Sodium is a mineral and necessary to our body’s health. Unfortunately, sodium has been vilified and become synonymous with salt, which is not entirely correct. Table salt is only 40% sodium and 60% chloride. Sodium has also been given a bad rap when associated with high blood pressure or hypertension; sodium intake is only one factor involved in the onset of high blood pressure. When sodium accumulates, our heart works harder and, coupled with other factors such as stress, poor nutritional choices and a lack of exercise, our blood pressure begins to rise. Sodium works with our kidneys to help maintain the right fluid balance in our body. Our kidneys excrete or retain sodium depending on whether we’re on the low side or the high side of the sodium see-saw. But, if for some reason they can’t excrete the overabundance, sodium begins to accumulate in our body.
The humble mineral salt seems to have had an influence on human existence almost from the very beginning. It allowed explorers to travel greater distances because food preserved with salt meant they would never be without sustenance. Many cultures incorporate salt into their traditions, such as offering bread and salt to a new home owner; “Bread, that this house may never know hunger, salt, that life may always have flavor…” Salt took on an economic and military importance which facilitated trading partnerships. And it’s been used to refer to someone as steadfast, trustworthy; “she’s the salt of the earth”. We’ve even endowed it with supernatural powers as we throw salt over our left shoulder to ward off misfortune.
But move forward a few centuries and now, knowing what we know, our love affair with salt is coming to an abrupt end. We’ve over-indulged and we’re suffering the consequences as conditions such as high blood pressure, which can lead to cardiovascular incidents, are on the rise. Luckily, with a little retraining and diligence, we can still enjoy that little boost of flavor that salt adds and manage to avoid the health concerns that over-indulgence brings.
Salt vs. Sodium
The Purpose of Sodium in the Body
You may have been told to keep the salt in your diet to a minimum but do you know the difference between sodium and salt? Whenever health experts refer to salt, what they’re really talking about is sodium because sodium is a major component of salt.
Salt is sodium plus chloride, sodium is an electrolyte.
Electrolytes are the smallest of chemicals that are important for the cells in the body to function and allow the body to work. Electrolytes such as sodium, potassium and others are critical in allowing cells to generate energy, maintain the stability of their walls, and to function in general. Electrolytes generate electricity, contract muscles, move water and fluids within the body, and participate in myriad other activities.
The concentration of electrolytes in the body is controlled by a variety of hormones, most of which are manufactured in the kidney and the adrenal glands. Sensors in specialized kidney cells monitor the amount of sodium, potassium, and water in the bloodstream. The body functions in a very narrow range of “normal”, and it is hormones like renin (made in the kidney), angiotensin (from the lung, brain and heart), aldosterone (from the adrenal gland), and anti-diuretic hormone (from the pituitary) that keep the electrolyte balance within those normal limits. Keeping electrolyte concentrations in balance also includes stimulating the thirst mechanism when the body gets dehydrated. 1
Regulation of Fluids – Sodium is most often found outside the cell, in the plasma (the non-cell part) of the bloodstream. It is a significant part of water regulation in the body, since water goes where sodium goes. If there is too much sodium in the body, perhaps due to high salt intake in the diet, it is excreted by the kidney and water follows.
Sodium is an important electrolyte that helps with electrical signals in the body, allowing muscles to fire and the brain to work. It is half of the sodium-potassium pump that works at the cellular level to move sodium into the plasma outside the cell and keep potassium inside the cell. When the balance needs regulating again, this pump “changes polarity” and lets sodium back into the cell and releases potassium out into the plasma.
For a quick video on how the sodium-potassium pump works, CLICK HERE .
Sodium also plays a role in maintaining the acid-base (pH) balance of blood which is no small task given the slim margin for error – the body must maintain blood pH between 7.35 and 7.45.
Regulation of Blood Pressure – Remember, water follows sodium, so if you have more sodium in your body than is necessary, you’re also going to have more fluid than is necessary. This increase in fluid increases pressure on the walls of your blood vessels, which in turn increases your blood pressure.
For a quick video explanation on sodium and blood pressure, CLICK HERE.
Keeps Muscles and Nerves Running Smoothly – Here again the dynamic duo of sodium and potassium work in tandem to conduct nerve impulses in your body so that your muscles can move…don’t forget, your heart is a muscle too! In short, nerve cells (mylenated neurons) use the movement of potassium (a negatively charged ion) and sodium (a positively charged ion) across the nerve cell membrane to transmit nerve impulses. When the nerve cell is at rest, the axon (tail of the neuron) has a higher concentration of sodium outside the membrane. Conversely, it has a higher concentration of potassium inside the cell. Again, it is the sodium-potassium pump that is responsible for changing the electrical state of the neuron (transmitting the nerve impulse) by moving sodium into the cell and potassium out.
Recommended Daily Intake of Sodium
Here’s a really good video that explains how nerve impulses travel down the axon of the nerve aided by sodium and potassium. It may seem a bit technical to some, but if you watch it two or three times, you’ll be an old pro on the Action Potential of a nerve.CLICK HERE .
If you’re trying to restrict your sodium intake, Health Canada recommends your daily intake, or Adequate Intake (AI) should hover around 1,200mg to 1,500mg, with the daily upper limit (UL) being 2,300mg.
anywhere between 4,000 & 6,000mg per day.
anywhere between 400 & 1,000mg per day.
The Canadian Heart & Stroke Foundation Health Check nutrient standard for sodium suggests, for the average Canadian, cutting back on salt and recommends setting a target of an UL of 2,300mg/day (the equivalent of 1 teaspoon of salt) which
can add up pretty quickly.
Adults – The United States Institute of Medicine (IOM) is commissioned jointly by the USA and Canada to establish the nutrient reference values that are used to set policies and standards. One of these reference values is the tolerable Upper Intake Level (UL), which is the highest intake level that is likely to pose no risk of adverse health effects. Based on the IOM’s UL, Health Canada recommends that adults do not exceed 2,300 mg of sodium per day. Recent data from the 2004 Canadian Community Health Survey (CCHS 2.2) Nutrition, indicates that Canadian adults consumed an average of 3,092 mg of sodium daily, more than double the level recommended and considerably higher than the UL. 2
Children – Salt in a child’s diet comes from the same places
an adult gets his salt; when it is naturally present in food, in
processed foods, and when it is added to prepared foods.
When your child is younger than six months, their kidneys are
not mature and this means they cannot remove any excess
sodium from the urine. A high level of sodium in their foods
could lead to dehydration and could be dangerous. If a child’s
diet is not monitored it is easy to exceed the RDI.
Watch Your Processed Foods!
You’ve heard it over and over; watch for all the salt in processed foods! But just which foods are most suspect when it comes to increasing the sodium levels in your diet? Let’s take a look at how sodium sneaks into your diet and ways you can “shake” the habit.
Processed and Prepared Foods – The largest contributors to hidden sodium in your diet come from breads, prepared dinners such as pasta, meat and egg dishes, pizza, cold cuts, bacon, cheese, soups, soda, and fast foods. Most manufacturers now have low sodium versions of their product, so look for the low sodium symbol/indication on the label and read the Nutrition Facts to see exactly how much you’re getting per serving.
Natural Sources – Certain foods just naturally contain sodium. The list includes vegetables, dairy products such as milk, meat and shellfish. While these foods don’t have an abundance of sodium, eating these foods does add to your overall sodium intake. For example, 1 cup of low-fat milk has about 107mg of sodium.
In the Kitchen and At the Table – Salt is a given in most recipes and then, over and above what’s in the recipe, people add salt to their food at the table. If you’re trying to reduce the amount of salt in your diet, take the salt shaker right off the table and switch to a salt substitute for cooking. Or better
yet, learn to cooks with herbs and spices and eliminate the need for salt to
be the main flavoring agent in your foods.
Managing A Lower Sodium Diet
Even if you don’t add salt, be mindful if you reach for the ketchup because condiments have salt in them too. One tablespoon of soy sauce has about 1,000 mg of sodium, two teaspoons of yellow mustard has 112 mg, and one tablespoon of ketchup has 178 mg.
|For an exhaustive list of sodium in foods,|
|For an interactive guide on how to read Nutrition Facts labels, CLICK HERE.|
A few suggestions that should help you manage your sodium intake include:
- Cooking with fresh ingredients rather than using pre-packaged or prepared foods.
- Choosing low-sodium foods or those without added salt.
- Substituting or eliminating high-sodium ingredients from recipes.
- Creating marinades for meat with a base of citrus rather than sodium-based liquids (pineapple, orange, lemon).
- Avoiding salt substitutes and learn to use fresh herbs and spices instead.
- If you eat a frozen meal, look for those with 600mg of sodium or less. Augment the frozen meals with freshly steamed vegetables or brown rice.
- Don’t flavor foods with seasoning mixes – they contain crazy-high amounts of salt.
The problem of getting too much sodium in our diet can be countered somewhat but increasing your potassium intake. Remember, sodium and potassium work in concert; the two electrolytes have opposite effects on blood vessels: sodium restricts blood flow and potassium helps its. The researchers suggest cutting back on salt and taking in more potassium. So forget the chips – a banana is a safer snack for your health. Just watch where you toss the peel. 3
Sodium and Your Kidneys
Replenishing After A Workout
Your kidneys, two bean-shaped organs about the size of your fist located in the middle of your back, work to filter out toxins and excesses from your body and maintain homeostasis; a state of relative stability, especially as maintained by physiological processes in the body. Kidneys maintain water volume and balance, as well as regulate different components of your blood such as proteins, glucose, and you guessed it, ions such as calcium and sodium. The excesses removed from the large quantities of blood that are sent through your kidneys every day are then excreted from the body in the urine. What your body needs is sent back into your body.
Where Sodium Goes, Water Follows
Why do you always hear the words “sodium” and “kidneys” used in reference to each other? Because, more than any other part of your body, excess sodium affects your kidneys and their ability to regulate your blood pressure appropriately. In simplest terms, when you eat too much salt (which contains sodium) your body holds extra water to “wash” the salt from your body, This can cause blood pressure to rise. The added water puts stress on your heart and blood vessels.
For an in-depth review of the anatomy of your kidneys, and what all the bits and pieces do, CLICK HERE.
To learn how excess sodium in your diet can affect blood pressure, inflammation, and your kidneys, CLICK HERE.
When you work hard at the gym or in the back yard, or if you are ill and are experiencing extensive vomiting and diarrhea, you are losing fluids. This loss of fluid causes you to lose sodium in your sweat and sodium is a necessary *electrolyte. These electrolytes must be replaced to keep the electrolyte concentrations of your body fluids constant.
Signs of an Overload or Deficiency
Electrolytes are important because they are what your cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses across themselves and to other cells. Your kidneys work to keep the electrolyte concentrations in your blood constant despite the changes in your body.
Commercial electrolyte solutions are available to replenish the electrolytes after a long workout or during an extended sickness; for sick children there is Pedialyte and for athletes there are sports drinks such as Gatorade.
*An electrolyte is a substance that breaks down into ions in a solution and acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium and phosphate are examples of electrolytes.
Sodium Overload Simple dehydration is a sign you may have consumed too much salt. Symptoms include dry skin, sleeplessness, headaches, fainting spells, or a fast and weak pulse.
When you become severely dehydrated and your kidneys cannot cope with the excess salt in your bloodstream, a condition called hypernatremia sets in. Symptoms include irritability, muscle cramps, confusion, depression, and vomiting.
Bloating occurs because of water retention as the body tries to dilute the salt with large amounts of water. It sounds at odds, but the best way to reduce the bloating is by drinking more water.
Excessive thirst is a symptom of people who consume too much salt. High blood pressure is a sure sign of a sodium overload.
Conditions & Diseases
Recognizing the symptoms of a sodium deficiency is important because, if left untreated, can become serious. Symptoms include gastrointestinal distress, vomiting, decreased appetite, and nausea.
Decreased sodium levels in your body might also cause mild cognitive impairment. Most tissues in the body can handle the expanding tissue cells caused by hyponatremia (too much water, not enough sodium), but the brain cannot. Symptoms include headache, lethargy, fatigue, and confusion. In the extreme, a person may experience hallucinations and a decreased level of consciousness.
Low levels of sodium can also cause problems for your muscles. Symptoms include spasms or cramps, or muscles that are weak and easily fatigued.
There are several reasons why a body would retain more fluid than is necessary including a reduced ability of the heart or kidneys to do their job, in which case, swelling most likely appears in the legs and ankles. However, the most common cause of fluid retention is excessive salt consumption, followed by the body’s inability to eliminate the excess. This sets up a kind of catch-22 situation; you eat salty foods, your body retains fluid to dilute the salt, salty foods make you thirsty, you end up consuming more liquid. While this is the more common of reasons for fluid retention, it is certainly not the most serious and generally does not cause gross water retention (even though it feels “gross”).
