High blood pressure: salt consumption may affect men and women differently

Highlights
- Hypertension, affects around 1.28 billion adults worldwide, many of them in low- and middle-income countries.
- If blood pressure is not controlled, it can increase the risk of heart, brain and kidney disease.
- A common but lesser-known cause of hypertension is salt sensitivity - where the body is unable to eliminate excess salt.
- A new study has revealed that women of all ages are more sensitive to salt than men, which may have implications for blood pressure control.
According to the World Health Organization (WHO), nearly 1.3 billion adults aged between 30 and 79 worldwide suffer from hypertension (high blood pressure). Since 1990, the number of people suffering from hypertension worldwide has doubled. In France, there are 15 million hypertensives. Women are less likely than men to be screened, treated and controlled for high blood pressure.
There are several well-known factors that increase the risk of hypertension:
- Age: hypertension is more common after the age of 65.
- Ethnicity: certain ethnic groups (notably Black Africa and North Africa) are more prone to hypertension than others.
- Obesity is a risk factor for hypertension
- Regular consumption of alcohol and tobacco.
- Gender: men have a higher risk of developing hypertension than women. However, this is only true up to the menopause.
- Existing health conditions: cardiovascular disease, chronic kidney disease and, especially as people age, sleep apnea syndrome.
- Pregnancy in some women, when the placenta fails to develop properly
- Certain drugs: contraception with ethynil-estradiol, corticoids, immunosuppressants, certain antidepressants, non-steroidal anti-inflammatory drugs...
- Certain tooxics: amphetamines, cocaine, popop....
A lesser-known factor that can increase blood pressure is salt sensitivity, which is the body's tendency to retain salt rather than eliminate it through the kidneys, in the knowledge that this will increase water retention, which follows salt, blood volume circulating in our arteries and therefore blood pressure.
A review of epidemiological data published in Hypertension, an American journal, suggests that women of all ages and ethnic backgrounds are more sensitive to salt than men, and this trend increases after the menopause.
What is salt sensitivity?
Salt comprises around 40% sodium ions and 60% chloride ions. We physiologically require only a small amount of sodium per day, around 500 mg (or a quarter teaspoon of salt).
However, most people consume more sodium than they need. In high-income countries, around 75% of salt intake comes from processed foods and meals eaten outside the home.
The Centers for Disease Control and Prevention (CDC) advises increasing fresh foods in the diet to reduce salt intake, and for processed foods, those containing less than 600 mg per serving.
According to the CDC, research shows a strong relationship between the amount of salt consumed and blood pressure levels. And for most people, reducing salt intake leads to lower blood pressure.
Worldwide, people consume an average of 9 to 12 grams of salt per day, around double the WHO recommendation of 5 grams per day for cardiovascular health.
Some people can effectively eliminate a higher salt intake, so that it doesn't increase their blood pressure. For many, however, changes in dietary salt intake can lead to noticeable variations in blood pressure. These people are said to be salt-sensitive.
An estimate by the American Heart Association indicates that salt sensitivity is present in approximately 51% of people with hypertension and 26% of people without hypertension.
Salt sensitivity is the cause of hypertension, but this hypothesis is not systematically evoked. Yet it then also often contributes to resistance to antihypertensive treatments.
How does salt consumption affect women compared to men?
It has long been recognized that men under 65 have a higher risk of hypertension than women, but the risk increases for women after menopause.
This study suggests that women are predisposed to salt sensitivity, which can increase blood pressure even though there is evidence that women's kidneys excrete salt better. The problem, it seems, is related to the vascular system, as salt should also relax blood vessels, but this is not the case in salt-sensitive people. When blood vessels relax and dilate, blood pressure falls, whereas if blood vessels don't relax, blood pressure rises.
The role of hormones in Blood Pressure.
The role of estrogens in controlling blood pressure has been debated at length. Salt sensitivity increases after menopause when estrogen levels were lower. Another hormone, aldosterone, secreted by the adrenal glands, is involved in salt metabolism: it retains salt, and also controls the ability of blood vessels to dilate. Women have inappropriate aldosterone production in response to salt ingestion.
In practice, you need to reduce your salt intake on a daily basis.
It is helpful, in terms of prevention, for salt-sensitive women to pay attention to their dietary sodium intake and try to reduce their consumption as much as possible."
This advice applies to everyone: Everyone should follow the American Heart Association's recommendations on salt intake. Currently, the average daily intake is 3.4 g, while the AHA recommends 2.3 g, with the ideal amount being 1.5 g.

The main foods rich in salt: