( CNN ) -- Michael Petrina 's mother passed away from Alzheimer 's disease 15 years ago . That 's one of the reasons the 67-year-old retired attorney works his mind so hard . Petrina took first place in the AARP National Spelling Bee on Sunday , beating more than 50 contestants in 47 rounds . The winning word ? Rhizoctonia , a genus of imperfect fungi . `` R-H-I-Z ... , '' Petrina started to spell before breaking into laughter as he spoke to CNN Monday . `` Is that right ? I hope . I 'll look it up while we 're talking . '' The AARP started the spelling bee in 1996 as a way to motivate members to keep their minds sharp . While Alzheimer 's and other types of dementia are a big concern for seniors , even normal aging can slow the brain 's processes over time . As fetuses at six months , `` we actually have more brain cells than we will ever have in our lives , '' Dr. Gregory Jicha says . `` [ After ] six months in the womb , nerve cells start dying . '' As an associate professor of neurology , Jicha works at the Sanders-Brown Center on Aging in Lexington , Kentucky . Since 1989 , the center has been studying the healthy brains of seniors in hopes of identifying exactly what keeps someone from developing a cognitive disorder . Researchers have some ideas , Jicha says , but there 's little definitive evidence . Part of the problem is the brain 's complexity ; each type of memory is affected differently as we age . The good news is that it 's not all bad news , says Dr. Suzanna Penningroth , a gerontologist from the University of Wyoming . Your brain 's processing speed -- how fast you can interpret and recall information -- slows as you age , according to Penningroth . Episodic memory , like what you ate for breakfast this morning , is also on the decline . But studies have shown seniors are much better at prospective memory , such as remembering to take a daily medication , and have larger knowledge bases than younger generations . Penningroth says that semantic memory stays strong as we age . The aging brain : Why getting older just might be awesome . In other words , you might not remember where you parked this morning but you 'll always remember how to drive . Here are some tips to keep your thinking skills sharp , starting now : . Engage the mind . To prepare for the spelling bee , Petrina wrote out 20,000 words on flashcards and went over them again and again . He also enjoys crossword puzzles and reads often to keep his mind active . Fortunately for those who are n't bookworms , mind engagement can come in many forms . Learning a new dance or musical instrument counts , Jicha says . So does playing card games or adding up scores during a game of golf . Enrich your environment . The amount of time we spend communicating often declines with age . Americans age 55 to 64 spend 13 % of their time socializing and communicating , compared to 8 % of those older than 75 , according to the 2010 Older Americans report . Studies have shown that lab animals in an empty cage form far fewer nerve cell connections than those who are given neighbors and toys . `` We can take that as a lesson , that we as human beings need to be in an enriched environment , '' Jicha says . `` In the face of the fact that we 're losing nerve cells every day , we need to keep making these new connections . '' Case in point -- the morning after the AARP competition , Petrina was packing for a trip to Turkey . Whether it 's for work or pleasure , Jicha says new experiences are an important part of keeping the mind healthy . Eat right . The mind uses nutrients as building blocks to form new connections , Jicha explains . Since the brain is one of the fattiest organs , eating omega-3 fatty acids from fish , seeds and nuts can help rebuild damaged tissue . Brain suffers when fish oil falls short . Also important is eating fresh vegetables and fruits . Their antioxidants help defend and repair our cells , Jicha says . `` Our brain , we 're only given one . If we 're going to live to 80 , we 've got 80 years of healthy nerve cell life we have to protect . '' Exercise . Petrina works out with a trainer twice a week . He knows exercise is important for keeping his brain fit . Exercise can stimulate cell growth , Jicha says . One area of the brain that can produce new cells is the hippocampus , which is responsible for memory . `` It 's nice to know that something as simple as physical exercise can actually lead to biological change , '' he says . Exercise also keeps the cardiovascular system working efficiently , increasing blood flow to the brain and reducing the risk of vascular dementia . Strength-training key in preventing Alzheimer 's . Encode better . Even if you eat right , exercise frequently and stay engaged with your environment , your mind is going to fade , Penningroth says . `` You just have to know what your weaknesses are . If you understand these weaknesses you can easily compensate . '' To boost memory , shut your eyes . Paying attention is the first step to encoding new information , she says . Use repetition , like saying a new friend 's name several times to make sure it sticks . Then keep checklists or other aids to help you complete important tasks . If nothing else , try to remember that everyone is in the same sinking boat as you are . `` I always like to kid that I think my brain was at its best at 25 , '' Jicha says . `` And it 's been downhill ever since . '' 10 best cities for successful aging .
The AARP National Spelling Bee started in 1996 to motivate members to keep minds sharp . Each type of memory is affected differently as we age , experts say . Hide Caption 1 of 10 Photos:Photos: