The sodium and potassium relationship with the rest of the body works, 24 hours a day, 7 days a week, and goes on without you thinking about it. I believe this is a miracle – that our bodies do this marvelous balancing act to protect our bodies from a catastrophe is a gift and a blessing. I am asking you, as you read this, to say thank you to the body for doing all of this hard work. And I want you to step away from criticizing the body as you often do, and find some gratitude for the hard work it does for you.
Sodium is a major powerful ion found in intra and extracellular fluids (fluids inside and outside of cells). It is important for water balance, conduction of nerve impulses, and muscle contraction.(1)The amount of sodium in the body largely determines the volume of extracellular fluids – where sodium goes, water follows.(1) Changing your sodium can change your blood pressure and change the regulation of many other ions like potassium and chloride.(1)
There is sodium in every cell of your body. It is a major part of the primary transport process of the body. The sodium binds to the pump in the cell membrane; ATP is then hydrolyzed and the phosphate energy is released; this releases the sodium from the cell, producing ADP. Now the pump changes shape and releases sodium to the outside. Now two potassium molecules bind to the outside of the pump. This potassium binding releases phosphate and allows the pump to return to its original position. The cycle repeats and the pump returns to its original position. It is able to moves both sodium and potassium against their electrical gradients that usually keeps potassium out of the cell and sodium in.
This complicated electrochemical process is essential for cardiac function, skeletal movement, and neuron function. It allows the muscle and nerve cells to function normally and allows the body to maintain its normal fluid balance. And this process repeats itself in the body, over and over each day, in each cell. What a miracle.
Changing your sodium intake can change your blood pressure and change the regulation of many other ions like potassium and chloride. Hyponatremia (an imbalance in the electrolytes in your body) is a common occurrence which can be associated with many serious conditions such as heart failure, pneumonia, and liver failure. It is the most common electrolyte abnormality because sodium is the most common electrolyte in the body. This is why a paramedic will start a normal saline IV before he takes someone to the hospital after an accident, and before he really knows what is wrong: without the right amount of sodium, death may ensue.
Sodium volume determines blood pressure and volume. Extracellular sodium is monitored by hypothalamic osmoreceptors (1) When these receptors determine that there is not enough fluid in the body, it releases a hormone that causes the kidneys to retain sodium, causing water to follow, thus increasing blood volume and blood pressure, while potassium is eliminated from the body (2).
Salts enter the body through foods and fluids; getting enough sodium is not usually a problem because of the amounts of salt containing foods we eat and the amount of sodium in our processed foods intake.
Sodium, the main ingredient in salt, is an essential part of our diet, and not just for flavor. It keeps our muscles and nerves working properly, and it helps our bodies maintain the proper balance of fluids.
But when sodium levels rise too high, blood pressure often goes up as well. Over time, high blood pressure can have serious, life-threatening consequences. It can lead to stroke, heart attack, kidney disease, and other health problems.(1,2,3)
To protect against high blood pressure, U.S. dietary guidelines recommend that we get less than 2,300 milligrams of sodium per day. That’s about a teaspoon of salt. According to the American Heart Association, the ideal target for most adults is no more than 1,500 milligrams daily.
Most adults, however, get far too much. The CDC estimates that the average American adult eats 3,400 grams every day. (2)
In the last several years, scientists have begun to investigate whether salt affects obesity. Here’s what they have found:
- In 2015, British and Chinese researchers reported that body fat increased for children and adults on high-salt diets. Eating an extra gram of salt each day increased the risk of obesity in children by 28% and in adults by 26%. The study authors said they don’t know why salt has this effect, but other studies suggest that it may change the way our bodies burn fat.
- An Australian study published last year linked high-salt diets with a 23% increased chance of obesity in schoolchildren. Those children may eat more because the salt makes the food taste good, the authors suggest. They also speculate that when they get thirsty after a salty meal, the children reach for easily available high-calorie sodas.
- Another Australian study from 2016, led by Russell Keast, PhD, tied salt to an 11% rise in the amount of food and calories that adults take in. The authors say salt improves the flavor, and that likely tempts people to eat more. (2)
Keast, a professor of food science and head of the Centre for Advanced Sensory Science at Deakin University, said in an email that he believes salt encourages people to eat more.
While these studies show a link between salt and body fat, increased eating, and obesity, they don’t show that salt makes any of those things happen. More research needs to be done to fully understand salt’s role. (2)
People who eat more salt tend to weigh more. But maybe not for the reasons you think.
Eating a lot of salt can cause your body to retain more water, which can show up on the scale as extra pounds. But we’re not just talking about water weight here. High salt diets appear to be linked to higher body fat—in particular, the kind of fat that accumulates around your middle.
There are a few obvious explanations for this. First, just think about what kinds of foods tend to be higher in salt: snacks, chips, fast food, fried foods, processed foods, and restaurant meals. It might also surprise you to know that bread is one of the primary sources of sodium in the Western diet.
All of these high-sodium foods are also relatively high in calories. Not only that, they are notoriously easy to overeat. So, if your diet contains a lot of snacks, chips, bread, fried foods, and restaurant meals, you’re not only going to be consuming a lot of salt, but probably also a lot more calories. That could certainly explain the link between sodium and weight. (3)
When you read the labels on these foods know that it is your responsibility to protect your body. Start with the serving size. Will that be reasonable for you? Then move to the mg of sodium. Calculate the mg of sodium you will get with your serving size. Your goal is 2000-2300 mg sodium per day. What part of your meal plan will this food become? Is that the same as your sodium portion? If not, make an adjustment that works for you.
(1) Marieb & Hoehn; Human Anatomy and Physiology; Pearson, 2018
Blessings to you,