The hysteria that environmental groups, journalists, and a handful of scientists have stirred up over exposure to trace amounts of chemicals in consumer products has run counter to a fundamental principle in toxicology: it’s the size of the dose that makes something poisonous.
Unfortunately, a British woman has illustrated the principle with two chemicals we can’t do without, water and sodium. Tragically, Dawn Page, who is now 52, was persuaded by a nutritionist to go on a detox diet that required consuming an extra four pints of water per day and reducing her salt intake. Within days, she began vomiting. Her nutritionist advised her to increase her water intake to six pints and cut back further on salt. Before a week had passed, Page suffered a massive epileptic fit because too much water and too little sodium in her blood (hyponatremia) caused her brain to swell. She now has permanent brain damage.
It wouldn’t make sense to call water a toxin, but at high levels it is toxic. Conversely, just because something is toxic at high levels, doesn’t mean it isn’t as benign at much smaller levels.