Alzheimer’s isn’t inevitable. Many experts now believe you can prevent or at least delay dementia — even if you have a genetic predisposition. Reducing Alzheimer’s risk factors like obesity, diabetes, smoking and low physical activity by just 25 percent could prevent up to half a million cases of the disease in the United States, according to a recent analysis from the University of California in San Francisco.

Here are 10 new ways you can boost your brain health now.

1. Get moving

“If you do only one thing to keep your brain young, exercise,” says Art Kramer, professor of psychology and neuroscience at the University of Illinois. Higher exercise levels can reduce dementia risk by 30 to 40 percent compared with low activity levels, and physically active people tend to maintain better cognition and memory than inactive people. “They also have substantially lower rates of different forms of dementia, including Alzheimer’s disease,” Kramer says.

Working out helps your hippocampus, the region of the brain involved in memory formation. As you age, your hippocampus shrinks, leading to memory loss. Exercise can reverse this process, research suggests.

How you work up a sweat is up to you, but most experts recommend 150 minutes a week of moderate activity. Even a little bit can help: “In our research as little as 15 minutes of regular exercise three times per week helped maintain the brain,” says Eric Larson, executive director of Group Health Research Institute in Seattle.

2. Pump some iron

Older women who participated in a yearlong weight-training program at the University of British Columbia at Vancouver did 13 percent better on tests of cognitive function than a group of women who did balance and toning exercises. “Resistance training may increase the levels of growth factors in the brain such as IGF1, which nourish and protect nerve cells,” says Teresa Liu-Ambrose, head of the university’s Aging, Mobility, and Cognitive Neuroscience Laboratory.

3. Seek out new skills

Learning spurs the growth of new brain cells. “When you challenge the brain, you increase the number of brain cells and the number of connections between those cells,” says Keith Black, chair of neurosurgery at Cedars-Sinai Medical Center in Los Angeles. “But it’s not enough to do the things you routinely do — like the daily crossword. You have to learn new things, like sudoku or a new form of bridge.”

UCLA researchers using MRI scans found that middle-aged and older adults with little Internet experience could trigger brain centers that control decision-making and complex reasoning after a week of surfing the net. “Engaging the mind can help older brains maintain healthy functioning,” says Cynthia Green, author of 30 Days to Total Brain Health.

4. Say “Omm”

Chronic stress floods your brain with cortisol, which leads to impaired memory. To better understand if easing tension changes your brain, Harvard researchers studied men and women trained in a technique called mindfulness-based stress reduction (MBSR). This form of meditation — which involves focusing one’s attention on one’s breath, sensations and feelings — has been shown to reduce harmful stress hormones. After eight weeks, researchers took MRI scans of participants’ brains that showed the density of gray matter in the hippocampus increased significantly in the MBSR group, compared with a control group.

5. Eat like a Greek

A heart-friendly Mediterranean diet — fish, vegetables, fruit, nuts and beans — reduced Alzheimer’s risk by 34 to 48 percent in studies conducted by Columbia University.

“We know that omega-3 fatty acids in fish are very important for maintaining heart health,” says Keith Black of Cedars-Sinai. “We suspect these fats may be equally important for maintaining a healthy brain.”

Data from several large studies suggest that older people who eat the most fruits and vegetables, especially the leafy-green variety, may experience a slower rate of cognitive decline and a lower risk for dementia than meat lovers.

And it may not matter if you get your produce from a bottle instead of a bin. A study from Vanderbilt University found that people who downed three or more servings of fruit or vegetable juice a week had a 76 percent lower risk for developing Alzheimer’s disease than those who drank less than a serving weekly.

6. Spice it up

Your brain enjoys spices as much as your taste buds do. Herbs and spices such as black pepper, cinnamon, oregano, basil, parsley, ginger and vanilla are high in antioxidants, which may help build brainpower. Scientists are particularly intrigued by curcumin, the active ingredient in turmeric, common in Indian curries. “Indians have lower incidence of Alzheimer’s, and one theory is it’s the curcumin,” says Black. “It bonds to amyloid plaques that accumulate in the brains of people with the disease.” Animal research shows curcumin reduces amyloid plaques and lowers inflammation levels. A study in humans also found those who ate curried foods frequently had higher scores on standard cognition tests.

7. Find your purpose

Discovering your mission in life can help you stay sharp, according to a Rush University Medical Center study of more than 950 older adults. Participants who approached life with clear intentions and goals at the start of the study were less likely to develop Alzheimer’s disease over the following seven years, researchers found.

