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Nutrition and Traumatic Brain Injury: Improving Acute and Subacute Health Outcomes in Military Personnel
much later after the injury, although they will still be a consequence of the initial insult. In this longer-term phase, TBI has been associated with neurological disorders, neurodegenerative disorders (e.g., Alzheimer’s disease, Parkinson’s disease, and chronic traumatic encephalopathy), neuroendocrine disorders, psychiatric and psychological diseases, nonneurological disorders, and musculoskeletal dysfunction. Managing this multifaceted disease is a challenge. Given TBI’s complex pathobiology and acute, subacute, and long-term effects, both the timing and duration of administration of any potential interventions are important to consider.
Nutrition has emerged as a possible approach for the prevention of or therapy for injuries to the brain, including neurodegenerative disorders and ischemia. DoD requested that the Institute of Medicine (IOM) convene an ad hoc committee to review the existing evidence for the potential role of nutrition in providing resilience or treating the acute and subacute effects of neurotrauma, with a focus on TBI.
SCOPE OF THE STUDY AND APPROACH OF THE COMMITTEE
This report reviews nutritional approaches that show promise in providing resilience or treating the acute and subacute effects of TBI. The committee was not asked to evaluate the role of nutritional therapies in the rehabilitation phase or the potential role of nutrition in ameliorating long-term effects of TBI. It is important to note that the chronological boundaries of acute, subacute, and long-term effects are not clear. For example, an event such as angiogenesis, which is typically associated with long-term wound healing, is initiated within the brain during the acute phase. This report therefore includes some studies that also evaluate seemingly long-term outcomes that may be initiated in the acute and subacute phases of the disease. This report does not address other outcomes such as neurodegenerative (e.g., Alzheimer’s disease, Parkinson’s disease), neuroendocrine, psychiatric, and other nonneurological disorders that appear later in life and may be associated with TBI but for which a causal relationship with the original injury has not been clearly established.
In spring of 2010, the IOM appointed a committee of 11 experts with extensive knowledge in the areas of neurology; nutritional sciences, clinical nutrition, and dietetics; physiology; physical medicine and rehabilitation; psychiatry and behavioral science; biochemical and molecular neuroscience; epidemiology/methodology; and the pathobiology of TBI. Two public workshops featuring presentations by civilian and military subject matter experts in TBI provided important information for the committee. A review of the scientific literature was conducted to examine physiological sequelae and metabolic responses to TBI, with the purpose of identifying mechanistic interventions. Nutrients were reviewed for their efficacy on TBI or on brain injuries with pathologies related to TBI, such as hypoxia, epilepsy, and subarachnoid hemorrhage. The committee also reviewed current practice guidelines for specific nutritional approaches to the clinical treatment of TBI on the battlefield, in garrison, or in hospital intensive care units (ICUs). In general, the nutrients were selected based on their potential role in restoring cellular energetics, reducing oxidative stress and inflammation, and repairing and recovering from the injury. The following nutritional interventions were identified for review: energy needs for severe cases of TBI, acetyl coA, antioxidants, branched-chain amino acids, choline, creatine, ketogenic diets, magnesium, nicotinamide adenine dinucleotide (NAD+), n-3 fatty acids, polyphenols, probiotics, vitamin D, and zinc. Three of the nutritional interventions (i.e., acetyl-L-carnitine, niacin, and probiotics) initially selected were not included in the report because of insufficient evidence to reach conclusions about effectiveness from animal and human studies, or concerns for harm.