Potatoes, an affordable source of precious potassium


The South African food-based dietary guidelines, recommend that all South Africans should eat plenty of fruit and vegetables daily.  However, a frequently expressed concern in the on-going public health debate, is that fresh fruit and vegetables, particularly those which are nutrient dense, are not affordable to the average consumer.

Amongst the many important nutrients provided by fruit and vegetables, potassium is starting to earn its right as a hero in the fight against heart disease. According to the American Heart Association Position Statement, one of the dietary modifications that effectively lower blood pressure, is the increased intake of potassium. This is one of the mechanisms through which, fruit and vegetables are thought to help in the prevention of hypertension and consequent cardiovascular disease.

Several studies from the THUSA Study group have shown that South African diets, especially of black South Africans, are generally low in potassium and vitamin C, as well as several other micronutrients provided by fruit and vegetables.

“While we as dieticians urge people to eat a variety of vegetables and fruits, the reality is that one of the perceived barriers to increasing consumption is cost,” says Leigh-Ann Silber, registered dietician. 

However, research  presented in September 2011 by the University of Washington, by Adam Drewnoski PhD and colleagues, has announced that potatoes (boiled, baked or cooked, and with skin) are one of the best nutritional values in the produce department, providing significantly better nutritional value per US dollar than most other raw vegetables.  

Nutritional value for money

Per serving, the research showed that potatoes were the largest and most affordable source of dietary potassium.  According to Drewnoski, the lead researcher, “Potatoes deserve credit for contributing higher diet quality and increasing vegetable consumption.”

Earlier this year, Potatoes South Africa (PSA) conducted a study to determine the nutrient profile of three different classes of potatoes. The results showed that the average 150g cooked potato, with skin, delivers 710mg of potassium. The daily recommended value for potassium in a 9 000 kilojoules diet for adults and children over four years, is 3 500mg. Thus one serving of boiled potato provides 20% of the recommended value.  

Although a US study such as this has not been undertaken in SA on the comparative cost of fruit and vegetables, we can assume that the situation on home soil is similar.  For example: the cost for 100g boiled potato, with skin, is only R0.38 and provides 474mg of potassium.  Compare this to the average cost of 100g of banana (with peel), which is R0.90* and excluding the peel, will provide a similar amount of potassium. We can assume that potatoes are definitely a cost-effective source of potassium in SA.

“This latest nutritional information available on South African potatoes, allows us, as dieticians and nutritionists, to advise the public on the best choices of the most nutrient dense foods.  Potatoes are definitely one of those foods, that also prove great nutritional value for money,” concludes Silber. 

In summation, not only does a medium-sized potato, cooked with skin, provide 710mg of potassium, they are also high in carbohydrates, naturally free of fat, high in chromium and naturally low in sodium.

Adapted press release from Potatoes South Africa (PSA)

(Photo of potatoes in basket from Shutterstock)

Read more:

Your complete guide to potassium

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