Experts from Germany's Public Health Insurance Fund have stated that bitter substances stimulate the digestive system, which helps regulate the feeling of hunger. They explained that the health effects of bitter substances include: stimulating appetite, enhancing saliva flow, improving gastric juice production, increasing bile production to facilitate fat digestion, and stimulating intestinal activity. Some bitter substances lead to increased insulin production. The fund also noted that the dietary sources of bitter substances are: salad vegetables such as dandelion and arugula, cabbage and Brussels sprouts, green vegetables like kale or spinach, 'bitter' spices such as turmeric, mustard seeds, thyme, and cinnamon, artichokes, ginger, olives, and eggplants, as well as coffee, lemon balm tea, green tea, and grapefruit juice.
