Randomized controlled trial examining the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells.

Andrew Pipingas,Stephen Myers,Matthew Pase,Kevin Croft,Andrew Sinclair,Andrew Scholey,Robyn Cockerell,Natalie Grima,Con Stough,Avni Sali

doi:10.3390/nu6051956

Abstract

The present randomized, placebo-controlled, double-blind, parallel-groups clinical trial examined the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells. Healthy adult humans (n = 160) were randomized to receive 6 g of fish oil, 6 g of fish oil plus a multivitamin, 3 g of fish oil plus a multivitamin or a placebo daily for 16 weeks. Treatment with 6 g of fish oil, with or without a daily multivitamin, led to higher eicosapentaenoic acid (EPA) composition at endpoint. Docosahexaenoic acid (DHA) composition was unchanged following treatment. The long chain LC n-3 PUFA index was only higher, compared to placebo, in the group receiving the combination of 6 g of fish oil and the multivitamin. Analysis by gender revealed that all treatments increased EPA incorporation in females while, in males, EPA was only significantly increased by the 6 g fish oil multivitamin combination. There was considerable individual variability in the red blood cell incorporation of EPA and DHA at endpoint. Gender contributed to a large proportion of this variability with females generally showing higher LC n-3 PUFA composition at endpoint. In conclusion, the incorporation of LC n-3 PUFA into red blood cells was influenced by dosage, the concurrent intake of vitamin/minerals and gender.

Highlights

Two of the most commonly consumed dietary supplements in the Western world are fish oils containing long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) and multivitamins [1,2]
The present study investigated the effects of fish oil supplementation, with and without the addition of a multivitamin, on LC n-3 PUFA and LC n-6 PUFA incorporation measured in red blood cells
Given that males and females may respond differently to LC n-3 PUFA supplementation across different clinical outcomes, we examined whether gender predicted the incorporation of LC n-3 PUFA and LC

Summary

Introduction

Two of the most commonly consumed dietary supplements in the Western world are fish oils containing long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) and multivitamins [1,2]. The high prevalence of fish oil use may be in response to recent health messages, made by respected medical authorities such as the American Heart Association, advocating the benefits of increasing dietary LC n-3 PUFA intake. A preclinical study demonstrated that an experimentally induced folic acid deficiency was associated with a fall in LC n-3 PUFA levels, suggesting that low levels of antioxidant vitamins may increase lipid peroxidation [7]. Based on their frequency of use and potentially synergistic actions, there is a clear need to understand how multivitamins and fish oils combine to affect potential health outcomes

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