They contain many vitamins and minerals, but also a concentrated portion of so-called "secondary plant substances". For a long time these were rather unknown, but nowadays science has discovered as many as 100,000 different substances. Behind complicated-sounding chemical names such as flavonoids, carotenoids or glucosinolates, there are broadly effective, above all colouring and flavouring substances. Many of them support the immune system in its task to defend the body against viruses and bacteria, especially through their antioxidant effect. Flavonoids in citrus fruits are also increasingly becoming the focus of scientific attention!
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