Supplementation with Krill Oil Significantly Improves Muscle Function and Size in Older Adults

by | Mar 13, 2023 | 2022, Aging, Omega - 3, Polyunsaturated

Written by Taylor Woosley, Staff Writer. 6-month supplementation of 4 g/day of krill oil resulted in an increase in muscle thickness of 3.5% compared to the control. 

aging couple lifting weightsSarcopenia is predominantly a geriatric condition, with a gradual loss of skeletal muscle mass and a loss of muscle function1. The pathophysiology of sarcopenia is complex and results from biological alterations in the structure of the muscles, hormonal imbalances, and external influences such as energy intake deficiencies2. In terms of human health, sarcopenia increases risk of falls and fractures, impairs ability to perform activities of daily living, leads to mobility disorders, and contributes to a lowered quality of life3.

Epidemiological data has shown that the consumption of fatty fish is positively associated with muscle function in older populations4. Krill is a novel source of omega-3 polyunsaturated fatty acids (PUFAs) that contain the bioactive ingredients choline and astaxanthin5. Krill oil has been shown to improve postexercise immune function, diminish postexercise oxidative damage, and increase muscle mass and function6.

Alkhedhairi et al. conducted a double blind randomized controlled study to determine the effect of krill oil on muscle function and size in healthy older adults, with a focus on changes in knee extensor muscle strength from baseline to 6 months. Secondary outcomes included changes in grip strength, muscle thickness, short performance physical battery test, blood lipids, fasting glucose, C-reactive protein, and erythrocyte fatty acid profiles. Subject inclusions consisted of having a BMI less than 35 kg/m2, who were over 65 years old, willing to partake in 1 hour per week of structured self-reported exercise. Subjects (n=94) were randomly assigned to either control (n=45) or krill oil (n=49) groups for the 6-month intervention period. Follow-up study visits took place at 6 weeks and 6 months, with participants avoiding exercise for 48 hours before each visit.

During the 6-month intervention, participants were instructed to maintain their normal dietary and physical activity habits. Control consumed 4 g/day of mixed vegetable oil, with the total LCn-3PUFA content being 4 mg/g, with <1 mg/g EPA and DHA. The krill oil group consumed 4 g/day of the krill oil supplement which had a total LCn-3PUFA content of 322 mg/g, with 193 mg/g EPA and 96 mg/g DHA, with each 1 g capsule also containing 79 mg of choline. All participants consumed 2 capsules with lunch and 2 with dinner. Muscle strength of the knee-extensor muscles of the right leg were measured using a dynamometer.

At baseline and 6 months blood samples were obtained from subjects. At 6 weeks a finger prick blood sample was collected to assess fatty acid levels. Blood samples were further analyzed for glucose, insulin, lipids, and C-reactive protein. Subjects also completed the EuroQol EQ-5D-5L questionnaire at baseline, 6 weeks, and 6 months to assess changes in quality of life. Baseline data was compared between groups via unpaired t-tests. A 2-way ANOVA with repeated measures was performed to determine the effects of time, supplement, and time*supplement interactions on the outcome variables. Significant findings of the study are as follows:

  • The ANOVA revealed group (p = 0.030), time (p < 0.0001) and interaction effects (p < 0.0001) for grip strength data, with post-hoc tests identifying that grip strength was higher (p < 0.05) in the krill oil, relative to control at 6 months.
  • The analysis of the fatty acid data revealed group*time interaction effects (all p < 0.0001) for EPA, DHA, and the omega-3 index, with post-hoc tests revealing that all were higher (p < 0.05) at 6 weeks and 6 months in the krill group, compared to control.
  • The change in muscle thickness data over the 6-month intervention period was 0.05 ±1% in the control group and 3.5 ± 4.5% in the krill oil group, giving a 6-month intervention effect of 3.5% (95%CI: 2.1, 4.9%).

Results of the study show that 6-month intervention of 4 g/day of krill oil significantly increased knee extensor grip strength and skeletal muscle thickness in healthy older adults. These finding suggest that krill oil could be an effective preventative strategy to reduce the age-related decline in muscle mass. Further research should continue to explore the effects of krill oil on muscle mass and function in people with lower physical function at baseline.

Source: Alkhedhairi, Saleh AA, Faris F. Aba Alkhayl, Ahmad D. Ismail, A. Rozendaal, M. German, Beth MacLean, Lynsey Johnston et al. “The effect of krill oil supplementation on skeletal muscle function and size in older adults: A randomised controlled trial.” Clinical Nutrition 41, no. 6 (2022): 1228-1235.

© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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Posted March 13, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Papadopoulou SK. Sarcopenia: A Contemporary Health Problem among Older Adult Populations. Nutrients. May 1 2020;12(5)doi:10.3390/nu12051293
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  4. Alkhedhairi SA, Aba Alkhayl FF, Ismail AD, et al. The effect of krill oil supplementation on skeletal muscle function and size in older adults: A randomised controlled trial. Clinical nutrition (Edinburgh, Scotland). Jun 2022;41(6):1228-1235. doi:10.1016/j.clnu.2022.04.007
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  6. Georges J, Sharp MH, Lowery RP, et al. The Effects of Krill Oil on mTOR Signaling and Resistance Exercise: A Pilot Study. J Nutr Metab. 2018;2018:7625981. doi:10.1155/2018/7625981