A shortened review: International society of sports nutrition position stand: nutrition for the warfighter
This post aims to provide an overview of the nutritional challenges imposed on warfighters (WF), outline the position statement recommendations by ISSN (International Society of Sports Nutrition), and provide some further background behind some of the recommendations.
To start, WFs perform some of society's most physically demanding jobs. Lifting heavy objects and tools, extracting casualties, moving quickly with PPE, as well as having a tremendous cognitive demand are only some of the job requirements.
Through all of that, there are two immense challenges for the WF:
Decrease energy intake in operational environments
Sleep deprivation
Decrease energy intake in operational environments
The WF is exposed to hypo-energetic environments. Variables like PPE (Personal Protective Equipment), current body mass, and occupational context (movement speed, climate) could result in calorie needs from a predicted EE (Energy Expenditure) of up to 6300 calories/day. In other circumstances, some expenditures may range between 2500-4500/ day.
Sleep deprivation
In specific operational and training contexts, sleep deprivation is commonplace. Sleep deprivation is related to many downstream adverse health outcomes, and some WFs report 3.6 hours of sleep over 72 hours. A decrease in energy intake and sleep deprivation have knock-on effects, such as self-reported increases in anger, fatigue, tension and confusion. Also, due to the nature of a chronic energy deficit, decreases in power output and muscle mass.
On top of that, a decrease in muscle mass, strength, and power can increase the risk of musculoskeletal injury, while sleep deprivation increases the risk of cardiovascular disease (CVD), substance abuse, and post-traumatic stress disorder (PTSD) and affects hunger hormones which can contribute to obesity.
For professionals whose occupation relies on their physical and mental health, these pose dangerous conditions for WFs.
Adequate nutrition and supplementation can help reduce the rate of catabolism (in this case, muscle breakdown) in the body and to maintain operational performance. Ensuring adequate protein, carbohydrates, and fats, as well as micronutrients facilitates a healthy body. Army regulations 40-25 outline nutritional guidelines; however, there may be room for improvement in various areas.
In some cases, simply eating a meal may not be an option in the field or during training. To maintain physical performance and cognition, some supplements can benefit the WF. According to the review, these supplements are considered to have "strong" evidence.
Beta-alanine
Caffeine
Creatine
EAA (Essential Amino Acids)
Omega 3's
L-tyrosine
Beta-alanine
Beta-alanine is an amino acid obtained through the diet. In skeletal muscle, beta-alanine combines with histidine to form carnosine. Carnosine is found in high amounts in muscle tissue, the brain, heart, and GI tract and is often used as a supplement for exercise.
Supplementing beta-alanine alone may increase focus, alertness, and cognitive function during demanding tasks. For example, marksmanship and shooting accuracy*, 50-m carry, and subtraction tests all improved while supplementing with beta-alanine.
*I have wondered about the benefits to marksmanship and shooting accuracy within the review. The review mentions a study where participants took 6g/day for 4 weeks and assessed their accuracy. Could this benefit not come from simply practicing their marksmanship for 4 weeks?
Caffeine
Caffeine has been shown to improve various marksmanship indicators following sleep deprivation for Hell Week candidates.
Army Regulations 40-25 recommends 100-200mg (100mg every 2 hours/200 mg every 4 hours up to 800mg/day) for military personnel during periods of excessive wakefulness.
Individual responses to caffeine and the recommended doses should be taken into consideration. For example, caffeine can cause heart palpitations, increased blood pressure, and feelings of anxiousness and jitteriness, which would all decrease performance.
Creatine
Creatine* is one of the most well-researched and recommended supplement for performance. The ISSN position statement on creatine shows no detrimental effects for short-term/long-term use. It is effective in high-intensity activity and reduces the risk of injury. The benefits of creatine certainly extend to the WF. The added benefit for WFs who operate in hot climates would be creatine's ability to increase intracellular water and reduce heart rate and sweat loss.
Finally, creatine may have cognitive benefits for the sleep deprived. For example, in elite Rugby players, creatine was shown to improve skill execution and maintain choice reaction time, mood state, and balance in young adults.
*I’m happy to see creatine on this list. It’s so well studied and the list of benefits it remarkable. Should creatine be recommended as a daily supplement for everyone?
EAA (Essential Amino Acids)
EAAs are amino acids that cannot be synthesized through endogenous means and must be obtained through the diet. The following are essential amino acids:
Histidine
Methionine
Leucine
Isoleucine
Lysine
Valine
Phenylalanine
Tryptophan
Valine
As mentioned above, a decrease in muscle mass, strength and power is a detriment to the WF. In conjunction with exercise, EAAs offer a potent anabolic effect on skeletal muscle and may augment muscle protein synthesis rates and the maintenance of body protein. Even small doses (3-6g servings) are likely efficacious, with the upper limit being 10-15g.
A challenge with WFs is the limitations with packing gear and refrigeration. However, EAAs can be packaged as water soluble and highly palatable in lightweight and compact containers.
Omega-3
Given their operational environments, WFs are at risk for traumatic brain injuries (TBI). Since 2000, an estimated 300,000+ service members have been diagnosed with a TBI, typically due to Improvised Explosive Devices (IED).
Omega-3 fatty acids are polyunsaturated fatty acids taken through the diet or supplement and primarily contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids become incorporated into tissue membrane phospholipids (muscle, cardiac, neural). More specifically, they form the hydrophobic/hydrophilic membrane around each cell, which allows specific molecules to enter. For example, the neuronal cell membrane's primary structure is DHA.
Phospholipids provide a barrier between the outside and inside of the cell. They are crucial for proper cell formation and function.
In preclinical models, TBIs have been shown to reduce DHA brain content. In contrast, DHA supplementation has enhanced resilience to TBIs in American football players subjected to repetitive impacts to the head. In addition, for athletes, there is evidence that omega-3 supplementation may improve mood, sleep quality, memory, and reaction time. Reduced DHA may induce pre-deployment stress that manifests in depression and suicide. There are also muscular recovery benefits from omega-3s, including decreased lower body soreness, reduced delayed-onset-muscle-soreness (DOMS), and a greater range of motion.
L-tyrosine
L-tyrosine is an amino acid precursor to dopamine, norepinephrine and epinephrine and is derived from the amino acid phenylalanine.
In sleep-deprived and stressful states, phenylalanine may not convert adequately to meet L-tyrosine demands due to increased catecholamine demand. Benefits of supplementing L-tyrosine may include improved speed and accuracy of information processing and vigilance.
Conclusion
To conclude this article, the general population should know the challenges WFs face within their occupational environment. These are some of the toughest, most capable, and bravest people in our society. Understanding the challenges they face inside and outside the theatre of war can illicit further change and research.
The WF experiences increased energy expenditure and sleep deprivation within their occupational environment. Nutrition is an important lever when considering body composition; however, there appear to be supplements that improve physical performance and cognition.
References
AR40-25_WEB_Final.pdf (army.mil)
Biochemistry, Essential Amino Acids - StatPearls - NCBI Bookshelf (nih.gov)
Phospholipid: Definition, Structure, Function | Biology Dictionary
Beta-Alanine — Health benefits, dosage, safety, side-effects, and more | Supplements - Examine
Carnosine — Health benefits, dosage, safety, side-effects, and more | Supplements - Examine
