How Salt Influences Our Body Functions and Health

Scientists have found that across all populations, when people are left to unrestricted sodium consumption, they tend to settle in at 3,000 to 4,000 milligrams of sodium per day. This amount holds true for people in all hemispheres, all climates, all ranges of cultures and social backgrounds-when permitted free access to salt, all humans gravitate to the same threshold of salt con-sumption, a threshold we now know is the sodium-intake range for optimal health.

False hypothesis

The hypothesis went like this: In the body, we measure blood pressure in two different ways. The top number of a typical blood pressure reading is your systolic blood pressure, the pressure in your arteries during contraction of your heart. The bottom number is your diastolic blood pressure, the pressure in your arteries when your heart is relaxed. When we eat salt, so the theory goes, we also get thirsty— so we drink more water. In the salt-high blood pressure hy-pothesis, that excess salt then causes the body to hold on to that increased water, in order to dilute the saltiness of the blood. Then, the resulting increased blood volume would automatically lead to higher blood pressure.

That’s the theory, anyway. Makes sense, right?

All of this did make sense, in theory, and for a while there was some circumstantial evidence supporting this claim. Data was gathered on salt intake and blood pressures in various populations, and correlations were seen in some cases. But even if those correlations were consistent, as we all know, correlation does not equal causation-just because one thing (salt) may sometimes lead to another thing (higher blood pressure), which happens to correlate with another thing (cardiovascular events), that does not necessarily prove that the first thing caused the third thing

Sure enough, data that conflicted with the salt-blood pressure theory continued to be published right along with data that supported it. A heated debate raged in the scientific community about whether salt induced chronically elevated blood pressure (hypertension) versus a fleeting, inconsequential rise in blood pressure, with advocates and skeptics on both sides, In fact, compared to any other nutrient, even cholesterol or saturated fat, salt has caused the most controversy.

And once we got on that salt-high blood pressure train, it was hard to get off.

Low-salt advocates posit that even a one-point reduction in blood pressure (if translated to millions of people) would actually equal a reduction in strokes and heart attacks. But evidence in the medical literature suggests that approximately 80 percent of people with normal blood pressure (less than 120/80 mmHg) are not sensitive to the blood-pressure-raising effects of salt at all. Among those with prehypertension (a precursor to high blood pressure), roughly 75 percent are not sensitive to salt.

And even among those with full-blown hypertension, about 55 percent are totally immune to salt’s effects on blood pressure.

Recent research even suggests that chronic salt depletion may be a factor in what endocrinologists term “internal starvation.” When you start restricting your salt intake, the body starts to panic. One of the body’s defense mechanisms is to increase insulin levels, because insulin helps the kidneys retain more sodium. Unfortunately, high insulin levels also “lock” energy into your fat cells, so that you have trouble breaking down stored fat into fatty acids or stored protein into amino acids for energy. When your insulin levels are elevated, the only macronutrient that you can efficiently utilize for energy is carbohydrate.

See where this is headed?

You start craving sugar and refined carbs like crazy, because your body believes carbohydrate is your only viable energy source. And, as the now-familiar story goes, the more refined carbs you eat, the more refined carbs you tend to crave. This overeating of processed carbs and high-sugar foods virtually ensures fat cell accumulation, weight gain, insulin resistance, and eventually type 2 diabetes.

Just a small dash of salt can take a bland dish and heighten all of its flavors, making it taste extraordinary. Salt knocks out bitterness and makes food taste sweeter, reducing the need for sugar. And just as much as we relish the satisfaction and savory heartiness that salt adds to our food, salt plays a fundamental role in dozens of critical functions in our bodies.

Salt is needed to maintain the optimal amount of blood in our bodies; it’s even needed by the heart to pump blood throughout our bodies. Salt is essential for digestion, cell-to-cell communication, bone formation and strength, and prevention of dehydration. Sodium is also critical to reproduction, the proper functioning of cells and muscles, and the optimal transmission of nerve impulses to and from organs such as the heart and brain. Indeed, our bodies rely on elements called electrolytes-such as sodium, potassium, magnesium, and calcium— in our bodily fluids to help carry out electrical impulses that control many of our bodies’ functions. Without an adequate sodium intake, our blood volume goes down, which could lead to the shutting down of certain organs, such as the brain and kidneys.

Our brain and body automatically determine how much sodium we eat, reabsorb, and excrete. The ability of our body to conserve salt and water is thought to be controlled by our hypothalamus, a part of our so-called reptilian brain that both receives and transmits signals that drive us to crave salt or feel thirsty.

Those signals, if we honor them, lead us to naturally create optimal levels of water and salt in the body—because those powerful instinctual drives are a direct result of evolutionary facts of life. The first living creatures on the planet were bathed in seawater, and when they came onto land, they took salt from the ocean with them.’ And, today, millions of years later, the makeup of our human body fluids still mimics that of the ancient ocean.

The ocean covers 71 percent of the earth’s surface, but because of its massive volume, the ocean also makes up 99 percent of the earth’s total living space.’ Sodium chloride, aka salt, constitutes go percent of the entire ocean’s mineral content, the same percentage of mineral content found in our blood. The only difference between the two is in concentration-the ocean is four to five times as salty as our own blood (around 3-5 percent NaCl versus 0.82 percent NaCl).+ Besides the ocean, salt can also be found in smaller seas, rock salt, brackish water, salt licks, and even rainwater. The vast amount of salt we find in numerous areas around the world only underscores the importance of salt to all forms of life.

The similarity between the mineral content and concentration of our own blood and seawater has been known for decades. Cells can’t survive outside a narrow range of electrolyte levels in the extracellular fluid that bathes them. In order for a species to leave the ocean and survive on land, several salt-regulating systems had to develop and evolve. Those systems operate all over our bodies, including in our skin, adrenal glands, and kidneys.

Source : The Salt Fix: Why the Experts Got It All Wrong–and How Eating More Might Save Your Life by James DiNicolantonio

Goodreads : https://www.goodreads.com/book/show/30555572-the-salt-fix