One health myth that will never die is that you should drink eight glasses of water every day.
It’s simply not true. There is no scientific basis for it.
Despite this, every summer we are bombarded with news broadcasts warning that dehydration is both harmful and common.
These reports instill panic in the public that otherwise healthy people and children are dehydrated, and that dehydration has reached epidemic proportions.
Let’s take a closer look at these assertions.
The first misconception was that people should consume at least eight 8-ounce glasses of water every day. This paper received more media attention than almost any other study I’ve ever conducted.
It didn’t make any difference. When we produced a book on medical misconceptions two years later, I assumed it would encourage people to cease worrying about the necessity for eight glasses of water every day. I was mistaken once more.
Many people believe that a 1945 Food and Nutrition Board guideline that people need roughly 2.5 liters of water per day is the root of this fallacy. They, on the other hand, were unconcerned with the phrase that followed closely afterward. “The majority of this quantity is contained in prepared foods,” it said.
Fruits and vegetables contain water. It can be found in juice, beer, and even tea and coffee. Before somebody writes to tell me that coffee dehydrates you, I’d want to point out that this is also untrue.
Although I promote water as the greatest beverage to drink, it isn’t the only way to stay hydrated. You don’t have to drink all of the water you need to stay hydrated. You also don’t have to be concerned about never becoming thirsty. The human body is well built to alert you to the need to drink before you become dehydrated.
Contrary to popular belief, there is no scientific evidence that drinking more water provides any health benefits for otherwise healthy people. For example, there is no proof that drinking more water keeps skin moisturized and makes it seem healthier or wrinkle-free, according to studies. Although some retrospective cohort studies have revealed that more water is linked to better outcomes, these studies are plagued by the standard epidemiologic issues, such as the inability to prove causation. Furthermore, they set the threshold for “high” water consumption at significantly less than eight glasses.
When healthy persons increase their fluid consumption, prospective studies show no improvement in renal function or all-cause mortality. With the exception of specific circumstances, such as avoiding the recurrence of certain types of kidney stones, randomized controlled trials have failed to reveal benefits. Dehydration is a critical problem that occurs when your body loses a substantial amount of water due to illness, intense exertion or sweating, or an inability to drink. Clinical dehydration, on the other hand, is virtually always accompanied by symptoms.
A large number of advertisers and news sources are attempting to persuade you differently. Every year, it appears that the number of people who carry water about with them grows. The sale of bottled water continues to rise.
A recent study published in the American Journal of Public Health sparked a wave of headlines this summer. Researchers examined 4,134 children aged 6 to 19 years old using data from the National Health and Nutrition Examination Survey from 2009 to 2012. Their mean urine osmolality, which is a measure of urine concentration, was measured. The urine is more concentrated the higher the value.
Moreover half of the youngsters had a urine osmolality of 800 mOsm/kg or greater, according to the researchers. They also discovered that kids who drank eight ounces or more of water per day had an 8 mOsm lower urine osmolality than kids who didn’t.
So, if “dehydration” is defined as a urine osmolality of 800 mOsm/kg or greater, the outcomes of this study are extremely alarming. That is exactly what this article did. The issue is that the majority of clinicians do not.
There is no official suggestion for how much water people should drink on a daily basis. That quantity certainly varies depending on what people consume, where they live, their size, and what they do. But, given that Americans live longer than ever before and have perhaps greater access to beverages than at practically any other point in history, it’s just not true that we’re all dehydrated.