The Link Between Salt Intake and Kidney Disease

Chemically known as sodium chloride (NaCl), it is primarily made up of two elements: sodium (Na) and chlorine (Cl). Salt is formed by combining these two elements in a 1:1 ratio. Sodium chloride is the most common type of salt, of course there are other types of salts; they are formed by combining different elements. Salt is an ionic compound composed of a cation (base) and an anion (acid). It is abundant in nature and present in large quantities in seawater. Unfortunately, the Western diet contains way too much sodium.

However, despite the danger of a high-sodium diet, sodium plays a role in regulating blood pressure and volume, supporting the transmission of impulses for muscle contraction and nerve function, and regulating pH balance and bodily fluids.

Saltiness is one of the basic human tastes, and I find this fascinating. I would like to first explain the benefits of salt from an Ayurvedic perspective, as it’s interesting to look at its actions from a different point of view.

In Ayurveda, each of the six tastes (Rasas) is associated with very specific properties. These properties interact with the doshas (Vata, Pitta, and Kapha, the three different constitutional types). First of all, let’s look at the qualities of the salty taste.

The salty taste is considered heating in nature. It is said to have a warming effect on the body, stimulating digestion and metabolism. The salty taste increases salivation and supports digestion, absorption, and assimilation of nutrients. The salty taste is also heavy in nature, meaning it has a grounding effect; it provides stability and nourishment.
Salty foods tend to have a moist quality, which can help lubricate tissues. It is also associated with oily or unctuous properties, which provide nourishment and lubrication to the tissues.

Effects on Doshas

In small amounts salt can pacify Vata, Vata tends to be cold, dry and light. Salt provides grounding and stability to help balance out the erratic, ungrounded properties of Vata in excess. Excess consumption of salty foods may aggravate the Pitta constitution, which is inherently already hot and fiery. This can lead to increased heat, inflammation and acidity in the body. The heating and drying qualities of salt can help balance out the heavy and cold qualities of Kapha, stimulate digestion, and counteract sluggishness.

Effects on Digestion

In Ayurveda, salt is said to stimulate digestive fire, supporting food digestion and assimilation. Salty foods also naturally increase appetite and improve taste.

We all need salt, salt is necessary for health, however, moderation is the key. Reducing sodium in KD is an accepted line of recommendation across the board. What we need to be aware of, though, is that salt is not the only isolated nutrient that drives high blood pressure. We also need to be mindful, as more often than not, a high salt diet is also accompanied by a high processed food intake, which also puts increased pressure on the cardiovascular system (CVS). Around 70% of sodium consumed in the States comes from restaurant food and processed foods. Once again, we need to consider a high salt diet often accompanies a refined diet and/or consuming readymade meals.

So often, we see clients diligently reducing their salt intake, but they still don’t see their blood pressure change all that much. In addition, there is no change in kidney function, and food ends up tasting pretty bland.

High Sodium Diet & Glomerular Hyperfiltration

What happens to the kidneys when they are put under pressure due to a high-sodium diet?

Let’s break it down…

Firstly, glomerular filtration is when your kidneys filter the blood to remove waste products. The glomerular filtration rate (GFR), refers to the rate at which the glomeruli in the kidneys filter blood. With increased blood volume and pressure, the kidneys can increase the GFR to accommodate the higher filtration demand. This increase in filtration rate is termed hyperfiltration.

So, when you increase sodium in your diet, your kidneys respond by increasing the GFR. Therefore, more blood is filtered through the tiny vessels (glomeruli), in the kidneys. The kidneys work in overdrive to handle the excess sodium load, fluid and pressure. Over time, this increased pressure on the glomeruli can cause damage. Prolonged hyperfiltration and increased pressure on the glomeruli can lead to kidney damage, and this damage can impair kidney function and contribute to the development of kidney disease. To add, consuming excess sodium drives thirst, if you are in end-stage kidney disease and fluid consumption needs to be monitored, this will add to unwanted pressure on your kidneys. Extra pressure on the kidneys will increase blood pressure.

