Injury Prevention and Recovery
By Kelly Pritchett, PhD, RD, CSSD
Today’s Dietitian
Vol. 25 No. 4 P. 18

Expert nutrition strategies for injury prevention and repair when athletes and active clients suffer a setback.

Injuries are an inevitable part of sport. In fact, they’re one of the leading sources of medical costs for those between the ages of 17 and 44.1 Compounding the problem is the underutilization of nutrition interventions in the standard care process.2

While injury may be an assumed risk associated with physical activity, there are various cost-effective nutrition strategies that complement standard therapy and can reduce the risk of injury and aid in recovery.2,3 Although a food-first approach should be the first line of defense with a focus on ensuring adequate energy availability (eating enough), supplements also may be beneficial for injury prevention and repair.

RDs who encounter individuals with activity-related injuries must gain an understanding of injury types and the current evidence-based nutrition guidelines for the treatment and prevention of these injuries. In particular, they need to become familiar with nutrition recommendations for energy, protein, carbohydrates, and fats and whether supplements may be of benefit for soft tissue and bone injuries.

Injury Types
The most common exercise-related injuries affect muscles, bones, tendons, and ligaments. Musculoskeletal injuries account for approximately 40% of reported injuries, with the lower leg being the primary site.3 Hamstring injuries are more likely to be reported in sprinters, whereas injury to the lower leg is more common in runners.

Primary concerns during an injury include muscle and strength loss. While the recovery process involves several stages, inflammation plays a key role in the initial healing phase. The initial reaction may be to employ anti-inflammatory aids; however, it’s important to resist nutrition interventions intended to counteract the initial inflammatory process. Due to stress response, this phase typically requires a greater energy demand, which increases the need for protein. Following this phase, minimizing excessive inflammation via dietary interventions may help accelerate the recovery process and get athletes back on the playing field more quickly.2

Treating and Preventing Soft Tissue Injuries
Soft tissue injuries can be acute or chronic (overuse) and may include damage to muscle, ligament, and tendon.3,4 Although there’s limited research in this area, laboratory studies that induce muscle damage through exercise provide a general guide for nutrition-based recommendations. However, it should be noted that these studies have limitations, given there are obvious structural differences between a muscle tear and exercise-induced muscle damage. With immobilization due to a major muscle tear, it’s important to consider nutrition’s role in preventing the loss of muscle mass. Changes in energy requirements and nutrients to help with muscle repair also must be considered.3

There are several potential nutrition strategies that may help treat—or possibly prevent—soft tissue injuries by reducing inflammation, promoting healing, or decreasing the loss of lean tissue. However, in the absence of a dietary deficiency, some of the following nutrition interventions have limited research to support a benefit.

RDs must gain a better understanding of changes in energy demands. For example, while recovering from injury, some athletes may want to decrease energy intake, given that energy expenditure is lower. However, adequate energy availability is needed to support healing. Though it’s important to prevent underfueling during this period, carbohydrate intake may be slightly reduced to offset the change in energy demands.

Increased protein may not prevent muscle injury, but higher protein intakes (1.6 to 2.5 g protein/kg of body weight, depending on injury phase) may help decrease the loss of muscle mass and promote repair during the immobilization period.2,3 Many athletes fail to consume enough protein at breakfast and lunch. An emphasis on equal protein distribution throughout the day will help attenuate muscle mass loss. RDs should emphasize a diet rich in high-quality protein from whole food sources, but a protein supplement can be an easy and effective way to meet protein needs during the recovery period. For example, whey protein contains the highest amount of leucine (2.7 g in a 25-g dose) and largest percentage of essential amino acids, which are important for stimulating muscle protein synthesis. If an athlete chooses a plant-based protein supplement, about 40 g of soy or pea protein—the highest quality of the plant-based options—is needed to match the 2.7 g of leucine found in whey.2

Carbohydrates provide energy for healing during injury recovery. Athletes’ needs typically are 3 to 5 g/kg of body weight in the form of complex carbohydrates (eg, grains, fruits, vegetables, and dairy), which are rich in vitamins and minerals that are crucial for the recovery process.2

