Cooking salt

This statement is biochemically justified when considering the actual physiology of kidney function and the role of sodium in regulating blood pressure, particularly renal pressure.

What is renal pressure?

Renal pressure is a part of the overall arterial pressure that directly depends on the functioning of the kidneys, their ability to filter blood, and regulate the volume of fluid in the body. It is particularly sensitive to blood volume and the condition of the vessels passing through the kidneys.

Why can sodium deficiency cause an increase in renal pressure?

Sodium deficiency = activation of the RAAS system. When there is insufficient sodium (and thus salt) in the diet, the body perceives this as a threat to the water-salt balance. This triggers the renin-angiotensin-aldosterone system (RAAS):

• The kidneys begin to produce renin to increase pressure and retain sodium.
• This leads to vasoconstriction (narrowing of blood vessels), including in the kidneys.
• As a result, arterial and renal pressure increase to "force" more blood through the kidneys and recover lost sodium.

Fluid retention in sodium deficiency. In the case of sodium deficiency, the mechanism of sodium reabsorption in the renal tubules is activated — the body starts to "take back" not only sodium but also water. The result:

• Increased circulating blood volume (CBV).
• Increased pressure in the glomeruli of the kidneys.
• Disruption of microcirculation, especially in the deeper parts of the nephron.

Low sodium = chronic stress for the kidneys. Constant "starvation" for sodium is perceived by the kidneys as chronic stress. This:

• Increases the production of aldosterone, which retains sodium while simultaneously increasing potassium loss.
• This disrupts the electrolyte balance and exacerbates vascular resistance.
• In the long term, this can lead to hyperfiltration, fibrosis of the kidney vessels, and persistent increases in pressure.

What about excess salt?

The myth about the harm of salt is based on a simplified logic: "the more salt — the more water — the higher the pressure." However, in a healthy person with normal kidney function, excess sodium is quickly excreted if the diet contains enough potassium, magnesium, and water.

Moreover, with adequate salt intake (8–10 g per day):

• The activity of the RAAS decreases.
• The kidneys function normally.
• Correct osmotic pressure of the blood is maintained.

Conclusion

Instead of a hypotensive effect with a low-salt diet, we get:

• Hyperactivity of the vascular system,
• Fluid retention,
• And, ultimately, a sustained increase in pressure.

How sodium participates in toxin elimination

Sodium — is the main extracellular cation, playing a key role in:

• maintaining osmotic pressure,
• regulating extracellular fluid volume,
• reabsorption and secretion in the kidneys,
• functioning of sodium-dependent transporters, including those involved in detoxification.

When there is enough sodium in the body, the kidneys freely regulate the excretion of excess and harmful substances, including toxins, thanks to complete filtration and active transport.

What happens in sodium deficiency

If sodium is deficient, the following occurs:

1. Activation of the renin-angiotensin-aldosterone system (RAAS)  → This leads to increased sodium reabsorption in the kidneys to conserve it.
2. Along with sodium, water is reabsorbed — and with it, dissolved toxins that the body has already tried to eliminate.
3. Low sodium levels also reduce the total volume of extracellular fluid, which decreases diuresis (urination). This leads to the stagnation of metabolites and toxins.
4. In chronic sodium deficiency (hyponatremia), even water-type intoxication is possible, when toxins are not eliminated and intracellular edema increases.

Why adequate sodium levels help eliminate toxins

• Sodium participates in the "transport capture" mechanism — it is necessary for the functioning of many active transporters in the kidneys, liver, and intestines that capture toxins and excrete them with urine or bile.
• An adequate amount of sodium provides the osmotic gradient necessary for urine production and the removal of soluble metabolites.
• Sodium indirectly supports normal liver function — it affects bile synthesis and the activity of sodium-dependent proteins involved in binding and excreting toxins.

Conclusion

Adequate sodium intake — is a necessary condition for effective detoxification. The optimal intake is 2.5-3.5 grams of sodium per day. This is equivalent to 6-9 grams of table salt.

In sodium deficiency, the kidneys, trying to conserve sodium, begin to reabsorb everything indiscriminately — including toxins, ammonium, urea, and even glycation products. This worsens the overall condition, leads to edema, chronic fatigue, and intoxication.

