How to keep your brain young

A third of the brain's volume is composed of blood vessels. Maintaining a healthy blood flow to those blood vessels is critical to keeping the brain young. Here are six ways you can keep your mind sharp:

Exercise Research has shown exercise improves brain health, and it's never too early or too late to begin. Even moderate exercise has been shown to increase memory, mental processing speed and the size of the hippocampus, the part of the brain responsible for forming new memories, even in previously sedentary adults. Simply walking three times a week has been shown to produce significant gains in memory and mental processing speed.

Eat rightNeurologists agree a diet rich in vegetables, fruits, whole grains and legumes will help keep the brain healthy. They also advocate eating fish, walnuts, flax seed or other sources of omega-3 fatty acids. Curcumin, found in the spice curry, may also be protective against Alzheimer's. Conversely, a high-fat diet and obesity raise the risk for dementia. So do high cholesterol, diabetes and high blood pressure if left untreated.

Watch your levelsResearch has shown high levels of the amino acid homocysteine is associated with a poor memory and doubles the risk of Alzheimer's. Vitamin B12 and folic acid lowers the level of homocysteine, which is also associated with heart disease and strokes. Green, leafy vegetables and fruits contain folic acid; meat, fish, yogurt and fortified cereals contain vitamin B12.

Ease stressLowering the amount of stress in your life lowers the risk for dementia. A glass of wine (or other moderate alcohol consumption), laughter and meditation are all considered beneficial. A Harvard Medical School study showed 30 minutes of meditation a day for eight weeks even increased the size of the hippocampus. Studies at Loma Linda University have shown laughter reduces the stress hormone cortisol, which is toxic to the hippocampus.

Stay socialMaintaining an active social life provides mental stimulation and lowers stress. It also lowers the risk for dementia and Alzheimer's disease. The more social activities, the better, and people who choose mentally challenging leisure pursuits such as playing cards with friends or joining a community organization do better in general than those whose activities are primarily physical or social. Living alone or avoiding social ties raises the risk of dementia.

LearnMore formal education is associated with lower rates of dementia and Alzheimer's, but "use it or lose it" applies at any age -- and more with the brain than the muscles, neurologists say. To keep the brain sharp, experts recommend learning new and fun mental activities. Crossword puzzles or sudoku, once mastered after a month or so, may not stimulate the brain the way learning a new language, picking up a musical instrument or joining a book club might.

• June is Alzheimer's & Brain Awareness Month


• The 86 billion neurons in your head use 20% of your body's energy to function


• Exercising and eating well are important to brain health

Editor's note: Jayatri Das is chief bioscientist and lead developer of "Your Brain," the nation's largest permanent museum exhibit dedicated to the brain, which opened at The Franklin Institute in Philadelphia this month.

(CNN) -- From the outside, the human brain might not be much to look at. What makes it fascinating is hidden within, in the complicated circuitry of neurons that makes you who you are.

Scientists are trying to understand this complex network and find the key to staying sharp as we age. In the meantime, use what they do know: that exercising these neurons can improve your memory and possibly stave off dementia.

In honor of Alzheimer's & Brain Awareness Month, spend some time getting to know your brain a little better.

The basic building blocks

Neurons, the functional building blocks of your brain, communicate using a combination of electrical and chemical signals. How and when do they fire? How are they wired together? How does that wiring change?

Understanding these fundamental mechanisms isn't just a trip back to biology class. This knowledge is essential to understanding how you can keep your brain healthy, and why these different strategies work.

The 86 billion neurons in your head are constantly active. Even though the brain doesn't account for much of your body weight, it uses 20% of your body's energy to function. It's a matter of gray and white.

This story is part of CNN Health's "Inside your Brain" series.

Gray matter, which contains the parts of neurons that carry out thought processing, uses most of this energy. White matter is more efficient. It contains the long axons of neurons that relay signals and coordinate different areas of the brain.

However, it's not enough for your brain cells simply to fire in the same patterns over and over. From moment to moment, throughout your life, your neurons need to rewire themselves based on your genes and experiences.

The differences in the connections between neurons are what make each of our brains unique, but characterizing those differences is among the biggest challenges facing scientists today. Even if scientists could record the network of a whole brain in an instant, it would only capture a single frame of a lifelong movie.

Keep your brain strong

There are things you can do on a daily basis to help your brain stay sharp.

Most importantly, stay in good physical health. Exercising and eating a healthy diet may sound as trite as "an apple a day," but repeated studies have shown how these practices help the brain at a cellular level.

Mediterranean diet is brain food

Exercise improves cognitive functions ranging from math to memory across the lifespan, and it can even benefit brain function during the early stages of Alzheimer's disease. Exercise enhances the growth and survival of new neurons in the hippocampus -- a region of the brain essential for long-term memory -- which may be able to replace others that degenerate as a result of the disease.

Blueberries, kale, coffee and nuts often get a lot of attention as good "brain foods" because of their high levels of antioxidants. Why?

Negatively charged oxygen compounds are produced as a byproduct of your body's normal metabolism. They can set off chemical chain reactions that eventually damage or kill cells. Because your neurons are so active, your brain is particularly susceptible, and antioxidants can prevent those chain reactions from occurring.

Give your brain an active lifestyle

You know you need to workout to keep your body in shape. Your mind is no different. Learning and practicing any challenging skill -- for example, a second language, reading, or even juggling -- can change the structure of your brain for the better.

This is your brain on knitting

This type of mental stimulation can delay cognitive decline associated with Alzheimer's disease, although there's evidence that once the symptoms of dementia begin, they progress faster.

Also, stay connected with friends and family -- as long as it doesn't create more stress! Several studies have shown that being part of a larger social network can reduce the cognitive effects of Alzheimer's disease.

Accept the things you cannot change

The fact that the brain is always changing gives us the opportunity to shape those neural connections through our behavior and environment. But beneath all of those factors lies the unchangeable role of genetics.

How do genes and your environment interact in normal aging, let alone result in diseases such as Alzheimer's? Neuroscientists are still looking at the effects of lifestyle choices, finding genes associated with elevated risk of disease, and studying the molecular mechanisms through which plaques and tangles of proteins damage neurons.

So far, however, the advances we are making are merely laying the groundwork for a future set of questions. We can only hope that someday, in a future June, we'll be celebrating a cure for Alzheimer's instead.

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