Dehydration & Sodium Levels
hyper=too much + natr=sodium + emia=in the blood
Hypernatremia is a condition which occurs because of dehydration when the sodium-to-water balance is upset. When there is too little water in the body, your body retains what little it has, thereby retaining sodium as well. This condition can occur during an illness when vomiting and diarrhea are exaggerated, when fever or overexertion causes excessive sweating, or from consuming liquids high in salt (soup broth, pickle juice).
Hyponatremia occurs when too much water is present in the body. In this case, the sodium in the blood becomes diluted to the point where the balance can’t be maintained and the kidney’s compensation mechanism becomes overwhelmed. Occasionally, the body secretes an inappropriate number of anti-diuretic hormones and too much water is retained. This is usually associated with conditions such as pneumonia and thyroid problems.
Hypertension (High Blood Pressure)
According to the National Heart Lung and Blood Institute, U.S. Department of Health & Human Services, “high blood pressure, or hypertension, affects about 50 million Americans – one in four adults. It is the leading cause of stroke and contributes to heart attack, heart failure, and kidney failure. …Sodium chloride, or table, salt, increases average levels of blood pressure.”
The Centers for Disease Control and Prevention notes that, “Too much sodium is bad for your health. It can increase your blood pressure and your risk for a heart attack and stroke.”
Because sodium ions attract water, increased amounts of sodium increases the amount of fluid in the body. Increased fluid in the body causes an increase in blood volume. As blood volume increases the blood pressure must increase in order for the heart to keep the blood circulating. When people consume excessive amounts of sodium, the kidneys work to remove more of the sodium and excrete it in the urine. However, sometimes the kidneys cannot remove all the excess sodium, which allows the sodium to affect blood pressure. 4
The best way to avoid unseen salt in your diet is by including more fresh fruits and vegetables, steering clear of processed foods, and making it a priority to become an avid label reader!
CLICK HERE to watch “Unseen Salt and High Blood Pressure”, CDC-TV
Your kidneys filter the blood that passes through them to remove excess water and waste products and to put back what the body still needs. They also maintain the proper balance of electrolytes, including sodium. Although a special part of the kidney, called the glomerulus, removes the majority of sodium from the blood, some of it is reabsorbed back into the bloodstream.
The relationship between the kidneys, sodium levels and blood pressure is cyclical. The kidneys regulate the amount of sodium in the blood. They also regulate blood pressure. High blood pressure damages blood vessels, including the tiny vessels in the kidneys. As the glomeruli become damaged due to high blood pressure the kidneys lose their ability to filter out excess water and sodium. This leads to an increase in blood volume which contributes to increasing blood pressure even more. 5
Specifically referring to salt, this is how kidneys can become damaged. However, this is only one of many different ways in which kidneys become damaged enough to cease functioning.
CLICK HERE to watch “Lead A Healthy Life – Salt, We Consume Far Too Much!” Fresh Food/Low-No Salt Recipes
Infuse your day with health-smart smoothies that incorporate both fruits AND vegetables. Great for busy people, portable enough to take to the office, power up your body in just minutes a day…
The Smoothies Bible – Second Edition, by Pat Crocker (384 pages)
Comprehensive book on not only vegetable and fruit smoothies, but it fully covers ingredients including herbs. There are dairy and non-dairy alternatives as well. An excellent book for healthy eating in the “liquid” form.
Green Smoothie Revolution: The Radical Leap Towards Natural Health, by Victoria Boutenko
A. William Menzin, MD, Harvard Medical School says about this book, “In more than thirty-five years of practice as a psychiatrist affiliated with the Harvard Medical School, I have learned one thing very well: Human behavior is very hard to change. Now Victoria Boutenko is persuading me otherwise.… Thirty days of green smoothies will change how you feel, and how you feel about yourself. That’s no small achievement for one small book.”
The Company’s Coming series of cookbooks by Jean Pare are excellent choices,
specifically the Heart-Friendly Cooking and Vegetables. Just be vigilant about the
amount of salt used for cooking.
CLICK HERE to listen to the audio file, Reducing the Sodium Intake in the United States,
from The National Academies Press, Sounds of Science Podcast.
1. Electrolytes, emedicinehealth.com
2. It’s Your Health, Health Canada and the Public Health Agency of Canada.
3. Sodium and Potassium Together Determine Risk for Heart Disease Death
4. & 5. Sodium & Your Kidneys