We all know that staying hydrated is good for human health – but a new study goes into more specific detail about all the various benefits that come along with drinking plenty of water, and you might not be aware of just how many there are.
Researchers from the University of California, San Francisco (UCSF) reviewed 18 previous studies, with a median average of 48 participants. The majority showed advantages in drinking lots of water.
Until now, research into high levels of water consumption – more than eight glasses a day, for example – hasn't come to any firm conclusions on the health benefits, with results varying due to factors like sex, age, and environment. What this review shows is that there's more to drinking lots of water than simply feeling refreshed.
"The amount of rigorous research turned out to be limited, but in some specific areas, there was a statistically significant benefit," says urologist Benjamin Breyer, from UCSF.
"To our knowledge, this is the first study assessing the benefits of water consumption on clinical outcomes broadly."
It's important to note that the benefits of drinking a lot of water weren't always clear in the studies the researchers analyzed here – in fact, only 10 out of the 18 previous pieces of research showed definite, measurable positives.
The most significant benefits associated with drinking more water were reducing the risk of kidney stones and assisting in weight loss. Individual studies also showed more water was linked to preventing migraines and urinary tract infections, and controlling diabetes and low blood pressure.
None of the studies reviewed were rigorous enough in their methods to prove causal relationships, but they do give us an indication of the varied areas of health where drinking more water can be good for you.
The science is more definitive when it comes to what happens to our bodies when we don't get enough water: dehydration has been linked to shorter lifespans and an increased risk of numerous chronic illnesses. We use water to keep ourselves cool and eliminate waste, and that loss needs to be continually topped up.
According to the World Health Organization, around 3.2 liters per day of water are recommended for men (roughly 14 cups), and 2.7 liters per day for women (11 cups) – if you live in a temperate climate. That will vary depending on your own body and environment, however.
As always, it's best to consult your doctor or other trustworthy sources of health information about whether or not changes in food and drink intake might be good for you in particular. As a previous study put it, listening to your body is a good idea too.
"We know that dehydration is detrimental, particularly in someone with a history of kidney stones or urinary infections," says Breyer.
"On the other hand, someone who suffers from frequent urination at times may benefit from drinking less. There isn't a one size fits all approach for water consumption."
The research has been published in JAMA Network Open.
