A 16-week randomized controlled trial of a fish oil and whey protein-derived supplement to improve physical performance in older adults losing autonomy-A pilot study

Abstract

Background: Low functional capacity may lead to the loss of independence and institutionalization of older adults. A nutritional intervention within a rehabilitation program may attenuate loss of muscle function in this understudied population.

Objective: This pilot study assessed the feasibility for a larger RCT of a nutritional supplementation in older adults referred to an outpatient assessment and rehabilitation program.

Methods: Participants were randomized to receive a supplement (EXP: 2g fish oil with 1500 IU vitamin D3 1x/d + 20-30g whey protein powder with 3g leucine 2x/d) or isocaloric placebo (CTR: corn oil + maltodextrin powder) for 16 weeks. Handgrip and knee extension strength (using dynamometry), physical performance tests and plasma phospholipid n-3 fatty acids (using GCMS) were evaluated at weeks 0, 8 and 16; and lean soft tissue mass (using DXA), at weeks 0 and 16.

Results: Over 2 years, 244 patients were screened, 46 were eligible (18.9%), 20 were randomized, 10 completed the study (6 CTR, 4 EXP). Median age was 87 y (77-94 y; 75% women) and gait speed was 0.69 m/s; 55% had low strength, and all performed under 420m on the 6-minute walk test, at baseline. Overall self-reported compliance to powder and oil was high (96% and 85%) but declined at 16 weeks for fish oil (55%). The EXP median protein intake surpassed the target 1.2-1.5 g/kg/d, without altering usual diet. Proportions of plasma phospholipid EPA and DHA increased significantly 3- and 1.5-fold respectively, at week 8 in EXP, with no change in CTR. Participants were able to complete most assessments with sustained guidance.

Conclusion: Because of low eligibility, the pilot study was interrupted and deemed non-feasible; adherence to rigorous study assessments and to supplements was adequate except for long-term fish oil. The non-amended protocol may be applied to populations with greater functional capacity.

Trial registration: ClinicalTrials.gov NCT04454359.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. CONSORT flow diagram of the progress of participants through the study phases, conducted between August 2016 and August 2018.

Fig 2. Boxplots showing changes between baseline and week 8, and week 16 in (A) plasma phospholipid EPA, (B) DHA, (C) serum 25(OH)D by group.

Boxes are interquartile ranges and horizontal lines inside boxes are medians. Whiskers represent the minimal and maximal value and the blue dots represent the participants’ individual value. The dotted lines indicate a change of 0.

Fig 3

Boxplots showing changes between baseline and week 8, and week 16 in (A) Timed up and go (TUG), (B) gait speed, (C) 6-minute walk test, (D) total lean mass, (E) trunk lean mass, (F) appendicular lean mass, (G) total fat mass, (H) handgrip and (I) knee extension strength by group. Boxes are interquartile ranges and horizontal lines inside boxes are medians. Whiskers represent the minimal and maximal value and the blue dots represent the participants’ individual value. The dotted lines indicate a change of 0.