;on behalf of the Korean Society of Nephrology Disaster Preparedness and Response CommitteeIntroduction
Because of global health crises such as the coronavirus disease 2019 (COVID-19) pandemic and natural disasters such as power outages and floods, patients undergoing dialysis treatment encounter unique and critical challenges. Hemodialysis, which is a life-sustaining treatment for individuals with end-stage kidney disease (ESKD), requires regular and uninterrupted access to dialysis facilities. However, during emergencies, this access can be compromised, thereby posing significant risks to patient health. Patients on dialysis are particularly vulnerable during disasters because of their stringent dietary restrictions and the critical nature of their treatment regimens. Dialysis interruptions can lead to the accumulation of waste products and fluid imbalances, potentially resulting in life-threatening conditions such as hyperkalemia and pulmonary edema. Therefore, preparing an emergency meal plan that can ensure nutritional adequacy and manage the risks of these patients is essential.
Countries such as the United States and Japan, which frequently experience natural disasters, have developed and implemented guidelines to support patients undergoing dialysis treatment during emergencies. For instance, the U.S. Centers for Disease Control and Prevention (CDC) has proposed disaster response meal plans for patients on dialysis [1]. However, these guidelines often do not align well with the local dietary habits and available resources in South Korea; therefore, a localized approach is necessary. To address this, the Korean Society of Nephrology Disaster Preparedness and Response Committee proposed a dietary plan tailored for patients who require hemodialysis during disaster situations in Korea. This plan utilizes the National Standard Food Composition Table and Integrated National Food and Nutrition Information Standard Data [2].
Methods
Principles for emergency meals for patients on hemodialysis during disaster situations
Strict fluid and sodium limitations
Patients with ESKD typically lack the kidney capacity to effectively excrete excess water and sodium. Consequently, excessive sodium intake can exacerbate thirst, leading to increased fluid consumption. Excessive fluid intake can result in several adverse effects, including elevated blood pressure, interdialytic weight gain, and edema [3–5]. According to the Kidney Disease Outcomes Quality Initiative guidelines, the generally acceptable salt intake for patients on hemodialysis is up to 5 g (2,000 mg of sodium) per day [6]; however, under suboptimal dialysis conditions, a more stringent restriction of less than 2 g/day is warranted.
Furthermore, it is essential to consider the source of water intake. The moisture content in foods such as fruits and vegetables is approximately balanced by insensible water loss, including that through respiration, perspiration, and stool [7]. Therefore, to effectively manage the fluid balance, patients must strictly limit their intake of liquid foods (such as soups and beverages) and plain water (limit of 500 mL/day). This approach can prevent fluid overload and its associated complications, thereby maintaining hemodynamic stability and overall patient well-being between dialysis sessions.
Methods that can be used to reduce the sodium content of Korean patients have been proposed, including avoiding salty foods, such as kimchi, salted fish, and pickles, and avoiding processed foods, such as bacon and ham. When cooking, it is advisable to reduce the use of salt, soy sauce, doenjang (soybean paste), and gochujang (red chili paste). Furthermore, the consumption of salty broths should be avoided. Spices, such as pepper, chili powder, garlic powder, ginger powder, onion powder, and curry powder, can be used to add variety and compensate for the reduced salt content. Vinegar and lemon juice, which have a sour taste, as well as sugar, which has a sweet taste, can be used instead of salt. The flavor and caloric content of foods can be enhanced by frying or sautéing with oils such as vegetable oil and sesame oil.
Strict potassium intake limitations
Potassium homeostasis is predominantly regulated by kidney excretion; therefore, stringent restriction of dietary potassium is necessary for patients with ESKD who are undergoing hemodialysis treatment. Elevated serum potassium levels (hyperkalemia) pose significant health risks, including muscle paralysis, cardiac arrhythmias, and cardiac arrest, which are potentially fatal [8–10]. For the general population, the daily potassium intake ranges from 2,000 to 6,000 mg; however, clinical guidelines for patients on hemodialysis recommend limiting potassium intake to less than 2,000 mg per day [11]. When dialysis is compromised because of a disaster, even more stringent potassium restrictions (1,000–1,500 mg/day) are imperative.
