Potassium – getting enough?

CarrotSelfPortraitSept28Are you getting muscle cramps? Palpitations? Constipated? There are a number of causes for such symptoms, but one of them may be a common and easy-to-fix culprit: potassium deficiency.

Potassium is an essential mineral, and one of the electrolytes upon which our bodies depend to convey electrical messages across our cell membranes. They are essential in muscle and nerve function. Other electrolytes include sodium, calcium, bicarbonate, magnesium, chloride, hydrogen phosphate and hydrogen carbonate. For good health, electrolytes, like so much in our bodies, must be in balance, and the best sources are from food. Deficiencies and excesses are common in these ill-fed times.

Electrolyte imbalances can occur with age, dehydration (from exercise, heat exhaustion or inadequate fluid intake), eating disorders, vomiting and diarrhea, or chronic conditions such as kidney disease, diabetes and high blood pressure. Because of the link to muscle function, heart disease and stroke have a strong association with electrolyte imbalances, and potassium deficiency in particular.

Imbalances in sodium and potassium are the most common in North American diets, where we typically consume more sodium than we need, and too little potassium. Because we rely on our kidneys to filter out excess electrolytes, people with kidney disease or impaired kidney function – such as the elderly, people with high blood pressure and/or diabetes – are at particular risk of imbalances. People on blood pressure medications such as ACE inhibitors or beta blockers as well as over-the-counter painkillers such as Ibuprofen or Aspirin may have excess potassium, while thiazide diuretics, steroids and laxatives deplete it.

Overall, potassium is needed for proper function of the heart, kidneys, muscles, nerves, and digestive system, and helps to regulate fluid balance, the body’s acid-base balance, bone health, and blood pressure.

It seems few adults reach the RDA of 4700 mg potassium/day. This will be particularly true for those eating diets high in processed foods and low in fresh fruits and vegetables, since processing depletes foods of potassium, and it’s not commonly added to processed foods. Moreover, there’s a gender gap. According to the World Health Organization,

Women consistently have lower levels of potassium intake than men, but both groups commonly consume a level that is below current recommendations.

Getting the balance of all electrolytes right is, as usual, down to eating a balanced, varied diet, and drinking enough water. Supplementation isn’t normally recommended, because you may not know if your kidneys are under-performing, and because of the complicating factors of medications and undiagnosed conditions.

Potassium-rich foods

Most people know that bananas are a good source of potassium (an average of 422 mg for a medium-sized one) but PotatoTeddyeven better sources are potatoes (610 mg for a smallish one) or sweet potatoes (694 mg) – both with skin – or a cup of butternut squash (600 mg). A large raw carrot is around 233 mg, while a cup of avocado has 727 mg.

Fish/animal protein sources are relatively high too: 3 ounces (=84g) of fish such asĀ salmon (528 mg) or halibut (490 mg) or chicken (around 550 mg); a pork loin chop (700 mg) or 6oz rib eye steak (around 600 mg). A cup of plain, full-fat yogurt is 380 mg;

Vegans and vegetarians can depend on protein sources such as beans; pinto (616 mg/cup) are highest (tofu is pretty low, at 121 mg per 100g). 100g of hazelnuts (about 2/3 cup) is 755 mg; same amount of almonds is around 700 mg.

A cup of tomato juice is around 430 mg, half a cup of prunes is about 700 mg, and a large fresh peach is 333 mg. Best of all, you’ll get 500-700 mg from a 100g bar of chocolate (dark – with >72% cocoa solids – has more than milk chocolate, and of course adding nuts will increase the value further!)

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