Fact checked by Elizabeth GallHaving walnuts with your dinner could improve the quality of your sleep.Credit: OsakaWayne Studios / Getty ImagesKey TakeawaysKey TakeawaysEating walnuts with dinner may improve sleep quality because they contain plant-based melatonin.Snacking on about 49 lightly salted or unsalted pistachios a day can help lower blood pressure when paired with a heart-healthy diet like DASH.Adding olive oil to a Mediterranean-style…