Written by Marcia Egles, MD. Study found that folic acid supplementation lowered homocysteine levels in adult hemodialysis patients.
Homocysteine is an amino acid formed in the body from the conversion of the amino acid methionine to the amino acid cysteine. (Amino acids are the building blocks of proteins.) People with higher than normal levels of homocysteine have been found to have a higher likelihood of heart and blood vessel disease, although it has yet to be determined whether homocysteine is a direct cause of disease. (1) Folate and other B vitamins help to break down homocysteine in the body. Several studies have shown that folic acid supplementation can help to lower high homocysteine levels. (2)
A recent study in Brazil found that folic acid supplementation lowered homocysteine levels in adult hemodialysis patients. Hemodialysis is a life-sustaining medical treatment for kidney failure. Impurities such as uric acid and excess fluid are removed from the blood by a dialysis machine. Water soluble vitamins such as B vitamins are also unavoidably removed by dialysis. Patients with severe kidney disease are prone to high rates of cardiovascular disease. High levels of homocysteine are present in the blood of the majority of kidney failure patients. (3)
After random selection, 26 male and female hemodialysis patients received folic acid supplements. Twenty hemodialysis patients received placebo. The 10mg oral supplements were given to the patients by dialysis nurses at the patients’ regular dialysis sessions three times per week for six months. Neither the caregivers nor the patients knew if they were receiving folic acid or placebo.
A hemodialysis unit affords a more controlled situation than might otherwise be encountered in a clinical study. A 100% compliance rate for the administration of the folic acid and placebo was reported, and no patients were lost to follow-up. Levels of folate, homocysteine, and TRAP (an anti-oxidant measurement) were obtained before and after the six months of folate treatment.
At the start of the study, no patients were B-12 deficient. Two patients in the control group and three in the folate group were folate deficient at the beginning of the study. All the patients had elevated homocysteine levels (average of 27 micromoles per liter). At the end of six months, all of the folate treated patients had reductions in their homocysteine levels. The majority of the folate treated patients achieved homocysteine levels in the normal range (8.39 +/- 4.6 micromoles per liter). The high homocysteine levels of the placebo group were unchanged. The folate group also showed a small improvement in TRAP, an experimental measure of anti-oxidant capacity in the blood.
The experiment showed that oral folic acid supplementation effectively lowered homocysteine levels in the hemodialysis patients. The larger question is whether this helps to prevent disease. The same group of researchers is presently collecting data on the effects of folic acid supplementation on death rates from cardiovascular disease in hemodialysis patients. They hope to publish these results in the near future.
Source: Delfino, Vinicius Daher Alvares, Areuza Célia de Andrade Vianna, Altair Jacob Mocelin, Décio Sabbatini Barbosa, Rosana Aiko Mise, and Tiemi Matsuo. “Folic acid therapy reduces plasma homocysteine levels and improves plasma antioxidant capacity in hemodialysis patients.” Nutrition 23, no. 3 (2007): 242-247.
© 2007 Elsevier Inc. All rights reserved
Posted July 23, 2008.
References:
- www.americanheart.org See homocysteine and folate.
- The Heart Outcomes Prevention Evaluation (Hope 2) Investigators. Homocysteine Lowering with Folic Acid and B Vitamins in Vascular Disease. The New England Journal of Medicine,Vol. 354:1567-1577, April 13, 2006.
- Buccianti G, Baragett I, et al. Plasma homocysteine levels and cardiovascular mortality in patients with end-stage renal disease. J. Nephro 2004: 17: 405-10.
