Nutritional Guidelines For Those With Renal Disease And Kidney Disorders
Besides the liver, the kidney plays an important part in removing waste products from the body. It acts like a sewer system for the body but with a difference, the kidney has the ability to excrete what the body does not need and re-absorb what it needs. It does this through millions of functional units called nephrons.
Fluid from the blood is pumped into these nephrons and waste products are pumped into the ‘sewer’ system and excreted as urine. The whole process is well regulated and controlled.
But when the kidneys fail because of whatever reason, the whole excretory system is thrown into disarray. Not only do waste products accumulated in the body, but the fine balance between the various constituents of the blood, such as electrolytes, is lost. This imbalance can have a significant impact on the well-being of the patient.
The main roles of the kidney are:
- To regulate the volume of fluids the body needs.
- To regulate the amount of nitrogen needed for protein synthesis.
- To balance the relative amounts of electrolytes like sodium, potassium, calcium and phosphates. These constituents can also be regulated by diet manipulation.
It must be appreciated that renal failure is a long, drawn-out process, with an ever changing scenario in kidney function. As such, diet constituents and their amounts must be adjusted accordingly.
The most important waste product the kidney deals with is the breaking down of proteins. This is excreted as urea. It is important, therefore, that protein intake be regulated.
Proteins come from animal products like meat, fish, eggs and milk products, and from plant sources such as soy, nuts, peas, beans and lentils.
A renal patient must restrict protein intake to about 60g per day. As a rough guide, one matchbox size of meat, fish or chicken, one egg, a cup of fresh milk, five teaspoon of peas or beans will each contain approximately 7g of protein. However, the amount required varies from one person to another and the degree of renal reserves present.
A word of caution – a low protein diet should be accompanied by a high-calorie diet in order to avoid malnutrition.
During the initial stages of renal disease, the reduced ability of the kidneys to concentrate the urine leads to a high urine volume. Therefore, at this stage, fluid restriction may be harmful.
However, as the disease progresses, the kidneys will be unable to excrete water and the restriction of fluid becomes important. It cannot be over-emphasized that you must get the proper information from your doctor on your renal status at all times.
Sodium And Potassium
The same applies to your intake of sodium especially potassium. Too much sodium in your diet will enhance thirst and make fluid control difficult. Furthermore, excess sodium may increase blood pressure.
Foods rich in sodium are flavoring sauces, salad dressings, food enhancers like MSG and most processed or preserved foods. On the other hand, foods that are low in sodium include fresh fruits, rice, vegetables and cereals.
Potassium is an important element for the body, but an excess or deficiency can cause serious problems, especially for the heart.
Foods that are low in potassium include condensed sweetened milk and canned fruits. The trick to having a low-potassium diet is to eat canned fruits without the syrup. Vegetables should first soaked and then cooked in a lot of water to leach out the potassium.
Hypercholesterolemia and excessive triglycerides may pose a problem to patients with renal disease because they promote atherosclerosis. This may predispose patients to hypertension and further aggravate renal function. Foods rich in these must be restricted.
In renal disease, a number of processes that regulate bone structure are affected, resulting in osteoporosis. This is due to the absence of activated vitamin D, in part due to an improper secretion of hormones which regulate bone structure, such as the parathyroid hormone, and also as a result of impaired calcium and phosphate metabolism. Supplements of activated vitamin D and calcium must be given in such cases.
At the same time, it is important to keep phosphate levels low. Diets rich in phosphates are chocolate, whole grain cereal, meats and legumes.
Most patients with renal failure are anemic, weak and lethargic. This is because the metabolism of vitamins and iron has been affected. Supplementation with vitamins B and C will improve wellbeing.
What was discussed so far involves manipulating the diet in order to help an ailing kidney deal with the problem, regardless of whether the patient is on dialysis or not.
You can stop the progression of renal disease by dealing with its underlying cause – for example, diabetics should maintain good sugar control and those with systemic lupus erythymatoses must receive treatment.