"The mind needs to be exercised, just as the body does, and exercises are beneficial in reducing the experience of some of these brain-related problems. Solving puzzles, brainteasers, discussing opposing ideas, creative painting or sculpting are just a few ways to engage the mind and keep it youthful and healthy."
(From "Ways to Exercise Your Brain")
I agree that keeping our mind active not only keeps us young, delaying the ageing process, but also prevents brain-related problems such as Alzheimer's disease. As we continue to learn new things and keep ourselves abreast with current events, we will naturally find opportunities for solving puzzles and discussing opposing ideas, such as how to address health and food issues, how to overcome inequality in the world, why and how people need to be free from bondages imposed by religions, and so on. These mental challenges stimulate the mind and give us a sense of purpose as we endeavour to help share the knowledge and insights we have gained with others for their benefit, even as we continue to learn new things and broaden our thinking.
The article also suggests some foods that improve the mind's functionality, such as egg yolks, fish, berries and avocados. I think I have read or heard before that fish is a recommended food for the brain too, so eating fish is good for us, and it is rich in proteins too.