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“We think the fact that females are more salt sensitive and more sensitive to obesity are among the reasons they have lost the natural protection youth and estrogen are thought to provide.”
“First reduce your consumption of salt, a message the American Heart Association has been pushing for years, which should also result in a reduction in your intake of highly processed, high-calorie food and drink.”, He says.
Estrogen protects blood vessels and it is considered a natural protection for premenopausal women yet, along with soaring rates of severe obesity in young women, heart disease is now the third leading cause of death in females between the ages 20-44 – fourth for males in that age group – then moves up to second place for the next 20 years in both sexes, and is the number one killer for both men and women looking at all ages, according to the National Vital Statistics Reports.
Bad nutrition as the “world’s biggest killer” and obesity as a major risk factor for hypertension in both sexes, his lab has mounting evidence that obesity and high salt intake are even bigger risks for females, who have naturally higher levels of two additional hormones, leptin and aldosterone, setting the stage for the potentially deadly cardiovascular disparities.
In obesity, the brain stops listening to the full message but the cardiovascular system of women starts getting unhealthy cues.
Females leptin prompts the adrenal glands, which make aldosterone, to make even more of this powerful blood vessel constrictor. Like leptin, females, regardless of their weight, already have naturally higher levels of aldosterone and actually bigger adrenal glands as well.
Obesity actually produces larger blood pressure increases in females, and studies comparing that females are also more prone to obesity associated vascular dysfunction – things like more rigid blood vessels that are not as adept as dilating.
Leptin increases production of the vasodilator nitric oxide – which reduces blood pressure – in the male mice, one of many cardiovascular differences they are finding between males and females.
“The major role of aldosterone is to regulate your blood volume,” Belin de Chantemele says. Increased salt intake should suppress aldosterone, and it does work that way in males, Belin de Chantemele says. But in females it appears to set them up for more trouble.
His team reported in 2019 in the journal Hypertension that the hormone progesterone, which enables pregnancy, also enables high levels of these mineralocorticoid receptors for aldosterone in the endothelial cells that line blood vessels in both female lab animals and human blood vessels.
Progesterone regulates the expression of the receptor in the females’ blood vessels.
When they deleted either the mineralocorticoid or progesterone receptor in the females, it prevented the blood vessel dysfunction that typically follows, and just knocking out the progesterone receptor also suppressed the aldosterone receptor.
The bottom line is that progesterone is key to the sex difference in aldosterone receptor expression on endothelial cells, which predisposes females to obesity associated, high-leptin driven endothelial dysfunction and likely high blood pressure, Belin de Chantemele says.
“If you have higher aldosterone levels you will retain sodium and your blood volume will be higher,” he says.
Females are more salt sensitive than males. High sodium intake is known to raise blood pressure, by increasing fluid retention, and both pre- and postmenopausal females are more salt sensitive than males, Black females even more so, he says.
In just seven days on a high-salt diet, the ability of female mice to relax blood vessels decreased as blood pressure increased. Treatment with the aldosterone agonist eplerenone helped correct both.
Females already make more aldosterone, and the normal response of the body when you eat a lot of salt is to make even more aldosterone to help eliminate some of it, his team now proposes that females appear to have an impaired ability to reduce both the levels of the enzyme that makes aldosterone and the hormone itself, which makes them more salt sensitive.
Salt raises females’ blood pressure without them actually retaining more salt than the males. It also means that they think that blood vessels are more important in blood pressure regulation in females than males, which means they may need different treatment than males.
High salt increases the adrenal leptin receptor in the females, providing more points of action for leptin, which probably helps explain why aldosterone levels don’t decrease in females like they do in males.
A new $ 2.6 million grant from the National Heart, Lung and Blood Institute is enabling them to further investigate, the female’s unique responses to a high-salt diet, include the specific contributions of the failure of aldosterone levels to drop, along with the increased expression of aldosterone and leptin receptors.
“We want to continue to put the puzzle together with the goal of helping restore protection from cardiovascular disease to young women, when a healthy diet and increased physical activity do not,” Belin de Chantemele says.
Source: Medindia
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