After an injury or surgery, one of the primary goals of all athletes is to be able to heal as quickly as possible and return to play. Trainers and coaches monitor the athlete’s rehabilitation process and attempt to use the most effective modalities and resources available to them. In this process, nutrition often is an underutilized component.
Many athletes use dietary supplements on a daily basis and have begun to associate nutrition with pills and powders instead of real food. One of the roles that health professionals can play is to guide athletes toward a return to whole foods. Whole foods offer the best nutrition, often at a better price than supplements, and include components that are not available in pills and powders, because of the synergistic value of whole foods. Postinjury or postsurgery is a critical time to get athletes eating better because this will aid in healing and enhance performance once they return to play.
ENERGY AND MACRONUTRIENT NEEDS FOR INJURY PREVENTION OR HEALING
The fact that nutritional aspects of healing are overlooked is unfortunate, especially when it is clear that a major injury alters an individual’s nutritional requirements. For example, an athlete’s metabolic rate increases approximately 15% to 20% after injury or minor surgery. Major surgery can increase these needs by almost 50% (1). This increase in energy expenditure is caused by the body’s “gearing up” to repair the injured tissues. Thus, an athlete who might require 2,000 kcal during a typical day with no exercise could see his or her energy requirements shoot up to 2,400 kcal after minor surgery. A good rule of thumb for athletes to follow is that when they’re injured, they should eat less than they did when they were training hard but more than they would if they were completely sedentary.
Injury repair requires more protein. Atrophy from muscle disuse after injury is attributed primarily to a decline in muscle protein synthesis rate. Research suggests that focusing on the amount, type, and timing of dietary protein ingestion throughout the day can decrease the loss of muscle mass and strength during healing from injury and stimulate muscle protein synthesis (8,11). Injured athletes should aim for 1.5 to 2.0 g/kg body weight, which is higher than the usual 1.2 to 1.7 g/kg for athletes and 0.8 to 1.0 g/kg for recreational exercisers. For example, a 150-lb (68-kg) athlete would require 102 to 136 g of protein daily during healing from an injury.
Many athletes already consume enough protein or even excessive amounts of protein, often through supplementation with powders. However, many athletes may not be eating protein in an optimal pattern to maximize muscle protein synthesis. To ensure optimal healing, athletes should consume protein consistently and distribute it evenly throughout the day at 20 to 30 g per meal or snack, rather than back-loading protein at dinner, which is common in American culture. A portion with 20 to 30 g of protein equates to one of these: 3 eggs; 1 cup cottage cheese; 1 cup Greek yogurt; 3 to 4 oz of meat, poultry, or fish; two thirds of a 14-oz cake of firm tofu; or 1.25 cups of black beans. Vegetarians also can get quality protein from soy-based food. Almond milk is popular, but it is low in protein compared with cow or soy milk.
Branched-chain amino acids (BCAAs) such as leucine, isoleucine, and valine are used clinically to boost healing after musculoskeletal injury or surgery. Individuals suffering from physical trauma need to rapidly manufacture new body tissues while making sure that cells not affected by the injury remain healthy. Some studies have shown that BCAAs have a special capacity to boost protein synthesis and inhibit protein breakdown that none of the other amino acids have. Of the BCAAs, leucine may be the most useful (8) and can be found readily in food such as chicken breast, lean beef, tuna, salmon, turkey breast, eggs, and peanuts.
Incomplete recovery from consecutive bouts of high-intensity training or competition can result in subsequent underperformance and injury (5). Research has shown that carbohydrate ingestion before and during prolonged periods of exercise helps maintain blood glucose during exercise, reduce stress hormones (12), and reduce the risk of injury (5). Carbohydrate ingestion shortly after prolonged and/or exhaustive exercise helps replenish muscle glycogen stores, thus providing energy to refuel muscles for the next exercise bout and to repair those same muscles.
