Nutrition and Injury: Is There a Link?

Injuries are a fact of life, and in many individuals, it is a race against time to get fit as soon as possible. Currently, research investigating the link between nutrition and injury is not forthcoming, despite strong logic and theory to support the importance of nutrition in the recovery phase of injury. It is therefore the aim of this article to discuss what we know in both the prevention and recovery from injury with special reference to nutrition. 

The Prevention of Injuries 

There is no evidence to support that nutrition per se will prevent injuries. Injury prevention occurs as a result of ensuring that, as an athlete, you are well conditioned for the sport in which you compete. That way, the risk of injury will be reduced. However, fatigue (both mentally and physically) during sport and exercise does increase the risk of injury.

As a result, conventional sports nutrition strategies, while paramount to preparation for performance, are often overlooked in their importance of reducing the risk of injury. Carbohydrate is the key provider of energy to the muscles and brain, helping to minimize the impact of fatigue, principally by enabling athletes to work harder for longer. In doing so, work rate, correct posture, movement and skill execution will be maintained, which indirectly can reduce the occurrence of injuries that occur in such circumstances.

What happens when you get injured? As we have already stated, injuries are a fact of life and almost inevitable. When injuries do occur, the healing process occurs over time and is generalized into three major phases:

1. Inflammation: This is the body’s first line of defence to an acute injury, lasting approximately two to five days. This phase is characterized by the removal/elimination of bacteria and the attempt to control cellular damage and blood loss.
2. Proliferation: This is the phase when the blood vessels in and around the wound are restored, while new connective tissue is formed. This phase can last anywhere between two days to three weeks, depending on the severity of the injury.
3. Remodelling: This constitutes the long term recovery from an injury lasting anywhere between three weeks and two years. The major process during this time is collagen renewal. 

Role of Nutrition

We do know that nutrition can play an important role during the recovery process from injuries. This is principally because the body utilizes more macro and micro-nutrients from the diet, including protein, vitamin C, zinc, calcium and vitamin D.

• Protein is a key nutritional component in the diet for three key reasons: 1) the manufacture and repair of new and old muscle tissue, 2) providing the building blocks for metabolic hormones and enzymes, and finally 3) providing when necessary a small yet important amount of energy. Given its role in the repair and regeneration of muscle, it is intuitive that protein intake should remain between 1.2 to 1.5 grams per kilogram of bodyweight. Furthermore, protein plays a role in the fibroplastic response and wound remodelling process in general, so it is important to maintain a good supply of protein.  
• Vitamin C has an important role to play in the formation of collagen, a major component of connective tissue and the main structural component of the body. Vitamin C helps to activate the enzymes responsible for the synthesis of collagen, in addition to providing tensile strength to newly formed collagen. The recommended nutrient intake for Vitamin C is 60 milligrams per day (mg/day) for adults. Fruit and vegetable remain your first choice. 
• Zinc is important for the development of the immune system and cell growth, particularly during the proliferation phase. More than 100 metalloenzymes have been identified as zinc-dependent, including those involved in the transcription of DNA and synthesis of proteins.  The body contains two to three grams of zinc. However, because there are no specific storage sites for zinc, a regular supply in the body is required. Zinc is present in a wide variety of foods, particularly in association with protein-based foods. Good sources include: dairy products, beans and lentils, yeast, nuts and seeds and wholegrain cereals. 
• Calcium is important for the formation and repair of bones and teeth, especially in adolescents and female athletes. Within the body, there is a continual process of calcium being deposited in the bone and removed. Consequently, it is important to ensure an adequate calcium intake. The best sources of calcium include dairy produce. All athletes should aim to include at least three servings of these foods in their daily eating plans (milk, cheese, carton of yoghurt, etc).  
• Vitamin D is required to aid calcium absorption and the promotion of bone health. One of the primary sources of Vitamin D is its synthesis by ultraviolet conversion in the skin. Consequently, individuals who live at northern latitudes or who train primarily indoors throughout the year – such as gymnasts and figure skaters – may be at risk for poor vitamin D status. Vitamin D is found in a small number of foods. Good choices include oily fish and eggs as well as fortified foods such as margarine and breakfast cereals.

A Word on Weight Management 

There are two key problems that can generally occur when individuals are recovery from injury. They include the following:

1. Athletes continue to eat the same amount of food, even though training is reduced, if not stopped. As a result, the excess energy intake results in weight gain.
2. Conversely, an athlete may overcompensate for the reduced training load by reducing energy intake too far, potentially contributing to a reduced muscle mass and decreased micronutrient intake, which could affect bodily functions, including the immune system.

In response to these issues, the key recommendations, depending on time spent injured, are as follows: 

• One week: In this instance, maintain a normal energy intake, despite a reduced training volume, which will help account for the requirement of a high energy intake during the inflammation stage.
• Greater than one week: At this stage, a reduction in energy intake is required to prevent weight gain. The macro-nutrient composition of the diet should remain similar, but overall energy intake should be reduced accordingly.

Injury is an unfortunate part of sport and exercise and will inevitably affect everyone at some stage of life. While it is understood that nutrition will not prevent injuries, correct nutritional practices in preparation for sport and exercise may help reduce the risk of injury by minimizing the impact of fatigue. Where nutrition can have a more direct effect is during the recovery phase from injuries, and as such, athletes should closely monitor some of the micronutrients within their diet while keeping an eye on their weight!