Why Potassium restriction comes along then?
Potassium restriction is advised as the failing kidneys are not able to excrete potassium which comes from diet and tissue breakdown. Higher levels of potassium have a great risk for cardiac arrests due to hyperkalemia. A potassium calculated diet is to be taken religiously.
Potassium is present in almost all the foods.Certain guidelines useful in daily practice :
Choose low potassium vegetables (see list below).
Potassium in vegetables can be reduced by peeling or scrapping them and chopping them finely into small pieces. Cook them in generous amounts of water and discard the water.
Dals can be soaked in excess water for a long time, discard the water and then cook them.
Salt substitutes usually contain potassium chloride, so to be avoided.
Fruit juices, coconut water, chutneys, chocolates, tea, coffee, aerated drinks are rich sources of potassium.
Certain low potassium foods:
- Fruits :
Guava (Psidium guajava, Psidium cattleyanum),
Apple (Malus sylvestris),
Pear (Prunus persica),
Papaya (Carcia papaya),
Pineapple (Ananus comosus).
- Vegetables :
Bamboo shoots– canned (Bambusa vulgaris,Phyllostachys edulis),
Cabbage (Brassica oleracea var. capitata),
Cucumber (Cucumis sativus),
Dudhi (Bottle gourd-Lagenaria vulgaris),
Lettuce– Salad patta-all varieties (Lactuca sativa),
Pepper-green,sweet (Capsicum annuum var.grossa),
Water chestnuts- Singhada (Trapa bispinosa),
Chard- raw (Beta vulgaris var. cicla)- commonly known as Swiss chard, Silverbeet, Spinach beet, Perpetual beet, Crab beet, Seakale beet, Mangold,
Endive- Gulsuchal (Cichorium endivia),
Escarole (Cichorium endivia var. latifolia).
Certain vegetables containing medium amount of potassium can be consumed after leeching them (see above):
Asparagus- Shatwar, Musli (Asparagus officinalis),
Broccoli (Brassica olerecea cultivar),
Carrots (Daucus carota),
Cauliflower (Brassica olerecea var. botrytis),
Celery (Apium graveolens var. dulce),
Collards (Brassica olerecea acephala group)—(Karam ka saag in Kashmir)
Eggplant- Brinjal (Solanum melongena)
Why is Salt intake restricted in a CKD diet?
Salt (sodium) intake is restricted to prevent swelling and overload on kidneys and heart.
In normal individuals, water intake always equals water output. Water output involves obligatory losses in urine, stool, sweat and evaporation through moist surfaces. The obligatory water loss through the kidneys is directly related to solute excretion which is mostly Sodium and potassium salts and urea.
Blood solute concentration is balanced by solvent-water, which maintains osmolality and electrolyte balance.
In CKD, kidneys fail to excrete sodium, which is retained in the body. Excess sodium retains water along with it, to maintain the balance. This causes swelling all over the body. It also increases workload on heart, as it has to pump extra fluid. So, sodium (salt) intake is restricted to such a level as to prevent overload on heart and kidneys.
But what about the taste and palatability?
Food can be made palatable with the use of certain flavors which do not harm our kidneys.
Why is water intake restricted?
A common perception is increased water intake will “flush” the kidney !
Fact is, Failing Kidneys cannot excrete excess water. So if extra water is taken ( i.e., more than the urine output), it will be retained in the body and swelling will appear on the feet and the face.
Summary and Recommendations
So, to summarize, a “kidney diet” has specific restrictions.
- Salt – less than 6 g, commonly.
- Water – Urine output amount plus 500 mL
- Proteins – 0.8g/kg/day. Intake should be increased if proteins are being taken in lesser amount than this.
- Potassium – needs to be restricted and commonly fruits and juices are reduced.There are methods to remove potassium from fruits or vegetables.