THE CARDIAC RISKS OF POTASSIUM DEFICIENCY

Potassium is very important for muscle and especially heart muscle function. Along with water, potassium is involved in multiple body processes. Low potassium on a blood test is a known risk factor for sudden cardiac death. The routine blood chemistry range is 3.5 - 5.5 mmol/l. However, this range is determined by life and death scenarios, not healthy scenarios. The medical literature on quality of life points to 4.5 - 5.5 as being an optimum potassium level. That means that a level in the low 3’s and 4’s is definitely a cause for concern. Even a level of 4.1 or 4.2 can reflect an increased risk of heart dysfunction.

Potassium and metabolic imbalances

Therefore, where potassium levels are consistently below 4.5, this tells us that there are things interfering with potassium metabolism and that we should be looking for cardiac risk factors. There is a need to look for metabolic imbalances driven by too much stress, too much caffeine, too much carbohydrate, too much inflammation, too much infection etc.

Potassium and sudden cardiac death

Why is low potassium a risk factor for sudden cardiac death? The heart is a muscle. Electrical signals that come from the central nervous system make muscles contract. The ability to contract is based on the relationship between water and all the electrolytes. The major electrolytes are sodium, chloride, calcium, potassium and magnesium and they need to be balanced. One of the problems is that people get too much dietary sodium and not enough potassium and magnesium. Potassium isn’t added to processed foods in the same way as sodium; it’s only really found in green leafy vegetables and some people eat very little of these.

Symptoms of low potassium

Some of the common signs of low potassium are:

• Muscle cramping and twitching.

• Fatigue on climbing stairs/walking.

• Aching muscles - potassium is an alkaline mineral, and when deficient, can trigger too much lactic acid production with consequent aches, cramps and fatigue.

• When potassium drops dangerously low - slurred speech, confusion and weakness can ensue.
  

Low potassium and cardiac events: the literature

There are a growing number of papers in the medical literature linking low serum potassium (known as hypokalaemia) and sudden cardiac events.

Urso et al. (2016) - Almost 50% of all fatal heart attacks are related to arrhythmias as a result of suboptimal fluid and electrolyte balance.

Hoppe et al. (2018) and  Nayyar et al. (2017) - Significant stressors can rapidly reduce serum potassium levels. This is not so much of a concern for the healthy population as the induced hypokalaemia will not last long enough to have a significant affect on a healthy heart. However, in people with pre-existing suboptimal heart function, even a period as short as a few seconds of low potassium could trigger ventricular fibrillation and possibly a life-threatening outcome. Therefore, the generally accepted potassium range may be acceptable for the healthy population but the ideal range tightens dramatically with heart dysfunction. 

Khan et al.(2013) and MacDonald et al. (2004) - Magnesium and potassium should be supplemented concurrently to get optimal clinical results for restoring potassium balance.

Geethavani et al. (2014) - 400mg of caffeine (approximately 4 cups of coffee) over 2 hours has been found to significantly deplete potassium.

Khan et al. (2013) The QT interval on an ECG examination and its abnormal prolongation to more than 440 milliseconds may identify a deficiency of myocardial potassium and magnesium. So, check the QT interval.

Refeeding syndrome and the dark side of fasting

The ‘Refeeding Syndrome’ was first reported among those liberated from the concentration camps in World War 2 (Burger et al., 1948, Schniker et al., 1951). Starving prisoners were given anything the liberating soldiers could lay their hands on - chocolate bars and biscuits - resulting in the sudden death of around 500 prisoners from Auschwitz and as many as 14,000 from Belsen. This is to do with the hormone insulin which puts things into the cells.  When you get a sudden spike in insulin from a sugar rush or stressful event increasing cortisol, you get a big increase in potassium moving into the cells and a sudden decrease in potassium out of the circulation. In susceptible people, this can result in tachycardia, arrhythmia and sometimes even death. This is particularly relevant if you haven’t eaten for quite a while. This is the dark side of fasting which has become fashionable in recent times.  The key message is: don’t fast if you are eating a junk food diet to avoid the dangers of refeeding syndrome.

Track your potassium levels 

If you have a heart condition, monitor your potassium level along with your other electrolytes. Watch out for scenarios like this: if you have been travelling for several hours and not eaten properly and your health is not that good, don’t break your fast with a cake and a coffee, otherwise you risk a sudden potentially dangerous potassium imbalance.

So, tracking your potassium level is important. But if it is low, this doesn’t necessarily mean reach for the potassium pills. A low potassium result on a lab test usually means imbalance - not necessarily deficiency - too much in the cell, too little in the serum.

Lifestyle changes are important

Lifestyle changes, as explained above, are potentially just as important as supplementing. You want to look at diet, stress, blood sugar regulation, caffeine consumption, eating too many sweets, drinking too much alcohol and levels of other electrolytes like magnesium.  Find out why your potassium is low and then work on those factors.

Dangerously high and low potassium

I have written about low potassium in this newsletter, however, you can get the situation where potassium is too high on your lab test (6.5 mmol/L). This is just as much a medical emergency as very low potassium.  When I see a potential hyperkalaemia (too high potassium) situation, I advise retesting potassium straight away to see if this is a false high (caused by too tight a tourniquet on the blood draw) or if they really have elevated potassium and need the appropriate emergency correction for hyperkalaemia.

If you are concerned about heart health and would like to track your potassium and other electrolyte levels, please contact the Good Health Clinic on goodhealthclinic@outlook.com to request a free 30 minute Enquiry Call or book an appointment.