There are six nutrients – protein, carbohydrates, fat, vitamins, minerals, and water. There are myths and misconceptions about all of them, and water is no exception. Perhaps the most common fallacy about water is that we need to drink eight 8-ounce glasses of water a day to be healthy. According to the Berkeley Wellness Letter November 2011 and the British Medical Journal (BMJ), there is no evidence to support this claim. The eight-glass rule of thumb is widely promulgated by health experts as well as the bottled water industry, but where it began no one knows.
Now that you’ve swallowed that one, here are a few other beliefs about water that can be shed: Kidney function does not improve with drinking lots of water, nor does water help the kidneys eliminate toxins. Drinking the recommended amount of water does not improve overall health or your organs’ function, lower blood pressure, improve concentration or skin tone, or prevent headaches. It will not promote weight loss, but it might help with weight management if you replace caloric beverages with water.
Water is still good for you; it’s inexpensive and available, so don’t give it up. How much you need depends on many factors such as your overall health, level of exertion, the climate you live in, and your diet. Fruits and vegetables, stews and soups all provide water, as do other beverages such as coffee and tea. (No, the caffeine in them does not negate their hydrating effect.) The best guide for how much to drink for most people except the elderly is thirst. (Older folks don’t tolerate the heat as well and may not be able to rely on their sense of thirst.) If your urine is light, you’re drinking enough.