Based on the results of a recent nephrology study, a combination of fish oil and wheat germ oil has beneficial effects on serum calcium levels in hemodialysis patients. Other mineral-bone and inflammatory markers were not affected significantly.
Chronic kidney disease is an important public health concern that can result in end-stage renal disease (ESRD) requiring hemodialysis (HD) or transplantation. Most of the pathological changes in the renal tissue are initiated by oxidative stress and inflammatory reactions. ESRD is associated with changes in the Calcium (Ca), Phosphorus (P), Parathyroid hormone (PTH), or vitamin D metabolism that can lead to metabolic disorders such as renal osteodystrophy with bone loss, osteoporosis, and the possibility of fractures and vascular calcification.
There has been a growing interest in Omega-3 fatty acid (w-3 FA) supplementation and multiple health benefits it offers to HD patients. It has been shown that HD patients have significantly lower levels of w-3 FA in the red cell membrane as compared to a healthy individual, resulting in inflammation and its associated complications. There have been many clinical trials that have studied the ability of w-3 FA to alleviate inflammation in HD patients but the results have been inconsistent and inconclusive.
A recent randomized, placebo-controlled trial published in International Urology and Nephrology, examined the impact of combined supplementation of fish oil (FO) with wheat germ oil (WGO) on mineral-bone and inflammatory markers in HD patients. The trial involved 46 patients, randomly divided into two groups. The supplemented group received 3000 mg of fish oil (1053 mg of w-3 FA) and 300 mg of wheat germ oil (0.765 mg of vitamin E) daily for 4 months. Participants in the placebo group received three capsules of placebo. Venous blood samples were collected at baseline and at 4 months to estimate blood concentrations of hemoglobin (Hg), white blood cells (WBC), mineral-bone parameters such as serum Ca, P, PTH, alkaline phosphatase (ALP), and osteoprotegerin (OPG). Serum concentrations of inflammatory markers including high sensitivity C-reactive protein (Hs.CRP), ferritin, and uric acid were also measured before and after supplement intervention.
The results showed significantly increased serum Ca levels in the supplemented group while the placebo group showed no notable change in Ca levels. There was no significant change in serum Hs.CRP levels in both the supplemented and placebo group. No significant alterations were observed in other Hg, WBCs, serum ferritin, uric acids, P, Ca x P, PTH, ALP, and OPG in the supplemented or the placebo group.
Research done on animal and in vitro models has shown upregulation of duodenal Ca absorption by docosahexaenoic acid (DHA) which is a polyunsaturated omega-3 fatty acid or PUFA, by increasing the activity of Ca-ATPase, an enzyme for regulating Ca uptake. This suggests an association between higher w-3 FA intake and improved Ca absorption. Furthermore, 1,25(OH)2D, an active metabolite of vitamin D, increases Ca absorption from the intestine. In uremic condition, the level of enzymes that affect 1,25(OH)2D may be down regulated. Fish oil and wheat germ oil supplementation may be useful in regulating the enzyme levels thereby modifying the uremic condition. The increased levels of Ca in the supplemented group of HD patients in this study may be attributed to an increased activity of Ca-ATPase or a modified uremic condition and activated vitamin D.
The strengths of this study include the randomized, double-blind, placebo-controlled design, the study length of 4 months, no adverse effects of the supplements used, and a high patient compliance with the trial medication. Some of the limitations of the study are its small sample size, short follow up period, and perhaps insufficient doses of the supplements used.
There have been only a few studies that investigated the effect of a combination of w-3 FA and/or vitamin E on inflammatory markers in HD patients. Most of the results have been inconsistent and inconclusive. The results of this study could not provide marked changes in the inflammatory markers. However, a beneficial effect of a fish oil and wheat germ oil combination was observed in serum Ca levels of HD patients. Future large scale, prospective trials are needed to confirm the effects of a fish oil and wheat germ oil supplementation on mineral-bone and inflammatory markers in HD patients.
Written by Preeti Paul, MS Biochemistry
Reference: Hadeer Zakaria, Tarek M.Mostafa et al., The impact of fish oil and wheat germ oil combination on mineral bone and inflammatory markers in maintenance hemodialysis patients: a randomized, double-blind, placebo-controlled clinical trial. Int Urol Nephrol, June 2017.