- Most people around the world consume between 9 and 12 grams of salt per day, which is well above the maximum recommended daily intake.
- A high-salt diet has been linked to an increased risk of high blood pressure and dementia.
- Researchers at Fujita Health University have identified the specific body systems involved in hypertension and cognitive impairment caused by high salt using a mouse model.
- Scientists have also discovered that the excessive addition of phosphates to tau protein – a key protein implicated in the development of Alzheimer’s disease – is mainly responsible for emotional and cognitive problems.
Researchers estimate that the majority of people around the world consume between 9 to 12 grams salt added daily. This is much higher than the recommended daily maximum sodium intake.
In addition, people with high blood pressure are at a increased risk to develop dementia.
Now, researchers at Fujita Health University have taken our knowledge of the link between hypertension and dementia even further by identifying specific body systems involved in hypertension and cognitive impairment caused by high salt. through a mouse model.
Additionally, the researchers found that adding excess phosphates to the tau protein is primarily responsible for emotional and cognitive problems.
Tau is a key protein associated with development a type of dementia called Alzheimer’s disease.
This study has just been published in the British Journal of Pharmacology.
According to the researchers, although high salt intake is considered a risk factor for high blood pressure, cognitive dysfunction and dementia, studies examining the interaction between the peripheral and central nervous systems have not been sufficiently studied this association.
In this study, scientists used a mouse model to further investigate this association. The researchers gave the mice high-salt drinking water for 12 weeks and monitored their blood pressure.
The research team also monitored the effects of high salt intake on their emotional and cognitive function and tau phosphorylation in the prefrontal cortex and hippocampus areas of the brain.
The researchers studied the roles of two systems – the hormone angiotensin II (Ang II) and its AT1 receptor, and the lipid molecule prostaglandin E2 (PGE2) and its EP1-receptor play in the development of salt-induced hypertension and neuronal damage.
Ang II-AT1 plays an important role in the regulation of blood pressure and body fluids. PGE2-EP1 also has a direct impact on blood pressure.
After the study, the research team observed several biochemical alterations in the brains of the mice. In addition to the excess tau protein phosphates, the scientists also found a decrease in the phosphate groups bound to the CaMKI enzyme. The CaMKI enzyme is involved in brain signaling.
The researchers reported that these biochemical changes were reversed when the mice were treated with the high blood pressure drug. losartan or when the EP1 gene has been knocked out.
Scientists believe these findings could pave the way for new therapies for hypertension-induced dementia by targeting the AGII-AT1 and E2-EP1 systems.
Dr Sandra Narayanana board-certified vascular neurologist and neuro-interventional surgeon from the Pacific Stroke & Neurovascular Center at the Pacific Neuroscience Institute in Santa Monica, California, said Medical News Today that several aspects of this research interested him.
“In this animal model, it was interesting to note how the adverse biochemical changes of high sodium intake (and) hyperphosphorylation of tau protein which is associated with cognitive impairment and neuronal loss and disease of ‘Alzheimer’s and other dementias were associated with shortened brain cell length, or dendritic length, particularly in brain regions involved in memory, such as the hippocampus,’ she explained.
“And also how there is a very complex interplay between the different components of the hormones that are associated with the activation of vascular disorders and the development of hypertension,” she added.
Dr. Narayanan also commented on how, in a very short period of six to 12 weeks, the undesirable changes that can occur as a result of a high sodium diet were evident in the mouse model.
She said once the harmful effects of a high sodium diet are known, therapeutic interventions can be designed to potentially reverse the changes.
“Dementia is not thought to be reversible with blood pressure medications, but if there is biochemical evidence that the early stages of these diseases can be slowed or reversed with aggressive lowering of blood pressure by some of these biochemical mechanisms and by (the) pharmacological mechanisms highlighted in the article, it is quite exciting,” added Dr. Narayanan.
Salt is a mineral composed mainly of sodium chloride.
It is also an essential nutrient for the body and its organs. Sodium in the body helps with:
- nerve function
- contract and relax muscles
- maintain balanced fluid levels, including water and electrolytes
- prevents low blood pressure
The body only needs a very small amount of salt. Currently, the recommended daily sodium intake for an adult is less than 2,300 milligrams or 2.3 grams per day.
A salt intake of 5% or less of this daily recommendation is considered a low-salt diet. And consuming 20% or more of the recommended daily amount is considered a high-salt diet.
When most people think of “added salt,” they think of table salt that they can shake on their food. However, most added salt comes from processed and prepared foods.
In addition to high blood pressure, a high-salt diet has also been linked to an increased risk of:
For those who want to reduce their salt intake to help reduce their risk of high blood pressure and dementia, Dr Narayanan said it is about minimizing going out to restaurants or eating processed foods and eating smaller portions.
“You can request that your dish be prepared with less salt, but recognize that there is not as much control when you do not prepare your own food, or see the ingredients, condiments and flavorings that go into it,” she added.
Dr. Narayanan advised using spices, fresh and dried herbs and fresh vegetables to add flavor and minimize usage. salty condiments such as soy sauce, mustard, pickles, ketchup, olives and cheeses when cooking at home.
For additional low-salt lifestyle and cooking tips, Dr. Narayanan suggested visiting the American Heart Association. website.