Unlike sodium, which has a salty flavor, potassium is tasteless, thus complicating its management. Consequently, it is important for patients on hemodialysis to avoid high-potassium foods and select alternatives with lower potassium contents. Potassium is ubiquitous in most food items, but not in simple sugars and fats. Notably high concentrations of potassium are present in fresh fruits, vegetables, dried fruits, nuts, potatoes, sweet potatoes, and chestnuts (Table 1). Additionally, low-sodium salt substitutes and soy sauce frequently contain a substantial amount of potassium; therefore, they should be avoided. Selecting low-potassium foods is essential to achieving these dietary constraints. However, when the inclusion of potassium-rich ingredients is unavoidable, culinary techniques, such as leaching, boiling, and double cooking, should be performed to mitigate the potassium content and reduce potassium absorption.
Additionally, thinly slicing potassium-containing ingredients and washing them under running water or soaking them in lukewarm water for more than 2 hours before blanching can remove 10% to 50% of the potassium content. Vegetables contain most of their potassium content in their peels and stems; therefore, it is advisable to remove the peels and stems and use only the leaves after cutting them into strips or small pieces. Vegetables that grow in a manner similar to that of fruits, rather than leafy vegetables, and light green or white vegetables, rather than dark green vegetables, are preferable. Canned fruits can be consumed because the canning process reduces the potassium content; furthermore, the consumption of canned fruits can help supplement the caloric intake. However, for individuals with diabetes, caution should be exercised when consuming canned fruits that are packed in syrup because this can rapidly lead to increased blood sugar levels. Fish and meat should be cooked rather than consumed raw. When attempting to increase the caloric intake, foods containing chocolate, nuts, coconut, and raisins should be avoided.
Active utilization of carbohydrates and fats to achieve an adequate caloric intake
Despite various dietary restrictions, patients on hemodialysis in disaster situations must ensure that their caloric intake is sufficient to maintain a proper nutritional status, aiming for 30 to 35 kcal/kg per day [12,13]. Inadequate caloric intake can lead to the breakdown of muscle protein and an increased risk of uremic complications [14]. Adequate caloric intake, primarily from carbohydrates, such as sugar, honey, and jelly, as well as from appropriate fats, is crucial to protein utilization. The National Kidney Foundation (NKF) recommends stocking high-calorie foods with long shelf lives as emergency supplies. However, patients with diabetes should manage their carbohydrate intake to avoid blood sugar spikes.
Additionally, supplementing the diet with water-soluble vitamins and minerals is beneficial. Dietary restrictions for patients on hemodialysis often result in deficiencies in essential vitamins such as thiamine (vitamin B1), riboflavin (vitamin B2), pyridoxine (vitamin B6), folic acid, vitamin C, and iron. Targeted supplementation of these vitamins, especially those containing folic acid, is important. However, it is crucial for patients on hemodialysis to avoid using multivitamins designed for the general population because some vitamins can accumulate to harmful levels in patients with reduced kidney function. For example, vitamin A should not be supplemented because it tends to accumulate in the body as chronic kidney disease progresses, potentially leading to toxicity.
Adequate high-quality protein consumption and limitation of phosphorus intake
In disaster scenarios in which adequate dialysis may not be feasible, maintaining an appropriately balanced nutrient intake is critically important for patients on hemodialysis. Although sufficient protein intake is essential for maintaining the caloric supply and overall nutritional status, a protein-rich diet can exacerbate uremia under conditions of impaired dialysis [15–17]. Therefore, a careful approach to protein consumption, particularly with regard to phosphorus content, is necessary.
