Drinking Plenty of Water Can Provide Number of Health Benefits, New Review Says

Drinking enough water can help with weight loss and prevent kidney stones, as well as migraines, urinary tract infections and low blood pressure, according to a new systematic review of 18 randomized clinical trials.

Water is a major constituent of the human body and is considered an essential nutrient that cannot be sufficiently produced by metabolism.

The National Academy of Medicine suggests a daily fluid intake of approximately 13 eight-ounce cups for men and 9 for women, respectively.

A common public health-related recommendation is to drink 8 cups of water per day, yet the supporting evidence is not clear.

Given the wide variability of body weight, activity level, and health status at the population level and the numerous mechanisms that regulate water balance, a single optimal amount of daily water consumption is a challenging concept.

Behavioral factors and hydration status have been widely studied in relation to health conditions owing to the known detrimental effects of dehydration.

University of California, San Francisco’s Professor Benjamin Breyer and his colleagues aimed is to summarize evidence from randomized clinical trials pertaining to the impact of increased daily water consumption on health-related outcomes.

“For such a ubiquitous and simple intervention, the evidence hasn’t been clear and the benefits were not well-established, so we wanted to take a closer look,” Professor Breyer said.

“The amount of rigorous research turned out to be limited, but in some specific areas, there was a statistically significant benefit.”

“To our knowledge, this is the first study assessing the benefits of water consumption on clinical outcomes broadly.”

The researchers found the most evidence in favor of drinking water to prevent kidney stones and to help people lose weight.

Drinking eight cups of water a day significantly decreased the likelihood of getting another kidney stone.

Several studies found that drinking about six cups of water a day helped adults lose weight.

But a study that included adolescents found that drinking a little more than eight cups of water a day had no effect.

Still, encouraging people to drink water before meals would be a simple and cheap intervention that could have huge benefits, given the increased prevalence of obesity.

Other studies indicated that water can help prevent migraines, control diabetes and low blood pressure, and prevent urinary tract infections.

Adults with recurrent headaches felt better after three months of drinking more water.

Drinking about four more cups of water a day helped diabetic patients whose blood glucose levels were elevated.

Drinking an additional six cups a day of water also helped women with recurrent urinary tract infections. It reduced the number of infections and increased the amount of time between them.

And drinking more water helped young adults with low blood pressure.

“We know that dehydration is detrimental, particularly in someone with a history of kidney stones or urinary infections,” Professor Breyer said.

“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 team’s paper was published in the journal JAMA Network Open.

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Nizar Hakam et al. 2024. Outcomes in Randomized Clinical Trials Testing Changes in Daily Water Intake: A Systematic Review. JAMA Netw Open 7 (11): e2447621; doi: 10.1001/jamanetworkopen.2024.47621