Water soluble vitamins in chronic hemodialysis patients and need for supplementation

Abstract

Forty-three patients on chronic hemodialysis who before the present study had only received a low-dose supplement of folic and ascorbic acid were studied prospectively for one year. After baseline values were obtained in month one, increasing doses of postdialysis vitamin supplements were prescribed for the vitamins which were found to be insufficient in order to determine the minimal amount of oral postdialysis supplement necessary to normalize vitamin levels. According to our results no systematic supplement was indicated for biotin, riboflavin or vitamin B12. For folic acid and vitamin C, supplementation with lower doses than those prescribed in many dialysis units allowed optimal vitamin levels in the majority of patients; 2 to 3 mg/week (300 to 400 micrograms/day) of folic acid and of 1000 to 1500 mg/week (150 to 200 mg/day) of vitamin C was considered sufficient. A severe pyridoxine deficiency was present in most (> 80%) unsupplemented patients, either as judged by pyridoxal-5-phosphate determinations in plasma or determination of specific enzyme activation in erythrocytes (EGOTo and alpha-EGOT); a postdialysis supplement of at least 100 to 150 mg/week of pyridoxine hydrochloride (> 15 to 20 mg/day) corrects this deficiency. The activity of the thiamine-dependent enzyme transketolase in erythrocytes (ETKo) was insufficient in 35% and marginal in 21% of the patients, while whole blood thiamine determined simultaneously in 10 of the ETKo-deficient patients was within the normal range. These results suggest that in uremia insufficient transketolase activity may be related to inhibition of the enzymatic system rather than to true vitamin deficiency. On a long-term basis a supplement of 200 to 300 mg/week of thiamine hydrochloride (30 to 45 mg/day) restored ETKo to satisfactory levels in most patients; whether this supplement is to be recommended warrants further studies.

Impacto do hábito de jantar sobre o perfil dietético de pacientes em hemodiálise

“…Adequate cobalamin intake helps in the folic acid metabolism, and, thus, in the homocysteine metabolism, because the folic acid deficiency in this study and in other studies was relevant. 33 According to Descombes et al 9 , cobalamin supplementation is not necessary, because its deficiency is uncommon in CKF patients. This suggests that an adequate dietary intake is sufficient to achieve the nutritional recommendations.…”

“…The most commonly deficient water soluble vitamins that often require supplementation 5 are pyridoxine, and ascorbic and folic acids. [9][10] According to the 2004 Resolution RDC 154, the nutrition professional becomes part of the minimum team required for the dialysis clinic functioning. 11 The presence of the nutritionist in that team is necessary to adequate the nutritional needs and to provide more efficient interventions.…”

The uremic toxin oxythiamine causes functional thiamine deficiency in end-stage renal disease by inhibiting transketolase activity

“…Thiamine (30 -45 mg per day equivalent) in HD patients was studied and found to alleviate transketolase deficiency. 24 These remedial effects found were consistent with reversal of OTPP antimetabolites effects but oxythiamine was not determined and the minimum dose of thiamine required for benefit is uncertain. High dose thiamine supplementation in renal failure is deserving of further attention to assess if it can consistently alleviate the metabolic impairment linked to transketolase insufficiency.…”

“…Supporting evidence for this is experimental and clinical studies in renal failure with high dose thiamine or related derivatives where transketolase activity was increased. [24][25][26] Maintained low or further decreased transketolase activity would be expected if formation of oxythiamine had increased.…”

Effect of Intravenous Ascorbic Acid Medication on Serum Levels of Soluble Transferrin Receptor in Hemodialysis Patients

“…Currently, in the case of suspected vitamin C deficiency, 1.0 to 1.5 g/wk oral ascorbate for chronic HD patients or 300 to 500 mg of parenteral ascorbate per dialysis session is recommended (11,12). However, prescription of vitamin C in different dialysis facilities varies between 55 and 1000 mg daily (37)(38)(39). For assessing the acute changes in serum levels of TfR, a high IVAA bolus dose of 1000 mg administered after each dialysis session was chosen in the present study.…”