Athletes should aim for daily carbohydrate intakes of 5 to 12 g/kg body weight, favoring the lower end during times of more limited energy needs to help prevent unwanted weight gain. Carbohydrate intakes of up to 60 g per hour during heavy training can help diminish immune inflammatory responses (12). Within the first 30 minutes after exercise, when muscles are most efficient at replacing muscle glycogen, goal carbohydrate intake is 1 to 1.2 g/kg body weight. Best sources of carbohydrates include fruits, starchy vegetables (like corn, peas, potatoes, yams), whole grains (such as brown rice or quinoa), and food made with whole grains like bread, cereal, rice, and pasta.
Several studies have shown that the combination of carbohydrate and protein consumed during and after exercise may include such benefits as decreased fatigue, delayed-onset muscle soreness (DOMS), reduced muscle breakdown, and optimized muscle damage repair (6,9). The suggested ratio is 3 to 4 g of carbohydrate to 1 g of protein, with as little as 6 to 20 total grams of protein (9). This mixture can be found naturally, as in many dairy products (e.g., chocolate milk), or you can create your own.
Fat intake may be an important factor in the prevention of injuries. Low intake of dietary fat has been associated with increased injury risk in female runners, including stress fractures. Furthermore, a low intake of omega-3 fatty acids may contribute to an enhanced inflammatory response and may increase the severity of injury (3). Dietary fat has gotten a bad rap during the past years, but athletes should be reminded that not all fats are created equal and should be encouraged to include healthy fats in their diet from whole foods such as avocados and nuts (especially walnuts, cashews, almonds, and nut butters made from these nuts), extra virgin olive oil, canola oil, and sunflower and safflower oils. Athletes should be advised to regulate their intake of saturated fat, including fatty red meats (like ribs) and deli meats (like salami), and products made with coconut and palm kernel oil. Athletes also should be advised to avoid or limit the use of trans fats found in margarine, vegetable shortening, and all products made with partially hydrogenated oils, which include many commercially prepared desserts, chips, and crackers.
It may sound odd to mention fiber with healing food, but pain medications commonly prescribed after injury or surgery can cause constipation. Prunes or prune juice (along with drinking plenty of water) have a natural laxative effect that can alleviate constipation while on pain medications. Other good sources of fiber include bran cereals, oatmeal, whole-grain bread (whole wheat or rye), brown rice, popcorn, lentils, and legumes (like black beans, kidney beans, chickpeas, pinto beans, white beans, etc.). Be sure to drink enough water when increasing fiber intake because fiber absorbs fluid in the gut.
Dietary intake and total body stores of iron, a key mineral, may have some effect on an athlete’s risk of injury. In research carried out at the Center for Sports Medicine in San Francisco, 101 female high school runners were monitored during the course of a cross-country season. During the cross-country season, there were 71 injuries severe enough to cause lost training time. Those runners who were injured had average ferritin levels (an indication of iron stores) that were about 40% lower than those found in noninjured runners, suggesting that iron status is an important factor in injury prevention (4).
Additional studies have not been able to identify a clear mechanism for increased injury rate when iron stores are low, although it may be related to the activity of the inflammatory-driven iron-regulatory hormone hepcidin. The inflammatory-mediated increases in hepcidin ultimately result in an accumulation of plasma iron in macrophages and hepatocytes, reduced intestinal absorption of iron by enterocytes, and a decreased plasma level. Inevitably, these processes can lead to anemia (10). Because long-duration or high-intensity exercise commonly results in inflammation, it is possible that hepcidin might be a mechanism or contributing factor behind the high incidence of iron deficiency and, perhaps concomitantly, injury among athletes (7).
Preventing iron deficiency can be accomplished by including iron-rich food sources in the daily diet such as lean red meats, lean pork, poultry (especially dark meat), beans and legumes, dark green leafy vegetables (like spinach), dried fruits (such as raisins and apricots), and iron-fortified cereals, bread, and pastas. Consuming iron-rich food with a good source of vitamin C such as oranges, tomatoes, or potatoes can enhance the absorption of iron.
