Kidney patients are often confronted with friends and family who ply them with all sorts of well-meaning, but uninformed, nutritional advice aimed at reversing their kidney disease. Instead of unrealistic goals such as reversing disease, nephrologists and renal dietitians recommend diets that compensate for activities that the kidneys used to be able to perform. Such diets are based upon the patient's individual laboratory results and other metrics such as blood pressure.
Kidney damage can be caused by high blood pressure, diabetes, congenital conditions or immunologically mediated diseases of the glomeruli, or kidney filters, such as IgA nephropathy. While liver tissue can regenerate, once the structures of the kidney are scarred, the damage is permanent. No amount of any drug or nutrient will reverse the damage done.
Vitamin B-1, also known as thiamine, was one of the first vitamins to be discovered. This vitamin is an essential cofactor in many enzymatic reactions involved in the breakdown of pyruvate and various proteins involved in the process of getting energy from food. A cofactor is a compound that helps an enzyme be an efficient catalyst.
Patients with advanced kidney disease rarely get enough thiamine because most foods high in thiamine are too high in potassium or phosphorus for many patients to consume. For example, 1/2 cup of cooked lentils has 0.17 mg of thiamine. One ounce of pecans has 0.19 mg. These foods are off-limits for kidney patients who can't regulate potassium or phosphorus levels. Other high-thiamine foods that patients with advanced disease may have to avoid include orange juice, cantaloupe, milk and wheat germ.
Even though thiamine doesn't reverse kidney damage, patients still need to get the recommended daily allowance of 1.2 mg for adult males and 1.1 mg for adult females. Many nephrologists prescribe specially formulated renal vitamins so patients don't become malnourished. These vitamins differ from regular vitamins in that they don't have vitamin A or forms of vitamin D that the patient cannot metabolize. Kidney patients usually have very high levels of vitamin A, so taking regular vitamins could be dangerous.