Everything You Need To Know About Potassium

Foods high in potassium are often glorified, what makes it all that great?

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Everythign You Need To Know About Potassium

What is Potassium?

Potassium is an essential mineral for the human body. Recently, the Dietary Guidelines for Americans and the Food and Drug Administration (FDA) designated potassium as “a nutrient of public health concern” because its generally deficient across the US population. [1]

Potassium plays a key role in several physiological processes because it preserves cell function, principally in excitable cells such as muscles and nerves. [2]

Potassium deficiency is related to hypertension (high blood pressure) and cardiovascular diseases, the two most common adverse diet-related health consequences in the US. In 2004, the Food and Nutrition Board of the Institute of Medicine established recommended intake levels for potassium at 4700 mg/day.  [1] [3]

Despite these recommendations, data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2008 evaluated an average intake to be 2290 mg/day for women and 3026 mg/day for men in the US, considerably lower than the proposed values. [4]

This virtual “deficiency” of dietary potassium is even more important if we consider the potassium intake of prehistoric humans was around 15,000 mg/day, over four times the NHANES recommendation. [2]

The body’s potassium supply varies according to an individual’s genetics, sodium intake, and blood pressure status. Blood pressure is presently the main criterion for establishing potassium requirements, and we know that

  • African Americans tend to be more vulnerable to hypertension, and more receptive to potassium supplementation, than Caucasians. [5]
  • Hypertensive persons (those who already have high blood pressure) are more receptive to increased potassium intake than normotensive people (those whose blood pressure is normal/healthy).
  • Potassium can decrease blood pressure even for those consuming a high-salt diet. [6] [7]

In Which Food(s) Can We Find Potassium?

NHANES data revealed that 99.2% of potassium in the US diet is found naturally, the remaining 0.8% coming from fortified foods. The potassium sources include milk and other non-alcoholic drinks, as well as potatoes and fruit, which are the highest sources of potassium among US adults. [7]

Potassium-rich foods include:

  • Potato, baked (1,081 mg per 1 medium with skin)
  • Avocado (over 1000 mg per whole fruit)
  • Tomato (909 mg per 1 small raw or 1 cup sauce or juice)
  • Spinach (839 mg per 1 cup cooked)
  • Sweet Potato (855 mg per 1 large)
  • Wild-caught Atlantic salmon (772 mg per 6 ounces)
  • Dried Apricots (756 mg per half-cup)
  • Carrots (689 mg per 1 cup juice or raw)
  • Flounder (585 mg per 3.5-ounce baked)
  • Bananas (487 mg per 1 large – but also high-carb/sugar, use for post-workout energy boost)

“Potassium intake decreased with the agricultural revolution when energy intake shifted from a variety of plants including potassium-rich tubers to cereals and animal products that have lower potassium concentrations and then further decreased with a shift to highly refined processed foods.” [6]

3 Interesting Facts About Potassium

  1.  “Dietary potassium supplementation attenuates (reduces) the effects of a high dietary salt intake, showing a linkage to reduction in blood pressure, stroke rates, and cardiovascular disease risk.” [8]
  2. Potassium increases both urine production and the excretion of excess sodium via urine.
  3. Potassium supplementation may improve sleep quality

Health Benefits of Potassium

Potassium and Hypertension (High Blood Pressure)

Several studies reported that potassium intake is inversely associated to the occurrence of hypertension. Furthermore, potassium supplements help to prevent low potassium levels in the blood, which lowers blood pressure in individuals with hypertension, while blood pressure rises in individuals with hypertension placed on a low-potassium diet. This rise in blood pressure is related to increased amounts of sodium reabsorbed from the kidneys. [2]

A study compared two diets: one with 3.5 servings/day of fruits and vegetables plus 1700 mg/day of potassium, and the other with 8.5 servings/day of fruits and vegetables plus 4100 mg/day of potassium. The authors found that a high-potassium diet is associated with lower blood pressure, as well as in those who consumed higher quantities of sodium. [9] [10]

Another study found that increasing potassium intake would reduce the incidence of hypertension in Americans by 17 percent and would raise life expectancy by 5.1 years. A dietary intake greater than 3500 mg/day is recommended for the prevention of hypertension. [11] [12]

