A concentrated source of minerals like Copper, Potassium, Calcium, Zinc, Manganese, Vitamin C, Iron, Selenium and Magnesium, the age-old practice does much more than simply beat bad breath. From regulating blood pressure to water retention, fennel seeds pack a bevy of nutrients. Drinking fennel tea, regularly helps flush out excess fluids as it works as a diuretic. Fennel seeds contain Vitamin A, which is important for eyesight.