For all the thinking we do with the brain, we rarely think about it. The 3-pound mass of crevices and folds is always out of sight – and too often out of mind. But the sooner we start paying attention to our brain, the better. Researchers, who once thought the brain’s neural circuitry was hardwired at a young age, have discovered that our brain is pliable and that we can fortify it through nutritional, physical and lifestyle habits throughout our life.
And we should. A healthy brain pays major dividends: Emerging research shows that the well-maintained brain is quicker, smarter, more resilient and more adept at stabilizing mood. It’s also less forgetful and less prone to age-related decline.
The human brain – at any age – is able to strengthen, deepen and change existing neural connections (a process called neuroplasticity), and to develop new neural cells (called neurogenesis). We can encourage these changes by adopting many of the same lifestyle habits that sustain healthy bodies, from focusing on good nutrition and physical fitness to managing stress. Indeed, Michael Craig Miller, MD, editor-in-chief of the Harvard Mental Health Letter, has described the health of the body and the health of the mind as virtually one and the same.
Think of the hemispheres of the brain as two cities connected by a network of telephone wires, says Thomas Perls, MD, MPH, associate professor of medicine and geriatrics at the Boston University School of Medicine and coauthor of Living to 100: Lessons in Living to Your Maximum Potential at Any Age (Basic Books, 2000). “Now we know there are things you can do to add more wires.”
With a focus on fitness, good food and stress relief, you can “add more wires” and help your brain stay strong, healthy and resilient at any age. Here’s how you can begin tailoring your choices to maximize your brain’s health.
Thanks to increased awareness of the mind-body connection, you probably already know that your mind affects your body. But do you know how much your body can affect your mind? A few years ago, Arthur Kramer, PhD, a neuroscientist at the University of Illinois at Urbana-Champaign, began to study how exercise affects the brain. Now one of the country’s top brain-and-exercise researchers, Kramer is convinced that working up a sweat is critical for brain health.
“Across the board, exercise increases brain function, memory retention and other key areas of cognition up to 20 percent,” he says. Although Kramer and his colleagues don’t understand precisely how working out bolsters brain health, they have a few theories.
For starters, exercise increases blood flow to the brain, which is crucial for a healthy head. The brain accounts for only 2 percent of the body’s overall weight, but it guzzles 15 percent of its blood flow. In many ways, a healthy brain and a healthy heart go hand-in-hand. Just as exercise gets blood flowing through the heart’s arteries, keeping them open, flexible and unclogged, it does the same for the blood vessels in the brain.
Another theory involves the protein IGF1, a biochemical released in the body every time a muscle contracts and relaxes. As outlined by reporter Mary Carmichael in a March 26, 2007, Newsweek article on exercise and the brain, IGF1 flows to the brain and prompts it to produce brain-derived neuro-trophic factor, or BDNF, the biochemical that fuels learning. It’s what helps our synapses store new facts and information as we gather them. Hence, the more BDNF we have coursing through our noggins, the more information they can hold.
Harvard psychiatrist John Ratey, MD, author of the forthcoming book Spark: The Revolutionary New Science of Exercise and the Brain (Little, Brown and Company, 2008), explained the process this way: “It’s like Miracle-Gro for the brain.”
In a December 2006 study published in the Journal of Gerontology: Medical Sciences, Kramer hints that exercise may actually encourage the brain to make new connections between neurons and to build new vascular structures. His team measured the brain volume of volunteers with high-tech scans. Then the participants exercised an hour a day, three days a week for six months. At the end of the study, when Kramer’s team repeated the brain scan, the exercisers’ brains were bigger than before.
The healthy brain also relies on good nutrition. Here are some of the best gastronomic ways to nourish it:
Roughly 50 to 60 percent of the brain’s overall weight is pure fat (the rest is a mixture of protein and carbohydrates). The brain uses fat as insulation for its billions of nerve cells. The better insulated a cell, the faster it sends messages and the speedier your thinking. Getting enough healthy fat in your diet is essential for brain health – but not all fat is created equal. (For more on how healthy fats benefit overall well-being and weight loss, see “All About Oils” and “Weight Loss Rules to Rethink” in the April 2007 and October 2006 issues, respectively.)
Like your car’s engine, your brain relies on good fuel. Put in high-quality gas and it’ll purr like a well-honed machine. But feed it junk and it spurts and sputters like a clunker. Good fats are premium gas for the brain. Any source of omega-3 fats, such as walnuts, flaxseeds, flaxseed oil, or dark, leafy greens, will help your brain run smoothly. But fish provide the brain with its favorite fat, docosahexaenoic acid (DHA) – which accounts for roughly half of its overall fat content.
“DHA is far and away the most important nutrient for brain health,” says neurologist David Perlmutter, coauthor of The Better Brain Book (Riverhead Books, 2004). A June 2006 study published in the American Journal of Clinical Nutrition bears that out: People who ate an average of 2.7 servings of fish a week reduced their risk of suffering from Alzheimer’s disease and other dementias – illnesses that result in brain function decline in 4.5 million Americans – by roughly 50 percent. (For folks who don’t eat fish, and for people who are concerned about mercury contamination, such as women who are pregnant or wanting to conceive, as well as children, algae-derived DHA is a good alternative.)
