Omega-3 fatty acids and vitamin D in immobilisation: Part B- Modulation of muscle functional, vascular and electromyographic profiles

Bostock, EL ORCID: https://orcid.org/0000-0001-9340-8459, Morse, CI, Winwood, K ORCID: https://orcid.org/0000-0002-8696-9976, McEwan, I ORCID: https://orcid.org/0000-0001-8036-0505 and Onambélé-Pearson, GL (2017) Omega-3 fatty acids and vitamin D in immobilisation: Part B- Modulation of muscle functional, vascular and electromyographic profiles. Journal of Nutrition, Health and Aging, 21 (1). pp. 59-66. ISSN 1279-7707

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Abstract

Objectives This study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would modulate the anticipated muscle functional and related blood vessels function deleterious effects of immobilisation. Design The study used a randomised, double-blind, placebo-controlled design. Setting The study took part in a laboratory setting. Participants Twenty-four male and female healthy participants, aged 23.0±5.8 years. Intervention The non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily). Measurements Isometric and isokinetic torque, antagonist muscle co-contraction (activation profile), muscle fatigability indices, and arterial resting blood flow were measured before, at the end of the immobilisation period, and two weeks after re-mobilisation. Results Muscle elbow flexion and extension isometric and isokinetic torque decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of supplementation, ω-3 and vitamin D supplementation showed trends (P>0.05) towards attenuating the decreases observed in the placebo group. There was no significant change in muscle fatigue parameters or co-contraction values with immobilisation and no effect of supplementation group (P>0.05). Similarly, this immobilisation model had no impact on the assessed blood flow characteristics. All parameters had returned to baseline values at the re-mobilisation phase of the study. Conclusion Overall, at the current doses, neither ω-3 nor vitamin D supplementation significantly attenuated declines in torque associated with immobilisation. It would appear that muscle function (described here in Part B) might not be as useful a marker of the effectiveness of a supplement against the impact of immobilisation compared to tissue composition changes (described in Part A).