Oatmeal might be a good source of iron, magnesium, zinc, and selenium, but other nutrients in oatmeal work together to lower blood pressure. According to a 2022 review in Nutrients, compounds called “avenanthramides” and “phenolic acids” boost nitric oxide in your blood vessels to improve blood flow. These compounds also reduce the inflammation and oxidative stress that can lead to high blood pressure. Substances in oatmeal also block enzymes that constrict your blood vessels. Your gut bacteria produce short-chain fatty acids when they process oats, and these fatty acids improve the function of your blood vessels.
Incorporating oatmeal into your eating plan can help reduce your blood pressure, particularly if you swap out refined grains. A 2023 review in the Journal of the Academy of Nutrition and Dietetics pooled the results of 21 studies involving the effect of oatmeal on high blood pressure. People who ate oatmeal lowered their systolic blood pressure (the top number) by an average of 2.82 mm Hg. If people had prehypertension before the start of the study, their diastolic blood pressure (the bottom number) went down after adding oatmeal to their diet.