The main onion season in Japan is from April to June. But in recent years, it has been grown all over the country and is available all year round as there are many local varieties. In particular, it is the harvest of young onions, which are distinguished by their thin skin and special sweetness, that is harvested in the spring from April to May.
Recent studies by Japanese scientists show that the beneficial properties of onions are much greater than previously thought.
Onions contain a blood-thinning component - allyl sulfide (allicin). It is because of him that it burns the eyes when chopping onions and is bitter in the mouth when consumed. Allyl sulfide prevents blood clotting by thinning it. It is effective against high blood pressure, atherosclerosis, cerebral infarction and myocardial infarction.
Also, onions prevent an increase in blood glucose levels, so it is recommended for people with high levels of neutral fat and cholesterol.
Onions contain quercetin, a type of polyphenol that is the pigment and astringent component of onions. It has antioxidant properties - removes active oxygen. Thanks to the antioxidant effect, aging of the body is prevented. It also contributes to the prevention of colds and oncological diseases resulting from a decrease in immunity.
In particular, purple onion red pigment contains anthocyanins, a type of polyphenol that has antioxidant properties, strengthens blood vessels, prevents eye fatigue and aging, reduces blood pressure and metabolic syndrome, and improves liver function. The same pigments are found in large quantities in potato varieties with purple flesh.
In addition, glutathione, which is part of the onion, is found in abundance in the human liver and eyes, so eating onions improves liver function and prevents cataracts.
Allyl sulfide has strong bactericidal properties, therefore it kills pathogenic bacteria. It helps to cope with asthma, colds, flu and food poisoning. It also strengthens the immune system, so onions should be actively consumed when the body is weakened.
Onions contain two types of dietary fiber - insoluble and soluble fiber. It also contains oligosaccharides that improve the intestinal environment. Quercetin helps reduce fat absorption, making onion an ideal weight loss food.
Potassium contained in onions helps to remove excess water and salt from the body and reduce swelling. It is also effective in relieving fatigue when taken with vitamin B1, found in pork, for example.