Heart disease is the leading cause of death for haemodialysis patients, and oxidative stress and hyperhomocysteinaemia (an abnormally high level of homocysteine in the blood) are thought to be contributing factors.
In addition, antioxidant depletion and lipid peroxidation are among the main causes of increased atherosclerosis risk in such patients.
Based on this, researchers from the Sabzevar University of Medical Sciences conducted a cross-sectional study, whereby they analysed the status of antioxidant and anti-homocysteine vitamins linked to heart disease in haemodialysis patients.
Insufficient intake
They assessed 75 patients — 33 men and 42 women — for height, weight, food frequency and food intake, the latter via a 24-hour dietary recall questionnaire for a minimum of two days (one non-dialysis and one dialysis day).
Their intake of all vitamins, except B12, was also studied, and found to be blow the recommended dietary allowance (RDA).
"According to our findings, receiving all nutrients except vitamin B12 was less than [recommended] in hemodialysis patients. Intake of vit A, vit E, vit C and vit B9 in men were 29%, 7%, 52%, 32% respectively and in women were 32%, 7.5%, 76% and 33% respectively."
At the same time, previous studies involving haemodialysis patients have shown that their levels of antioxidant vitamins C and E are typically low.
Dialysis and its detriments
This was due in part to vitamin depletion during dialysis. For instance, vitamin C — which lowers oxidative stress by obstructing free radicals and lipid peroxidation — dissolves in water and does not bind to plasma proteins, therefore passing easily through the dialysis membrane.
This results in approximately 200mg of vitamin C being lost every week through dialysis.
The loss of other water-soluble oxidants, along with “contact lymphocytes with dialysis filters, microbial contamination of dialysis solution, accumulation of peroxidants…and (the) use of drugs, including erythropoietin and intravenous iron”, contribute to oxidative stress.
In addition, antioxidant vitamin E levels in haemodialysis patients were lowered due to free radicals produced during dialysis.
A and E against mortality
The study stated: “It seems that low intake of vitamins A and E is due to reduced oil consumption and high-fat dairy products. On the other hand, hypercholesterolemia and hyperlipidemia are common in haemodialysis patients.”
It added that there was a direct link between regular intake of water-soluble vitamins and reduced risk of death from heart disease in haemodialysis patients.
The researchers concluded: “If further studies confirm, the results could have great public implication, as diets rich in B-vitamins and antioxidants are inexpensive means of targeting cardiovascular disease risk in haemodialysis patients.”
Source: Electronic Physician
http://dx.doi.org/10.19082/4895
“Status of antioxidant and homocysteine-lowering vitamins related to cardiovascular diseases in hemodialysis patients”
Authors: Akram Kooshki, et al.