefit. Just take a walk. Or get into a pool. Don’t be like “Bootstrap Bill” Turner, from another movie my kids enjoyed watching. It’s the third installment of the Pirates of the Caribbean series, At World’s End. In the movie, Bootstrap has been cursed, and we find him nearly lifeless in the bowels of the pirate ship Flying Dutchman. He’s gradually fusing to the interior walls of the hull, limbs turning to wooden planks, encrusted with sea creatures. For a few moments, he has reason to peel himself off this dangerous hull to talk to his son’s fiancée. But it’s only transitory. Bootstrap returns to the wall, sedentary once more, the hull resuming its absorption.
Sadly, some people allow the ageing process to act like the dangerous walls of the Flying Dutchman. They slowly become absorbed into the walls of their years—and into inactivity. If you want to avoid Bootstrap’s fate, you must fight inertia. You don’t have to do much to get the brain boost. In fact, it may be hard to believe how little you have to do.
A little exercise goes a long way
Research shows you get a cognitive boost with as little as thirty minutes of moderate aerobic activity, essentially walking too fast to talk, two or three times a week. (Some studies recommend thirty minutes five times a week.) The effect is dose dependent—the more you exercise, the better your brain functions—though there is a limit. In one study, seniors walked three hundred city blocks each week; they experienced the welcome increase in grey matter volume. So did seniors who walked only seventy-two blocks each week, however—and by the same amount. Researchers call this a “ceiling effect.”
If you add strengthening exercises to your aerobic routine—resistance training for your big muscle groups—you also benefit, regardless of the shape you’re in. You have to do strength training two or three times a week as well. Once a week was measured, and that doesn’t cut it.
These data act like strong magnets, pulling other recommendations toward them. One is reminiscent of our Bootstrap Bill story. Seniors naturally experience a decrease in mobility as they age. There are many reasons for this slowing down, including reduced energy levels, increased physical pain during movement—even anxiety and depression. Researchers designed a program for people with limited mobility involving aerobic workouts, flexibility exercises, and resistance training. All participants were ambulatory but had limited mobility, as assessed by a test called Short Physical Performance Battery. At the end of the program, the exercising group was able to walk about 104 minutes more per week than the controls. And they showed a lot less “major mobility disability.” Simply by regularly coaxing Bootstrap Bills to pop out of the immobilising walls of their lifestyles, they saw positive results.
And that’s important. Because we also know that doing even a little bit of exercise goes a long way toward cognitive health—and may even reduce the risk of Alzheimer’s. Small incidental experiences of physical exercise are astonishingly effective for seniors, like regularly getting up to cook a meal, walking up small flights of stairs, or going to a movie. Even fidgeting provides health benefits.
One study tracked the physical habits of a group of seniors for four years. The researcher examined limited “range activities,” like going for a short walk around the neighbourhood, walking out in the yard, or even getting out of their bedrooms. Those who were sedentary were twice as likely to get Alzheimer’s as those with “the largest life spaces.” Movement even helps people who are wheelchair bound. The bottom line? Shoot for regular exercise—of any kind—even if your body has other ideas. After all, you aren’t exercising because you want to move your body. You’re exercising because you want to move your brain.
Cheese lovers, beware the bedsheets!
Tyler Vigen’s website doesn’t seem very provocative at first. It looks like a collection of boring-as-PowerPoint graphs. Each graph consists of two undulating, differently colored lines, looking like Loch Ness Monsters doing some synchronised swimming. In one chart, a line labeled “Divorce rate in Maine” shows a decline from 2000 to 2009. The other line is where things become interesting: it’s the “Per capita consumption of margarine in the United States.” The two lines are startlingly similar—nearly identical, in fact. The next slide is even funnier. The first line is labeled “Per capita cheese consumption” in the United States. The second is “Number of people who died by becoming tangled in their bedsheets.” It lines up perfectly with the cheese, just as Maine divorces stay coupled with the margarine.
What do these slides have to do with this chapter? They are the reason I am reluctant to get into our next subject: nutrition and ageing. Like Vigen’s slides, a great deal of the published research exploring practical diets for seniors is associative in nature. And as the slides beautifully illustrate, association does not mean causation. Chicken-and-egg problems abound in this work, too. As a result, most of the causal work has been done in lab animals. I have several large problems thinking any of this illustrates something meaningful about human ageing. That’s why I’m reluctant.