Potassium and Stroke

Several studies have indicated that increased potassium intake is related with a decreased risk of stroke. It has been found that men who consumed around 4300 mg/day of dietary potassium  were less likely to have a stroke than those who consumed only 2400 mg/day. This inverse relationship was particularly strong in men with hypertension. [13]

Moreover, a 4500 mg/day potassium chloride supplement improved salt-induced homeostatic anomalies (situations that throw the body’s balance out of whack) related to the risk of cardiovascular disease and stroke in rural populations in China. [6]

While more related to fruit and vegetable consumption than to potassium itself, one study made some interesting discoveries. It evaluated the effect of white fruit and vegetable consumption on stroke outcomes. In a Dutch population study, categorizing fruits and vegetables by color, an increase consumption of 25 g/day of white fruits and vegetables was related with a 9 percent lower risk of stroke. Those fruits and vegetables classified as “white” for the purpose of the study were as follows: garlic, leek, and onion; apples, pears, applesauce and apple juice; Banana, cauliflower, chicory, cucumber, and mushroom. This study confirms the benefit of fruit and vegetable consumption in reducing the risk of stroke. [14]

Potassium and Osteoporosis

Potassium is good for our bones.

Fruits and vegetables, the highest sources of potassium, are rich in substances that buffer acids in the human body. The contemporary Western diet is moderately low in sources of foods like fruits and vegetables, and high in sources of acidic foods (fish, meats, and cheeses). When the amount of these acid-buffering substances isn’t enough to preserve normal pH, the body activates and diverts calcium from our bones to counteract acids consumed in the diet and those produced by metabolism. An increased intake of fruits and vegetables decreases the acid of the diet and could conserve calcium in bones; less calcium needs to be mobilized to preserve normal pH. [2]

In a study of 266 elderly (70-80 years) post-menopausal women, increased dietary potassium was associated with higher hip (at 1 and 5 years) and total body (at 5 years) amount of bone mineral as compared with those with lower amounts of potassium intake. A high consumption of fruits and vegetable accompanied by higher levels of potassium consumption were reported to have similar beneficial effects on bone mineral density, including indicators of bone formation in pre-menopausal and post-menopausal women and elderly men.

The study concluded: “Potassium intake shows positive association with bone density in elderly women, suggesting that increasing consumption of food rich in potassium may play a role in osteoporosis prevention.” [15]

Potassium and the Kidneys

Potassium homeostasis (balance in relation to the rest of the body) is regulated by the kidney. Urinary excretion of excess potassium may attain 3600 mg/day unless more than 90% of kidney function is lost. Therefore, a healthy kidney has good ability to maintain potassium homeostasis in case of excess potassium.

Too much calcium in our urine—either from calcium supplements or because our body is having to pull it from our bones to offset an acidic diet—increases the risk of kidney stones, super-concentrated crystals of calcium that form in the kidneys and which are very painful to excrete through the narrow tubes of the urinary tract. Potassium intake has been related with a decrease of urinary calcium excretion.

Lower levels of calcium in the urine persevered over 3 years in men and women given 540, 900, or 1620 mg/day potassium bicarbonate. Some studies reported that high intake of potassium is related with a reduction in recurrent kidney stones. This suggests that potassium has a role beyond its de-acidifying effect. By lowering the calcium loss, potassium may contribute to calcium retention in the blood and bones, thereby limiting bone mineral dissolution. Limit the dissolution, the calcium doesn’t accumulate in the kidneys and kidney stones can’t form.[6]

Is Potassium Ever Bad For You?

Potassium is essential for health in proper amounts.

But while potassium is essential for health, an excess of potassium may cause feelings of burning or tingling, weakness, mental confusion, paralysis, listlessness, dizziness and irregular heart rhythm.

The Takeaway

A wide range of evidence exists to conclude that consumption of foods rich in potassium is beneficial for health. Studies suggest that an intake of 3600–3800 mg/day may be acceptable for heart and bone health, though the FDA recommends 4700 mg/day.

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In 2014, she discuss her Ph.D. thesis in Food Science and Biotechnology entitled “Use of Biotechnology to increase the content of bioactive compounds in Fermented Foods of Plant Origin” at the University of Bologna in Italy. She has been a Postdoctoral Fellow in Food science and Biotechnology for more than 2 years, working on development of new bakery products, study of the impact of cereal based diet on health and the effect of processing on bioactive compounds. She collaborated on various national and international research projects.

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