It’s an aquatic vegetable, often grown underwater in marshy and muddy areas. The grass-like plant is native to Asian countries like China, India, the Philippines, and Japan. The water chestnut also grows in Australia, tropical Africa, and some Pacific and Indian Ocean islands. Reduced stroke risk and improved blood pressure. Potassium, which is present in water chestnuts, may reduce your risk of stroke and high blood pressure, both of which are linked to heart disease.