Cold-water fish. Increasing serum measurements of DHA/EPA, markers of fish intake, are related to lower blood pressure (12, 13, 14). However, steer clear of most fish oil supplements and instead have patients obtain beneficial nutrients from whole foods whenever possible. A recent analysis showed that the three top-selling fish oils in the United States contained oxidized lipids that may be causing more harm than good (15). Beyond DHA and EPA, fish also have selenium, zinc, iron, and a highly absorbable protein that also may reduce blood pressure (16). Aim for cold-water fatty fish three times a week.
In a 2014 review of previous studies, people who consumed probiotics—healthy bacteria found in yogurt and other fermented foods—saw their systolic blood pressure reduced an average of 3.6 points, and their diastolic reduced 2.4 points, compared to those who didn’t. Those with blood pressure higher than 130/85 experienced the greatest reductions, along with those who took probiotic supplements or ate probiotic foods for longer than two months. (Any blood pressure over 120/80 mm Hg is considered elevated.) Experts say any effect probiotics have on blood pressure is likely modest, but that they may play a role in an overall heart-healthy lifestyle.
Sleep. Short and poor-quality sleep are both associated with raised blood pressure (40). On the other side of the spectrum, excessively long sleep may also be harmful. One study found increased blood pressure in those who got fewer than five hours of sleep per night and in those who averaged more than nine hours of sleep per night, when compared with people who slept around seven hours (41). I suspect that it’s not the long sleep itself that is the problem, but that some underlying condition is both increasing sleep requirement and raising blood pressure.