But, I hope, not unfair. Research into human nutrition is ridiculously hard—and surprisingly expensive—to do well. Food is complex stuff: even a simple sandwich is composed of hundreds of biomolecules. The metabolic machinery we marshal to extract energy from foodstuffs is many times more complicated than, and as individualised as, a fingerprint. Extracting truth from this pile of variability is like eating soup with a fork. And this complicated field is woefully underfunded.
That doesn’t mean research into ageing and nutrition is bereft of good—even heroic—work, and we will cover some of the best stuff. To discover where ageing fits into the practical world of what’s on your plate, we return to the theme of repair breakdown, starting with a very peculiar type of evolutionary gluttony.
Free radicals in a hungry brain
The brain uses a lot of the food it craves for a familiar Darwinian purpose: to project its owner’s genes into the next generation. Though it is only 2 per cent of your body’s weight, your brain consumes 20 per cent of the calories you eat. The brain is also quite finicky. It happily extracts energy from sugar molecules, but it turns up its neural nose to fats. If the brain could metabolise fats, you’d literally be able to lose adipose-related weight by simply thinking hard. Unfortunately, the organ is more into sugar than butter, and so taking math tests is never going to be part of anyone’s weight-loss program.
As in any normal manufacturing process, the brain generates lots of toxic wastes. Particularly deadly are a few famous molecules humorously (at least for ageing hippies) called free radicals. It is important to get rid of free radicals. If allowed to accumulate, they will do considerable damage to the cells and tissues of the body. The damage is termed oxidative stress. Any tissues experiencing oxidative stress in an uncontrolled manner, including neural tissues, start dying. So it’s a big deal. Fortunately, your body has an army of molecular defenses designed to neutralise these ever-accumulating toxins. Several prominent battalions in this army are called antioxidants. They get rid of toxic wastes the same way paper towels absorb spilled orange juice. There are many kinds of antioxidants, from proteins you’ve never heard of like superoxide dismutase to more familiar molecules like vitamin E. As long as antioxidants and other repair-oriented molecular battalions remain on active duty, a balance occurs between towel and spill. The lethal molecular orange juice gets cleaned up, and your body stays healthy.
The sad problem is that as we age, our defenses against oxidative stress literally begin breaking down. Our molecular army goes AWOL for various reasons, divided into our familiar nature and nurture components. The desertion usually occurs in earnest after we’ve left child-bearing age.
This is really bad news. Those damaging, damnable free radicals accumulate in our tissues, gradually turning our bodies into Superfund sites. It hurts to have such trauma in any part of the body, but it’s an especially bad break for the brain, given its extraordinary 20 per cent surtax on our energy supplies. The food we eat makes a difference here: keep an eye out in the next few pages for the word “phytochemicals.”
Given the connection between the brain and energy from food, it’s not surprising that researchers attempting to beat back Father Time have looked at diet. Horace Fletcher in 1913 decreed you could become younger if you simply chewed your food until it was liquid slush. Recommended activity: thirty-two to seventy-five chews per bite. You really can lose weight if you just slow down the process of eating. And since obesity is linked to early death, perhaps old Horace was on to something.
History is replete with the gravestones of people claiming to have discovered the Fountain of Youth. It thus takes a certain bravado for modern researchers to cross swords with our most fantastical mythologies and investigate life extension. Efforts to link healthy ageing to food intake can be divided into two groups: the amount of food people consume and the type of food they consume.
Less is more—maybe
It’s been observed for centuries that people who eat less seem to live longer—and are oddly happier—than those who gorge themselves. This has striking confirmation in the laboratory, at least if you’re a rodent. Severe calorie restriction can lengthen life expectation in certain animals by a whopping 50 per cent compared with typically fed controls. The incidence of their many age-related diseases (cardiovascular disorders, numerous types of cancers, neurodegenerative disorders, cancers, diabetes, etc.) goes down—way down—with calorie restriction. The earlier they start, the better the numbers become. Lengthenings have been shown in virtually every animal tested—even fruit flies.
