I was looking for a discussion of vitamin metabolism under fasting conditions (which seems important in terms of one's health) - not a word, even though it seem

I was looking for a discussion of vitamin metabolism under fasting conditions (which seems important in terms of one's health) - not a word, even though it seems to be studied quite a bit - and the body appears to halt elimination of watrer-soluble vitamins under fasting conditions, so it's worth thinking about. Most people fast because they want to lose weight, I imagine. Here's a good discussion, including of uncertainties and unknowns: "The circulating metabolome of human starvation" (2018) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141167/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6141167/ > "Human starvation is marked by an early period of glycogenolysis and gluconeogenesis (3, 4). By 2–3 days into a fast, fatty acids released from lipid stores become the primary source of fuel; this critical transition to lipid metabolism allows for protein sparing during prolonged periods of starvation (3). What are the hormonal signals that mediate this transition from glucose to lipid metabolism?" I'd guess vitamin supplementation under fasting is a good idea if the goal is to get your body to start consuming its stores of lipid fats.