8. Get a (social) life

Who needs friends? You do! Having multiple social networks helps lower dementia risk, a 15-year study of older people from Sweden’s Karolinska Institute shows. A rich social life may protect against dementia by providing emotional and mental stimulation, says Laura Fratiglioni, director of the institute’s Aging Research Center. Other studies yield similar conclusions: Subjects in a University of Michigan study did better on tests of short-term memory after just 10 minutes of conversation with another person.

9. Reduce your risks

Chronic health conditions like diabetes, obesity and hypertension are often associated with dementia. Diabetes, for example, roughly doubles the risk for Alzheimer’s and other forms of dementia. Controlling these risk factors can slow the tide.

“We’ve estimated that in people with mild cognitive impairment — an intermediate state between normal cognitive aging and dementia — good control of diabetes can delay the onset of dementia by several years,” says Fratiglioni. That means following doctor’s orders regarding diet and exercise and taking prescribed medications on schedule.

10. Check vitamin deficiencies

Older adults don’t always get all the nutrients they need from foods, because of declines in digestive acids or because their medications interfere with absorption. That vitamin deficit — particularly vitamin B12 — can also affect brain vitality, research from Rush University Medical Center shows. Older adults at risk of vitamin B12 deficiencies had smaller brains and scored lowest on tests measuring thinking, reasoning and memory, researchers found.

Tips to improving memory

Brain Games

By Kayt Sukel

AARP The Magazine

American consumers spend close to $300 million a year on computer-based brain-training programs — “mind workouts” — from such companies as MindSparke, Lumosity and PositScience. For just a few minutes (and a few dollars) a day, these programs promise enhanced memory and improved productivity. But do they work?

It depends on whom you ask. Much of the excitement around brain training is due to the relatively recent discovery that the brain remains plastic — able to change structurally and functionally —throughout life. But while a plastic brain means cognitive improvement is possible, clinical studies examining computer-based brain-training programs offer mixed results. Some show slight improvement with regular use; others find they’re nothing more than a fun distraction. The largest clinical trial to date, conducted by British researchers and published in the April 20, 2011, issue of Nature, found no significant cognitive gains after several weeks of brain training.

Here are some of the more established brain-training programs on the market and their costs.

1. Company: MindSparke

What you get: Access to the Brain Fitness Pro program online.

Cost: $24.95 per month or $395 lifetime subscription fee

2. Company: Lumosity

What you get: Online and mobile access to a variety of brain games designed to enhance memory, problem-solving and attention.

Cost: $14.95 per month, $79.95 per year or $299.95 lifetime subscription fee

3. Company: PositScience

What you get: Visual and auditory training programs,

Cost: $345 for the Total Training Software Package

4. Company: Cogmed

What you get: The Cogmed training software, plus one-on-one assessments of your progress with a trained Cogmed coach.

Cost: $900 – $1,800, depending on your local Cogmed Practice Center

5. Company: NeuroActive (neuroactive.ca/EN/)

What you get: A “whole brain”-training software package that the company says will strengthen more than 18 cognitive abilities, including memory, stress reduction and attention.

Cost: $99.95 for Complete Brain Training software

Ask actress Marilu Henner about a lunch date with 60 Minutes correspondent Lesley Stahl almost 20 years ago, and she can not only recall the date (June 1, 1993) and the restaurant (Aureole in New York) but also what she ate (the salmon). Henner is one of a handful of people who have superior autobiographic memory: the ability to remember, in vivid detail, almost every day of her life. If you’re struggling just to recall where you parked your car, here are a few tricks that can help you learn to be more like these memory geniuses.

Rehearse: It’s the simplest way to retain new information, such as the name of a new acquaintance. Repeat the name when you first hear it and then again in the context of conversation, as in “How long have you lived in the neighborhood, Karen?”

Visualize: Create an image or video in your mind incorporating items to remember. Say you are going to 76 Forest Avenue with instructions to take a left on King Street and then a right on Forest Avenue. “Imagine a king hopping on his left leg and then falling to the right into a forest of trees planted in the shape of the numerals 7 and 6,” says Cynthia Green, author of 30 Days to Total Brain Health.

Downsize: Memory champs break up long strings of numbers into shorter units, which they then associate with something easy to recall. For example, your wedding was in 1962 and your first grandchild was born in 1993, so make your debit card pin 6293.

— Beth Howard, AARP The Magazine