Lower-than-normal levels of zinc in the body may contribute to high blood pressure by altering the way the kidneys handle sodium, a study warned Thursday. Zinc deficiency is common in people with chronic illnesses such as type 2 diabetes and chronic kidney disease, according to the study published in the American Journal of Physiology - Renal Physiology.
The way kidneys either excrete sodium into the urine or reabsorb it into the body -- specifically through a pathway called the sodium chloride cotransporter (NCC) -- also plays a role in blood pressure control.
Less sodium in the urine typically corresponds with higher blood pressure, said researchers. Recent studies have suggested that zinc may help regulate proteins that in turn regulate the NCC, but a direct link between zinc-deficiency-induced hypertension has not been examined.
Researchers compared male mice with zinc deficiency to healthy controls with normal zinc levels. The zinc-deficient mice developed high blood pressure and a corresponding decrease in urinary sodium excretion.
The control group did not experience the same changes. A small group of the zinc-deficient mice were fed a zinc-rich diet partway through the study. Once the animals' zinc reached adequate levels, blood pressure began to drop and urinary sodium levels increased.
"These significant findings demonstrate that enhanced renal (sodium) reabsorption plays a critical role in zinc-deficiency-induced hypertension," the researchers said.
"Understanding the specific mechanisms by which zinc deficiency contributes to blood pressure dysregulation may have an important effect on the treatment of hypertension in chronic disease settings," they added.