Soaking onions helps to lower blood sugar. The substance contained in onion can make better use of glucose, lower blood sugar and provide heat energy for brain cells. It is a good diet vegetable for patients with diabetes and listlessness. Reducing blood fat 2 Soaking onions with vinegar helps to reduce blood fat. The amino acids contained in onion can reduce blood fat and resist arteriosclerosis. Soaking onions with vinegar can keep the activity of amino acids in onions. Generally, eating for half a day for 2~3 months can reduce the bad cholesterol content. Lowering blood pressure 3 Soaking onions with vinegar helps to lower blood pressure. Prostaglandin A contained in onion can dilate blood vessels and reduce blood viscosity, thereby lowering blood pressure, reducing peripheral blood vessels, increasing coronary blood flow and preventing thrombosis. But also help to promote sodium excretion and lower blood pressure. Promoting digestion 4 Soaking onions in vinegar helps to promote digestion. Acetic acid in white vinegar can stimulate the secretion of digestive juice. Onion has a pungent smell, which can also stimulate the secretion of stomach, intestine and digestive glands, promote digestion and enhance appetite.