The cross-sectional study drew on data from the UK Biobank, a large population-based cohort of participants between the ages of 40 and 69, recruited from 22 assessment centers between March 2006 and December 2010 in England, Scotland and Wales.
“Frailty is a common geriatric syndrome characterized by unintentional weight loss, exhaustion, slow walking pace, low physical activity and low grip strength, which results in adverse health outcomes including falls, fractures, hospitalization, disability and death,” the researchers noted. “As populations age, the prevalence of frailty increases rapidly, ranging from 12% to 24% in 62 countries around the world.”
Supported with funding from the National Research Foundation of Korea, the study was carried out by researchers from Hanyang University, The Fatty Acid Research Institute, University of Illinois and Sanford School of Medicine.
Omega-3s and frailty
This latest research builds on findings that associated circulating levels of omega-3 polyunsaturated fatty acids (PUFAs) with frailty among Koreans, a population with a high intake of fish.
Previous studies have also reported an inverse correlation between frailty and fish intake in an elderly rural coastal population in Ecuador, in Irish elderly community-dwelling adults, in Japanese older women consuming more than three to seven servings of fish a week and in an older Spanish population that included fish as part of a Mediterranean Diet. Chen et al reported that frail older adults had lower use of fish oil compared to non-frail older adults in Taiwan.
Regarding circulating omega-3s, the Korean population study reported average erythrocyte levels of EPA+DHA of 11.8% and 10.9% in non-frail and frail Korean older adults, which was the highest of any population yet tested. The estimated level in the UK Biobank was 5.58%, similar to that reported from a global sample of healthy individuals across the United States, Canada, Italy, Spain, Germany, South Korea and Japan).
“This suggests that within any given cultural context, higher levels (and intakes) of n-3 PUFAs could be helpful in reducing the long-term risk for frailty,” the researchers noted.
Dr. William Harris, head of The Fatty Acid Research Institute and editor on the paper, said that ideal red blood cell docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) content is still greater that 8%, as measured by the Omega-3 Index.
“If you start at 4% (low) and want to get to 8% (in about four months), you need about 1,400 mg/d of EPA+DHA in the triglyceride form (~2000 mg of the ethyl ester form),” he added. “If you start at 5%, you would need about 1,000 mg/d.”
Study details
Of the 502,411 subjects analyzed from the UK Biobank, the researchers included a total of 18,802 participants 65 years and older with plasma fatty acid data.
Frailty was defined using a modified Cardiovascular Health Study index consisting of five criteria (weight loss, exhaustion, low physical activity, low grip strength and slow walking pace), plasma levels of n-3 PUFAs were measured by nuclear magnetic resonance, and intake of oily fish and/or fish oil supplements was collected via food frequency questionnaire.
“Frailty prevalence was inversely associated with n-3 PUFA levels, with oily fish intake, and with the use of fish oil supplements after adjusting for confounding factors,” the researchers reported. “All three exposures were also associated with each frailty criterion, particularly low physical activity and walking pace.”
Commenting on the study findings, Dr. Harris noted the significance of the link between low omega-3 levels frailty as evidence of associations with diminished function of the whole body rather than with just one specific condition like cardiovascular disease.
“Together with data showing that higher omega-3 levels are strongly linked to greater longevity, the need for optimizing omega-3 FA blood levels—by diet or by supplementation—is all the more acute,” he said.
For future study, the researchers plan to look at incident frailty in the UK Biobank and called for further large population-based longitudinal studies to verify the associations identified.
Source: The Journals of Gerontology: Series A
“Association of plasma n-3 polyunsaturated fatty acid levels and the prevalence of frailty in older adults: a cross-sectional analysis of UK Biobank”
Authors: Junghyun Kim et al.
