Beloved as a refreshing summer treat, watermelon may also have major benefits for heart health, new research has shown. Thirteen obese adults with high blood pressure were randomized to receive watermelon extracts of l-citrulline and l-arginine or a placebo for 6 weeks. Each day during the 6-week study period, their blood pressure was also subjected to “cold stress”—the participants held one hand in cold water, which causes blood vessels to contract and blood pressure to go up. This cold stress is one reason why heart attack rates go up in the winter. Taking the watermelon extracts was associated with a lower systolic blood pressure as well as improvements in other parameters of vascular health, both at rest and during the cold stress. These preliminary results suggest that low-calorie, high-fiber watermelon can be an especially important part of a heart-healthy diet, and supplements of watermelon extract can be taken year-round to help keep blood pressure down even in the depths of winter.
(Source: American Journal of Hypertension, 2014; doi: 10.1093/ajh/hpt295.)