Your kidneys remove waste and excess fluid from your blood and remove it from your body through your urine. If you have any type of kidney deficiency, your kidneys cannot perform this function properly. Medical nutrition therapy for kidney disease focuses on reducing the amount of waste in the blood to reduce the stress on the kidneys. While specific recommendations differ based on level of kidney function and your individual circumstances, general recommendations are the same between individuals.
Protein
When you eat protein, your body breaks it down into a waste product called urea. Healthy kidneys remove urea from the blood and deposit it into your urine. If your kidneys are deficient, urea accumulates in the bloodstream. Eating too much protein can also put excess stress on the kidneys because they will attempt to filter the urea out of the blood. This can exacerbate the decline of your kidney function. Specific protein recommendations vary based on your weight, kidney function and health conditions, but a doctor or dietitian will generally recommend that you lower your protein intake.
Potassium
Your kidneys regulate the amount of potassium in your blood. If your kidneys are deficient, they do not properly remove potassium. This can lead to increased levels of potassium in the blood, a potentially dangerous condition called hyperkalemia, that can disrupt your heart beat and proper nerve function. If you have kidney disease, your doctor or dietitian may recommend that you limit the amount of potassium-rich foods, such as bananas, broccoli, potatoes and tomatoes, in your diet.
Phosphorus
Your kidneys also regulate phosphorus, a mineral that binds with calcium to create your bone structure. Diseased kidneys cannot control the phosphorus in your blood so levels rise. In response to the rise in phosphorus, your body pulls calcium from your bones in an attempt to correct mineral balance. Over time, this can cause your bones to become weak and brittle and lead to joint pain. Your dietitian may recommend that you lower your intake of high-phosphorus foods, such as soda, peanut butter, cheese and nuts.
Fluids
As your kidney function declines, your kidneys lose the ability to filter excess fluid from your blood. If the amount of fluid in your blood gets too high, it can cause swelling, shortness of breath and high blood pressure, according to the Medical College of Wisconsin. Your dietitian may recommend that you limit the amount of fluids you drink. The specific amount of fluid depends on your individual condition.
