Page 85 - JSOM Spring 2021

Muscle Disuse SOF personnel are exposed to environments and training sce-
While serious injury may be the most likely reason for limb narios that may increase their susceptibility to injuries, includ-
immobilization in Special Operators, reconnaissance missions ing concussions or mild TBIs. It is plausible that FOS may
have been shown to cause similar muscular changes as seen in reduce the occurrence and severity of mild TBIs.
classical limb immobilization or muscle disuse models. Chris-
tensen et al. created a realistic 8-day multistressor exercise in It is well established that TBI leads to a reduction in brain
which Special Operators conducted a covert reconnaissance DHA content and low DHA levels exacerbate the response
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of a farmhouse for suspected enemy activity. Operators were to TBI. 90–92 Animal models of TBI have consistently shown that
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in the prone position for most of the 8-day period and were omega-3 supplementation, primarily DHA, is an effective strat-
able to observe roving patrols with dogs, helicopter searches, egy to mitigate brain damage and promote recovery. 93–97 Eth-
and suspicious activity at the target location. Despite the ad- ically, it can be difficult to study FOS before or after TBI in
equate provision of water and nutrition, Special Operators humans. Despite this, two case studies and one study in colle-
experienced significant decrements in performance to include giate athletes highlight the potential application of FOS to at-
~10% decline in power, a nearly 11% reduction in strength, tenuate the effects of TBI and enhance recovery. 98–100 In support
and a staggering 19.5% reduction in the rate of force develop- of preclinical data, Oliver et al. found that prophylactic high-
ment, and, finally, a 5% loss of muscle mass. 38,84 The decline in dose (2 –6g) DHA supplementation significantly reduced serum
LBM and strength are likely attributable to the observed 42% levels of neurofilament light, a marker of head trauma, that was
reduction in the mechanistic target of rapamycin protein. otherwise elevated in athletes without DHA supplementation. 100
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This finding is significant since FOS has been shown to upreg-
ulate this protein pathway in young to middle-aged adults. 44
Cognitive Performance
Two human trials have been conducted to determine if FOS In conjunction with physiological stress, SOF personnel are
preserves muscle mass and strength during short periods of also under heavy psychological strain during SUSOPS. Cogni-
muscle disuse in young, healthy adults. Bostock and col- tive performance is an important component of mission suc-
leagues assigned healthy adults to receive 2.16g EPA+DHA, cess that may be influenced by FOS. A committee of subject
1000 IU vitamin D, or placebo accompanied by 2 weeks of matter experts were commissioned to investigate the poten-
nondominant arm immobilization for 9 hours/d. 86,87 Arm im- tial impact of omega-3 PUFAs on cognitive functions deemed
mobilization in the placebo group led to a significant reduc- critical for mission readiness. The variables identified were
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tion in muscle thickness (3.2 –7.8%), arm girth (0.8–1.3%), memory, verbal fluency, reaction time, attention and vigilance,
and muscle mass (3.6%) and an increase in subcutaneous adi- and problem solving and reasoning. Based on the systematic
pose thickness (10.3%). FOS attenuated the decline in muscle review, no recommendations were given due to a lack of evi-
thickness, upper arm girth, and muscle mass. However, FOS dence. Pomeroy et al. updated this analysis, but reported that
did not attenuate the decline in strength following immobili- the evidence was still inconclusive. In contrast, Lewis et al.
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zation. This may partially be due to the short duration of the found that FOS significantly and clearly improved reaction
intervention. Evidence suggests that FOS should be > 2 weeks time and mood in a population similar to SOF personnel.
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to maximize omega-3 assimilation into the muscle cell, since Interestingly, three of the four studies showing a benefit for
immobilization occurred concurrently it is unlikely that com- FOS in athletes were not included in the previous two system-
plete incorporation was accomplished. 88 atic reviews.

McGlory et al. investigated the influence of FOS on changes Reaction Time
in muscle mass and strength following 2 weeks of leg immo- Three trials in athletes reported that FOS significantly reduced
bilization in young women. FOS began 6 weeks prior to leg simple and complex reaction time. 103–105 Fontani et al. found
immobilization and continued throughout the study. The that athletes in the FO group exhibited superior information
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decline in muscle volume elicited by short-term leg immobi- processing speed. In a cohort of elite female soccer players,
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lization was attenuated by 6% with FOS (–8%) compared to DHA supplementation improved complex reaction time and
placebo (–14%). After 2 weeks of rehabilitation and recovery, efficiency. These findings have been replicated in some, but
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muscle volume returned to baseline levels in the supplementa- not all studies in healthy adults. 106–110 Jackson et al. determined
tion group but remained below baseline in the placebo group. that 1g FO significantly improved one measure of reaction
Interestingly, FOS also attenuated the decline in strength time, while 2g FO improved two measures of reaction time. 111
(35%) versus the placebo group (50%).
Attention and Vigilance
A systematic review found that omega-3 PUFA supplementa-
Overall: Other Relevant Scenarios
tion did not consistently improve attention and vigilance mea-
As illustrated in Table 2, during catabolic or physiologically sures. Although 11 studies were available during the review
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stressful situations such as muscle disuse or energy deficit, period, four of the studies were in older adults. Removing
FOS likely preserves strength. However, LBM may only be these studies from consideration does not influence the results.
preserved during muscle disuse. A recent trial in young adults found similar results and con-
cluded that FOS does not improve attentional control, with or
without an added stressor. 112
Cognitive Protection
Mild Traumatic Brain Injury/Concussion Mood States
During Operation Iraqi Freedom and Operation Enduring In a study of healthy participants, FOS significantly improved
Freedom, rates of TBI ranged between 15% and 22.8% with mood states such as increased vigor and reduced anger, anxi-
the majority being classified as mild TBIs. Similar to athletes, ety, fatigue, depression, and confusion. Similar results were
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Fish Oil and Performance | 81