That is why salt-free or severely salt-restricted diets are dangerous in diseases related to detoxification disorders: liver failure, chronic fatigue, edema, skin rashes, and also in cases of high inflammation levels.

When a person switches to a salt-free diet or consumes very little salt (3–3.5 g per day — this is about 1.1–1.3 g of sodium), a sodium deficiency occurs. Since the physiological need for sodium in an adult is approximately 2–2.5 g per day, and for many it is even higher (depending on the level of physical activity, climate (sweating), health status, and other factors).

What happens with a sodium deficiency:

The compensation mechanism through the kidneys is activated. The kidneys receive a signal about the sodium deficiency through the renin-angiotensin-aldosterone system (RAAS). In response, they begin to actively reabsorb sodium from the primary urine back into the blood to compensate for the deficiency.

Sodium reabsorption leads to water retention. Since sodium is osmotically active, its reabsorption is always accompanied by the absorption of water.

For approximately every gram of reabsorbed sodium, the body additionally retains up to 1 liter of water. This is explained by the fact that sodium retains water in the vascular system and in the interstitial (intercellular) fluid.

Edema develops. Constant fluid retention leads to the accumulation of water in tissues (edema), both in subcutaneous fat and in organs.

The load on the cardiovascular system increases. The increase in circulating blood volume raises blood pressure, leads to heart overload (especially in the elderly and people with heart failure), and contributes to the development of hypertension.

Additional consequences of prolonged sodium deficiency:

• chronic fatigue (due to impaired neuromuscular transmission);
• muscle cramps;
• headaches (due to cell hypohydration during hypovolemia);
• hyponatremia, which in severe cases is life-threatening (seizures, altered consciousness, coma).

Key physiological paradox

When there is little salt — the body tries to retain it at any cost, even at the expense of accumulating excess water.

When there is enough salt — the balance is maintained more easily: excess sodium is easily excreted, and water is not retained.

For most people, the physiological norm is considered to be 5–7 g of salt per day (that is, 2–2.8 g of sodium), and in hot climates and with intense physical activity — even more.

Most symptoms mistaken for kidney failure are actually related to disturbances in water-salt balance, rather than damage to the kidneys themselves.

The term «kidney failure» refers to a persistent impairment of glomerular filtration function, meaning the kidneys cannot effectively eliminate metabolic waste products (such as urea, creatinine) and maintain homeostasis. This can occur either:

• in acute kidney injury (AKI), for example, due to severe hypotension or toxic shock,
• or in chronic kidney disease (CKD), most often caused by diabetes, hypertension, or systemic inflammatory diseases.

But true kidney failure is always a severe clinical condition that requires either intensive medical therapy or dialysis.

Most «kidney symptoms» are due to sodium deficiency

Many complaints (edema, weakness, headaches, tachycardia, decreased urination, hypotension) are actually caused by a lack of sodium and plasma volume, rather than kidney damage.

In the case of salt (sodium) deficiency in the body, the following occurs:

• The kidneys reabsorb everything they can, including urea and other toxins. This creates the illusion of «poor filtration», even though the glomeruli are functioning normally—they are simply conserving fluid.
• Aldosterone levels rise, trying to retain sodium—this enhances reabsorption, decreases urine volume, and causes edema.
• The osmotic gradient is disrupted, causing urine to become either poorly concentrated or, conversely, excessively concentrated—depending on the stage.
• Decreased pressure leads to renal hypoperfusion, and then they indeed start to function worse, but secondarily—this is not «kidney failure», but a response to hyponatremia and hypovolemia.

How a salt bath helps

Physiological saline is a 0.9% sodium chloride solution, similar in osmolarity to blood plasma (approximately 300 mOsm/L). When using salt baths, the following occurs:

• Passive absorption of sodium and chloride ions through the skin, especially with prolonged contact (30–40 min), when capillaries are actively opened.
• Increased osmotic pressure of plasma, which pulls excess fluid from tissues (including edema).
• Normalization of circulating blood volume, which improves renal perfusion and filtration.
• Reduction in aldosterone levels and restoration of normal urination.

After sodium replenishment:

• edema disappears,
• blood pressure normalizes,
• urination is restored,
• electrolyte balance improves,
• false markers of «kidney failure» disappear—such as creatinine normalizing if it was elevated due to dehydration.