( CNN ) -- The number of people with dementia globally is estimated to nearly double every 20 years , according to a report released Monday for World Alzheimer 's Day . It 's common for people with Alzheimer 's or other types of dementia to wander from their homes . Much of the growth will be fueled by longer life spans and population growth , especially in developing nations . `` Over the next 20 years , the numbers of people with dementia are anticipated to increase by 40 percent in Europe , 63 percent in North America , 77 percent in the southern Latin America ... and 89 percent in the developed Asia Pacific countries , '' the report said . `` In comparison , the percentage increase is expected to be 117 percent in East Asia , 107 percent in South Asia , 134-146 percent in the rest of Latin America , and 125 percent in North Africa and the Middle East . '' By 2010 , an estimated 35.6 million people around the world will be living with dementia . The number is expected to hit 65.7 million in 2030 and 115.4 million in 2050 . One in seven Americans age 71 and older , or about 3.4 million , have dementia , according to the National Institutes of Health . In this age group , 2.4 million people have Alzheimer 's disease , NIH research has shown . Alzheimer 's disease is the most common cause of dementia , according to the Mayo Clinic . Some of the causes of the disease are believed to be genetic , while others are thought to be preventable . Studies have shown that physical exercise , the kind that keeps the heart healthy , also keeps the brain healthy , according to the National Institutes of Health 's Cognitive and Emotional Health Project . Mental stimulation can help too . `` Our brains can be made stronger through exercise , '' Andrew Carle , assistant professor in the department of health administration and policy at George Mason University , told CNN late last year . `` In the same way physical exercise can delay many of the effects of aging on the body , there 's some evidence cognitive exercise can at least delay the onset of Alzheimer 's . '' A combination of antioxidants , supplements and curry may also help . Vitamins A , C , and E are antioxidants , which prevent cell damage and are believed to slow down diseases of aging , said Edythe London , a professor of psychiatry and pharmacology at the University of California , Los Angeles . `` There are studies that suggest antioxidants might prevent dementia , '' she said . Fish oil and phosphatidylserine supplements may also help . Aging brains show signs of inflammation , and fish oil has anti-inflammatory properties , said Gary Small , director of the UCLA Center on Aging . Phosphatidylserine is a lipid found naturally in the body and is a major component of cell membranes . Small said he 's not 100 percent convinced these supplements will help stave off dementia , but they 're worth a try . There 's also curry . Small said that as he gets older , he might try eating more foods with curry in them . `` Some studies in Singapore show that those who ate curry once a week had better memory scores , '' he said .
Number of people with Alzheimer 's estimated to nearly double every 20 years . Report : By 2010 , around 100 million people globally will be living with Alzheimer . Studies show mental stimulation and exercise can help delay onset of symptoms .