Low sodium Salt - a solution for high blood pressure or another risk?

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Food industry has seen numerous debates on low fat, zero calorie, artificial sweeteners, low sodium salts etc. The Low Sodium Salt diet recommendation is nothing new. But, with growing awareness due emergence of various scientific research supporting it , low sodium salts are increasingly finding its numbers rising in groceries self. So let us examine if it has ability to make significant contribution to our health.

I believe (important to insist that it is my belief) before blindly following diet trends, it is important to know a thing or two about the subject matter.

About Table Salt (NaCl)

As we hit adolescence, our salt requirement increases from 2 g (1-3 years old) to 6 g in adults. The chemical formula for salt is NaCl which basically means chemically salt is 40% Na (Sodium) and 60% Cl(Chlorine). Na is an absolute necessity for normal nerve and muscle functioning. It plays important role as an electrolyte, maintaining intracellular and extracellular fluid level.

Many of you who might think about highly reactive Chlorine in salt and it’s harmful effect on human body. Let me clarify that Chlorine in table salt is ionised, meaning it has gained an electron and now it is negatively charged (chloride ions). The chloride ions are stable and is required for normal functioning of body processes such as nerve signalling and muscle function.

For adequate functioning of Human body, Na-K (Sodium - Potassium) need to be in balance. Even if one of them goes up or down, it causes adverse effect on human health. Various research done in the past decades, clearly supports that it is Na-K, that together control blood pressure.

How sodium(Na) controls blood pressure?

Sodium is dissolved in the blood. It attracts and holds water, so the sodium in the blood helps to maintain the liquid portion of the blood (aka plasma). When one consumes excess sodium, the body starts retaining more water as sodium holds water. Human blood vessels are not expandable. Thus the increased blood volume exerts pressure on blood vessels to accommodate the increased volume of blood causing rise in blood pressure. Frequent rise in BP is a risk factor for heart problems. The increased pressure damages blood vessel and can form plaque. Plaque blocking the blood flow to prime organs can be fatal.

Role of Potassium (K) 

To balance the negative effect of water retention by sodium, body has potassium. The increase in potassium concentration causes kidney to remove excess water thereby reducing water content in the blood and hence reducing Blood pressure. Potassium also plays vital role in maintaining your heartbeat, muscle contraction, cell-to-cell communication and digestion.

Before I delve into the topic of Low Sodium salts, I want to stress on a very important point - Moderation is the key, maintain balance and do not go overboard. Too much of anything is bad. If one has too much of K(potassium), body will flush out lot of water leading, loss fluid part of blood will cause drop in BP, which is again is a problem. This is why, Na-K level has to be balanced. Just above the kidney lies a gland called adrenal gland, which produces a steroid hormone called aldosterone.This hormone sends the signals to kidney and determine when to retain sodium. It also regulate the release of Potassium in urine. So kidney, together with adrenal glands monitor the levels of Sodium or potassium by expelling out excess electrolyte in urine when either of them becomes imbalanced. 

Now that we know basics of our everyday salt and its function, let us see how much salt we humans need per day and examine if low sodium salt has health benefits or it’s just a marketing gimmick to increase sales.

Daily requirement 

Sodium : ~2.4 grams (2400mg)

You can get this much sodium in just 6 grams of table salt( i. e 1 teaspoon).

Potassium : ~ 4.7 grams (4700mg)

A teaspoon of table salt (~6 g) has 2400 mg (~2.4 g) of sodium, which is around 40% of salt. So, you can suffice your daily need with just a teaspoon of salt. With increase in consumption of high salt diet like canned and fast food, we can easily surpass this limit. Normally inside the cells potassium level is high and outside, sodium level is high (Why is it so? May be evolution, that is how first cell evolved in primitive conditions (in ocean), which is rich in salt. To read more - http://www.pnas.org/content/109/14/E821.abstract. Also, to maintain the resting potential across plasma membrane of ~ 60-70mV for healthy functioning). 

Sodium(Na) has affinity for water. When the Na level in blood crosses the threshold, the excess sodium outside can pull water out of the cells causing them to shrink, damaging its organelles and collapsing internal machinery. To avoid this, a signal is sent to kidney to retain water to dilute sodium level in blood so that it doesn’t pull water out of vital cells. This saves the cells but increased blood volume exerts pressure on blood vessels. In long run, increased blood pressure can rupture the blood vessels forming plaques. Plaques can block the blood flow to vital organs leading to stroke.

The kidney has Na-K pump to pull or push the water out of system to maintain Na-K level in suitable ratio.

So, is low sodium salts the solution?  Well, it is not a solution. 

What are low sodium salts?

Low-sodium salts replace some of the sodium in sodium chloride with potassium. Basically, they contain sodium and potassium chloride. The amount replaced is so little that it does not makes much difference. Moreover, it increases potassium level (hyperkalemia) which is a cause of concern. As a consumer, it is important to know what you are increasing in your diet when you are aiming to go low on sodium. The reason behind this is due to the fact that we get potassium easily from junk food, fruits and vegetables and excess of potassium has it’s own side effects. I recently found a research article, which clearly shows potassium ill effects in a woman who went for low sodium salt and ended with hyperkalemia (High potassium in blood). Click here to read https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3692158/ . 

Everyone but patient with diabetes, cardiac, and renal diseases in particular, need to be very careful using low sodium salts.

To verify this, check below how much sodium is in normal table salt vs low sodium salt

Tata Table salt (per 100g)

Sodium    38,700 mg

Potassium      N.A

In 1 tsp (6 grams) - 2322 mg Sodium 

Tata salt Lite (A low sodium salt, per 100 g)

Sodium     33,200 mg 

Potassium  7,800 mg 

In 1 tsp (6 grams) - 1992 mg Sodium (just little less than its counterpart nothing significant to make a difference)  and 468 mg potassium.

The level of Potassium is not high but still a significant amount. Therefore, it needs to be highlighted so that we have clarity about the sold product, its intend use and its safety. 

Other famous low sodium salts like Lo salt has 33% sodium chloride and 66% potassium chloride, which is quite alarming.

In conclusion, I believe it is better to manage sodium with overall low salt intake and diet restriction. Most low sodium salts contain only little less sodium than its variant to make a significant health impact in people with high blood pressure. Moreover, low sodium salts increase the risk of developing hyperkalemia due to its high potassium percentage.

Read on : 
Natural ways to reduce salt uptake
Potassium (K) rich food

~Ren