<qa>  What is the chemical that ingested is found to increase blood flow to the brain?This is a double-blind, randomized, placebo-controlled, pilot study. Participants will be randomized to receive either beetroot juice or a beetroot juice placebo, as a dietary supplement, for 30 days. Beetroot juice is high in nitrates, a chemical when ingested is found to increase blood flow to the brain. The purpose of this research study is to determine the safety and feasibility of using this nutritional intervention in ischemicstroke survivors, and prove that plasma levels of nitrate and nitrite increase as expected. Secondary outcomes includes measuring a comprehensive set of outcomes related to functional status post-stroke, including mobility, upper extremity strength, cognition, depression, and disability. Patients will also be randomized to MRI perfusion scanning in the region of the stroke to measure cerebral blood flow. 