But there are some potential side effects, including headaches, anxiety and insomnia. Additionally, one study on a small group of healthy older adults found that taking 200 mg of resveratrol per day for 26 weeks improved memory . Nootropics are natural supplements or drugs that have a beneficial effect on brain function in healthy people. Beet roots contain high concentrations of nitrates, which are converted into nitrites by bacteria in the mouth. These nitrites help open blood vessels in the body, increasing blood flow and oxygen to the brain, which helps boost its function.