The importance of potassium

The importance of potassium and calcium in muscle contraction

Electrolytes are often overlooked when discussing athletic performance in the fitness and bodybuilding fields. Indeed, it's much easier to find information on the stimulating effects of caffeine or creatine, ingredients in some performance-enhancing supplements, than to find recommendations on maintaining the correct electrolyte balance and how to consume them. Yet, electrolytes are essential, and their role in muscle function is far more important than the mere status of accessory minerals to which they are often relegated in the public consciousness.

Carbohydrates that are quickly absorbed have a high glycemic index, carbohydrates that are slowly absorbed have a low glycemic index.
The glycemic index of a carbohydrate is measured relative to that of glucose, which is 100 and is the simplest sugar most easily and quickly assimilated by the body.
A glycemic index of 50 for a carbohydrate means that the increase in blood glucose for that carbohydrate corresponds to 50% of the blood glucose that would have been obtained with glucose.

Low GI foods are considered to have a GI below 50, and high GI foods are considered to have a GI above 70.

The body's response to increased blood sugar is the production of insulin, which serves to regulate blood glucose levels and convert sugars into fats.

People who regularly consume high-glycemic index foods are more prone to diabetes, cardiovascular disease, and being overweight. Those who consume low-GI foods tend to have better weight control and are less susceptible to metabolic sugar disorders such as diabetes.

But what exactly is an electrolyte?

An electrolyte is a chemical compound containing mobile ions that acts as a conductive substance. They are generally found in solution (dissolved in water), but molten and solid forms also exist. For example, solid sodium chloride dissolves in water into Na+ (sodium ion) and Cl- (chloride ion). Once in solution, these electrically charged particles act as conductors and are responsible for numerous biochemical reactions.
Electrolytes play a vital role in the body. They regulate the body's pH, help maintain normal blood pressure, and are involved in muscle function and the functioning of the nervous system. Each has its specific role, and without them, the body cannot function. Yet, the body regularly loses significant amounts of electrolytes, even through perspiration alone. Fortunately, a balanced diet and proper hydration allow the body to replenish its electrolytes.

And what about muscle function?

Because ultimately, that's what it comes down to: when we talk about "native" proteins, we're actually referring to the separation technique between whey and caseins. So, is it even better to filter directly through "whole" milk? Well, that depends on whether you want to obtain casein or whey protein. Indeed, the system of separating whey and caseins by filtering directly through milk produces micellar casein, which is far superior to calcium caseinates. If the goal is to obtain micellar casein, we could simplify things and say that so-called "native" whey is a byproduct of micellar casein production. This is the same logic as saying that traditional whey is a byproduct of cheesemaking. Which, as we saw earlier, is nonsense. That said, while modern casein coagulation techniques are non-denaturing for whey, the technique of filtering whey directly from milk offers an advantage. For whey proteins, this technique allows for a slightly higher leucine concentration. A recent scientific study from 2017 (1) conducted by Norwegian researchers shows that so-called "native" whey increased blood leucine concentrations more than WPC-80 and milk, but despite the greater increases in blood leucine concentrations with so-called "native" whey, it was not superior to WPC-80 in terms of its effects on muscle protein synthesis during a 5-hour period following the end of exercise.

Furthermore, the term "native" in the sense of "original" or "unmodified" is not appropriate. The fragile original structure of whey proteins is altered from the very first mandatory milk treatments, such as flash pasteurization, necessary to kill pathogenic germs, and mechanical homogenization, required before any filtration. Thus, another scientific study from 2015 (2) examining the effect of homogenization and pasteurization on the structure and stability of milk shows that in both cases—homogenization alone and followed by HTST treatments (72°C for 15 seconds)—the tertiary structure of whey proteins was disrupted due to the homogenization of whole milk, as indicated by both near-UV circular dichroism and intrinsic fluorescence. In-depth structural stability analyses revealed that, while milk processing had little impact on secondary structural stability, the tertiary structural stability of whey protein was significantly altered, without, however, denaturing its intrinsic biological value. In other words, the "native" protein is no longer truly "native" in the "original" sense.

And what about muscle function?

When discussing electrolytes in the human body, we are primarily referring to calcium, magnesium, sodium, and potassium. Here, we will focus mainly on calcium and potassium in terms of their role in muscle contraction.

Calcium contributes to normal energy metabolism and normal neurotransmission. It also plays a role in the process of cell division. Potassium, for its part, contributes to the normal function of the nervous system and muscle contraction. It also contributes to normal blood pressure. The importance of these electrolytes is therefore clear.

The myosin head binds ATP molecules. The energy from the hydrolysis of ATP to ADP+P induces the activation of the myosin head and a change in its orientation, allowing an actin-myosin cross-bridge to form in the presence of calcium ions, which bind to troponin. In the absence of calcium ions, these cross-bridges cannot form.

Once formed, the actin-myosin cross-bridge triggers the release of ATP hydrolysis products ADP and P, causing the myosin head to return to its resting position. This return causes the actin and myosin filaments to move past each other, resulting in muscle contraction. The binding of a new ATP molecule leads to the breakdown of the actin-myosin cross-bridge, and a new cycle can begin. This repeated, larger-scale mechanism results in muscle contraction and movement.

Potassium, along with sodium, helps maintain fluid balance in the body. It contributes to normal muscle function, particularly normal muscle contraction. While our diet is often high in sodium, it is often low in potassium, even though our needs increase with physical activity.

Processed foods and modern eating habits, which are high in calories and low in fiber or vegetables, are often also low in potassium but high in sodium. This creates a functional sodium-potassium imbalance responsible for numerous potential dysfunctions or pathologies such as high blood pressure, cellular aging, or kidney stones. But let's be clear: before taking dietary supplements to balance your sodium and potassium levels, you must opt for a varied and balanced diet. A balanced and appropriate diet naturally contains everything you need to be healthy.
Foods that contain significant amounts of potassium include dried fruits (almonds, dates, dried figs, walnuts, dried apricots…), legumes (lentils, chickpeas…), red beets, and bananas (non-exhaustive list).

In short, you should opt for a varied and balanced diet, richer in legumes, dried fruits and fresh vegetables, consume less red meat, limit salt, and ban industrial dishes and sauces in order to naturally consume more potassium.