Monday, 19 September 2011
The Role of Nutrition Injury
Scientific literature of the role of nutrition in injury, particularly in athletes, is lacking, therefore, the medical literature is a good place to consult to get an idea of the interaction between diet, supplements and healing.
The role of nutrition in injury to athletes is often overlooked. Probably because the evidence is lacking and mostly because support staff may not be aware of how nutrition can help support healing. I have been lucky enough to work alongside forward thinking medical staff (particularly in Premiership football) who have really embraced the role of nutrition to support injured players.
Figure 1 below illustrates how nutrition can be integrated within a support team. The team Doctor and physio lead the injury management of the athlete and the physio works alongside the massage therapist, typically instructing when and how aggressively massage is used. The physio usually tends to work closely with the S&C coach but this commonly occurs during the rehabilitation phase (called phase 2 – more on this later) and nutrition also links in with the S&C coach during this second phase. Immediately following the injury
Figure 1. The Role of Nutrition in Injury within a Sport Science/Medicine Team
From a nutrition perspective, an easy way to think of nutrition and injury is to separate the acute injuries (i.e. this is where the injury will stop training from 7 days or less) or a chronic one (where the athlete may be out for several weeks/months). The way you might advise an athlete on an acute injury (i.e. a minor ankle sprain) would be very different to a fracture or break. For the chronic injury we have to think about inflammation, healing and weight management whereas the acute one it might simply be an increased/decreased macronutrient/micronutrient intake.
The two distinctive phases of an injury are summarised below:
Phase 1 - Immobilisation/Atrophy
At the onset of an injury, an athlete will be immobilised and that will result in muscle atrophy over time. Metabolic changes in the tissues resulting from inactivity can lead to loss of strength and function.
Phase 2 - Rehabilitation & Increased Activity
This is the phase when the athlete is rehabbing and can return being mobile which can aid muscle hypertrophy and the return of functionality
The way a nutrition practitioner can support each phase obviously depends on the injury, but typically, the support given during phase 1 is very different to the advice given during phase 2. More specifically, phase 1 could be about reducing inflammation however, this should be lead by the medical team. Inflammation should not be reduced at the very early stages of an injury, as it is part of the healing process. When inflammation does need to be reduced, nutrition can play a crucial role. The following strategies can be effective in helping to reduce inflammation:
· Strategic use of phytochemical antioxidants. Phystochemical antioxidants have been found to reduce inflammation and muscle soreness.
· Tumeric supplementation. Although research is lacking in the athletic population, the athletes I have used it with have reported some positive feedback.
· Reducing Omega-6 and increasing Omega-3 fatty acids in the diet. A diet high in Omega-6 can increase inflammation.
· Avoid alcohol consumption as it can further increase inflammation.
Increasing amino acid intake (particularly leucine) is also important during this initial phase as the body will have an increased need for essential amino acids during repair. The phytochemical antioxidants can also help reduce soreness (Howatson et al. 2009. Scandinavian Journal of Medicine & Science in Sports; Bowtell et al. 2011 Med Sci Sport Exerc).
During a chronic injury, it is common for athletes to lose muscle mass. Muscle atrophy occurs during long periods of immobilisation and that can consequently lead to reduced muscle function. Complete inactivity with a poor diet results in rapid muscle loss. decreased muscle protein, particularly myofibrillar protein creation (J Physiol 27-10-2008). Therefore, it is crucial that nutritional interventions should focus on alleviating, as much as possible, the decrease in muscle protein synthesis so that any period of negative muscle protein balance is minimised. Not only does immobilisation decrease basal levels of muscle protein synthesis, but the muscle also fails to respond properly to protein intake. Thus, increased protein intake during inactivity may not have the impact on maintenance of muscle mass that could be expected from studies on active, healthy muscle.
During the first 5-7 days of the onset of an injury, energy expenditure can increase therefore it may be important for the athlete to consume BMR + EE + an addition 300-400 kcal. Energy intake can later be reduced if a long period of inactivity is foreseen. After this period carbohydrate intake should not exceed 3-4 g/kg and majority of this should be derived from fruits, vegetables and dairy rather than wheat based products such as pasta, bread, cereals. A general multivitamin supplement may be useful if energy intake is dropped to 1500 kcal for longer than a few weeks.
During Phase 2, when the athlete becomes more mobile and starts gym work, there is an increased requirement for protein therefore an intake of around 1.8-2 g/kg is advised.
There is also a role for other supplements as summarised below:
•Glucosamine Chondroitin – joint protection
•Collagen Hydrolysate – collagen synthesis
•Vitamin C – collagen synthesis
•Zinc – Wound healing
•HMB – reduce catabolism during inactivity and rehab
•Creatine (J Physiol 15-10-2001; 536:625-633)
•L-Arginine/Dietary nitrates to increase blood flow
It is also important to consider other aspects other than nutrition. For instance, belief and the placebo effect could have a massive impact on how quickly an athlete responds. If a supplement does no harm and the athlete believes it will help them then why not use it? It is also crucial to know your athlete’s personality as this will help you adapt your recommendations/advice. Some athletes are very anal and need to have a prescriptive program whereas other need more of a generic/adaptable one. Some athletes like having their body composition measures (includes skinfolds and girths) every few weeks to ensure they are not losing too much muscle or gaining too much body fat.
The medical team usually leads the injury and rehab treatments of athletes however, I hope this article has helped you see how nutrition fits in and its importance on both the physiological and psychological components of recovery and rehab.