A healthy diet can help reduce the risk of many chronic diseases such as heart disease or diabetes. It may also help keep your brain healthy.

In general, a healthy diet consists of fruits and vegetables; whole grains; lean meats, fish, and poultry; and low-fat or nonfat dairy products. You should also limit solid fats, sugar, and salt. Be sure to control portion sizes and drink enough water and other fluids.

Researchers are looking at whether a healthy diet can help preserve cognitive function or reduce the risk of Alzheimer's. For example, there is some evidence that people who eat a Mediterranean diet have a lower risk of developing dementia.

While scientists aren’t sure yet why the Mediterranean diet might help the brain, its effect on improving cardiovascular health might in turn reduce dementia risk. In contrast, the typical Western diet often increases cardiovascular disease risk, possibly contributing to faster brain aging.

Researchers have developed and are testing another diet, called MIND, a combination of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. According to observational studies of more than 900 dementia-free older adults, closely following the MIND diet was associated with a reduced risk of Alzheimer’s and a slower rate of cognitive decline.