LOW POTASSIUM DIET IN CKD
Kidney failure and Chronic kidney disease (CKD):
The healthy kidney functions to remove nitrogenous wastes from the body in the form of urea, creatinine and drugs. Kidney failure is defined as the kidney’s inability to function properly. Kidney failure can be divided into two categories: acute kidney disease and chronic kidney disease.
Acute renal failure can be defined by a sudden onset and decreased kidney function over a short period of time. Chronic renal failure, on the other hand, can be defined as a progressive loss of kidney function over time. Chronic kidney disease is a more serious form that develops gradually and results in decreased kidney function.
- Chronic kidney disease and GFR: CKD is defined as a decrease and decline in renal function that lasts more than three months. It is far deadlier than acute kidney disease. The decline in GFR is the cause of CKD (Glomerular filtration rate). Glomeruli are capillary tufts found in the kidney. It measures how frequently kidney filtrate moves from the glomerulus into the renal tubules. This measurement is termed as GFR (Glomerular filtration rate) and is an assessment of the kidney’s working efficiency. This begins to decline in CKD patients (less than 90mL/min), falls below 45mL/min in case of later stages of CKD (Stage III onwards).
Functional role of potassium in the body:
Potassium (K+) is essential for the maintenance of normal cellular function. K+ is the most abundant intracellular cation, and forms an essential part of the ‘Na+-K+-ATPase pump. This pump helps in sodium efflux and potassium influx, moving sodium (Na+) out of the cell in exchange of K+ into the cell. This results in the establishment of a K+ gradient across the cell membrane, which is partially responsible for maintaining the potential difference across the membrane. Many cell functions are dependent on this potential difference, especially in excitable tissues like nerve and muscle.
The kidney is the primary organ in charge of maintaining total body K+ balance.
Low serum potassium concentrations (normal range: 3.5–5.0 mEq/L) characterize hypokalemia.
Potassium levels of 2.5 mEq/L are considered severe and may be life-threatening.
Hypokalemia can be caused by either a decrease in potassium intake or by excessive potassium losses in the urine or through the GI tract. The second is more common. Excessive potassium excretion in the urine (kaliuresis) can be caused by diuretics, endocrine diseases such as primary hyperaldosteronism, kidney disorders, and genetic syndromes affecting renal function.
- Causes of hypokalemia:
Hypokalemia does develop as a result of a low potassium intake. However, other factors can also contribute to it, such as those mentioned below:
- Excessive alcohol consumption.
- Sweating profusely.
- A lack of folic acid.
- A few antibiotics dicloxacillin, ampicillin, amphotericin B, aminoglycosides, and penicillin which are administered to patients with renal dysfunction and complications.
- Diabetes-related ketoacidosis (high levels of acids called ketones in the blood).
- Laxatives used over an extended period of time.
- Certain tobacco products.
- Certain asthma medications.
- Diuretics administration like Furosemide or hydrochlorothiazide (HCTZ) (Lasix).
- Vomiting and diarrhea.
- Impaired functioning of the adrenal glands of the kidney.
- Magnesium deficiency.
- High potassium foods/dietary regimen for hypokalemia:
Apricot, avocado, cantaloupe, banana , dates, dried fruits, figo, dried grape, honeydew, kiwi, mango, nectarine, orange, orange juice, pomegranate juice, brunel, prome juice, raisins, acorn squash, bamboo, baked beans, butternut squash, refried beans, beets, black beans, broccoli, cooed, brussels, carrots, dried beans, and peas, raw carrots, lentils, legumes, okra, potatoes, sweet potatoes, nuts, and peanuts are all examples of high potassium foods and can come handy for patients with hypokalemia.
Hyperkalemia and its association with CKD:
When the kidneys fail to work owing to chronic kidney disease or CKD, the body’s potassium levels are elevated. This is because the kidneys can no longer remove excess potassium. Hyperkalemia, or high potassium levels in the blood, can occur in people with advanced stages of chronic kidney disease (CKD). High potassium levels can cause nausea, weakness, numbness, and a slow pulse rate. In CKD, the kidney is not able to excrete waste and those wastes end up accumulating in the bloodstream. Biochemical tests are performed to measure the amount of potassium in the blood. The normal level is between 3.8 to 5mEq/L, >6mEq or <3mEq can be considered alarming. Symptoms usually don’t appear until very high levels are reached. Cardiac arrhythmia, muscular paralysis are some associated comorbidities and can eventually lead to death.
Dialysis is required for people with stage 5 CKD (also known as end stage renal disease or ESRD) to help regulate potassium. However, potassium levels rise between dialysis treatments, and high-potassium foods must be avoided.
The potassium levels must be checked on a regular basis, and the outcomes must be discussed in detail with a renal dietitian or physician.
- Things to do for hyperkalemic patients:
- Potassium-rich foods should be avoided.
- Milk and milk products must be substituted with non-dairy alternatives.
- Liquids from canned fruits and vegetables should be discarded.
- Potassium-containing salt substitutes and seasonings must be avoided.
- Potassium chloride must be avoided.
- Dialysis should not be skipped and needs to be performed on a regular basis as directed by the physician (3 times a week).
- Some of the potassium from high-potassium vegetables can be leached to reduce the potassium content as leaching releases potassium into the water when vegetables are soaked in water.
- Recommended dietary intake:
Intake of potassium should be 4700 mg/day for normal people. Low potassium diet with 2000-3000 mg of potassium per day should be consumed by CKD patients for substantial improvement in the GFR.
The normal GFR ranges between 90 to 120mL/min.
- Dietary regimen or low potassium food list for hyperkalemic patients:
Low potassium foods for hyperkalemia patients include the following:
Apple, apple juice, apricots, black berries, cherries, apricots, cranberries, fruit cocktail grapes, grape juice, pears, pineapple, plums. Veggie include lettuce cucumber, eggplant, mixed vegetable, white mushroom, onion, parsley, radish, water chestnuts, yellow squash, rhubarb, cooked rice with rice, white bread and pasta are all examples of low potassium foods which can of great help for patient developing hyperkalemia. Leaching of vegetables leads to release of potassium into water, so care should be taken with regards to this.
Estimation and assessment of potassium intake:
- Dietary potassium intake can be measured using a food diary or questionnaire, dietary recall, or urinary potassium excretion measurement. However, diaries and recalls rely on self- reporting of patients on all food consumed and may be inaccurate or subjected to recall biases and give an inauthentic picture of the actual potassium exposure.
- Urinary potassium excretion is generally thought to be a better predictor of potassium intake, but other variables should be measured to increase its validity.
- Replacing animal protein diet with plant-based diet:
Strict adherence to a healthy plant-based diet (fruits, vegetables, whole grains, nuts, and legumes) was linked to a lower risk of developing CKD whereas a higher animal-based protein intake was linked to an increased risk of kidney hyperfiltration and rapid kidney function decline.
Although red meat consumption is strongly linked to an increased risk of kidney failure in the general population, replacing daily serving of red meat with another source of protein such as for poultry), for soy, legumes, or eggs), or adopting healthy dietary regimen like fruit, vegetables, whole grains, legumes, nuts, and fish and diet low in sodium, sugar-sweetened drinks, and red and processed meat can be of great help to CKD patients.
Conclusion: Potassium is an important mineral which plays a key role in maintenance of normal function of the kidney. Too low or high potassium can result in hypo and hyperkalemia respectively and can interfere with the normal functioning of the kidney. Potassium may accumulate in the blood or may be over-excreted in the urine. Both the aforementioned scenarios can have fatal consequences if left unaddressed over a period of time. Proper dietary chart needs to be followed by the patients which can greatly improve patients health and their quality of life.