Does this work in humans? And if so, should you do it, claiming your 50 per cent life-lengthening medal? The real answer is we don’t know. There are suggestions that calorie restriction lowers risk factors commonly associated with early death. Consider this research, which involved groups of healthy thirty-seven-year-olds undergoing a 25 per cent reduction in their caloric intake—for two long years. Researchers looked at various physiological markers and behavioural traits compared with unrestricted controls.
The results were somewhat predictable—and also extraordinary. The “well duh” result is they lost weight—about 10 per cent compared with controls. But they also had declines in blood-based chemicals associated with age-wrecking inflammation (one obnoxious molecule, called c-reactive protein, was 47 per cent lower in the dieters). Another unexpected result is that dieters slept better. They had more energy (weird, because they were actually consuming less energy) and were in a better mood (even though they were probably hungry all the time).
These happy findings are associated with longer life, but no one knows if they actually result in longer life. Yet I have a hard time thinking humans would be an experimental exception to nearly every other creature on the planet. It really does appear that what doesn’t fill you makes you stronger. If you’d like to try calorie restriction, I suggest you show your physician this page and discuss a plan.
Are you nuts?
Other researchers have looked not at the amount of food eaten but at the type of food eaten. As with restriction research, consistent findings emerge. And it is good news, especially if you’ve spent your life eating like a native of sunny southern Europe.
I’m obviously referring to the famed Mediterranean diet, so named because it contains ingredients found in Greek, Italian, and Spanish cuisines. The seminal paper was published several years ago in the New England Journal of Medicine by, appropriately enough, a Spanish research group. It was called the PREDIMED (Prevención con Dieta Mediterránea) study. The headliner was that people on this diet suffered less often from cardiovascular diseases, including brain-based pathologies like strokes (unsurprisingly, they also lived longer). That gave the researchers a tantalising idea. Would this diet change other types of brain-health issues besides stroke, say, nonpathological age-related memory loss?
The answer was yes. Though eating southern European food was associated with cardiovascular health, the most interesting result was discovering a big-time arrest of cognitive decline, not associated with cardiovascular issues at all.
These researchers showed many cognitive benefits to the diet, ranging from changes in executive function to changes in working memory. One study randomly assigned three hundred people to three groups: a Med diet supplemented with extra-virgin olive oil, a Med diet supplemented with nuts, and a non-Mediterranean diet. Researchers followed them for four years. Those eating the Med diet plus nuts had composite memory scores a hefty +0.1 above baseline. The Med diet plus olive oil scored +0.04. That may not sound like much, but it’s actually huge compared to the controls, which were a depressing –0.17 below baseline. Changes also were noted in frontal cognition scores (essentially executive function) and even global cognition—a kind of gross domestic product test of your ability to think. Both Med diet plus nuts and Med diet plus olive oil scored far above controls here, too. These numbers were obtained from a randomised, intervention-based research design. You don’t have to channel your inner statistician to see these are significant findings.
Other studies on the fatty shores of the United States appear to confirm these results. One in particular, called the MIND diet, essentially combined the Mediterranean diet with another program previously shown to lower blood pressure (the DASH diet). Researchers here found not only an arrest in age-related cognitive decline but a reduced risk for dementia. David A. Bennett, director of the Rush Alzheimer’s Disease Center in Chicago, wrote about the results of the center’s longitudinal studies in Scientific American: “[Nutritional epidemiologist] Martha Clare Morris has found that the so-called MIND diet—which is rich in berries, vegetables, whole grains, and nuts—dramatically lowers the risk of developing Alzheimer’s.”
Bennett’s quote provides the answer to a question you may be asking: “What is the secret sauce in all these diets?” Some of the ingredients are familiar, probably sounding like a cross between your mother and your doctor, no cream sauce in sight. Instead, there are tons of fruits and vegetables and legumes. Tons of whole grains, too. And fish, every day. Salt is swapped out for yummy Mediterranean spices.
Some of the recommendations may not be as familiar, however. Nuts are fatty, but they’re very much a part of the diet. Oil is the very definition of flab, but in limited amounts—as long as it’s from olives—it provides a specific brain boost. The MIND diet is a little different, emphasising servings of berries and keeping fish consumption to once a week. If you are an American, this is everything you are not already eating. That’s why it’s called the Mediterranean diet and not, say, the McDonald’s diet.
