Simple preventive steps
There is a lot of information about dementia and APOE available on this site and elsewhere. If you carry the ε4 variant of the APOE gene and just want some basics about how to stay healthy and reduce your risk for dementia, here are a few non-controversial tips on which virtually all researchers agree (for a clearly written, non-technical, but much lengthier introduction, see Stavia's introductory posts on our forums):
-- Don't smoke.
-- Don't drink heavily. Many, though not all, researchers believe that APOE-ε4 carriers shouldn't drink at all; that is, that the "light to moderate drinking is good for the brain" advice doesn't apply to APOE-ε4 carriers. Research is ongoing. But one thing on which all researchers agree: getting drunk is particularly bad for the long-term brain health of APOE-ε4 carriers.
-- Don't be sedentary. What kind of exercise is best is not known, but it is known that motion of any kind is better than non-motion.
-- Eliminate all, or nearly all junk food, especially sweets and foods with added sugar and foods with trans-fats) from your diet, and consume a varied, balanced diet with plenty of vegetables. The question of precisely how much meat, fruit, grains, and so on should be consumed, and what the optimal targets are for overall nutrient percentages -- 10% fat? 30% fat? More? -- is controversial. But virtually all researchers agree that avoiding junk food and eating a lot of vegetables will reduce your risk of dementia and many other diseases.
-- Via diet or exercise (or both), don't be overweight. The cut-off for "overweight" is controversial, but aiming for a BMI no higher than 25 is a goal virtually all researchers would agree on.
-- Avoid all head trauma. Do not box, and consider not engaging in other sports that put you at risk of head trauma -- soccer and American football, for example.
-- Get enough sleep. How much is "enough" varies from person to person, but typically is between seven and eight hours per night.
-- Stay mentally engaged. It's particularly important to learn new things.
-- Stay socially active. Close personal relations in which you can discuss matters of the heart appear to be particularly important.