Does Salt Really Cause High Blood Pressure?

By Carol Chuang, MS, CNS, CMTA, FDN

For decades, doctors have been telling you to eat less salt as it causes hypertension or high blood pressure, which raises your risk of heart disease. Current dietary guidelines in the U.S. recommend limiting your salt intake to anywhere from 1.5 to 2.4 grams of sodium per day, which varies depending on which organization you ask. (For reference, one teaspoon of regular table salt contains about 2.3 grams of sodium.) According to some estimates, Americans get roughly 4 grams of sodium per day, which has long been thought to be too much for heart health.

However, recent publicized research found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes, or death in people with normal or high blood pressure. In fact, research showed that too little salt in your diet may also increase your risk of heart disease! 

This article will shake up the salt myth. It discusses the role of salt in the human body and the differences between processed table salt and natural unprocessed salt. It reveals the latest research findings on salt intake and how it affects your health, and finally, other factors that may help to normalize your blood pressure.

Physiological Roles Of Salt In The Human Body

Salt has been a highly prized substance for thousands of years across all cultures and continents. Salt provides two main elements - sodium and chloride - both of which are essential for life. Your body cannot make these elements on its own, so you must get them from the diet. 

Sodium is a vital nutrient and is responsible for many vital functions in the body. It:

• Is a major component of your blood plasma, lymphatic fluid, extracellular fluid, and amniotic fluid.
• Maintains and regulate blood pressure through a delicate sodium-potassium balance in the body. This function is handled by the kidneys which are capable of adjusting to fluctuating levels of sodium and potassium in the diet to maintain homeostasis (internal stability). 
• Carries nutrients into and out of your cells.
• Maintains your acid-alkaline balance.
• Helps your brain communicate with your muscles.
• Increases the glial cells in your brain, which are responsible for creative thinking and long-term planning. Both sodium and chloride also play an important role in the communication among nerve cells.
• Supports the functions of your adrenal glands, which produce dozens of vital hormones

Many people wonder why the natural salts are so much more expensive than regular table salt. Is it really worth it? Here are the differences.

Natural unprocessed salt, such as Celtic sea salt and Himalayan salt, contains about 84 percent sodium chloride. The remaining 16 percent are naturally-occurring minerals and trace elements, such as potassium, magnesium, calcium, phosphorus, sulphur, bromine, boron, zinc, iron, manganese, copper, and silicon, that the body can use for many different functions.

Processed table salt contains 97.5 percent sodium chloride and hardly any other minerals. The rest is man-made chemicals, such as moisture absorbents and flow agents.

It is, hence, obvious that natural unprocessed salt has much more nutritional value than processed table salt, not to mention that it does not contain any artificial chemicals.

Among the various types of natural salt, Himalayan salt, in addition to being naturally lower in sodium, is also much higher in potassium compared to other salt. Himalayan salt contains 0.28 percent potassium, compared to 0.16 percent in Celtic sea salt and 0.09 percent in processed table salt. Therefore, Himalayan salt has a much more preferable sodium-potassium ratio than any other salt.

Research Findings On Sodium Intake And Health

Conventional understanding is that excess salt causes hypertension which increases heart disease risk. However, when you look at the long list of publicized studies, you cannot find strong evidence that reducing salt intake will cut down your risk of dying from heart disease.

In 2014, the New England Journal of Medicine published a four-year long observational study named the Prospective Urban Epidemiology Study (PURE), which included more than 10,000 people in 17 countries. It found that while higher sodium levels correlate with an increased risk for high blood pressure, potassium helps offset sodium's adverse effect.

In addition, those with the lowest risk for heart problems were consuming 3 to 6 grams of sodium a day, far more than the current U.S. dietary guidelines of 1.5 to 2.4 grams daily.

However, when sodium level went above 6 grams or go below 3 grams a day, the risk for heart disease went up. Other recent studies also confirmed this observation. That means while there is some relationship between sodium and high blood pressure, it is not exactly a linear relationship.

Long-term salt restriction may have other serious health consequences too. A 2010 Harvard study showed that low sodium intake is associated with poor outcomes in type 2 diabetes. Low-salt diets led to an immediate onset of insulin resistance, a precursor to type 2 diabetes. This calls into question the appropriateness of dietary guidelines advocating sodium restriction for patients with type 2 diabetes.

Salt restriction may also be especially dangerous for the elderly. Studies found that elderly people who have hyponatremia (low sodium level in the blood) have more falls and broken hips and a decrease in cognitive abilities. Hyponatremia is a common finding among the elderly due to universal guidelines recommending sodium restriction for those with acute illness.

Studies have shown that restricting salt is also problematic for athletes, particularly those who engage in high intensity or long duration exercises. Such athletes should make sure they adequately replace the salt lost through sweat.

When Is Salt Reduction Warranted?

While most people have no reason to restrict salt to the levels recommended by various health organizations, there are a few health conditions in which lower salt consumption may be warranted.

1. Salt sensitivity

For those who have high blood pressure, there is evidence that some individuals have inherited salt sensitivity, which is thought to be caused primarily by impaired sodium transport in the kidneys. People with this trait will have a significant blood pressure response to a high salt intake. However, increasing dietary potassium seems to mitigate such effect and may even eliminate the salt sensitivity.

