BITTER GOURD (NATI) Juice contains a train of important nutrients ranging from iron, magnesium, potassium and vitamin C. An excellent source of dietary fiber, it also contains twice the calcium of spinach, beta-carotene of broccoli, and the potassium of a banana. The World Health Organization has estimated that over 382 million people worldwide suffer from diabetes. Bitter gourd contains an insulin-like compound called Polypeptide-p or p-insulin which has been shown to control diabetes naturally.