In a systematic review and meta-analysis of 29 randomized controlled clinical trials that examined the effects of vitamin C supplementation on blood pressure, researchers found that in short-term trials, vitamin C supplementation reduced systolic blood pressure (SBP) and diastolic blood pressure (DBP) with more study needed on the longer term effects. The median dose was 500 mg/d, median duration was 8 wk, and trial sizes ranged from 10 to 120 participants, and occurred between 1966- 2011. Researchers found evidence that vitamin C intake was correlated to lowered blood pressure in hypertensive patients. Additional research is needed to understand the long-term impact of vitamin C supplementation on blood pressure.
