High blood pressure linked to zinc deficiency

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By
Tim Newman  
Fact
checked by Paula Field
A new study demonstrates a
link between zinc deficiency and high blood pressure. The findings could help
scientists design new ways of intervening in at-risk patient populations.
Woman
checking blood pressure
Hypertension is incredibly
common; understanding how it works is vital.
High blood pressure, or
hypertension, is a huge and growing health concern in the United States.
According to the American
Heart Association, hypertension affects more than 100 million people in the
U.S.
Over recent years, researchers
have noted a relationship between lower zinc levels and hypertension.
However, to date, scientists
have been unable to pinpoint zinc’s exact role in the development of
hypertension.
For instance, individuals with
certain conditions, such as type 2 diabetes and chronic kidney disease,
commonly have a zinc deficiency and high blood pressure. Scientists are still
unclear whether zinc levels are a cause or an effect of elevated blood
pressure.
Similarly, other studies have
shown that individuals with lower zinc levels are more likely to be
hypertensive.
As further evidence of zinc’s
involvement in hypertension, rats that are particularly sensitive to salt and
readily develop high blood pressure have lower levels of zinc in their blood.
Recently, a group of
researchers set out to investigate the links between zinc and blood pressure.
They wanted to dig a little deeper into the mechanisms of action. The team
published their findings in the American Journal of Physiology–Renal
Physiology.
Kidneys
and blood pressure
Sodium absorption plays a
vital role in moderating blood pressure. The sodium chloride cotransporter
(NCC) in the kidney is particularly important. It reabsorbs sodium from the
fluid that is destined to become urine and feeds it back into the body.
Generally, lower levels of
sodium in the urine correspond with increased blood pressure. In other words,
when the NCC is too active, it pumps more sodium back into the body, the urine
removes less, and blood pressure rises.
As the authors write,
“Renal modulation of urinary sodium excretion is the cornerstone of [blood
pressure] control.”
A number of proteins can
interact with the NCC to alter the amount of sodium that the body reabsorbs and
excretes.
Zinc acts as a cofactor, which
means that it influences the activity of a wide range of proteins, including
enzymes, transcription factors, and regulatory proteins.
Researchers think that zinc impacts
one of the proteins that moderates the NCC, although they have struggled to
find evidence for this.
Zinc
and hypertension
In this latest study, the
scientists ran a series of experiments to investigate the relationship between
zinc and hypertension, and observe the role of the NCC.
Firstly, they demonstrated
that mice that ate a diet with lower levels of zinc developed hypertension.
Then, they split these animals into two groups. They fed half of the animals on
a diet that contained adequate levels of zinc. As expected, their blood
pressure soon returned to normal.
The researchers gave the
remaining mice hydrochlorothiazide, a drug that inhibits the NCC. The blood
pressure of these animals also returned to normal. This is because the NCC
stopped pumping sodium back into the body, which allowed the urine to flush it
away.
In other experiments, the
researchers worked on animal tissue in the laboratory. They demonstrated that
the NCC is responsible for hypertension that is mediated by zinc deficiency.
They also showed that NCC
activity is altered by the presence of zinc — specifically, NCC activity
increases when zinc is at a lower level. The scientists believe that when zinc
is in short supply, the NCC is more stable and therefore able to function for
longer.
These results tie together
findings from earlier work and confirm the role of zinc in hypertension. The
authors write:
“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.”
SOURCE:
MEDICAL NEWS TODAY
Kayode Ojo
Kayode Emmanuel Ojo is the Co-Founder and Managing Director at SHEFFA Limited. He is presently studying Computer Science at the National Open University, Victoria Island, Lagos.