Dementia means loss of brain function, and your chance of having dementia increases with age: it affects three percent of people ages 65-74, 17 percent of those age 75-84 and 32 percent of those age 85 or older (Neurology, 2013;80(19):1778-83). Doctors can now predict increased risk for developing dementia by ordering an MRI which can show decreased volume of grey matter in the brain (Brain Imaging and Behavior, May 9, 2018). Grey matter is where the brain processes speech, hearing, feelings, seeing and memory. Middle-aged women who have low levels of the good HDL cholesterol are the ones most likely to suffer loss of brain tissue and develop dementia 20 years later (Brain Imaging and Behavior, September 26, 2018). HDL carries cholesterol from your blood and arteries to be removed by your liver.

Factors that Increase Risk for Dementia
Risk factors for dementia are close to the same as those for heart attacks (Alzheimer’s & Dementia, May 12, 2018):
• obesity during middle age
• high blood pressure
• high blood sugar levels (JAMA Psychiatry, 2018;75(10):1033-1042)
• history of heart disease
• history of a heart attack
• smoking
• history of strokes

Preventing Dementia
Today there is no cure for dementia, but several reports show that it may be delayed and perhaps prevented by:
• training your brain with regular challenging use and possibly special exercises
• exercising your muscles regularly
• avoiding smoking and smokers
• following a healthful Mediterranean-style diet
• preventing and treating everything that damages arteries because the same factors also can damage your brain: heart disease, strokes, diabetes, high blood pressure and so forth.

Exercising your Brain
At the Alzheimer’s Association’s International Conference in Toronto on July 24, 2016, data was presented showing that older adults averaging 73 years of age, who had practiced increasing the speed at which they processed visual information for 10 years, reduced their chances of suffering dementia by 33 percent, compared to the control group who did no special training. This is supported by several previous studies showing that people who work in jobs requiring complex thinking are at reduced likelihood to develop dementia.

At this time there are no “proven” exercise programs for the brain, but the studies suggest that any activity that stimulates the brain may help to delay or prevent dementia: counting steps when you walk, writing letters, reading, doing puzzles and games that require thinking and so forth.

Physical Exercise
• Researchers followed the physical activity and did brain MRIs of 3700 men and women over 60 years of age for more than 10 years and found that the most active people had larger hippocampi (the part of the brain that controls short-term memory) and that those over 75 had the greatest benefit from exercise (J of Geron Ser A: Biol Sci and Med Scien, August 2016).

• Canadian researchers analyzed brain scans of 330 healthy adults, ages of 19 and 79, and showed that those who walked up and down stairs regularly had younger-appearing and larger brains (Neurobiology of Aging, April 2016;40:138–144). They estimated that every added flight of stairs walked each day reduced the person’s brain age by half a year.

• A group of 100 men, aged 55-68, with mild cognitive impairment (progressive impaired memory) did a supervised program of lifting increasingly heavy weights twice a week for six months. Compared to those who had a program of just stretching, the weightlifters had a significant improvement in their memories and ability to solve problems and the greater the gain in strength, the greater their improvement in mental function (J of American Geriatrics, Nov 30, 2016).

• A study of 3050 twins, followed for 25 years, showed that moderately vigorous physical activity is associated with higher memory and better problem solving (J of Alzheimer’s Disease, September 2, 2016).

• Very strong data show that regular exercise improves memory. Exercising muscles produce and release into the bloodstream a substance called Cathepsin B (CTSB) that has been shown to increase memory and grow nerves in mice, monkeys and humans (Cell Metabolism, June 12, 2016). Many previous studies show that the higher the blood level of CTSB, the greater the improvement in fitness level and memory. Researchers showed that after just one week of exercise, a normal mouse’s memory improved dramatically. However, mice who were genetically engineered to be unable to produce CTSB gained no improvement in memory tests from exercise. Other studies are proceeding to find out if CTSB can be given to people to help prevent and treat the amyloid plaques that characterize Alzheimer’s disease.

• When healthy, regularly-exercising master athletes, ages 50-80 years, stopped exercising for just 10 days, MRI brain scans showed a marked reduction in blood flow to the hippocampus, which controls memory. As people start to develop Alzheimer’s disease, the hippocampus in their brains become smaller. (Frontiers in Aging Neuroscience, August 5, 2016).

A Healthful Diet
A review of the incidence of Alzheimer’s disease around the world shows that the rates of Alzheimer’s disease are rising everywhere people eat a lot of meat, sweets and high-fat dairy products characteristic of the Western Diet, and that eating a Mediterranean-style diet with vegetables, fruits, whole grains, legumes, and fish is associated with reduced risk (J of Amer Coll of Nutrition, Aug 2016; 35 (5):476).

Diets recommended to help prevent heart attacks also appear to help prevent dementia. The “Mediterranean-DASH Intervention for Neurodegenerative Delay” (MIND) study showed reduced risk for Alzheimer’s disease by 53 percent in those who followed the diet rigorously, and by 35 percent in those who generally followed the diet most of the time (Alzheimer’s & Dementia, March 2015;11:1015-1022). One in four North Americans will suffer from high blood sugar levels which increase risk for dementia (N Engl J Med, Aug 8, 2013;369:540-548). People who eat a Mediterranean diet have lower rates of Alzheimer disease and Parkinson disease (BMJ, 2008;337:a1344).

Avoiding Smoking
Smoking causes inflammation and oxidative stress. People who smoke develop dementia 23 years earlier than nonsmokers, from damaged blood vessels (J Cell Mol Med, 2008;12(6B):2762-2771) and nerves (Dement Geriatr Cogn Disord, 2010;30(3):277-84).

My Recommendations
It now appears that you may help to delay and perhaps prevent Alzheimer’s disease and other forms of dementia if you:
• Exercise regularly
• Engage in lots of activities that require thinking, memory and calculation
• Eat a plant-based, Mediterranean-style diet
• Avoid alcohol, tobacco and recreational drugs
• Avoid being overweight
• Control high blood pressure, high cholesterol, high blood sugar and other heart attack risk factors

Checked 11/1/20