How potassium fights high blood pressure
Is it possible that high blood pressure and heart disease may not be caused by too much salt, but by an imbalance in our diets between sodium and potassium?
We're constantly being told that too much salt is bad for us and that we need to limit our salt intake. The medical establishment tells us that salt raises our blood pressure, which can lead to strokes, heart failure and heart attacks, one of the leading causes of death and disability in developed nations.
High salt consumption is further linked to osteoporosis, stomach cancer, kidney disease, kidney stones, vascular dementia, obesity and water retention. It’s also believed to contribute to the symptoms of asthma and diabetes.
According to registered dietician Dr Ingrid van Heerden, "Certain populations are what is called ‘salt sensitive’ and react to high salt intakes by developing dangerously high blood-pressure levels."
If you take into account that more than 3 million Australian adults (32%) aged 18 years and over have high blood pressure, according to the National Heart Foundation of Australia, it certainly is worth taking a long, hard look at the factors that contribute to hypertension – our salt intake being one of them.
While the World Health Organization (WHO) recommends a daily salt intake of 4g to 6g of salt per day, the mean salt intake in Australia is an estimated 10g per day. This has led the National Health and Medical Research Council to set a "suggested dietary target" of 1600mg of sodium (equivalent to about 4g of salt) for Australian adults.
Too little sodium is even worse!
However, a 2011 study, published in the Journal of the American Medical Association (JAMA), indicated that when there’s too little salt in the diet, stroke, heart attack and death are more likely than when there’s too much salt in the diet.
Also, a 2012 study in the American Journal of Hypertension found that low-salt diets contribute to an increase in hormones and lipids in the blood. The conclusion of the authors was that the small reduction in blood pressure as a result of lowered sodium consumption was counteracted by the higher plasma levels of rennin, cholesterol and triglycerides, and that strongly reduced sodium levels may actually have negative effects on the population at large.
Potassium to the rescue
It seems almost impossible to maintain an optimal sodium level at all times, so how do we manage to stay healthy? Is it possible that high blood pressure and heart disease are not caused by too much salt, but by an imbalance in our diets between sodium and potassium?
A recent four-year long observational study (the Prospective Urban Rural Epidemiology [PURE] study) found that while higher sodium levels correlate with an increased risk for high blood pressure, potassium helps offset sodium’s adverse effects.
The authors of the study indicate that it would be a better strategy to concentrate less on sodium restriction and focus more on higher levels of potassium in the diet to counteract the hypertensive effects of sodium. (A diet high in processed foods is notoriously high in sodium and low in potassium.)
Our bodies need potassium to maintain the correct pH levels and to regulate blood pressure, and according to the PURE study, potassium deficiency may actually be more responsible for hypertension than excess sodium.
Potassium deficiency is called hypokalemia and symptoms include water retention, hypertension, arrhythmias, muscle cramps and constipation.
How to achieve a good sodium-to-potassium ratio
To make sure you obtain the correct ratio of salt and potassium, you need to:
- Avoid processed foods.
- Eat whole, unprocessed foods to increase your potassium intake.
Good dietary sources of potassium include:
- Sweet potato
- White beans
How much potassium do we need?
People 14 years and older need a daily potassium intake of 4,700mg as part of a balanced diet. White beans contain 561mg per 100g, baked potatoes 535mg and bananas 358mg. Note that boiling depletes potassium, so rather roast or steam your veggies.