You may know that the omega-3s found in seafood – DHA and EPA – are essential to the brain and eyes.
That's why one of these so-called "long-chain” omega-3s – called DHA – abounds in our brain and retinal cells.
Both of the major seafood-type omega-3s occur in almost every cell in the body, and play key roles in bone, skin, and metabolic health.
Omega-3 DHA and EPA are also critical to our immune systems, including infection control and moderating inflammation.
Researchers are still exploring the full range of effects that these omega-3s exert in the human body, and continue to discover more.
Clinical studies published over the past several years suggest that dietary omega-3s support and modestly enhance muscle strength and endurance.
Two new studies add more evidence that seafood source omega-3s have significant roles to play in maintaining muscle strength – and immunity against infections – as people age.
Workouts plus omega-3 fish oil boosted women's infection defenses and muscle strength
People's immune functions are known to degrade over time, making older people more vulnerable to infections and degenerative or autoimmune diseases.
Physical activity and diet also play important roles in helping or harming immune system responses.
For example, mild exercise raises the number of immune system T-cells, while strenuous exercise tends to impair people's inflammatory responses.
(T-cells are crippled by the virus that causes AIDS, which is why people with that insidious syndrome are vulnerable to infections.)
The first of two new clinical trials was conducted by researchers from Brazil's Paraná Federal University and Pequeno Príncipe Research Institute. (Rodacki CL et al. 2015)
They recruited 45 healthy women (average age 64) for a novel clinical trial designed to test the effects of strength training – with or without supplemental fish oil – on strength and immunity.
The women were randomly assigned to one of three groups:
  1. Strength training for 90 days, without omega-3 fish oil.
  2. Strength training for 90 days, plus 2,000mg of omega-3 fish oil per day.
  3. Daily fish oil (2,000mg) daily for 60 days, followed by strength training and daily fish oil for 90 days.
They performed strength training three times a week, which included floor exercises and upright hip, leg, knee and foot exercises.
The researchers measured the function of various aspects of the immune system before and after the participants completed their assigned regimens.
Compared with strength training alone, the combination of strength training plus supplemental fish oil resulted in more muscle and strength, and improvements in the women's defenses against infections.
As the researchers wrote, "The immune parameters improved in response to fish oil supplementation; however, strength training alone did not enhance the immune system.” (Rodacki CL et al. 2015)
And they made a larger point: "These increases highlight the modulatory effects of fish oil and exercise in the elderly, which is helpful in restoring the immunity balance.” (Rodacki CL et al. 2015)
Specifically, the group who took fish oil boosted the functioning or numbers of immune system factors involved in defense against infections:
  • Neutrophils
  • Lymphocyte cytokines
  • Cytokines IL­2 and IFN­g
  • CD4þ and CD8þ lymphocytes
It's interesting to note that higher doses of fish oil (i.e., more than 2,000mg a day) did not further improve the women's immune capacities, but did yield greater improvements when compared to strength training alone.
Fish oil enhanced muscle strength in older men and women
Aerobic exercise (e.g., running, cycling, and swimming) is critical for heart and lung health.
But it's also important to routinely engage in resistance (strength) training to maintain muscle mass and strength.
After about age 35, sedentary people can lose 3 to 5 percent of their muscle mass per decade, which can impair daily activities and raise the risk of falls and disability.
Dangerously substantial loss of muscle mass (sarcopenia) typically begins around age 65 and accelerates around age 75.
There is no substitute for strength training when it comes to maintaining or building muscle.
However, the results of a new clinical trial support previous findings that supplemental omega-3 fish oil alone can increase muscle mass modestly.
The research comes from Washington University School of Medicine in St. Louis, and follows prior research by the same team (see Omega-3s May Reduce Age-Related Muscle Loss).
They recruited 60 healthy older men and women (aged 60-85) for a 6-month, double-blind, randomized, placebo-controlled clinical trial (Smith GI et al. 2015).
Out of the 60 people they recruited, 44 people completed the full study.
The participants who completed the study had been randomly assigned to one of two regimens:
  • Omega-3 fish oil capsules* - 29 volunteers
  • Corn oil (placebo) capsules - 15 volunteers
*Containing 3,350 mg of EPA + DHA (a little less than the amount in four, 850mg capsules of High Potency Omega-3 fish oil).
Before and after the trial, the researchers measured the participants' thigh muscle volume, hand-grip strength, 1-RM (one-repetition maximum) weight-lifting capacity, lower- and upper-body strength, and average power during isokinetic leg exercises.
(One-repetition maximum is the amount of weight you can bench-press once but not twice. Special isokinetic exercise machines, including certain kinds of stationary bikes, provide variable resistance, so that no matter how much effort is exerted, movement takes place at a constant speed. Isokinetic exercise one of the fastest ways to increase muscle strength.)
Compared with the control (corn oil) group, the omega-3 fish oil group gained thigh muscle volume, handgrip strength, and 1-RM muscle strength, and tended to show improvements in average isokinetic power.
They also noted that the group that took fish oil 6 months reduced the expected, age-related muscle loss and function by the equivalent of being 2-3 years younger.
As the Washington University researchers wrote, "Fish oil-derived omega-3 therapy slows the normal decline in muscle mass and function in older adults and should be considered a therapeutic approach for preventing sarcopenia and maintaining physical independence in older adults.” (Smith GI et al. 2015)
So while you shouldn't expect fish oil to make you feel noticeably stronger, daily consumption may help maintain muscle mass and slow the rate of age-related muscle decline.
And for folks approaching middle age – or those already well into that age range – this is no minor matter.
  • Gray P, Gabriel B, Thies F, Gray SR. Fish oil supplementation augments post-exercise immune function in young males. Brain Behav Immun. 2012 Nov;26(8):1265-72. doi: 10.1016/j.bbi.2012.08.002. Epub 2012 Aug 10.
  • Rodacki CL, Rodacki AL, Coelho I, Pequito D, Krause M, Bonatto S, Naliwaiko K, Fernandes LC. Influence of fish oil supplementation and strength training on some functional aspects of immune cells in healthy elderly women. Br J Nutr. 2015 Jun 10:1-10. [Epub ahead of print]
  • Rodacki CL, Rodacki AL, Pereira G, Naliwaiko K, Coelho I, Pequito D, Fernandes LC. Fish-oil supplementation enhances the effects of strength training in elderly women. Am J Clin Nutr. 2012 Feb;95(2):428-36. doi: 10.3945/ajcn.111.021915. Epub 2012 Jan 4.
  • Santos VC, Levada-Pires AC, Alves SR, Pithon-Curi TC, Curi R, Cury-Boaventura MF. Effects of DHA-rich fish oil supplementation on lymphocyte function before and after a marathon race. Int J Sport Nutr Exerc Metab. 2013 Apr;23(2):161-9. Epub 2012 Dec 7.
  • Smith GI, Julliand S, Reeds DN, Sinacore DR, Klein S, Mittendorfer B. Fish oil-derived n-3 PUFA therapy increases muscle mass and function in healthy older adults. Am J Clin Nutr. 2015 May 20. pii: ajcn105833. [Epub ahead of print]