On the flip side, bad fats are the brain’s rotgut gas. These saturated and trans fats – plentiful in processed foods, red meat and whole-fat dairy products – inflict double damage on the brain. Bad fats make bad cellular insulation, which creates sluggish thinking.
Deprive the brain of enough healthy fats, and memory and learning suffer. In an April 2007 American Journal of Clinical Nutrition study, researchers monitored the diets of 2,251 people for nearly 10 years and discovered that those who ate the least good fat were most likely to experience a loss of “verbal fluency,” a marker of brain health.
When it comes to good fat, it’s OK to indulge, says Perlmutter, who recommends looking to the Mediterranean diet (rich in whole foods and olive oil) for inspiration. “Too much fat is better than too little, and nothing is worse for the brain than a fat-free diet.”
Per gram of tissue, the brain produces more free radicals – highly reactive molecules that can contribute to cell damage, especially in the brain’s delicate fat tissue – than any other organ. Some scientists suspect damage from free radicals is one of the biggest culprits in the memory loss associated with aging. “Fat is much more susceptible to free-radical damage than other types of tissue,” says Perlmutter. “And its repair mechanisms don’t work as well.”
Luckily, antioxidants are the brain’s cleanup crew. Found primarily in fruits and vegetables, antioxidants work around the clock to scrub the body clean of free radicals. Numerous studies show that people who eat the most fruits and veggies throughout life are less likely to suffer from dementia later on.
The brain needs sugar (glucose) for energy, but it likes a nice, steady, natural supply – the kind you get from the sugars found in fruits and veggies – not the refined sugars heaped into an energy drink or a candy bar. “It’s not good for the brain to swing wildly from one blood-sugar extreme to another,” says Carol Lippa, MD, neurologist and director of the Memory Disorders Center at the Drexel University College of Medicine in Philadelphia. “Sugar molecules slip into the brain and other organs easily, so you want to be careful not to overload your system.”
In a 2006 double-blind study at Loughborough University in Leicestershire, England, researchers fed sleep-deprived participants a light lunch, then gave them 8 ounces of either an energy drink containing high levels of sugar and some caffeine or a similar-tasting control drink that had no caffeine and no sugar. Ten minutes later, each participant took three 30-minute tests that measured reaction time. They repeated the design a week later, but provided each person with the opposite drink.
The results? Not only did the caffeine and glucose-laden drinks not counteract feelings of sleepiness, they actually made the participants’ reaction times worse.
What’s more, when high-sugar foods such as colas and processed foods send a tsunami of glucose crashing into the bloodstream, those surges eventually overwhelm the body’s ability to restore balance. When that happens, you become insulin resistant (your body no longer responds to insulin), so your blood sugar rises and type 2 diabetes develops. Studies link insulin resistance to higher rates of vascular dementia and Alzheimer’s disease.
Another deleterious side effect of insulin resistance is inflammation. When the body’s systems are out of whack, the immune system goes into overdrive trying to fix the problem. The result is chronic inflammation, a pattern of constant swelling and related biochemical reactions that become highly destructive over time.
“It’s like keeping your car in park but putting your foot on the gas – eventually you’ll overheat,” says Jack Challem, author of The Inflammation Syndrome (John Wiley & Sons, 2003). Left unchecked, chronic inflammation can damage the brain’s memory center and speed up age-related memory loss.
Relax Your Lobes
Chronic stress can take a heavy toll on the brain. That’s because stress hormones, such as corticosteroids, not only contribute to a general environment of inflammation, they also attack the hippocampus – the brain’s memory center – causing atrophy, or shrinkage, in this important area.
Brain imaging studies of people with posttraumatic stress disorder show a significant reduction in the size of the hippocampus. “Stress may shorten the lifespan of brain cells,” says Lippa. “It certainly impacts memory functioning. Over and over again, I see patients’ memories get worse during stressful events.”
Fortunately, how you deal with stress may be more important than the amount of stress you’re shouldering, says Perls. In his studies of centenarians, he found that several of them had aged gracefully despite having had very stressful jobs.
Since some people thrive on stress, Perls thinks the key to staying healthy is not internalizing it. “Stress is most damaging if you let it eat away at you,” he says. “Find a way to do something about it, even if it’s just taking a deep breath.”
If you want to take deep breathing to the next level, you might try meditation. The Eastern approach to relaxation and enlightenment has long been known to alter brain waves, but recent research published in the journal NeuroReport shows it can change the physical structure of the brain as well.
When researchers did a side-by-side comparison of brain scans – half the scans from experienced meditators and the other half from people who’d never tried meditating – they found the meditators’ brains were thicker in areas of the brain charged with interpreting emotions, sights, sounds and touch. The thickest brains belonged to the most experienced meditators, leading the authors to surmise that meditation might strengthen and deepen our neural connections.
The bottom line on brain health? “We have more control than we think,” says Gary Small, MD, director of the Memory and Aging Research Center at the University of California, Los Angeles.
Small estimates that only about one-third of what determines brain health comes from genetics, indicating that factors such as diet, exercise and stress management have a major impact. And, he says, the sooner you get started, the better.
So now you have even more good reason to invest ample time and energy in getting plenty of exercise, eating healthy whole foods and actively managing your stress level. After all, it’s not just your body, but your brain that’s at stake.
And as Small reminds us: “Protecting a healthy brain will always be easier than repairing the brain once it’s damaged.”