Although long-term issues such as vascular calcification and secondary hyperparathyroidism are concerning, elevated phosphorus levels in the blood are less likely than imbalances in potassium or sodium levels to cause immediate and life-threatening complications. Therefore, a relatively relaxed phosphorus restriction may be considered if it ensures an adequate caloric intake. This approach allows some flexibility in phosphorus management because it prioritizes caloric sufficiency while considering potential long-term effects. The selection of high-quality proteins that are low in phosphorus but rich in essential amino acids is crucial. Foods such as eggs, lean meat, and fish are recommended because of their favorable phosphorus-to-protein ratios and provision of essential nutrients [18].
To reduce the phosphorus intake of Korean food ingredients, the following dietary methods should be considered. White rice should be consumed rather than brown rice, mixed grains, and legumes. Dried fruits, nuts, milk, and dairy products should be avoided as much as possible. Soft drinks, such as cola, and instant foods should be limited.
Results
Proposed disaster response diet for Korean patients on hemodialysis
Based on this information, we proposed a Korean-style disaster response diet (3 days) with stricter dietary restrictions for situations in which adequate dialysis treatment is difficult. This plan assumes two scenarios: one in which cooking is possible and another in which cooking is impossible. To ensure adequate protein intake, two to three items from the fish and meat group are included. To remove potassium, all salad vegetables should be soaked in water and leafy greens should be boiled before they are cooked.
Situations involving a complete resource outage
The NKF in the United States has suggested a pre-disaster shopping list and a 3-day dietary plan for patients on dialysis who experience situations involving a complete resource outage [19]. Accordingly, we proposed a dietary plan that is applicable to large-scale disasters in Korea (Table 2). This diet plan is designed for large-scale disaster situations involving natural disasters, such as earthquakes, typhoons, floods, and heat waves, that lead to societal disasters, such as fires and blackouts, thus making electricity and water unavailable. The plan assumes that the necessary food items have been purchased in advance and that electricity and water are not available at home, thus making food preparation and cooking difficult.
When preparing for disasters, it is advantageous to purchase and store food products. Small cans or packs are preferable. Sterilized milk can be stored and consumed for more than 6 months with minimal microbial growth; however, slight changes in taste and appearance may occur over time. Because milk has a high phosphorus content, its intake should be limited to one cup per day. Fresh foods should be used first. Canned and frozen foods should be discarded if they are not kept cold or consumed within 4 hours after opening. Caution is necessary for items such as chicken, tuna, salmon, and mayonnaise, which can spoil without refrigeration.
Situations with limited resources
We proposed a 3-day diet applicable to individuals in Korea during natural disaster scenarios such as earthquakes, typhoons, floods, and heatwaves (Table 3; Supplementary Fig. 1, available online). This plan assumes that necessary supplies and food items can be purchased in advance, but that dialysis and outdoor activities are not feasible. This plan also assumes that there are no restrictions on the use of electricity and water at home. This diet provides 1,600 to 1,700 kcal, 40 to 50 g of protein, and 1,000 to 1,500 mg of potassium. Soups are excluded. Each day, cooking involves 10 to 15 g of soybean oil or sesame oil.
Bread can be stored for up to 3 months if frozen in sealed bags. Salad vegetables should be soaked in water before use, leafy greens should be boiled to remove potassium before they are cooked, and vegetables pickled in vinegar should be used instead of kimchi. Soups should be avoided because they have a high sodium content. Seasonings such as pepper, chili powder, garlic powder, and curry powder are permitted to compensate for the reduced salt content. Sour and sweet flavors should be used appropriately. The taste of foods can be enhanced with vegetable oils. Instant rice, which is available in stores, can be used. When purchasing canned foods, low-sodium options are preferable.
