Nutritional Support for Sport Injuries - Eating your Way to Recovery
By Sunny Blende, M.S., Sports Nutritionist
You’re an ultrarunner and you have an injury. Bad combination for training, not to mention your sanity. While ice, rest and physical therapy are significant in the treatment of cuts, bruises, muscle and joint injuries, broken bones and swelling, researchers are discovering that what an athlete consumes after being injured and during treatment can either delay healing or promote recovery. The following article will talk about the macronutrients and how they can affect injuries in a positive way. Not only can nutrition facilitate the healing of injuries, but it can also aid in the recovery of delayed onset muscle soreness (DOMS) following intense or long runs. In addition, an anti-inflammatory diet is excellent for health in general, and post-workout muscle and joint recovery in particular.
Immediately following an injury, the healing process begins. Wounds and cuts heal, strained and torn muscles, tendons and ligaments are repaired and bone fractures mend and remineralize. First, “clean-up” cells are sent to the injured area to remove damaged tissue. This is followed by an appropriate inflammatory response that includes laying down collagen fibers and rebuilding healthy connective tissue. The normal healing process can include redness, heat, swelling and pain, but if this response goes on too long, or is too excessive, loss of function may continue and healing may be delayed. If, on the other hand, total elimination of the inflammatory response occurs (such as with cortisone or other drugs) delayed healing may also occur. With time and healing, full recovery can occur and an ultrarunner can be back on the trails and back to his or her training schedule. Nutritional support can make a big difference to speeding this process along.
The fact that nutritional aspects of recovery are overlooked is unfortunate, especially when it is clear that a major injury alters an individual's nutritional requirements. For example, studies show that athletes who have broken their femur may experience an increase in basal metabolism of around 20 percent. This is because their bodies “gear up” to repair the injured bone. Thus, an athlete who might require 2,000 calories during a typical day with no exercise, could see their caloric requirements shoot up to 2,400 calories with a broken bone to repair. However, the changes in nutrient requirements in response to an injury are not simply a matter of increased calories. Various parts of the body have unique nutritional needs to heal a particular injury. Bone and cartilage tissue might require something very different from muscle or nerve tissue.
Below are the macronutrients, how they affect sports-injury healing and their mechanism of action. The best food sources and related research is included too. The next issue of UltraRunning will discuss micronutrients including vitamins, minerals, herbs and phytochemicals.
The body makes millions of new proteins every day to replace worn-out proteins that make up connective tissue, red blood cells and muscles. During exercise, muscle tissue is being broken down at a high level and additional protein building blocks, known as amino acids, are needed to make repairs and stop small injuries from becoming major ones. Long protein chains made from these amino acids make up the basic structural unit of a collagen fiber. Collagen fibers give connective tissue its tensile strength; a load of at least 22 pounds is needed to break a one mm (in diameter) cell fiber.
There are two types of proteins – animal proteins and vegetable proteins. Animal proteins include milk protein (or “complete milk protein”), which has both casein and whey together. Casein protein prevents muscle breakdown, whereas whey protein builds muscles. Whey is easy to digest, absorbed more quickly than casein and is therefore the animal protein of choice for injuries. Vegetable proteins include soy protein (excellent for recovery), rice protein and legumes such as beans. Rice and beans are not a complete source of protein, meaning that they do not contain all the essential amino acids, but in combination they become complete. Soy protein is the only vegetable source of complete protein.
Top quality protein-rich foods like eggs (or egg whites), soy products, lean meats, fish and non-fat or low-fat dairy products will aid healing and are essential in coming back from a sports injury. And don’t skimp on calories during an injury because this can delay healing. If you do not provide enough fuel for your brain, muscles or other organs to function, your body will raid your cells to function. If you are losing weight, be careful. You may not be getting enough protein to fully recover.
Branched Chain Amino Acids (BCAA)
The term “branched chain” refers to the molecular structure of three particular amino acids - leucine, isoleucine, and valine - and plays an important role in protein synthesis. Muscles have a particularly high content of BCAAs, making up approximately one third of skeletal muscle in the human body.
BCAA’s are currently used clinically to boost recovery after musculoskeletal injury or surgery. Scientists have known that individuals suffering from physical trauma need to rapidly manufacture new body tissues while making sure that any cells not affected by the injury remain healthy and viable. To quickly create new tissues, the body uses amino acids to assemble mint-condition proteins that will be the foundation for new muscles, tendons and ligaments. Some studies have shown that branched-chain amino acids have a special capacity to boost protein synthesis and inhibit protein breakdown that none of the other amino acids have. Indeed, trials have suggested that BCAA supplementation, in addition to post-exercise carbohydrates, attenuates muscular damage during prolonged endurance exercise and reduces post-exercise CPK (creatine phosphokinase - a marker of muscle breakdown) activities as well as DOMS.
