Basically, many people run the risk of drinking too little rather than too much. But some people drink more than three liters a day, which can be a harmless habit or the result of a rare hormonal disorder. A reliable diagnosis is required here in order to avoid dangerous mix-ups.
In rare cases, the extremely high daily fluid intake can be due to a deficiency in the hormone vasopressin, although it is important to differentiate this from the “harmless” causes of drinking liters, reports the University of Basel.
How much do we have to drink?
The body should be supplied with around 2.5 liters of water every day, although a certain proportion is already contained in solid food, so that, according to the German Nutrition Society (DGE), only around 1.5 liters need to be consumed through drinks.
However, over time, some people become accustomed to consuming more than three liters of fluid per day, explain the experts at the University of Basel. Drinking such a high amount could also be a side effect of a mental illness.
Hormone deficiency as a trigger?
Last but not least, in rare cases a deficiency in vasopressin can trigger excessive fluid intake. The pituitary gland hormone controls the water and salt content in the body via vasopressin and people with vasopressin deficiency are unable to concentrate their urine.
Vasopressin causes the kidneys to recapture more water from the urine, which is why it is also called an antidiuretic hormone. When there is a vasopressin deficiency, those affected lose large amounts of fluid and feel extremely thirsty.
In order to take appropriate countermeasures and not endanger the health of those affected, a clear distinction between “harmless” causes of high fluid intake and a vasopressin deficit is extremely important, emphasize the experts at the University of Basel.
The two research group leaders Prof. Dr. Mirjam Christ-Crain and Dr. In recent years, Julie Refardt from the University of Basel has worked intensively on test methods for diagnosing vasopressin deficiency, with one test, for example, stimulating vasopressin release using a salt infusion.
The test is considered very reliable, but due to the sharp increase in salt, it requires constant monitoring and half-hourly salt measurements in the patients’ blood are necessary, explains Prof. Christ-Crain.
In addition, a greatly simplified and more tolerable test using arginine infusion could also be used to make the diagnosis, since arginine also stimulates the release of vasopressin.
Comparison of diagnostic tests
In a current study with 158 participants, the researchers, in collaboration with an international team, directly compared the two tests and published the results in the “New England Journal of Medicine”.
The study shows that over 95 percent of patients were correctly diagnosed using salt infusion, whereas the test using arginine infusion only led to the correct diagnosis in almost 75 percent of cases, the researchers report.
In view of these results, the saline infusion test is recommended as the gold standard for a reliable distinction between polydipsia and vasopressin deficiency, concludes Dr. Refardt.
If the test does not reveal a vasopressin deficit, behavioral therapy can be carried out with the aim of slowly reducing the amount of water consumed. In the case of a vasopressin deficiency, however, the hormone vasopressin is administered, which, if incorrectly diagnosed, can lead to life-threatening water intoxication. (fp)