Eating a lot of salty foods like salted fermented seafood increases the risk of high blood pressure. However, some people tend to crave salty foods more than home-cooked meals. If eating out feels more delicious than homemade food, it may be because more salt (sodium), sugar, or flavor enhancers have been added to the food.

Research has shown that the craving for salt is caused by the hormone aldosterone acting on specific neurons in the brainstem. A research team from the University of Iowa in the United States announced that the hormone aldosterone produced by the adrenal gland above the kidney acts on HSD2 neurons in the brain to induce a desire for salt intake.

 

The sodium component in salt is a very important nutrient. If sodium levels are too low, blood volume decreases, which can lead to serious health problems. On the other hand, if sodium levels are too high, it can cause hypertension and cardiovascular diseases. Associate Professor Joel Gearing, the corresponding author of the study (Neurology), said, "Understanding the brain circuits that regulate the desire for salt intake is not easy. We have newly identified 'HSD2 neurons,' which are closely related to this."

According to the research team, above both the left and right kidneys, there is a triangular endocrine gland called the adrenal gland. The adrenal cortex secretes aldosterone, cortisol, and sex hormones, while the adrenal medulla secretes catecholamines. Dr. Sylvia Gasparini, the lead author of the study and a postdoctoral researcher in neurology, said, "Aldosterone, which is a key hormone regulating sodium levels, is generally produced when the amount of body fluids, including blood, is deficient." For example, when a person does not drink enough water and sweats, or experiences bleeding, vomiting, or diarrhea, aldosterone is produced in the adrenal cortex.

 

Aldosterone instructs organs such as the kidneys to retain sodium, playing a role in maintaining a constant fluid volume. However, excessively high levels of aldosterone can cause an unknown cause of primary adrenal cortex disease (aldosteronism), which can lead to severe hypertension. Adrenal cortex disease accounts for 10-30% of hypertension cases. Patients with hypertension caused by adrenal cortex disease have three times higher risk of stroke, heart failure, and arrhythmia (abnormal heart rhythm) compared to other hypertensive patients. However, the exact reason for this has not yet been clearly identified.

 

According to previous research, patients with aldosterone-producing adrenal cortex hyperplasia (aldosterone syndrome) consume significantly more salt than other hypertensive patients. The research team confirmed that when sodium is deficient in the diet of mice, aldosterone production and salt intake increase. They also found that activity of HSD2 neurons in the brainstem increases. Dr. Gasparini said, "The most interesting fact is that HSD2 neurons are expressed in humans, mice, and pigs," adding, "There are about 1,000 HSD2 neurons in humans and about 200 in mice." As a result of this study, which identified the genetic identity and location of neurons that control salt intake cravings, it is expected to aid in developing treatment strategies to promote sodium intake in patients with hypotension and reduce excessive salt consumption in patients with aldosterone syndrome.

 

This research result (Aldosterone-induced salt appetite requires HSD2 neurons) was published in the journal JCI Insight, published by the American Society for Clinical Investigation (ASCI).

 

===========

There are people who particularly like salty foods such as salted fermented seafood.

Eating salty foods is said to increase the risk of high blood pressure, kidney disease, and stomach cancer.

 

Fermented seafood is called a rice thief, you know.

It seems like we always have salted seafood at home too.

 

High blood pressure, kidney health should be kept in mind.