evidence: Both of my children were born with a faint blue vein on the bridge of their noses, and like any sufficiently paranoid mother, I would squint and study it trying to figure out what it could possibly be… a bruise, a birth mark, something else? For years in the Chinese medicine community I heard whisperings of this blue vein being a reliable diagnostic tool for predicting a sensitivity to sugar. I took note, and have used this as a good excuse to limit sweets in my children's diets. [...] If you see a blue vein, don't panic! [...] Let me know in the comments below!