2. Impaired renal function

Patients with chronic renal disease typically have reduced glomerular filtration rates and may have more difficulty excreting high levels of sodium. Therefore, increased sodium intake may become toxic to the kidneys when sodium filtration is impaired and may lead to unsafe levels of proteinuria (abnormal amount of protein in urine).

3. Kidney stones

Those who are prone to kidney stones may need to reduce their salt intake. High sodium intake leads to high sodium as well as high calcium excretion in the urine. High calcium excretion may lead to kidney stone formation, particularly if fluid intake is inadequate.

4. Osteoporosis 

Since higher sodium intake is associated with increased calcium excretion, those with low bone density may benefit from a lower salt intake. However, a high salt intake is not believed to be the cause of osteoporosis, and the potential negative effect of a high salt intake can be offset by an adequate intake of calcium and potassium.

Strategies To Control Hypertension

1. Reduce excessive carbohydrates intake, especially refined carbs and sugars.

Those who have high blood pressure tend to have chronically high blood sugar, high insulin, and high triglycerides, all of which are caused by eating too much carbohydrates, in particular, refined  grains and sugars. Cutting out sugary beverages, white carbs, and sugary snacks should be your first step in managing hypertension. However, do not switch to "diet" foods made of artificial sweeteners as they too contribute to hypertension.

2. Alter your sodium-potassium ratio in the diet

Rather than severely restricting your level of sodium, which is essential for many vital functions in the body, focus instead on eating a high quality diet that is rich in potassium, as it helps to relax blood vessel walls and lower blood pressure. 

• Avoid processed foods, which are notoriously high in sodium (processed salt) and low in potassium.
• Eat whole, unprocessed foods, ideally organic and chemical-free.
• When using salt, use a natural salt. Himalayan salt contains less sodium and more potassium compared to other salts.
• Eat more potassium-rich foods every day. Lima beans, winter squash, cooked spinach, and avocado are particularly high in potassium. Other potassium-rich vegetables include broccoli, Brussels sprouts, asparagus, and pumpkin. Bananas, cantaloupes, papayas, and prunes are high in potassium too but watch out for the sugar content in these fruits.
• Green vegetable juicing is another way to increase your intake of potassium. Be careful not to use too much fruits or carrots in the juice as they contain high amounts of sugar.

3. Increase intake of other beneficial minerals like magnesium and calcium

Both have been shown to play a role in blood pressure management. 

• Magnesium-rich foods - dark leafy greens, avocados, nuts and seeds, beans and lentils, and whole grains.
• Calcium-rich foods - dairy products (preferably full-fat, grass-fed), dark leafy greens, canned sardines and salmon with bones, and bone broth.

4. Optimize your Vitamin D and K2 levels

• Research shows that vitamin D relaxes your arteries and improves blood pressure. Deficiency is associated with arterial stiffness and high blood pressure. Therefore, make sure you get adequate sun exposure safely, or alternatively, take a vitamin D3 supplement. Most people need at least 4,000 I.U. a day, some even up to 8,000 I.U., to achieve the optimal D3 level of 50-70ng/ml in the blood.
• Vitamin K2 is also important for preventing arterial plaque buildup and heart disease. The best sources of vitamin K2 are fermented foods, such as sauerkraut, kim chee, and other fermented vegetables, yogurt, kefir, and certain cheeses like Brie and Gouda.

5. Eat 3-4 servings of fatty fish per week

Fatty fish is high in essential omega-3 fats and these fats have been shown to reduce the risk of hypertension and heart disease in multiple studies. Wild salmon, sardines, and herrings are your best bet as they are lowest in mercury.

6. Eliminate caffeine

There is ample evidence that coffee and other caffeinated drinks may exacerbate your condition.

7. Increase nitric oxide in your blood

This compound can help to open constricted blood vessels and lower your blood pressure. Methods for increasing nitric oxide include taking a warm bath, breathing in and out through one nostril, and having bitten melon and beet juices.

8. Exercise regularly

If you are inactive, start with walking slowly and gradually build up your pace. If you are pre-diabetic or diabetic, high intensity interval exercises and weight training are most beneficial in regaining insulin sensitivity, which is essential for blood pressure management.

9. Learn how to effectively address and handle your day-to-day stress

Whether it is related to an issue at work, an argument with a friend, or problems with family, everyone feels stressed at times. Understand that most problems and solutions take time to deal with. In the meanwhile, give yourself time to de-stress. Try some of these methods and see if they work for you - deep breathing, meditation, yoga, guided visualization, aromatherapy, take a warm bath, listen to music, exercise, get a massage, write in your journal, take a nap, take a stroll, or cuddle your pet.

© Carol Chuang 2015

About the Author 

Carol Chuang earned a Master of Science degree in Nutrition from Huntington College of Health Sciences. She is a Certified Nutrition Specialist from the American College of Nutrition, a Certified Health Counselor from the Institute for Integrative Nutrition, a Certified Metabolic Typing Advisor, a Certified Functional Diagnostic Nutritionist, and a Certified Gluten Practitioner. She is also board certified by the American Association of Drugless Practitioners.

Carol is a Professional Member of the American College of Nutrition and the Price-Pottenger Nutrition Foundation. Apart from having her private practice counseling individual clients, she writes a monthly nutrition newsletter, and conducts regular seminars on various topics of nutrition and wellness.