Vitamins and Minerals
The changes in nutrient requirements in response to an injury are not simply a matter of increased energy needs. Various parts of the body have unique nutritional needs to heal a particular injury. For example, many athletes already take vitamin supplements regularly. They know that they need vitamins but do not understand that vitamins are only one piece of the nutritional picture. In addition, because many processed foods that athletes eat are already fortified and enriched with vitamins, they may actually be ingesting more of certain vitamins than they realize. Advice should focus on purchasing and eating whole food, such as fruits, vegetables, and whole grains, to promote the most balanced and optimal nutrition. Nature has packed the perfect synergy of nutrients into whole foods. Some nutrients that have taken center stage in the research on healing include vitamin C, flavonoids, vitamin A, protein, and zinc. These will be discussed in the sections below.
NUTRITION TO COMBAT INFLAMMATION
Inflammation plays a critical role in the recovery and healing process. One of the primary goals in rehabilitation is to reduce inflammation and oxidative stress. Nutrition can serve as a powerful adjunct in this process. A direct result of inflammation is an increase in the production of free radicals. Free radicals are highly reactive oxidized molecules that cause damage to cells. One major by-product of muscle contraction is free radicals. The more training an athlete performs, the more free radicals are generated, and these levels build up. Antioxidants are nutrients that neutralize these damaging effects and help repair the cellular damage they cause. Important antioxidants in the body are vitamin C, vitamin E, beta-carotene, vitamin A, selenium, and zinc. The body produces some antioxidants naturally, whereas others need to be obtained from the diet. A general suggestion is to include a variety of fruits, vegetables, whole grains, legumes, lean meats, poultry, fatty fish, and nuts and seeds in the daily diet to help ensure adequate intake of these important nutrients.
During acute phases of injury, we do not want to suppress the inflammatory response completely; we just want to keep it under control. Flavonoids found in cocoa, tea, red wine, fruits, vegetables, and legumes can help manage inflammation through their antioxidant actions. It is probably good to eat more flavonoid-rich food in general and more so during acute injuries. The protective role of flavonoids during inflammation may be associated with their ability to sequester iron and the regulatory effect they exert on immune components involved in inflammatory processes (10). A variety of whole food, herbs, and spices can assist in this process. Garlic, turmeric (found in curry powder), green tea, blueberries, apples, citrus fruits, and pineapples also contain nutrients helpful for combatting the inflammation that occurs with training each day.
Tip: Eat more flavonoid-rich food such as blueberries, strawberries, carrots, broccoli, and pineapple in general and more so during acute injuries.
In addition to antioxidants, there are other nutrients known to decrease inflammation. A class of essential fatty acids best known for controlling general inflammation is omega-3 fatty acids, which come in different types: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Our bodies can convert ALA into DHA and EPA, but not very efficiently. Although omega 3s can be obtained in pill form, whole foods sources of DHA and EPA include algae and fatty fish such as salmon, halibut, herring, oysters, sardines, trout, and fresh tuna. Plant-based ALA sources include flax seeds, chia seeds, hemp seeds, walnuts, and sunflower, safflower, and seed oils. Foods that are fortified with omega 3s may include eggs, milk, soy milk, yogurt, and buttery spreads. For a reduction of inflammation, animal sources of omega-3, because of their higher DHA and EPA content, are better absorbed and used by the body.
Tip: Did you know that turmeric is a flowering plant in the ginger family and that turmeric has long been used as an anti-inflammatory agent and in wound healing? Current research shows that the active ingredient, curcumin, is responsible for some of the benefits of turmeric.
