Does drinking more water equal health? A new study gives us an answer

We are encouraged to drink a lot of water because it is ‘good for us.’ Now, a new study has tested that claim, examining evidence from previous studies to see if increasing your water intake actually provides health benefits.

Our body consists of about 60% water. This vital fluid contributes to many important functions, such as regulating body temperature, removing waste, acting as an absorbent for the brain and spinal cord, making saliva and lubricating the joints.

We are advised to drink a certain amount of water every day to prevent dehydration, which can prevent the body from performing these functions. But, more than that, what are the benefits that drinking water – specifically, drinking a lot – has for our health in general? In a new study led by the University of California San Francisco (UCSF), researchers looked for an answer to that question.

“For such a widely available and simple procedure, the evidence is not yet clear, and the benefits were not well established, so we wanted to take a closer look,” said Benjamin Breyer, MD, chairman of the Department of Urology at UCSF. senior academic writer.

Amounts vary depending on who you ask, but the US National Academy of Medicine recommends a daily fluid intake of 13 to 8 cups of water (3 L) for men ages 19 to to 30 and nine (2.1 L) for the same women. age. Note the use of the word liquid, which includes drinking water and other drinks.

The researchers systematically reviewed data from early clinical trials that looked at whether increased water intake (except for one study, where water intake was reduced) affected health. beauty and health related issues. The studies looked at different populations, and the most common side effects included weight loss, rapid blood sugar levels, headaches, urinary tract infections (UTIs), and kidney stones. Here’s what the researchers found.

In three studies, overweight and obese adults who drank 51 fl oz (1.5 L) of water per day before meals for a period of 12 weeks to 12 months had and significant weight loss compared to the control groups: 100%, 87 %, and 44% more weight compared to the control groups. In a fourth study with 38 participants, however, drinking 68 fl oz (2 L) of water per day was not associated with a change in body weight over a six-month period. This study was different from the other three because some of its participants were young.

In a study of 40 people with type 2 diabetes diagnosed recently (within the past five years), drinking 8.5 fl oz (250 ml) of water before breakfast, 17 fl oz (500 mL) before lunch, and 8.5 fl oz before dinner for 8 weeks. produced a significant difference in fasting blood glucose levels (-32.6 mg/dL) compared and the control group (5.3 mg/dL). Although that is a significant drop in fasting blood sugar, it is not clear from the study whether it was due to hemodilution; literally, watering the blood. Furthermore, because water is consumed before meals, the observed benefits may be due to reduced food intake or weight loss (which occurred in the treatment group).

On the other hand, another study of 60 participants found that drinking 18.6 fl oz (550 mL) of water within two hours of waking up and 18.6 fl oz before bed for 12 weeks actually increased levels fasting blood sugar of about 0.6 mg/dL. This study included adults who were not receiving medication and/or lifestyle for diabetes.

Two studies examining the effect of increasing water intake by 50.7 fl oz (1.5 L)/day for three months in patients with persistent headaches produced conflicting results. Another, which recruited 102 adults, found that the intervention was associated with an improvement in the participants’ Migraine Specific Quality of Life (MSQL) score by 4.5 points and reporting fewer days per at least moderate headache; however, the findings were not statistically significant. Furthermore, only 21% of the participants in the intervention group completed the experiment.

Another study used the same intervention in adults with migraine or tension headache, and the effect was not statistically significant on MSQL, medication use, number of episodes, mean headache , or head hours. However, the sample size for that study was less than 18 participants.

In a randomized trial, 140 premenopausal women with frequent UTIs who drank less than 50.7 fl oz (1.5 L) of fluid per day increased their fluid intake by 50.7 fl oz/day. Drinking more water each day was associated with a lower number of UTI episodes over a 12-month period, as well as less antibiotic treatment, and more time between episodes.

Another study investigated whether increased water intake changed the pathogenic bacteria found in the urinary tract. Fourteen dehydrated (drinking less than 50.7 fl oz/d) premenopausal women increased their daily water intake to 64 fl oz (1.9 L), but there was no difference in bacteria between those who drank a lot of water and those who did not: 7% versus 8%, respectively. However, another study took 24 adults with bladder problems, which causes sudden, uncontrollable urges to urinate, and tested the effect of increasing or decreasing intake. when liquid symptoms. A 25% reduction in fluid intake was associated with decreased frequency of urination, urinary urgency, and nocturia or frequent urination at night.

For a long time, those with kidney disease or prone to kidney disease have been encouraged to drink plenty of water to prevent or help pass it on. The researchers looked at two studies that examined the relationship between drinking a lot of water and the risk of kidney stones. One study of healthy adults aged 25 to 50 compared drinking 68 fl oz (2 L) of extra water per day to a control group and found that the risk of the formation of kidney stones decreased in the treatment group and increased in the control group.

Then there was a study of 221 patients who, after a first episode of kidney stones, were asked to increase their fluid intake until they excreted 68 fl oz (2 L)/day or not change their water intake. Over five years, the rate of recurrence of kidney stones was significantly lower – reduced by more than half – in the intervention group.

In summary, drinking more water was associated with statistically significant effects for weight loss and avoiding kidney stones. One other study showed that drinking plenty of water provided benefits related to the prevention of headaches, UTIs, and diabetes control but did not reach statistical significance.

The researchers say the low cost and very low potential for the water to cause adverse effects should encourage well-designed studies to test the health benefits suggested in the single studies they reviewed.

“The number of strong investigations became less, but in some areas, there was a significant statistical advantage,” said Breyer. “To our knowledge, this is the first study that examines the benefits of water use on clinical outcomes.

“We know that dehydration is dangerous, especially for someone with a history of kidney disease or a urinary tract infection. On the other hand, someone with frequent urination can sometimes Benefit from drinking less. There is no equivalent method of water consumption.

The study was published in a newspaper JAMA Network Open.

Source: UCSF