32). And even though some types of dietary fat and alcohol can provide brain benefits (25, 26), the wrong kinds or excessive amounts can negatively affect your cognitive health over time if you’re not careful.As you might suspect, certain substances wreak havoc with your brain, and you should avoid them at all cost. Illicit drugs like marijuana increase paranoia and psychosis, and cocaine puts you at great risk for stroke and may also raise your risk of Parkinson’s disease. Even legal drugs like nicotine can restrict blood flow to the brain, damaging it and causing premature aging. But not all brain agers are that clear-cut. For example, while small amounts of caffeine can increase alertness and even boost mental performance, downing too much can also restrict blood flow to the brain and interfere with much-needed sleep (32). And even though some types of dietary fat and alcohol can provide brain benefits (25, 26), the wrong kinds or excessive amounts can negatively affect your cognitive health over time if you’re not careful.
Emerging research links saturated and trans fats to an increased risk of age-related cognitive decline and dementia, including Alzheimer’s disease, although researchers aren’t sure exactly how they raise your risk. Saturated and trans fats trigger inflammation in the brain and actually prevent healthy fats like monounsaturated and omega-3 fatty acids from entering your brain cells. Additionally, a 2009 study in the journal Progress in Lipid Research suggested that regularly eating too much saturated fat and cholesterol disrupts the blood-brain barrier, allowing plasma proteins like amyloid-beta (sticky substances that clump together to form plaques typical in Alzheimer’s disease) to leak into the brain and accumulate. A large 2006 study by Swedish researchers followed a group of nearly 1,500 people for twenty years and found that even a moderate intake of saturated fat at midlife increased risk of dementia and Alzheimer’s. For the best brain health, get less than 7 percent of your daily calories from saturated fat. An anti-inflammatory diet (25) is a smart choice because it limits foods high in saturated fat and cholesterol (animal products like meat and full-fat dairy).
Trans fats, or partially hydrogenated oils, undergo a chemical process to make them stable and solid at room temperature. Like other fats, they get incorporated into your cell membranes, but trans fats make your brain cells hard and rigid, slowing mental response time and accelerating brain aging. Trans fats are primarily found in commercial baked goods (cookies, cakes, chips, crackers, etc.) and fried foods like doughnuts and french fries. Thanks to a sneaky loophole, food products in the United States are allowed to claim they have 0 gram of trans fats when they contain less than 0.5 gram per serving. That may not seem like much, but those little bits can add up quickly. Instead of looking at the nutrition facts label, you’ll need to examine the ingredients list. If you see the word shortening or partially hydrogenated anything, put the package back on the shelf.
Yes, a glass of red wine can provide brain-protecting antioxidants and calm inflammation (26), but overdoing it can deplete levels of glutathione (the brain’s primary antioxidant) and thiamin (a B vitamin critical for brain function) and dehydrate you. A 2007 study in the Journal of the American College of Nutrition noted that being dehydrated can also cloud cognitive performance.
Not surprisingly, continually drinking too much can lead to alcohol-related brain damage. Heavy drinking also interferes with your brain’s ability to process and use docosahexaenoic acid (DHA), a type of omega-3 vital for brain health (25). And Australian researchers identified a history of harmful alcohol consumption as one of the biggest risk factors for cognitive impairment in older people.
But research shows that even moderate drinking may cause your brain to shrink over time and lead to abnormalities in how your brain transports glucose, oxygen, and other substances. The effect is more noticeable in women, possibly because they are smaller. To set yourself up for the best brain health in late life, limit your intake to no more than one drink a day (even better, two drinks a week for women and three for men), and be sure to drink a glass of water for each alcoholic beverage you imbibe to stay hydrated. You may also want to nix the nightcap: Alcohol can interfere with the deepest levels of sleep and cause you to wake up frequently, leading to daytime sleepiness and decreased cognitive function (32).