Given the highly restricted diets recommended for many patients with advanced kidney disease, it's easy to see why malnutrition is a very real problem. Many fruits and vegetables are off limits because of the high potassium content. Dairy products are off limits because of the high phosphorus content. Many high protein foods are ruled out because of cholesterol issues. Special vitamin supplements fill the gap, supplying nutrients that patients would otherwise be unable to get from food.
Renal Vitamins
Nephrologists often recommend specific renal vitamins. Common brand names include Renaltab, Dialyvite, Nephrovite, Nephrocaps and Nephplex. Some of these are available over-the-counter and others require a prescription. These vitamins are very different from other commercially available multivitamins because they are tailored for the unique needs of kidney patients.
Vitamin D
The vitamin D found in most multi-vitamins is an inactive form. The body must convert this vitamin D to the biologically active form known as 1,25-dihydroxyvitamin D, or calcitriol. Part of this conversion is performed by the kidneys. Since the kidneys of patients with scarred organs are less able to make biologically active vitamin D, renal vitamins include calcitriol, which needs no such conversion.
B Vitamins
Since many patients with advanced kidney disease must also observe low potassium and low phosphorus diets, they frequently lack B vitamins found in fruits and vegetables. Renal vitamins make up for this deficit and include thiamin, riboflavin, pantothenic acid and other water soluble B-vitamins. Unlike other many other multi-vitamins, renal vitamins do not include potassium or phosphorus, which are problematic for many kidney patients.
Vitamin A
Renal vitamins do not include vitamin A. Kidney patients tend to have high levels of this fat soluble vitamin because their kidneys no longer effectively remove this vitamin. Since vitamin A is toxic in high levels, additional supplementation could be dangerous.
Research
In the January 2011 "Journal of Renal Nutrition," University of Massachusetts-Lowell researcher G. J. Handelman writes that patients should be individually evaluated so that an optimal vitamin supplement can be provided. Supplements should not be given without considerable thought because the kidneys of these patients are no longer able to prevent hypervitaminosis and toxicity may result. Handelman further notes that, without supplementation, many patients are unable to get sufficient nutrition. He cautions, however, about exceeding the recommended daily allowance.
