People with reduced kidney function need to be aware that some parts of a normal diet may speed their kidney failure.Typical recommended daily adult requirements are total energy 35 kcal/kg body weight, protein 1 g/kg but and nitrogen 0.16 g/kg but there is no good evidence on which to base stipulations and some would advocate more calories and more protein for those who are catabolic.

If patients with acute kidney failure are oliguric, the nutritional support should be given in a restricted fluid volume, with reduced amounts of sodium, potassium, and phosphate.

Protein

Protein is important to your body. It helps your body repair muscles and fight disease. Protein comes mostly from meat. As discussed in an earlier section, healthy kidneys take wastes out of the blood but leave protein. Impaired kidneys may fail to separate the protein from the wastes.

Some doctors tell their kidney patients to limit the amount of protein they eat so that the kidneys have less work to do. But you cannot avoid protein entirely. You may need to work with a dietitian to find the right food plan.

Cholesterol

Another problem that may be associated with kidney failure is too much cholesterol (koh-LES-tuh-rawl) in your blood. High levels of cholesterol may result from a high-fat diet.

Cholesterol can build up on the inside walls of your blood vessels. The buildup makes pumping blood through the vessels harder for your heart and can cause heart attacks and strokes.

Sodium

There is little regulation of sodium intake in humans, although some animals demonstrate a specific sodium appetite and have sodium receptors in the hypothalamus. Sodium balance is maintained largely by the kidney, which is normally capable of controlling sodium excretion over a very wide range, 1 to 5000 mmol/24 h.

Sodium is a chemical found in salt and other foods. Sodium in your diet may raise your blood pressure, so you should limit foods that contain high levels of sodium. High-sodium foods include canned or processed foods like frozen dinners and hot dogs.

In Western countries, including Britain, the usual intake of sodium is grossly in excess of body needs, being about 100 to 200 mmol/24 h. There is little sodium loss from the healthy bowel and in temperate climates sweating is minimal (the sodium concentration in sweat is 40 to 50 mmol/litre). Most people are therefore at continuous risk of sodium excess, which is prevented by the kidney.

Potassium

When renal function is compromised, the absolute magnitude as well as the proportion of potassium in the faeces is increased, but variation in renal excretion of potassium is usually the only means by which the body achieves external potassium balance by ensuring that excretion equals intake.

With normal intake of potassium, 10 to 20 per cent of the load filtered at the glomerulus is excreted, but fractional excretion of potassium can vary from 1 per cent when intake is restricted to over 100 per cent when intake is excessive.

Micropuncture studies have shown that the amount of potassium reaching the distal convoluted tubule does not vary in these circumstances, indicating that modulation of renal potassium excretion is normally a property of the distal nephron. Factors that modify potassium excretion by the distal nephron are clearly interrelated; it is rare that one is modified in isolation and the overall effect on potassium excretion is almost invariably the aggregate result of several complementary or competing stimuli.

Dietary potassium intake in Western society typically varies between 50 and 150 mmol/day, but balance can be attained with intake of up to 500 mmol/day if homeostatic mechanisms are intact. In normal circumstances potassium excretion in the stool is not regulated, but it amounts to only 5 to 15 mmol/day.

Smoking

Smoking not only increases the risk of kidney disease, it contributes to deaths from strokes and heart attacks in people with chronic kidney disease. You should try your best to stop smoking.

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