Staying hydrated may slow the aging process. NIH researchers followed 11,255 adults for 30 years and found that compared to those who didn’t drink enough fluids, those who stayed well-hydrated:
• aged more slowly,
• lived longer, and
• were far less likely to develop chronic diseases such as those of the heart, lungs and kidneys (EbioMedicine, January 02, 2023). These findings were first presented August 27, 2021, at the European Society of Cardiology Congress.
How Not Drinking Enough Fluids May Shorten Your Life
Studies in mice found that lifelong water restriction increased the blood sodium levels by five millimoles per liter and shortened their life spans by six months, which equals about 15 years in humans (JCI Insight, Sept 5, 2019;4(17):PMC6777918). Not drinking enough fluids can raise your blood levels of sodium salt that raises blood pressure to increase risk for arterial damage.
Blood levels of sodium can be used as an indicator of levels of hydration or dehydration. All of the people in the NIH study had “normal American blood levels of sodium” from 135 to 146 millimoles per liter. So the researchers looked at those on the high end of “normal” (above 143) and found that they had a 20 percent increased risk of premature death than people with sodium levels below 144. Those with sodium levels of 145-146 were 50 percent more likely to show signs of physical aging. Those who had blood sodium levels between 142 to 143 were also at increased risk for high blood pressure, high cholesterol, high blood sugar, heart failure, stroke, chronic lung disease, diabetes and dementia.
Precaution on These Findings
This study does not prove that drinking more water prevents chronic disease. It is more likely that the people with high normal blood levels of sodium have much higher sodium levels when they are stressed, such as during exercise or exposure to hot weather, and therefore are being damaged by normal body stresses that would not have damaged them otherwise. Severe dehydration can also cause kidney damage.
How Much Water Should You Drink?
The CDC says that the average U.S. adult drinks more than five cups of fluid a day. No solid research supports the often-recommended “drink eight glasses of water a day.” The National Academies of Medicine recommend six to nine cups of fluid per day for women and eight to 12 for men, but this also is not supported by good research because fluid requirements vary tremendously depending on the person and the conditions. You get 27-36 percent of your intake of fluids from the food that you eat, and low fluid drinkers do not compensate by eating more water-rich foods (Nutrients, Oct 14, 2016 Oct;8(10):630). I believe that you should drink when you are thirsty and have at least a glass of fluid with each meal, and then probably some more several times during the day. If you have any health problems, you should check with your doctor for recommended fluid intake.
Problems From a High-Salt Diet?
A high-salt diet increases risk for high blood pressure, heart attacks, strokes and premature death (Kidney Int Suppl, Dec 2013;3(4):312-315). High blood pressure affects 108 million adults, increasing risk for heart attacks, the leading cause of death in the United States. Low-salt, plant-based diets dramatically lower both high blood pressure and markers of heart muscle damage in just four weeks (J Am Coll Cardiol, Jun 2021;77(21):2625-2634). In one study, salt restriction lowered systolic blood pressure by less than 5 mm Hg and diastolic blood pressure by only 2.5 mm Hg (JAMA Intern Med, 2014;174(4):516-524). However, the subjects in that study were already on a high-plant diet which, by itself, can lower high blood pressure because plants contain potassium and a high-potassium diet can counter some of the harmful effects of taking in too much salt (JAMA Pediatr, June 2015;169(6):560-568). You should be on a high plant, low-processed food diet that restricts meat. A review of 85 studies, following participants for up to three years, found that low-salt diets were associated with significantly lowered blood pressure (Circulation, Feb 15, 2021).
My Recommendations
Chronic dehydration can damage your cells and appears to increase risk for premature aging. Dehydration and the typical high-salt North American diet increase blood pressure risk to increase risk for heart attacks, strokes, kidney and other organ damage and premature death. I recommend that you:
• Drink a glass of water with every meal, and more fluids throughout the day or whenever you are thirsty.
• Eat lots of vegetables. They contain potassium which will counter the effects of taking in too much salt.
• Restrict processed foods that often contain added salt; check the labels.
The healthful low salt, high-potassium diet I recommend includes (per day):
• Up to 8 servings (1/2 cup cooked or equivlent) of whole grains
• At least 5 vegetables
• At least 5 fruits
• Up to 3 servings of plain yogurt or cheese (optional)
• 2 servings of seafood per week (I recommend that you avoid meat from mammals)
• Beans or legumes (no limit)
• A few handfuls of unsalted nuts or snack seeds
• A few tablespoons of olive oil (optional)
Many cases of high blood pressure can be controlled with a high-plant, low-salt diet and other lifestyle changes that include:
• trying to exercise every day
• maintaining a healthful weight
• avoiding alcohol
• avoiding smoking and second hand smoke
• keeping blood levels of hydroxy vitamin D above 30 ng/mL