Omega-3 fatty acids, such as olive oil, fish, flaxseeds, nuts, and avocado, may decrease the extent of prolonged inflammation (after the initial inflammatory phase), which can be counterproductive to recovery.2 Studies have found that supplementation with 5 g/day for two weeks of omega-3 fatty acids is beneficial for muscle repair. However, this is based on studies examining inflammation and function after exercise-induced muscle damage.3 A study by Smith-Ryan and colleagues suggests that supplementing with 2 to 4 g of fish oil per day may reduce inflammation and enhance protein synthesis. Given the potential risk of mercury contamination in fish oil supplements, the quality of fish oil should be taken into consideration.2

Creatine has been shown to be one of the most effective supplements for increasing lean body mass when combined with exercise.2 Some studies have suggested that a dosage of 20 g (4 X 5 g) per day over a two-week period of creatine monohydrate can help decrease the loss of muscle mass and strength during limb immobilization.2,3,5 However, based on recommendations from a recent review from Smith-Ryan and colleagues, a loading phase of 20 g (4 X 5 g daily) for five days, followed by a daily maintenance dosage of 3 to 5 g per day after immobilization and injury, is recommended to maintain elevated phosphocreatine stores.2

Diets rich in fruits and vegetables provide polyphenols and micronutrients, each of which can help speed the recovery process. For example, polyphenols may help decrease muscle damage caused by inflammation.3

Since vitamin D plays a role in skeletal muscle function, it also may be a factor in the recovery process, although there’s debate about the optimal vitamin D concentration. The Endocrine Society defines a vitamin D deficiency as < 50 nmol/L, insufficiency as 50 to 75 nmol/L, and > 75 nmol/L as being necessary for optimal bone and muscle metabolism.6 It has been suggested that a vitamin D deficiency (< 50 nmol/L of 25-hydroxyvitamin D [25(OH) D]) may impair muscle repair and regeneration. If an active individual has a serum 25(OH)D > 75 nmol/L, supplementation is unlikely to be of benefit.2,7 However, 2,000 to 4,000 IU of vitamin D3 may be needed during winter months to ensure serum 25(OH)D concentrations are greater than 75 nmol/L.3 As a result, RDs should assess vitamin D levels to determine whether supplementation is needed.

While these strategies provide more benefits for the muscle, vitamin C and gelatin have been suggested to stimulate greater collagen synthesis following a tendon or ligament injury.3 Research recommends taking 10 to 15 g gelatin combined with 50 mg vitamin C around an hour before exercise.4

Active individuals should focus on a food-first approach before supplementation. Keep in mind that for many of these findings, more research is needed to examine the benefits of the role of macro- and micronutrients in the prevention of or recovery from muscle injuries.

Bone Injury Treatment and Prevention
Bone strength is determined earlier in life, yet bone loss occurs as a natural part of the aging process. Due to bone-related consequences (ie, reduced calcium absorption and bone mineral density) associated with a higher incidence of relative energy deficiency in sport syndrome, stress fractures are more common in active females.3,8 Stress fractures also are a common overuse injury in endurance sports due to repetitive mechanical loading.3

Although there are many nutrients that play a role in bone health, the following nutrition factors may help support bone health and aid in the recovery and healing from bone injuries.

First, maintaining ongoing adequate energy availability (> 45 kcal/kg of lean body mass/day) is the most important factor for optimal bone health, protection against injury, and healing support. Many female athlete triad and relative energy deficiency in sport studies have found that reductions in energy availability, especially if chronic, have been shown to reduce hormones (estrogen, testosterone) that are vital to bone formation and resorption.3,9

Protein plays a role in the production of hormones that affect bone health and provide structure for the bone matrix. Adequate protein intake (~1.6 to 2.2 g protein/kg of body weight) can help decrease muscle mass loss and promote repair. Contrary to previous beliefs, protein intakes higher than the recommended daily intake have no negative impact on bone health if calcium intake is adequate. In fact, although more research is needed, higher protein intakes have been shown to have a small, beneficial impact on bone.3,9

Calcium also plays a major role in bone formation; bones serve as a storage reservoir for 99% of the body’s calcium. Therefore, inadequate calcium intake can impair bone healing. Studies have shown that consuming 1,500 to 2,000 mg/day is required to support healing. Furthermore, one study found that consuming a calcium-rich meal or supplement (~1,000 to 1,300 mg) before exercise can offset sweat calcium losses in endurance athletes.10 However, more research is needed to determine how much calcium is lost in sweat.9

Calcium-rich foods include milk, fortified orange juice, kale, tofu, yogurt, and sardines. Athletes can boost calcium intake by consuming milk (dairy or soy) and yogurt. Kefir makes an ideal recovery beverage/snack after training.

