low-salt diet

A study published in Hypertension investigated whether women or men benefit more from a low-salt diet to lower blood pressure.

 

Previous studies suggest women suffer from salt-sensitive high blood pressure more than men. Salt intake can raise blood pressure and can be dangerous for the heart, resulting in heart disease. Therefore, people who suffer from salt-sensitive high blood pressure are typically advised to have a low-salt diet.

Aldosterone regulates salt, affects blood pressure, and is higher in females

Aldosterone levels, a hormone in the body that regulates salt and water, also has an effect on blood pressure and it is naturally higher in females compared to males. A high-salt diet can also cause aldosterone levels to increase. Therefore, it was hypothesized that if females have higher levels of aldosterone than males, they should be more salt-sensitive.

It is quite common for many people to consume a high amount of salt on a daily basis. Typically, our body tries to balance this intake of salt by reducing aldosterone levels to ensure we do not retain too much salt. However, this causes an increase in fluid retention and blood pressure.

A study conducted by researchers in the United States has looked at the effects of a high-salt diet on female mice compared to male mice. The mice were given a high-salt diet for one week. Their blood pressures were similar at the start of the study and the results were recently published in Hypertension.

A high-salt diet resulted in higher blood pressure in females

After seven days, the blood pressure of the female mice increased by a clinically significant amount compared to the male mice. However, when the female mice were given a high blood pressure medication (eplerenone) that blocks aldosterone, healthier blood pressure was achieved. The medication did not have any effect on the blood pressure in males or alter the function of blood vessels contraction and relaxation.

Hence, the study also showed that the interaction between salt and aldosterone works in male mice. An increase in salt intake suppressed the level of aldosterone and helps reduce the risk of high blood pressure. However, the results suggested that females with a high-salt diet were not suppressing aldosterone levels and therefore, both aldosterone levels and blood pressure were higher in females.

Salt retention may not be the cause of higher blood pressure in women with a high-salt diet

The scientists found that the cause of the problem was aldosterone impairing the blood vessels’ ability to relax and not with the kidneys, as the kidneys are responsible for removing sodium and excess fluid from the body. The study provides evidence that aldosterone causes higher blood pressure in women with a high-salt diet and salt retention may not actually be the cause. This makes aldosterone a good target for treatments for females suffering from conditions such as obesity and high blood pressure. However, a low-salt diet would also be much more beneficial in lowering blood pressure in women than men.

Written by Lacey Hizartzidis, PhD

References:

  1. Faulkner JL, Harwood D, Bender L, Shrestha L, Brands MW, Morwitzer MJ, KennardS, Antonova G, Belin de Chantemèle EJ. Lack of Suppression of AldosteroneProduction Leads to Salt-Sensitive Hypertension in Female but Not Male Balb/CMice. Hypertension. 2018 Dec;72(6):1397-1406. doi:10.1161/HYPERTENSIONAHA.118.11303.
  2. New evidence that females might benefit most from a low-salt diet. EurekAlert website https://www.eurekalert.org/pub_releases/2018-12/mcog-net121018.php. Accessed January 26, 2019.
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