The Beverage Guidance Panel, which included such heavyweights as Dr. Walter Willett, nutrition department chair at Harvard University School of Public Health, ranked beverage categories from best to worst. Soda ranked last, and whole milk was grouped with beer, with a recommendation for zero ounces a day. Tea and coffee—preferably without creamer or sweetener—tied as the number-two healthiest beverages, second only to water, the top-ranked drink.
Not drinking enough water appears to be associated with such problems as falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancers, urinary tract infections, cavities, decreased immune function, and cataract formation.
A Harvard University study of nearly 48,000 men found that bladder cancer risk decreased by 7 percent for every extra daily cup of fluid consumed, and a high intake of water—say, eight cups daily—may reduce risk by about 50 percent, potentially saving thousands of lives.
The original Adventist Health Study, involving 20,000 men and women, found that those who drank five or more glasses of water daily had about half the risk of dying from heart disease compared to those who drank two glasses or less. About half the cohort consisted of vegetarians, so they were getting extra water by eating more fruits and vegetables. As in the Harvard study, this protection appeared to remain even after controlling for factors such as diet and exercise, suggesting that water may play a causal role, perhaps by improving blood flow.
Authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend about 8 to 11 cups of water a day for women and 10 to 15 cups for men. This includes water from all sources, not solely beverages. We get about 4 cups from the food we eat and the water our body produces on its own, so the guidelines roughly translate into a daily recommendation of drinking 4 to 7 cups of water for women and 6 to 11 cups for men (assuming only moderate physical activity at moderate ambient temperatures).
Unless you have a condition like heart or kidney failure or your physician advises fluid intake restriction, I recommend drinking five glasses of tap water daily. I prefer tap not only because it’s less economically and environmentally costly but because it may have less chemical and microbial contamination than bottled water.
Image Credit: Ethan Sykes / Unsplash. This image has been modified.
Popular Videos for Water
All Videos for Water
Trailer for How Not to Diet: Dr. Greger’s Guide to Weight Loss
17 ingredients to an ideal weight-loss diet and the 21 tweaks to accelerate the further loss of excess body fat.
Evidence-Based Weight Loss – Live Presentation
In his newest live presentation, Dr. Greger offers a sneak peek into his new book How Not to Diet.
Is It Best to Drink Tap, Filtered, or Bottled Water?
Given the disinfection byproducts in tap water, Brita, PUR, ZeroWater, and refrigerator water filters are put to the test.
Which Is a Better Breakfast: Cereal or Oatmeal?
The remarkable impact of the structure of food beyond nutritional content or composition.
Is Ginger Beneficial in a Diabetic Diet?
Ground ginger and ginger tea are put to the test for blood sugar control.
Which Coffee Is Healthier: Light vs. Dark Roast?
Dark roast coffee is more effective than light roast coffee in reducing body weight.
Are There Benefits of Energy Drinks?
The effects of Red Bull and Monster brand energy drinks on artery function and athletic performance.
Are There Risks to Energy Drinks?
Red Bull and Rockstar brand energy drinks are put to the test.
Pros & Cons of a Macrobiotic Diet
What happens when you put diabetics on a diet composed of largely whole grains, vegetables, and beans?
Coconut Water and Depression
The science behind the marketing of foods for antidepressant effects.
Are Sports Drinks Safe & Effective?
Commercial influences may have corrupted American College of Sports Medicine hydration guidelines.
Coconut Water for Athletic Performance vs. Sports Drinks
Coconut water is tested head-to-head against plain water and sports drinks in athletes.