Source What are the Benefits of Potassium for your Body..? | Medicover Hospitals

The main electrolytes that become a problem in kidney disease are phosphorus, calcium, and potassium, and high potassium is of the most concern. However, eliminating potassium from the diet is not necessary in every case.

Potassium is essential for good health, the body uses potassium to store carbohydrates, it supports nerve and muscle function, it plays a vital role in the body’s acid-base balance and helps to control the electrical activity of the heart.

Pretty important, yeah?

Imbalances in potassium can lead to fatigue and the development of kidney stones. Potassium also plays a key role in supporting healthy blood pressure.

The Dietary Approaches to Stop Hypertension (DASH) diet is a diet rich in fruits, vegetables, and low-fat dairy foods that has been shown to reduce blood pressure significantly. The landmark clinical trial below investigated the effects of diet on blood pressure, with a particular focus on the role of potassium-rich foods.

The study enrolled 459 participants with systolic pressure of less than 160 mm Hg and diastolic blood pressure of 80-95 mm Hg over an eight-week period. Participants were assigned to one of the three dietary groups;

1. Control Group– Typical American diet, high in saturated fat and cholesterol.
2. A diet rich in fruits and vegetables– Similar to the control group, with the addition of fruits and vegetables.
3. DASH Diet Group– Emphasis on fruits and vegetables, whole grains, lean protein and low-fat dairy products. This diet is rich in potassium, calcium, magnesium and fibre.

This research showed that although the DASH diet is lower in sodium in contrast to the typical American diet, the reduction in blood pressure was primarily attributed to its high potassium content rather than the low sodium content. The greatest result was seen with sodium reduction in the diet, with the addition of potassium. The study suggests increasing potassium intake is just as important, if not more, than reducing sodium intake for the management of blood pressure.

DASH (Dietary Approaches to Stop Hypertension) Diet Is Effective Treatment for Stage 1 Isolated Systolic Hypertension | Hypertension (ahajournals.org)

Taking potassium out of the diet can sometimes make no changes to blood pressure, or it can even potentially elevate it in some cases. If you are in the late stages of kidney disease and your blood results show high potassium, you may need to temporarily use a potassium-restricted diet to correct the matter. Your health professional will assist you in this process. Remember, your doctor will monitor your potassium levels during the treatment of kidney disease.

Unfortunately, a lot of the time, potassium is demonised. Potassium intake is restricted, thinking it will help the kidneys when, in actual fact, it can have the opposite effect as the positive effect of potassium on blood pressure is eliminated. In addition, potassium plays an essential role in supporting the acid-base balance, helping the body to become more alkaline. The kidneys spend a lot of energy ensuring our pH is in a healthy range. Therefore, if you are consuming a highly acidic diet and not consuming enough plant-based foods, your kidneys will be spending valuable energy correcting the alkalinity, putting an extra, unnecessary load on the kidneys.

How Much Salt is The Right Amount?

The recommended daily sodium intake for a healthy person is 2,300mg or less, equivalent to one teaspoon of salt.

Your consumption of sodium is going to be evaluated on a case-by-case basis.

If you have cut down on sodium and you have not seen a difference in blood pressure, other drivers will need to be addressed.

Which Type of Salt is Best?

If you are going to use a little bit of salt, which type is the best to use?

• Choose a salt with no additives and anticaking agents.
• A good salt will have a good micromineral profile content.
• If you have swapped from an iodised salt over to something like a Himalayan salt, add a little seaweed to it to ensure you don’t miss the valuable nutrient iodine. You could even add seaweed snacks to your diet or cook with kelp or other types of seaweed.

How to Reduce Your Intake of Salt

• Cook simple, unprocessed meals at home.
• If you are going to eat, really look at the quality of the food you are eating.
• Use herbs and spices to add flavour to your dishes.
• Read food labels properly. Pay close attention to the sodium content. Choose lower sodium label options such as ‘low sodium’, ‘no added salt’ or ‘sodium free’.
• Choose fresh fruit and vegetables over packaged foods.
• Limit eating out.
• Be very mindful about the salt content in condiments; homemade sauces and condiments are your best choice.

I hope you found this article of use.

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