A study has found that women of all ages are more salt sensitive than men, which may have implications for blood pressure control.
According to medicalnewstoday.com, hypertension, or high blood pressure, affects an estimated 1.28 billion adults worldwide, many in low and middle-income countries.
If blood pressure is not controlled, it can increase the risk of heart, brain, and kidney diseases.
A new review has found that women of all ages are more salt sensitive than men, which may have implications for blood pressure control.
According to the World Health Organisation, almost 1.3 billion adults aged 30-79 worldwide have hypertension (high blood pressure). And since 1990, the number of people globally with hypertension has doubled.
There are several well-known factors that increase the risk of hypertension. These include:
Age: Hypertension is more common over the age of 65
Ethnicity: Some ethnic groupsTrusted Source are more prone to hypertension than othersWeight: ObesityTrusted Source is a primary risk factor for hypertension
Regular alcohol and tobacco
Sex: males have a higher risk of developing hypertension than females. However, this is only until females reach menopause
Existing health conditions: Cardiovascular disease, diabetes, chronic kidney diseaseTrusted Source, and high cholesterol levels can lead to hypertension, especially as people age
A less recognized factor that can drive up blood pressure is salt sensitivity — the tendency of the body to hold onto salt rather than excrete it through the kidneys.
A review of epidemiological data published in HypertensionTrusted Source suggests that women of all ages and ethnicities are more salt sensitive than men. And this tendency to hold onto more salt increases after menopause.
A study author and physiologist at the Vascular Biology Center at the Medical College of Georgia at Augusta University, Dr. Eric Belin de Chantemèle, said, “The most important fact highlighted in this review article is that women, whether pre or postmenopausal, are more salt sensitive than men.”
What is salt sensitivity?
Salt comprises around 40% sodium ions and 60% chloride ions. We need a small amount of sodium, around 500mg (or a quarter teaspoon of salt) per day, to conduct nerve impulses, contract and relax muscles, and maintain the proper balance of water and minerals.
However, most people take in more sodium than they need. In higher-income countries, some 75% of salt intake comes from processed foods and meals eaten outside the home.
The Centers for Disease Control and PreventionTrusted Source advises increasing the fresh food in your diet to reduce salt intake, and if eating processed foods, look for those that have less than 600mg per serving.
According to the CDC, research shows a strong relationship between the amount of salt consumed and raised Trusted Sourceblood pressure levels. And for most people, reducing salt intake results in reduced BP.
Globally, people consume an average of 9 to 12 grams of salt daily — around double the WHO recommendationTrusted Source of 5 grams daily for cardiovascular health.
Some people can effectively excreteTrusted Source a higher salt intake, so it does not increase their BP. However, for many, changes in dietary salt intake can cause noticeable increases or decreases in BP. These people are said to be salt sensitive.
The American Heart Association estimatesTrusted Source that salt sensitivity is present in approximately 51% of people with hypertension and 26% of people who do not have high blood pressure.
And this review suggests that salt sensitivity is a factor in about half of the cases where the cause of hypertension is not apparent and that it also often contributes to treatment-resistant hypertensionTrusted Source.
How salt intake affects women vs. men
It has long been recognised that men under 65 have a higher risk of hypertension than women, but the risk increases for women following menopause.
This review, however, suggests that because females are predisposed to salt sensitivity, which may raise BP, the reality is not as straightforward as that.
The explanation they suggest is, perhaps, surprising. According to Dr. Belin de Chantemèle, human and laboratory animal evidence indicates that female kidneys are better at excreting salt. The problem, it appears, is with the vasculatue, because salt should also relax the blood vessels, but it does not in those who are salt-sensitive.
A genetic engineer at the London Regenerative Institute, Sebnem Unluisler, said, “Although sex steroid hormones are important in the regulation of the cardiovascular system, new research suggests that sex chromosomes may also be involved. […] Increased vascular resistance from salt sensitivity leads to endothelial dysfunction, which may be more of a factor in females than in males.”
“When the blood vessels relax and expand, BP reduces. However, if the blood vessels do not relax, BP increases.”
Dr. Belin de Chantemèle said the blood vessels do not relax in many women, making them prone to salt-sensitive BP changes.
