Brain-draining foods

While some foods are known for enhancing cognitive fitness, others have the opposite effect. Many of the same foods that are harmful to your heart and blood vessels can also lead to strokes. Therefore, you should limit your intake of the following foods: 

Red meat, butter, cream, whole milk. All of these animal-based foods are high in saturated fat, which raises blood levels of unhealthy LDL cholesterol. When cholesterol builds up in arteries, it sets off a chain of events that can ultimately lead to a stroke.

An examination of four studies that together included more than 8,600 people found that eating more saturated fat led to a 39% higher risk for Alzheimer's and more than double the risk for dementia in general. For each additional 4 grams per day of saturated fat people consumed, the risk for dementia increased by 15%.

Added sugars. Soft drinks, cookies, cakes, and pies are all loaded with sugar. It's in almost everything we eat, including foods not known for their sweetness, like ketchup and salad dressing.

Sugar stimulates the brain's reward center in much the same way addictive drugs do. That's why you may have cravings for sweets. But sugar has also been linked to diabetes and obesity, both of which are detrimental to brain health.

Try to cut back on foods with added sugars when possible. Substitute berries for cake and ice cream, and eat eggs for breakfast rather than a muffin or sweet cereal. Note that ingredients like honey, molasses, fruit juice concentrate, brown rice sugar, glucose, corn syrup, and sucrose are just other names for sugar. 

Refined flour. When flour is "refined" or "enriched," that means manufacturers have stripped away the healthiest parts of the grain—the fiber-rich bran and vitamin-rich germ—and then added a few vitamins and other nutrients back in. In the process, they have also created an easy-to-digest foodstuff that quickly floods the bloodstream with glucose. The result is that white flour and products made with it (pasta, bread, crackers, cake) cause blood sugar levels to spike and then plummet, leaving you feeling hungry again soon after you eat them.

Eating too many foods made with refined flour can affect your blood pressure and diabetes risk over time. Look for foods labeled "100% whole grain" to maximize the fiber and nutrient content of the grain products you buy. 

Diet soda. A study in the journal Stroke linked regular consumption of diet soda to a higher risk of strokes and dementia. However, the reasons for the association are not clear, and the study does not prove cause and effect, so the warning is preliminary.

For more on staying sharp as you age, read  A Guide to Cognitive Fitness , a Special Health Report from Harvard Medical School.

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