Kidney patients are often seriously malnourished by the time they reach end-stage kidney disease. Some of this may be unavoidable because nutritional trade-offs must be made if potassium and phosphorus levels get too high as the disease advances. However, specially formulated renal vitamins make the best of a bad situation. Working vigilantly with your nephrologist or renal dietitian can prevent many serious issues.
Vitamin A
Many patients with advanced disease have elevated levels of vitamin A. This can occur even though many foods high in vitamin A are already excluded from the renal diet because they are high in potassium. Reports of vitamin A toxicity, such as the one by S. Fishbane in the February 1995 "American Journal of Kidney Disease," occasionally appear in the literature. Specially formulated renal vitamins avoid this problem because they do not have vitamin A.
B Vitamins
Many patients are unable to enjoy fruits and vegetables regularly because they are on low-potassium diets. Many healthy foods such as melons, broccoli, carrots and legumes must be eaten very sparingly. Under these circumstances, it is not surprising the patients become malnourished. Renal vitamins compensate for this by providing an adequate amount of B vitamins such as thiamine, pantothenic acid, folate, niacin, riboflavin and others.
Vitamin C
Patients are often lacking vitamin C because citrus fruits, tomatoes and broccoli are high in potassium and must be eaten sparingly if high levels of serum potassium are a problem. Renal vitamins provide vitamin C that cannot be easily obtained through dietary sources. However, the amount of vitamin C in renal vitamins is relatively small because kidney patients are vulnerable to oxalate deposits in bone and soft tissue if they take too much vitamin C.
Vitamin D
Vitamin D is problematic for kidney patients who often remain vitamin D-deficient regardless of how much they sunbathe or how much vitamin D they get in foods. Vitamin D from these sources is transformed by the kidneys to a form of biologically active vitamin D called calcitriol, or 1,25 dihydroxyvitamin D. Unfortunately, scarred kidneys lack the enzyme that makes calcitriol. Renal vitamins get around this problem by providing calcitriol directly.
