It's been described as the mineral of the moment. Millions of us are taking magnesium for a whole range of reasons. Can it help us sleep better? Sort our digestion problems? Give our busy brains a moment of peace? In the fast-moving world of supplements, it's magnesium's time to shine. And the industry is booming. The global magnesium market is worth nearly £3bn and that's set to nearly double over the next decade. In a small factory, nestled in the Yorkshire Dales, huge plastic barrels of