Experts recommend taking in a generous supply on the days leading up to an endurance race to avoid the dangerous effects of hyponatremia — low sodium levels in the blood, which can cause everything from nausea and muscle cramps to blackouts and coma. (One 1997 study estimated that 30 percent of Ironman Hawaii finishers were both dehydrated and hyponatremic.) The real thing is also better for you than salt tablets: It stimulates thirst, and it’s harder to overdo it. These hand-harvested Eden Foods sea salts from northern France are several cuts above the usual table-shaker variety in flavor, quality and nutritional value. They contain trace minerals that aren’t available in mined rock salt, they’re processed without chemicals, and the smooth taste and crunchy texture are just delightful. About $4 a jar at your natural grocery; you can also order online from www.edenfoods.com.