Bok choy of the Daily Value, DV) of vitamin A (30% DV), vitamin C (54% DV) and vitamin K (44% DV), while providing folate, vitamin B6 and calcium in moderate amounts (10–17% DV) (table). Chinese cabbage was ranked #2 for nutrient density out of 41 nutrient-rich plant foods. Bok choy contains glucosinolates. These compounds have been reported to prevent cancer in small doses, but, like many substances, can be toxic to humans in large doses, particularly to people who are already seriously ill. In 2009, an elderly diabetic woman who had been consuming 1 to 1.5 kg of raw bok choy per
Fat choy This may be one reason why some commercially available fat choy has been found to be adulterated with strands of a non-cellular starchy material, with other additives and dyes. Real fat choy is dark green in color, while the counterfeit fat choy appears black. The last two syllables of this name in Cantonese sound the same as another Cantonese saying meaning "struck it rich" (though the second syllable, "coi", has a different tone) -- this is found, for example, in the Cantonese saying, ""Gung1 hei2 faat3 coi4"" (恭喜發財, meaning "wishing you prosperity"), which is often proclaimed during Chinese New Year.