Increased water intake suppresses key hormone to reduce obesity in mice

It is known that drinking water and staying hydrated is an important part of staying healthy, but not so well known are the intricate mechanisms by which a little H20 improves our physiological state. A new study has examined the role increased water intake can play in obesity, and found that it can work to reduce the condition in mice by suppressing a key hormone called vasopressin.

Water makes up around 60 percent of the adult human body, so it follows that we are hugely dependent on it to keep things running smoothly. Studies have shown how it may stimulate our metabolism, promote weight loss, reduce stress levels and improve cognitive performance. But in this new research, scientists from the University of Colorado investigated how its influence on vasopressin might contribute to weight-loss.

Vasopressin is a hormone that plays a number of roles in the human body, including helping regulate blood pressure and body temperature, while studies have found that it could also serve as a biomarker for autism in babies. Vasopressin is also one of the fundamental hormones that regulates hydration levels, and is elevated in people suffering from obesity and diabetes.

This last point is what inspired the new research from the University of Colorado team, which conducted experiments on mice to find out why vasopressin levels are heightened in those with diabetes and obesity. This involved feeding the rodents sugar water, which the researchers found stimulated the brain to produce more vasopressin. The vasopressin then stored that water as fat, which drove dehydration and, in turn, triggered obesity.

Lanaspa says this is the first time a study has demonstrated how vasopressin influences dietary sugar and causes obesity. In follow-up experiments, the team knocked out a vasopressin receptor called V1b in the mice, which then did not exhibit the same responses to the sugary water. Additionally, giving mice non-sugary water served to reduce their obesity.

"We found that [vasopressin influences obesity and diabetes] by working through a particular vasopressin receptor known as V1b," says lead author Miguel A. Lanaspa. "This receptor has been known for a while but no one has really understood its function. We found that mice lacking V1b were completely protected from the effects of sugar. We also show that the administration of water can suppress vasopressin and both prevent and treat obesity."

Through their experiments, the researchers were also able to show how water therapy could protect against a range of metabolic conditions, such as high blood pressure, high blood sugar and high triglyceride levels, which are linked to outcomes such as heart disease, stroke and type 2 diabetes.

A wide range of factors play into the onset of these conditions, however, so preventing them isn't as simple as drinking an extra glass of water before bedtime. But the researchers hope these findings can act as a springboard for further investigations into the relationship between vasopressin, water and a healthy metabolism.

"The clinical significance of this work is that it may encourage studies to evaluate whether simple increases in water intake may effectively mitigate obesity and metabolic syndrome," says Lanaspa.

The research was published in the journal JCI Insight.

Source: University of Colorado