Association of Fish Oil and Physical Activity on Mobility Disability in Older Adults

Anoop Balachandran; David M. Gundermann; Michael P. Walkup; Abby C. King; Walter T. Ambrosius; Stephen B. Kritchevsky; Marco Pahor; Anne B. Newman; Todd M. Manini

Disclosures

Med Sci Sports Exerc. 2020;52(4):859-867. 

In This Article

Abstract and Introduction

Abstract

Purpose: This study aimed to examine whether long-term fish oil (FO) supplementation is associated with a lower risk of mobility disability and enhances benefits of physical activity (PA).

Methods: A total of 1635 sedentary adults age 70 to 89 yr from the Lifestyle Interventions and Independence for Elders single-blinded randomized, multicenter clinical trial, which compared a structured PA program to a health education program. Primary outcome was incident major mobility disability (MMD), defined by loss of ability to walk 400 m, measured every 6 months for an average of 2.6 yr. Secondary outcomes included persistent mobility disability, Short Physical Performance Battery, 400-m walk speed, and grip strength.

Results: A third of participants reported using FO at baseline (456 (28%); mean age, 78.5 yr; 70.5% women). MMD was experienced by 131 participants (28.7%) in the FO group and 405 (34.4%) participants in the nonuser group. After adjusting for confounders, FO supplementation was associated with a lower risk (HR, 0.78; 95% confidence interval (CI), 0.64–0.96) of incident MMD. However, there was no interaction (P = 0.19) between FO supplementation and PA intervention for MMD. For the secondary outcome of persistent mobility disability, the intervention association differed by supplementation (P = 0.002) with PA intervention associations of (HR, 1.36; 95% CI, 0.83–2.23) for users and (HR, 0.61; 95% CI, 0.46–0.81) for nonusers. Changes in physical performance outcomes were not modified by baseline FO supplementation or combination with PA.

Conclusions: FO supplementation was associated with a lower risk of MMD in low to moderate functioning older adults. However, supplementation did not enhance the benefit of PA on risk of mobility disability. These results are hypothesis generating and need to be confirmed in randomized trials.

Introduction

Aging results in a progressive decline in physical function, leading to the loss of physical independence, an increased probability of falls, and reduced quality of life.[1–3] Maintaining function is as important as prolonging life expectancy in older adults.[4] Considering the expected rise in the elderly population,[5] preserving physical function is a significant public health concern. Despite the potential public health impact, few interventions exist to slow the decline in physical function.

Fish oil (FO)—also known as long-chain omega-3 polyunsaturated fatty acids—is the most widely used natural dietary supplement in the United States[6] and has been the focus of a substantial amount of health research in the past three decades.[7–11] Dietary intake of FO has a multitude of potential biological mechanisms related to lowering inflammation,[12] increasing muscle protein synthesis,[13,14] and improving muscle quality,[15] which are closely related to the loss of physical function in older adults. As such, dietary fish intake or FO supplementation could preserve or enhance physical function in older adults. In general, the literature evaluating FO supplementation and physical function in older adults has shown encouraging results: For example, a majority of observational studies in this area have shown favorable associations between FO supplementation and physical function.[16–18] Longer-duration randomized controlled trials (RCT; 6 months) also have shown a beneficial effect of omega-3 supplementation on walking speed,[19] muscle strength,[20] and muscle volume[20] in nonphysically impaired older adults. Meanwhile, trials with short supplementation duration (<6 months) have failed to show any benefits on physical function or performance,[21,22] suggesting that a more sustained regimen may be necessary to see measurable effects.

Although physical activity (PA) is known to improve physical function in older adults, there is significant variability in responses.[23,24] Coupling PA with FO supplementation may result in an augmented effect on biological pathways, resulting in a larger effect on physical function. Notably, a 5-month RCT of omega-3 supplementation has shown a potentiating effect when combined with exercise compared with exercise alone in older adults without physical limitations.[15] The purpose of this article was to test the hypothesis that long-term FO supplementation is associated with a reduced risk of major mobility disability (MMD). A second purpose was to evaluate if long-term FO supplementation modifies the association of a PA intervention with respect to MMD, persistent mobility disability (PMD), and physical functional outcomes[23] in low-to-moderately functioning older adults.

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