NUTRITION FOR REGENERATION AND ANABOLIC SUPPORT
Once inflammation begins to subside, the injured part of the body begins to make scar tissue and remake connective tissue, which will have to be regenerated for complete healing. This is especially true after surgery, when the proinflammatory response causes muscle dysfunction that can lead to muscle atrophy. Research suggests that antioxidants, like vitamins C and E, can help modulate the activity of these proinflammatory molecules (cytokines) (12). Vitamin C– and flavonoid-containing citrus fruits (like oranges and grapefruit), bell peppers, and berries, as well as wheat germ and whole grains that contain vitamin E, might be useful at this stage of rehabilitation. Vitamin E also can be found in foods such as nuts and oils.
Connective tissue, which includes tendons, ligaments, joints, cartilage, and muscle fascia, has a very unique structure that is different from most tissues in the body because it is not composed of cells but rather a matrix of proteins, fibers, and cross-purpose molecules (part carbohydrate and part protein in many cases) all embedded in a fluid environment. Evidence supports a focus on several major nutrients when connective tissue healing is required: vitamin C, vitamin A, vitamin E, the B-complex vitamins, and zinc (12).
Tip: One small stalk of broccoli can provide the recommended daily allowance of vitamin C, a nutrient known to enhance healing.
Vitamin C is needed to make collagen and also is needed for repairing tendons and ligaments and healing surgical wounds. Citrus fruits are high in vitamin C; however, do not overlook other sources of vitamin C, such as strawberries, kiwi fruit, baked potatoes, broccoli, and bell peppers. Vitamin A also may enhance the development of collagen. Beta-carotene is a precursor to vitamin A and can be found in whole foods such as sweet potatoes, carrots, kale, squash, romaine lettuce, prunes, dried apricots, cantaloupe melons, sweet red peppers, and mangos. Emphasizing green leafy vegetables could allow the athlete to cover all of his or her bases well in combatting inflammation and oxidative stress. For example, kale is considered an excellent source of vitamins A (as in beta-carotene) and C, a good source of vitamin E, and also contains a variety of B-complex vitamins, including B1, B2, B3, B6, and folate. Zinc is a mineral also involved in wound healing and is found mostly in animal foods: meat, fish, poultry, and dairy foods. It also is present in whole-grain breads and cereals, dried beans and peas (legumes), and nuts.
NUTRITION FOR BONE HEALING
Athletes should be sure to consume adequate amounts of calcium and vitamin D, which help to strengthen bones. This is an important consideration for athletes prone to stress fractures or while healing from broken bones. The best sources of these nutrients are low-fat dairy products. Nonfat milk has slightly more calcium than full-fat or low-fat milk and is fortified with vitamin D to help absorb calcium. Yogurt, also a good source of calcium, is not always fortified with vitamin D, so check the nutrition label of your favorite yogurt to make sure you are getting vitamin D. Nondairy sources of calcium and vitamin D include fortified soy, rice, and almond milks, as well as fortified orange juice.
APPLICATION TO PRACTICE
Table 1 shows the estimated energy and macronutrient needs for injury recovery for a case scenario featuring a 20-year-old male runner, “TK,” who is healing from knee surgery. The sample meal plan described in Table 2 meets TK’s estimated nutritional needs exceptionally well. At 2,585 calories, 115 g protein, 340 g carbohydrate, 85 g total fat, and 45 g dietary fiber (2), this delectable menu also is rich in vitamins and minerals. Equipped with a well-planned whole foods diet that can be further developed in consultation with a sports dietitian/nutritionist, TK is well on his way to returning to play!
BRIDGING THE GAP
Nutrition should have a starring role in keeping athletes ready to play and in hastening their return to competition after an injury. Whole foods offer synergistic and medicinal value in combatting inflammation, supporting regeneration and anabolism of injured tissues, and promoting healing and recovery. Helping athletes gain access to a wide variety of whole foods that meet energy, macronutrient, and micronutrient needs and assisting them in making sound nutritional choices can help maximize athletic performance and return to play.
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Keywords:© 2016 American College of Sports Medicine.
Recovery Nutrition; Injury Recovery; Healing; Inflammation; Whole Foods; Antioxidants