NUTRITION
The importance of managing energy intake following a Spinal Cord Injury.
Introduction
Metabolism is made up of all the reactions that occur within our bodies that either synthesis (anabolism) or breakdown (catabolism) biomolecules. The total daily energy expenditure (TDEE) in humans is made up of three components that contribute to our metabolism. Firstly, the resting metabolic rate (RMR) which is roughly 60-75%, secondly, the thermic effect of physical activity (15-30%) and lastly, the thermic effect of feeding (10%). RMR may also be referred to as a basal metabolic rate (BMR), which is very similar, but measured under slightly stricter conditions. BMR/RMR refer to the amount of energy needed to maintain vital bodily functions and is influenced by gender, muscle mass, hormone levels and protein turnover. The other two variables are influenced by how much we are moving, whether it be planned exercise or our daily activities and the food we eat or the temperature of our environment.
The importance of knowing these variables allows an energy baseline to be established so that weight control strategies can be put into action. Physical activity can exert a significant effect on overall TDEE. It has been shown that increases to fat free mass (muscle tissue) through resistance training can substantially increase BMR. Additionally, any form of aerobic exercise (arm ergometer/cycling) will increase metabolic rates.
Diet induced thermogenesis (DIT) is another factor that can be manipulated to assist in managing TDEE. The energy used to digest and absorb food will vary based on what nutrients are being consumed. This is highly variable among individuals, but consuming higher protein content in meals has shown to require more energy to process. Additionally, it has been shown that increasing physical activity following ingesting food, results in the body increasing DIT (McArdle, Katch & Katch, 2015)
What changes following a SCI?
Recent advances in technology and interventions have improved life expectancy outcomes of those with a SCI, to be similar to the general population, however nutritional education is recommended to be able to avoid developing secondary conditions (Groah, et al. 2009). Whilst a lot of effort may be put into a regular exercise routine, the beneficial effects of this can be outweighed if caloric intake and macronutrient (protein, carbohydrates and fats) are not adjusted concurrently (Ashgraf, et al. 2012).
The prevalence of developing obesity, type 2 diabetes mellitus, dyslipidemia and cardiovascular diseases is much higher in the SCI population, when compared to the general population (Ref). Promisingly, in a 12-week trial comparing two groups of individuals with a SCI with an intervention of resistance training and dietary intervention, compared to standard dietary control only, the results clearly demonstrated better body composition (less fat and more muscle) and metabolic profile markers (cholesterol, triglyceride and hormone levels). Importantly, resistance training was aimed at increasing muscle mass with progressively more challenging weights, twice per week, combined with a diet that followed a protocol of roughly 45% carbohydrates, 25% protein and 30 % fats. The food was self-selected, and no supplements were used (Gorgey, Mather, Cupp & Gater, 2012). Therefore, with education on exercise and nutritional choices that will promote better health, complications can more likely be avoided.
This advice is aimed at being general to all individuals with a SCI, however it is known that several individual factors will play a role in dietary choices, such as level of injury, educational background, social and family interactions and financial status. There are no SCI specific guidelines and the guidelines given to the general population, do not consider the physiological changes that occur post injury, such as the change in calorie expenditure, macronutrient distribution and daily routine will impact an individual with a SCI (Khalil, et al. 2013). Therefore, this is a summary of the best available advice.