It has been suggested that active individuals who are vitamin D deficient are at greater risk of bone fracture.9 Therefore, it’s important that vitamin D levels are adequate to support bone health and help with calcium absorption. Depending on vitamin D levels, supplementation may be needed (especially during the winter months) to ensure levels are adequate. Of course, sunlight is the best source of vitamin D, but dietary sources include fatty fish, sun-exposed mushrooms, sardines, and milk.

In addition, magnesium and vitamin K play an important role in bone health. Vitamin K deficiency has been associated with increased fracture risk; magnesium deficiency may contribute to poor bone health. If intakes are below the dietary reference intake, supplementation may be needed.

Considering that reversing low bone mineral density later in life is difficult, good nutrition habits that promote bone health and support the demands of sport should be emphasized during adolescence.9 Active individuals should focus on a food-first approach before reaching for supplements. A diet containing dairy/dairy alternatives, fruits, and leafy green vegetables provides support for bone health. Finally, more research is needed to examine the long-term effects of dietary patterns on bone health in athletes.

Final Thoughts
Nutrition can play a vital role in the injury recovery and repair processes. During the recovery process from a bone or soft tissue injury, it’s important to ensure that active individuals meet their energy demands.2,9 Adequate energy intake combined with increased protein intake can help offset losses in lean mass and strength due to immobilization.2 Although a food-first approach should be the first line of defense, there are certain supplements that may be beneficial for the healing process. Before taking a supplement, active individuals with an injury should consult with a sports dietitian to determine whether the supplement is safe, effective, and necessary.

(TEAM USA nutrition provides nutrition fact sheets for active individuals with a soft tissue or bone injury. It’s available at www.teamusa.org/nutrition.)

— Kelly Pritchett, PhD, RD, CSSD, is an associate professor in nutrition and exercise science at Central Washington University. As a board-certified specialist in sports dietetics, she has consulted with elite and collegiate athletes as well as with active individuals. She has authored research articles for scientific journals and presented at regional and national conferences. Her current research interests include vitamin D and energy availability in athletes with spinal cord injury. In her spare time, she enjoys running and spending time with her three active boys.

References
1. Harlan LC, Harlan WR, Parsons PE. The economic impact of injuries: a major source of medical costs. Am J Public Health. 1990;80(4):453-459.

2. Smith-Ryan AE, Hirsch KR, Saylor HE, et al. Nutritional considerations and strategies to facilitate injury recovery and rehabilitation. J Athletic Training. 2020;55(9):918-930.

3. Close G, Sale C, Baar K, et al. Nutrition for the prevention and treatment of injuries in track and field athletes. Int J Sport Nutr Exerc Metab. 2019;29(2):189-197.

4. Nutrition. Team USA website. https://www.teamusa.org/nutrition. Accessed January 10, 2023.

5. Johnston APW, Burke DG, MacNeil LG, Candow DG. Effect of creatine supplementation during cast-induced immobilization on the preservation of muscle mass, strength, and endurance. J Strength Cond Res. 2009;23(1):116-120.

6. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930.

7. Owens DJ, Allison R, Close GL. Vitamin D and the athlete: current perspectives and new challenges. Sports Med. 2018;48(Suppl 1):3-16.

8. Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the female athlete triad—relative energy deficiency in sport (RED-S). Br J Sports Med. 2014;48(7):491-497.

9. Sale C, Elliott-Sale KJ. Nutrition and athlete bone health. Sports Med. 2019;49(Suppl 2):139-151.

10. Haakonssen EC, Ross ML, Knight EJ, et al. The effects of a calcium-rich pre-exercise meal on biomarkers of calcium homeostasis in competitive female cyclists: a randomised crossover trial. PLoS One. 2015;10(5):e0123302.