The study, published in the journal Obesity, is the first of its kind to investigate the effects of krill oil on muscle mass and strength during diet-induced weight loss.
Growing global interest in weight-loss interventions — from calorie-restricted diets to pharmacological approaches such as GLP-1 receptor agonists — has brought increased attention to the potential health implications of rapid weight reduction.
One concern is the simultaneous loss of skeletal muscle, which can negatively impact metabolic health, physical function and long-term weight maintenance.
Although this study did not include participants on GLP-1 medication, the findings provide relevant insights for a broad range of weight-loss scenarios.
“Although losing weight is often a good thing, one of the unintended consequences is that we don’t only lose fat, but we also lose muscle."
"In this study, we have found that krill oil can help to preserve our muscle mass and strength as we lose weight. As maintenance of muscle is very important for our overall health and quality of life, these are extremely exciting findings,” says Dr Stuart Gray, a Professor at the University of Glasgow and coauthor of the study.
Clinical study background
The study was based on the premise that weight loss during a fasting diet can lead to a decline in muscle mass, which can negatively impact muscle strength.
The scientists at the University of Glasgow hypothesised that krill oil, as a source of long-chain omega-3 polyunsaturated fatty acids, could minimise this decline.
They put this theory to the test by enrolling 52 adult participants (between 25-65 years of age with above-average BMI) in the randomised placebo-controlled trial, using krill oil and placebo supplements supplied by Aker BioMarine.
The participants received either 4 g of Superba Boost krill oil per day or 4 g of vegetable oil per day (placebo), both before and during the weight loss period.
During fasting days, participants consumed no more than 500 Kcal during a 2-hour window. On feeding days, participants were allowed to eat normally but were told to avoid overeating.
Results of the trial
The 41 participants who completed the trial underwent several tests following the weight loss period, including handgrip strength, chair rising, body composition and a fatty acid composition analysis. The key results included
- the loss in muscle mass was lower in the krill oil group compared to the placebo group
- the resulting loss in handgrip strength was lower in the krill oil group compared with the placebo group.
- the amount of time to rise out of a chair was shorter for participants taking the krill oil supplements.
- the reduction in systolic blood pressure was greater in the krill oil group than in the placebo group.
- the amount of fatty acids (EPA, DHA) and the omega-3 index were higher among participants in the krill oil group.
Following this experiment, the scientists concluded that 4 g per day of krill oil during a period of weight loss can help reduce losses in muscle mass and strength, making it a viable strategy to mitigate some of the associated unwanted effects.
They also noted that future studies are recommended to explore the underlying mechanisms behind the impact of krill oil in terms of preserving muscle function.
“We are pleased to continue our work with the University of Glasgow to further explore krill oil and its positive effects on muscle mass and function,” says Line Johnsen, SVP Human Health Ingredients R&D, Aker BioMarine.
“We have previously conducted scientific studies with Dr Gray and his team to show how the important nutrients found in krill impact muscle strength and mass with age, and this follow-up study helps strengthen our understanding of this area.”
