They may not be a crowd-pleaser, but these red root veggies contain loads of nitrates that increase blood flow and oxygen to the brain and raise mental performance. Research has focused mainly on beet juice, and the results are impressive. In one study by scientists at Wake Forest University, adults aged 70 and older who drank 16 ounces of beet juice a day had increased blood flow to the white matter of their frontal lobes. This is the part of the brain most often linked to the deterioration that causes dementia and cognitive declines. Researchers hold out great hope that drinking beet juice regularly (and presumably eating whole beets) could help prevent or slow the progression of age-related brain degeneration.