Krill oil may be a clinically relevant and nutritional intervention to promote muscle size and function and to support athletic performance and recovery. Krill oil contains high levels of omega-3 (n-3) polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), similar to common fish oil supplements. Krill oil differs from fish oil with its clinically significant levels of choline and astaxanthin, with each of these having distinct benefits for muscle health. 

The n-3 PUFAs in krill oil have anti-inflammatory and antioxidant properties that attenuate age-related muscular atrophy from chronic low-grade inflammation. The n-3 PUFAs also support athletic performance and reduce recovery time by lowering the risks of prolonged oxidative stress and inflammation from highly demanding metabolic exercise. 

Choline is the precursor to the neurotransmitter acetylcholine, which is responsible for muscle contractions. The body has a limited ability to produce choline endogenously from folate metabolism; therefore, the majority of choline is supplied through the diet. 

Unfortunately, 90% of Americans have suboptimal choline intake. Furthermore, those with genetic polymorphisms in folate metabolism, such as the MTHFR gene mutation, are at increased risk of choline deficiency. If plasma choline is low during exercise, the body will break down phosphatidylcholine instead, which is the building block of cell membranes. Lower cell membrane integrity and reduced acetylcholine production can accelerate muscle damage and exhaustion. Krill oil prevents choline depletion stores exogenously. 

The carotenoid pigment astaxanthin present in krill oil demonstrates strong antioxidant properties that can support a healthy immune system and fight against excessive free radical production during exercise. The phospholipids of krill oil increase the intestinal absorption of astaxanthin, which optimizes its bioavailability. 

Krill oil has been shown to promote athletic performance and muscle recovery in high-intensity training athletes due to n-3 PUFAs, choline, and astaxanthin. In a recent randomized, double-blind study, healthy athletes taking 2.5 g per day of krill oil for 12 weeks showed improved levels of n-3 PUFAs, choline, and total antioxidants relative to a control group. 

Krill oil may also help prevent sarcopenia, the age-related loss of muscle mass and function in individuals who are 65 years of age and older. Krill oil supplementation could be a useful muscle-building alternative to resistance training exercises in older populations with individuals who exercise infrequently and are at increased risk of sarcopenia. A randomized controlled trial demonstrated that supplementation of 4 g per day of krill oil for 6 months in healthy older adults significantly increased knee extensor strength, grip strength, and skeletal muscle thickness in both men and women. 

More research is needed to fully understand the combined effects of n-3 PUFAs, choline, and astaxanthin levels on muscle health and recovery for both athletes and nonathletes. However, current evidence suggests that krill oil may prevent the slow age-related deterioration of muscle mass and function while promoting muscle health, strength, and recovery at any age and exercise level.   

By Danielle Moyer, MS, CNS, LDN