Hydration linked to lower risk of disease, study finds

Editor’s note: Sign up for CNN’s Eat Better: Mediterranean Style. Our eight-part guide shows you a delicious, expert-backed nutritional lifestyle that will boost your health for life.

CNN
—

You may know that adequate hydration is important for everyday bodily functions such as as regulating temperature and maintaining skin health.

But drinking enough water is also associated with a significantly lower risk of developing chronic diseases, a lower risk of early death, or a lower risk of being biologically older than your chronological age, according to the National Institutes of Health. study published on Monday in the journal eBioMedicine.

“The results suggest that adequate hydration may slow aging and prolong disease-free life,” said study author Natalia Dmitrieva, a researcher in the Laboratory of Cardiovascular Regenerative Medicine of the National Heart, Lung, and Blood Institute, a division of the NIH, in news release.

Learning which preventive measures can slow the aging process is “a grand challenge in preventive medicine,” the authors said in the study. That’s because an epidemic of “chronic age-related diseases” is emerging as the world’s population ages rapidly. And extending a healthy lifespan can help improve quality of life and reduce health care costs more than just treating disease.

The authors thought that optimal hydration could slow down the aging process, based on previous similar research in mice. In those studies, lifelong water restriction increased the mice’s serum sodium by 5 millimoles per liter and shortened their lifespan by six months, the equivalent of about 15 years of human life, according to the new study. Serum sodium can be measured in the blood and increases when we drink less fluid.

Using health data collected over 30 years from 11,255 black and white adults from the Atherosclerosis Risk in Communities, or ARIC, study, the research team found adults with serum sodium levels at the higher end of the normal range — 135 to 146 milliequivalents per liter (mEq/L) — had worse health outcomes than those at the lower end of the range. Data collection began in 1987 when participants were in their 40s or 50s, and the average age of participants at the final assessment during the study period was 76 years.

Adults with levels above 142 mEq/L were 10% to 15% more likely to be biologically older than their chronological age compared to participants in the 137 to 142 mEq/L range. Participants with higher the risk of aging faster also had a 64% greater risk of developing chronic diseases such as heart failure, stroke, atrial fibrillation, peripheral artery disease, chronic lung disease, diabetes and dementia.

And people with levels above 144 mEq/L had a 50% greater risk of being biologically older and a 21% greater risk of early death. Adults with serum sodium levels between 138 and 140 mEq/L, on the other hand, had the lowest risk of developing chronic disease. The study did not have data on how much water the participants drank.

“This study adds to the observational evidence that reinforces the potential long-term benefits of improved hydration on reducing long-term health outcomes, including mortality,” said Dr. Howard Sesso, associate professor of medicine at Harvard Medical School and associate epidemiologist at the Brigham. and Boston Women’s Hospital, via email. Sesso was not involved in the study.

However, “it would be nice to combine their definition of hydration, based only on serum sodium levels, with actual fluid intake data from the ARIC cohort,” Sesso added.

Biological age is determined by biomarkers that measure the performance of various organ systems and processes, including cardiovascular, renal (kidney-related), respiratory, metabolic, immune, and inflammatory biomarkers.

High serum sodium levels weren’t the only factor associated with disease, early death, and faster aging risk—the risk was also higher among people with low serum sodium levels.

This finding is consistent with previous reports of increased mortality and cardiovascular disease in people with low regular sodium levels, attributed to diseases that cause electrolyte problems, the authors said.

The study analyzed participants over a long period of time, but the findings did not prove a causal relationship between serum sodium levels and these health outcomes, the authors said. Further studies are needed, they added, but the results may help doctors identify and target at-risk patients.

“People whose serum sodium is 142 mEq/L or higher would benefit from an assessment of their fluid intake,” Dmitrieva said.

Sesso noted that the study did not strongly address accelerated aging, “which is a complicated concept that we are just beginning to understand.”

“There are two key reasons behind this,” Sesso said. The authors of the study “relied on a combination of 15 measures for accelerated aging, but this is one of many definitions for which there is no consensus. Second, their data on hydration and accelerated aging were a ‘snapshot’ of time, so we cannot understand cause and effect.”

About half of the world’s people do not meet the recommended total daily water intake, according to some studies the authors of the new study stated.

“Globally, it can have a big impact,” Dmitrieva said in a press release. “Decreased water content in the body is the most common factor that increases serum sodium, which is why the results suggest that maintaining good hydration can slow the aging process and prevent or delay chronic diseases.”

Our serum sodium levels are affected by fluid intake from water, other fluids, and fruits and vegetables with high water content.

“The most impressive finding is that this risk (for chronic disease and aging) is evident even in individuals who have serum sodium levels that are at the upper end of the ‘normal range,'” said Dr. Richard Johnson, a professor at the University. Colorado School of Medicine, via email. He was not involved in the study.

“This raises the question of what is really normal and supports the concept that as a population we are probably not drinking enough water.”

More than 50% your body is made up of water, which is also needed for multiple functions, including digesting food, creating hormones and neurotransmitters, and delivering oxygen throughout your body, according to Cleveland Clinic.

The National Academy of Medicine (formerly known as the Institute of Medicine) recommends women consume 2.7 liters (91 ounces) of fluid per day, while men have 3.7 liters (125 ounces) per day. This recommendation includes all liquids and foods rich in water such as fruits, vegetables and soups. Since the average ratio of liquid to food in water intake is about 80:20, this amounts to a daily amount of 9 cups for women and 12 ½ cups for men.

People with health problems should talk to their doctor about how much fluid intake is right for them.

“The goal is to make sure patients are getting enough fluid, while assessing factors, such as medications, that can lead to fluid loss,” study co-author Dr. Manfred Boehm, director of the Laboratory for Cardiovascular Regenerative Medicine, said in a press release. “Doctors may also need to delay the patient’s current treatment plan, such as limiting fluid intake for heart failure.”

If you have trouble staying hydrated, you may need it help in acquiring a habit into your usual routine. Try leaving a glass of water by your bed to drink when you wake up, or drink water while your morning coffee is brewing. Anchor your hydration habit to where you are several times a day, behavioral scientist BJ Fogg, Ph.D., founder and director of Stanford University’s Behavioral Design Lab, he previously told CNN.