Recent press reports negating traditional suggestions of drinking at least eight glasses of water every day are under scrutiny from Seventh-day Adventist health officials. They say drinking more water can significantly decrease chances of heart attack and stroke.
The press reports said the origin of the eight-glasses-of-water-a-day recommendation is unknown and recommends drinking when thirst arises to keep adequately hydrated.
But this recommendation is doing the public “a big disservice,” says Dr. Jacqueline Chan, assistant research professor at Loma Linda University, and co-investigator of the Adventist Health Study.
“Thirst is not sufficient for you to get enough water,” she says.
In an article in the American Journal of Epidemiology, (January 11, 2002, Volume 155 No.9) Chan reported that people who drank more water had significantly fewer fatal heart attacks than those who drank less water. The results were dose related—the more water, the fewer fatal heart attacks.
Women and men who drank five or more glasses of water a day had about a 40 percent and 60 percent reduction of heart attacks respectively versus those who drank only one or two glasses of water per day.
Chan points out the recommended fluid intake referred to in recent press reports were partly deduced from experiments to determine the needs for fluid therapy patients.
“People may not feel thirsty; however, if you look, you find that a lot of them are under hydrated, especially in hot areas.”
Chan mentions a study once conducted in Israel where many people had maximally concentrated urine all the time—their kidneys couldn’t concentrate it any more. “They weren’t getting enough water,” she says. “[Researchers] found with education there were fewer kidney stones and less kidney disease.”
“More water is better,” says Dr. DeWitt Williams, health ministries director for the church in North America. “Thirst is a poor indicator of how much water you should drink.”
He says many people are in a building where the air is dry and need more water. Some people drink coffee and alcohol which dehydrates the body, which makes the body excrete water. “Combine that with salt and sugar, the average person doesn’t get enough to drink,” says Williams.
“As people get older their thirst mechanism deteriorates.”
He recommends two glasses of warm water each morning.
“Drinking water should become a planned habit, rather than a response to a feeling,” says Chan.
Both Chan and Williams point to research showing most heart attacks occur in the morning. The viscosity of the blood is thick after many hours of not drinking water because of sleeping.
Even juices raise blood sugar which, Williams says, many experts feel is why insulin levels go up and down. Drinks with caffeine irritate the kidneys and act as a diuretic—increasing urine output.
“Water is the only thing you can drink that has no calories,” says Williams. On average, Americans drink 500 cans of soda each year—about one and a half per day. “Soda is our favorite drink. Most of those drinks are loaded with sugars and calories.”
Sports drinks have sugar which gives energy but at the expense of hydration. “Only people who run marathons or do other extreme exercise over a prolonged period of time need to drink [sports drinks],” says Chan.
“This may be why two-thirds of Americans are overweight—they’re drinking too many calories,” says Williams.
But he doesn’t recommended drinking water while eating as it dilutes the salivary glands. “Digestion starts in the mouth,” he says. “Water is for between meals, not with meals.”
“[Water] requires no digestion. But wait a couple hours after a meal to begin drinking water and drink water up to 15 minutes before a meal,” says Williams.