Urtica dioica traces of zeaxanthin or between 20 – 60 mg / kg of dry matter. Nettle contains ascorbic acid (vitamin C), riboflavin (vitamin B), pantothenic acid, vitamin K and tocopherols (vitamin E). The highest vitamin contents can be found in the leaves. In laying hens, nettle can be used as an egg yolk colorant instead of artificial pigments or other natural pigments (derived from marigold for yellow). Nettle has high carotenoid contents, especially lutein, β-carotene and zeaxanthin, of which lutein and zeaxanthin act as yellow pigments. Feeding as little as 6.25 g dry nettle per kg feed is as effective as
Vitamin C infection. The mega-dosing theory is to a large degree discredited. Modest benefits are demonstrated for the common cold. Benefits are not superior when supplement intakes of more than 1,000 mg/day are compared to intakes between 200 and 1,000 mg/day, and so not limited to the mega-dose range. The theory that large amounts of intravenous ascorbic acid can be used to treat late-stage cancer is - some forty years after Pauling's seminal paper - still considered unproven and still in need of high quality research. However, a lack of conclusive evidence has not stopped individual physicians from prescribing intravenous ascorbic acid