Discussing the nutritional needs of patients in kidney failure is complex. For example, healthy kidneys are involved in the activation of vitamin D and the clearance of vitamin A. When kidneys fail, they are unable to perform these functions; this often results in patients not having enough biologically active vitamin D and too much vitamin A. Moreover, since patients often have varying abilities to make urine, it is hard to make generalizations about their abilities to excrete water-soluble vitamins. Fortunately, there are reliable guidelines about how much folic acid patients should take. Do discuss this with your nephrologist, because your situation may have different requirements.
Folic acid is a water-soluble B vitamin. The names "folic acid' and "folate" are often used interchangeably; folate is the naturally occurring form of the vitamin, while folic acid is the synthetic form. In addition to being essential in the synthesis of DNA, this vitamin is also involved in the synthesis of the amino acid methionine.
DaVita is one of the largest dialysis providers in the United States. It recommends 1.0 mg/day of folic acid for patients on dialysis and patients with chronic kidney disease who are not on dialysis. Doctors should monitor the patient's levels of vitamin B-12 while on folic acid because folic acid supplements can mask a vitamin B-12 deficiency.
Getting enough folic acid is important for kidney patients because many foods that are rich in this vitamin, such as orange juice, lentils, garbanzos, and lima beans, are off limits to patients in kidney failure because they contain too much potassium or phosphorus. Renal vitamins are specially formulated for patients on dialysis who need to avoid many nutrients. Talk to your nephrologist to see if taking renal vitamins is right for you.
The National Kidney Foundation reports that there is an inverse relationship between serum folate levels and plasma homocysteine levels, such that low levels of folate are associated with high levels of homocysteine. Homocysteine is an amino acid. High levels of homocysteine are associated with cardiovascular disease. This is particularly important for patients who have experienced kidney failure and who are on dialysis because cardiovascular disease is the leading cause of death among these patients.
- Linus Pauling Institute; Folic Acid; Jane Higdon, Ph.D.; April 2002
- DaVita: The ABCs of Vitamins for Kidney Patients
- "Cochrane Database System Review; Homocysteine Lowering Interventions for Preventing Cardiovascular Events. A.J. Martí-Carvajal et al.; October 2009
- National Kidney Foundation: KDOQI Clinical Practice Guidelines for Cardiovascular Disease in Dialysis Patients
- National Kidney Foundation: Phosphorus and Your CKD Diet
- National Kidney Foundation: Potassium and your CKD Diet