Using a food exchange list for patients on hemodialysis during disasters
During disasters, acquiring specific ingredients can be challenging. Despite these constraints, a food exchange list tailored to patients with renal disease can help them manage their dietary preferences and restrictions. This list, which is categorized into seven food groups (grains, meat and meat substitutes, vegetables, fats, milk and dairy, fruits, and caloric supplements), facilitates the planning of balanced diets tailored to individual tastes and available ingredients. Each food group is divided into units; one exchange unit represents the weight of food with a comparable nutrient content. A key benefit of this method is the ease of substituting foods within the same group without complex calculations. Using this list, patients can select alternative foods while adhering to their nutritional requirements. For instance, one-third of a cup of steamed rice and one slice of bread each represent one exchange unit in the grain group, thus making them interchangeable (Supplementary Table 1, available online). By expressing diets in exchange units, patients can use the suggested meal plan as a reference and substitute the desired foods within the same group according to the designated number of units. Tables 4, to 6 show an example of how the suggested meal plan for Koreans during a natural disaster can be expressed in exchange units using the food exchange list.
Discussion
Disasters such as earthquakes, floods, and power outages can damage infrastructure, leading to the closure of dialysis centers and the disruption of essential utilities such as water and electricity, which are crucial for dialysis machines. For example, the Great East Japan Earthquake in 2011 caused significant destruction of medical facilities, causing 314 dialysis units to become non-functional immediately following the disaster [20]. In disaster situations, patients undergoing dialysis treatment must meticulously plan their diets to manage their unique nutritional needs and minimize health risks. Such diets should ensure low-potassium, low-sodium, and low-phosphorus contents to prevent electrolyte imbalances. This was particularly evident during the Hurricane Katrina disaster, when the lack of appropriate dietary planning led to increased hospitalization because of missed dialysis sessions and subsequent health complications [21].
Patients must be aware of safe foods during emergencies and avoid foods with high electrolyte content. Education regarding portion sizes and preparation methods is essential to prevent the excessive intake of restricted nutrients. The CDC and the NKF in the United States offer comprehensive guidelines for patients on dialysis in emergency situations [22,23]. These plans emphasize a 3-day emergency food supply to ensure patients have access to low-potassium, low-sodium, and low-phosphorus foods. The CDC provides a detailed shopping list and guidance on emergency food storage, including shelf-stable items like canned meats, low-sodium crackers, and bottled water. Importantly, the United States guidelines focus on low-sodium canned goods, unsalted nuts, and long-lasting carbohydrates such as instant oatmeal. The NKF highlights the importance of pre-preparing snacks and meals that can withstand long-term storage, thus ensuring nutritional continuity when refrigeration is not possible. However, applying these guidelines directly to Korean patients undergoing dialysis treatment may be challenging because of differences in dietary habits and food availability. For instance, Korean diets are rich in vegetables and fermented foods that may have different nutritional profiles than those of Western diets. This challenge is not unique to Korea, however. Studies conducted during the COVID-19 pandemic showed significant variations in dietary behaviors and food security across different countries, thus emphasizing the need to consider cultural and geographic factors when developing dietary guidelines for disaster situations [24]. Guidelines that align with the local food culture and available resources are essential to increasing the likelihood that patients can effectively adhere to them.
In South Korea, the number of patients on dialysis has been increasing rapidly, thus outpacing the expansion of the medical infrastructure and capacity [25,26]. This surge in the number of patients on dialysis presents significant challenges for the healthcare system, especially during disasters. Even minor disasters can have a substantial impact because of the strained capacity of dialysis centers. For instance, small-scale power outages and localized flooding can disrupt services at dialysis facilities that are already overburdened, thus leading to delays in treatment. The most recent significant earthquake in South Korea was the Pohang earthquake in 2017; during that disaster, a local dialysis clinic experienced a power outage that halted dialysis treatment and required patient evacuation [27]. Although this incident was managed without severe consequences, it highlighted the potential for much greater disruptions and health crises in similar or more severe scenarios.
The proposed dietary plan should be integrated into education programs at dialysis centers to provide patients with clear guidance regarding maintaining an emergency food supply comprising low-potassium, low-sodium, and low-phosphorus options. Regular disaster preparedness drills, including dietary planning, are essential to identifying gaps and ensuring readiness. Collaboration with local government and nongovernmental organizations is crucial to the widespread dissemination and integration of these guidelines into broader disaster response efforts and ensuring that patients on dialysis receive the necessary support during emergencies.
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