Magnesium: sleep and muscle cramps

Magnesium is needed for muscle contraction, nerves, sleep and hundreds of enzymes. Athletes lose a lot in sweat.

• 200–350 mg a day as a supplement, in the evening with food.
• Form matters: glycinate (sleep, gentle on the stomach) and citrate absorb well; oxide is cheap but can loosen the stool.
• For cramps, water and electrolytes matter too.

With kidney disease, only with a doctor's approval. Food sources: nuts, seeds, legumes, greens, dark chocolate.