There’s still a lot of work to be done trying to tamp down all the hundreds of variables that make scientists like me skeptical. The data still probably boil down to that Ernest Hemingway-esque quote by Michael Pollan: “Eat food. Not too much. Mostly plants.”
But these efforts create a nice start. They are the first nutrition studies in years that caused me to sit up and say, “This is worth a look.” They form the basis of a series of research projects investigating how the diets work.
Wall posters, oddly enough, turn out to be helpful.
No pain, no gain
Wall posters were trendy when I was an undergraduate. One popular print pictured a bodybuilder lifting weights. As you may know, weight lifting makes big muscles by creating small tears in the muscle fibers, which are then repaired. It is the repair process that provides the bulk. You have to continuously introduce those minor stressors—rips and micro-gashes—in order to look like the poster boy. This is not comfortable—he is actually grimacing in the poster—with the famous caption below: “No pain, no gain!” (A second poster, showing an overweight beer drinker guy eating a cheeseburger, was often stapled over the bodybuilder; its caption was “No pain? No pain!”)
This idea of the positive effect of low-level minor irritations—called hormesis—describes something unexpected about diets to fight ageing. It actually explains why they work.
Stated biologically, hormesis is the ability to stimulate normal molecular repair mechanisms by constantly stressing the cells carrying them. This includes nerve cells. The stress is always minor, but it’s persistent. Annoy them enough times, and the cells start ringing up maintenance, asking the molecular fix-it squads for assistance. These maintenance teams are the very crews that start retiring as we age. Continuously calling them back to service keeps them active, with the happy results that the cells are kept in a better state of repair, the body in better shape, people transiting through old age more comfortably.
Both calorie restriction and plant-based diets exert their anti-ageing effects through hormesis, at least in lab animals, and there’s increasing evidence of similar mechanisms at work in humans, too. These repair mechanisms fix everything from faulty proteins to leaky cell membranes. They allow extra calcium into nerve cells, strengthening their activities. Certain growth factors become stimulated, such as neuron-loving BDNF (which, as you recall, does many positive growth-related things for the brain’s neural constituencies). Dietary restriction stimulates hormesis by convincing the cells that their owner is starving. If calorie reductions are continuously experienced, the repair mechanisms are continuously activated.
Please note that I am not actually recommending you partake of the severe calorie restriction regimens needed to achieve laboratory results. Indeed, researchers show that experiencing such restrictions only five days a month confers the age-related benefits; more than that and you risk negative physiological effects. Not everybody agrees that even that amount is a good idea, however.
Plant-based diets exert their effects because they are filled with so-called phytochemicals, which endlessly tell your brain cells that they are, well, vegetables. These phytochemicals somehow persuade those antioxidant armies we discussed earlier to come out of retirement and start taking out the trash, free radicals and all. Combined with the way exercise boosts blood flow, critical for waste removal, you’ve got a powerful maintenance crew. Phytochemicals also persuade nerves to make more BDNF, jump-starting the process of making new neurons. That the body might think of eating vegetables as an irritating stressor is not lost on this author. But as long as you continue annoying your cells, you also stimulate their life-extending molecules.
We are starting to understand not only what foods you should eat but why they work. And it turns out that the complexity of the foodstuffs we dine on, the aspect of nutrition research that drives me so crazy, may actually be what gives them their anti-ageing properties. Consuming individual supplements—like taking vitamin E pills or other antioxidants—doesn’t work very well for most people. You mostly just excrete them, which means folks who take a laundry list of supplements just have very expensive urine. The secret appears to be in the synergy between the components themselves, all of which are housed in actual fruits and vegetables, many of which are undefined. This makes sense from an evolutionary perspective. Nothing in our eating history gave us the punch of purified supplements, mostly because they don’t exist naturally in such powerful concentrations. Indeed, these nutrients were—and are—always tucked inside their plant-based “hosts,” and we evolved to eat them the way nature gives them to us. Not the way a pharmacy does. If you want the benefits described in this chapter, you first need to get out there and walk, swim, or just fidget—then go have a plate of phytochemicals.
And make sure it’s a small plate.
SUMMARY
MIND your meals and get moving