Preparation method developed to lower potassium in potatoes for patients with CKD
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Researchers have developed a method for preparing potatoes that reduces potassium content, providing patients with chronic kidney disease the ability to safely incorporate potatoes into their diet.
“Traditional renal diets used to be very restrictive for consumption of many foods rich in potassium and phosphorus, especially fruits, vegetables, legumes, nuts, and dairy products, to maintain normal mineral serum levels and avoid complications derived from this disease such as hyperkalemia or hyperphosphatemia,” Montserrat Martinez-Pineda, PhD, of the University of Zaragoz in Spain, and colleagues wrote. “It has been widely demonstrated that cooking procedures affect the nutritional value of food. For example, they can play an important role in the control of potassium intake, so that patients are educated to apply special culinary methods to reduce the amount of potassium in food before its consumption. The culinary methods proposed are usually long and laborious.”
Because the potato has significant nutritional value, researchers sought both to analyze the effect of various culinary treatments on the reduction in potassium content in potatoes and to offer an alternative preparation method that could be implemented by patients with CKD.
For the study, they used fresh potatoes, canned potatoes, and frozen fried potatoes. Cooking treatments applied to the potatoes included soaking, normal cooking and frying. Researchers noted that the soaking procedure was conducted for 12 hours and that the soaking of fresh potatoes was performed before and after normal cooking (which lasted approximately 8 minutes).
While researchers found that neither soaking a fresh raw potato or normal cooking achieved a sufficient reduction in potassium, a soaking procedure performed after normal cooking leached up to 70% of the potassium (final values of under 130 mg/100 g). This technique also allowed for the subsequent frying of the potatoes, as they retained the low-potassium content.
Additionally, only 6 hours of soaking at home before frying were required to minimize potassium content to an acceptable level for frozen fried potatoes since, according to the researchers, they have been previously peeled, blanched, dried and shortly fried.
“The results of this study reveal that continued research into the effect of culinary treatment on different components of food is needed, especially for minerals, to update dietary guideline recommendations for the treatment of chronic kidney disease,” the researchers wrote. “It is necessary to know and take into account the different behavior of each vegetable with respect to the culinary treatment applied to minimize their potassium contents and try to individualize as much as possible.” – by Melissa J. Webb
Disclosures: The authors report no relevant financial disclosures