Glucosamine is another amino acid that is increasingly being recommended by orthopedists and other doctors to decrease inflammation and pain associated with degenerative joint disease and osteoarthritis. The cells that make up cartilage in your joints are called chondrocytes and in order to function properly, they require glucosamine. Glucosamine is also used in the production of glycoproteins, which are found in ligaments, tendons and synovial (joint) fluid and may also assist in healing these tissues when injured. Studies have shown that oral ingestion normalizes cartilage metabolism by stimulating synthesis and inhibiting degradation while also decreasing pain and inflammation and increasing function. Although glucosamine is almost universally found in most foods, the lack of quantifiable levels and data on bioavailability makes supplemental forms the best source. The usual dose is 1,500 milligrams daily spread out over three doses.
Low energy production from reduced or low-fat diets results in poor tissue maintenance, incomplete repair of muscle damage and hindrance of bone matrix mineralization. The consequences of severe fat reduction can result in disruption of bone resorption, suppressed bone formation and an increased risk of stress fractures.
Chemical mediators, including eicosanoids, regulate inflammation, blood clotting, vascular dilation and immune function suppression that occur with injuries. Eicosanoids (including prostaglandins) are short-lived, hormone-like substances produced from the polyunsaturated fatty acids (PUFA’s) omega-6 and omega-3. One way of controlling the outcomes of injuries is by regulating these mediators. Eicosanoids can have pro-inflammatory effects as well as anti-inflammatory effects. It is all a matter of balance. Problems arise when one type of eicosanoids predominates over the other; the type produced is determined by the composition of cellular membrane fats and those are directly influenced by the type of fats included in the diet. Omega-6 fatty acids are much more predominant in foods and therefore it becomes necessary to specifically seek out omega-3 fatty acids. In the United States, the dietary ratio of omega-6 to omega-3 has been estimated to range between 20 - 25:1. A more balanced ratio would be 5 - 10:1
Fat intake was the most useful dietary factor in predicting future injury in female runners in several current studies that reported correlations between low-fat diets and incidence of stress fracture. These injured runners consumed a diet significantly lower in total fat and lower in percentage of total energy from fat. In addition, the studies revealed that runners consuming less than the commonly recommended 30 percent of total calories from fat were two-and-a-half times as likely to sustain an injury compared with runners consuming 30 percent or more. Interestingly, the higher fat intakes enjoyed the least injuries, as long as carbohydrate and protein needs were also met.
Include avocados and nuts (especially walnuts, cashews, almonds and nut butters made from these nuts), extra virgin olive oil, canola oil and some sunflower or safflower oils. Reduce your intake of saturated fat, poultry skins and products made with coconut and palm kernel oils. Avoid margarine, vegetable shortening and all products made with partially-hydrogenated oils.
Carbohydrates are critical in sports injuries for their caloric value - supplying the energy needed to support healing - and the nutrients they bring with them in food sources. But they usually do not directly repair tissues, as they are not part of the structures of cells the way proteins and fats are. However, carbohydrates are the preferred fuel source used during exercise. Excess carbohydrate is stored in the muscles in the form of glycogen. During prolonged endurance exercise, glycogen levels begin to become depleted within the muscle and the body may start to utilize an alternate fuel source – protein – for energy through a process known as gluconeogenesis. The breakdown of muscle protein leads to soft tissue damage. It is because of this indirect process that carbohydrates become important. Many studies have shown that the benefits of a post-exercise carbohydrate-protein replacement regime include decreased fatigue, DOMS and reduced muscle breakdown as indicated by CPK levels. Protein, added to the carbohydrate mix, enhances additional absorption of carbohydrates not only for refueling muscles for the next exercise bout, but also for energy for repairing those same muscles.
The best sources of carbohydrates – vegetables, fruits and whole grains, all of which provide a low glycemic (less blood sugar-spiking) load.
A Word about Inflammation, Free Radicals and Anti-oxidants
A direct result of inflammation is an increase in the production of free radicals. Free radicals are highly-reactive molecules (they have missing electrons) that cause damage to cell membranes, enzymes and protein structures. They are dangerous in that their presence can cause a series of events to produce even more of themselves. One single free radical can destroy an entire membrane through a cascading chain reaction. Although ultrarunning and other endurance exercise produces many positive benefits, this high level of activity puts athletes at greater risk for producing more free radicals than their sedentary friends. When exercise is performed, the muscles use oxygen in a chemical reaction to create energy to drive muscular contraction. The by-product of this reaction 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. The most important anti-oxidants in the body are vitamin E, vitamin C, beta-carotene, vitamin A, selenium and zinc. The body produces some anti-oxidants naturally, whereas others need to be obtained from the diet. A variety of fruits and vegetables daily will help ensure adequate intake.
The majority of injuries incurred by endurance athletes are “overuse” problems such as those resulting from chronic stress to muscles and connective tissues. The idea is simply that the body can't quite keep pace with the small-scale muscle, tendon and ligament irritations that occur during daily training (i.e. the body doesn't complete the repair process before a new bout of exercise is initiated). As a result, nagging irritations gradually increase in magnitude until they are full-blown injuries. Nutrients that can hinder the damage portion of this “tearing down/building up” equation slow down or prevent small problems before they become full-scale injuries. And once an athlete has a full-blown injury or is recovering from surgery, nutrients and an anti-inflammatory diet can reduce recovery time, lessen the chance for extended damage and promote healing to get that athlete back training and competing again.