Onion contains phytoncide, which has strong bactericidal ability, can resist influenza virus and prevent colds. When phytoncide is excreted through respiratory tract, urinary tract and sweat gland, it can stimulate the secretion of cell pipeline wall, so it has expectorant, diuretic, sweating, bacteriostatic and antiseptic effects.
Moreover, onions contain allicin, which has a strong aroma, so when we cut onions, our eyes will cry because of its pungent smell. This special smell can stimulate gastric acid secretion to increase our appetite, and also promote our gastrointestinal peristalsis, thus playing an appetizing role.
Moreover, onion can also prevent cancer, and its efficacy comes from its rich selenium, which is an antioxidant that can stimulate our immune response, thus inhibiting the division and growth of cancer cells and reducing the toxicity of carcinogens.
Onion is the only plant rich in prostaglandin. It is a natural blood thinner, which can dilate blood vessels and reduce blood viscosity, thus lowering blood pressure, reducing peripheral blood vessels, increasing coronary blood flow and preventing thrombosis.
Of course onions are so good, but some people are not allowed to eat onions. First of all, their eyes are not good, because cutting onions will release a lot of irritating liquid, so splashing into their eyes will cause harm. Patients with kidney problems are also not allowed to eat, because onions have high phosphorus content, which will increase the burden on the kidneys.