Nutrition and the Immune, Injury and Inflammatory Processes of Athletes: What You Need to Know

November 18, 2020 9 min read

Reposted from:

Whether you’re an athlete or a member of the sports performance staff, your 2020 season is probably unlike anything you’ve ever experienced. While training, pre-season camp or even competition may look a little different, making sure your athletes are ready so they can perform and recover at their best remains the same. This includes focusing on the relationship between the immune system, inflammatory response and injury process, which collectively play a role in maintaining the health of athletes and active individuals of all levels.

This year, more than ever before, it’s critical to manage the internal (e.g., psychological responses, sleep disruption) and external (e.g., nutrition deficits, heavy training and competition workloads) factors that threaten this process. If not kept in check, it could lead to decreased immune function, increased susceptibility to illness and increased injury incidence.That may mean compromised exercise performance, inadequate recovery from exercise, interruptions in training, missed competitive events, and risk of serious medical complications in a season that’s already stressful enough for your athletes. 

Nutrition plays a huge role in the immune, inflammatory and injury processes of athletes, and it’s important to learn about the compounds, nutrients, foods, beverages and eating patterns that can help or hinder this relationship. Even my colleague Dustin Little, ATC, PT, DPT, CSCS, Head Athletic Trainer, San Francisco 49ers, agrees, “To optimize results with your athletes, members of the sports performance staff, including Athletic Trainers, need to educate their athletes on the importance of nutrition. Set up a plan to help them prior to a workout or treatment session and then also after this is completed. Work with a sports dietitian, like Jordan, if available.

Let’s take a look at some of the evidence-based nutritional strategies involved in these processes and how you can apply them with your athletes. 

Micronutrients and the Immune, Inflammatory and Injury Process of Athletes 

First and foremost, no matter the dietary preference of your athletes, following a well-balanced diet that meets individualized energy, macronutrient and micronutrient needs is key. Athletes sometimes struggle to maintain normal levels of certain micronutrients involved in the immune, inflammatory and injury process. Monitor and focus on micronutrients that are critical and tend to be under consumed, including:

  • Calcium- Essential for bone health, growth and reduces risk of stress fracture.
  • Encourage athletes to include low- or whole-fat real dairy products as part of a balanced diet. 
  • Vitamin D - Maintains normal calcium levels in the body, develops healthy bones and helps skeletal muscle function.
  • Educate athletes on what foods have vitamin D, including fatty fish, egg yolk, fortified milk, yogurt or ready-to-eat cereal.  
  • Iron- Influences endurance and performance because of its role in respiration and energy metabolism.
  • Let your athletes know there are plant-based and animal sources of iron. Animal sources include eggs, meat and fish, and plant-based sources include nuts, seeds or tofu.
  • Some antioxidants (e.g. vitamin C) - Play a role in immune and inflammatory processes, tissue growth and repair, and wound healing.
  • At your training tables, encourage snacks high in vitamin C such as kiwifruit, oranges and strawberries. Broccoli and even potatoes are also vegetables rich in vitamin C. 

Macronutrients and the Immune, Inflammatory and Injury Process of Athletes 

Of the three macronutrients, let’s start with carbohydrates and their relationship with the immune, inflammatory and injury processes of athletes. 

  • Carbohydrates:
  • Carbohydrates are stored as glycogen (which is the body’s stored form of energy) in the skeletal muscle and liver, and maintain blood glucose during exercise, lowers stress hormones (e.g. adrenaline, cortisol) and inflammatory markers after activity, and may counter immune dysfunction.
  • Athletes who restrict or remove carbohydrates may actually increase the stress hormone response that suppresses the immune system, and stress fractures have been associatedwith pre-existing deficiencies in carbohydrate intake.
  • Protein: 
  • Protein isn't stored like carbohydrates in the body, so protein intake throughout the day is important to get the full impact on the immune, injury and inflammatory processes. Protein recommendations among athlete populations are likely met or exceeded, and while additional protein in the diet may not prevent a muscle injury, it can be beneficial after an injury both in terms of reducing continued breakdown and promoting repair.
  • Fat:
  • Poor attention has been paid to fats and the injury, immune and inflammatory process of athletes. Recently, polyunsaturated fatty acids, mainly the omega-3 fatty acids, have been receiving increased attention due to their anti-inflammatory effects post-exercise. 

Fluids and the Immune, Inflammatory and Injury Process of Athletes 

Don’t forget about fluids. Athletes who are training at high volumes and intensities may have an increased risk for immunosuppression and inflammation post-exercise. Achieving adequate hydration status in these athletes and monitoring over time is especially important. Fluids can also facilitate blood flow and nutrient delivery to injured areas.

One of the best recovery options that is affordable and convenient is milk. Milk has been shown to be an excellent way to replace fluid that is lost during exercise. Chocolate milk specifically not only tastes great, but it is also an affordable source of nine essential nutrients. Three of the nutrients – vitamin A, vitamin D, and protein – are essential for a healthy immune function. Calcium, vitamin D, phosphorus, protein and potassium in chocolate milk can build and maintain strong bones and help reduce the risk for stress fractures.

Foods, Beverages and Eating Patterns and the Immune, Inflammatory and Injury Process of Athletes 

Promoting a strong immune function, blunting inflammation and supporting bone and muscle health can be done through encouraging your athletes to eat a consistent, high-quality diet. Yet athletes may intentionally or unintendedly experience energy deficits because they eliminate one or more food groups from the diet, consume poorly chosen diets or engage in extreme weight loss behaviors.

These actions can result in low energy availability for training or competition and suboptimal intake of macro and micronutrients. In the short-term, this can compromise performance, the ability to fully recover from activity, immune function and increase injury proneness. In the long-term, it has even been associated with illness in Olympic athletes and is a major risk factor for bone injuries. 

Training volume and intensity vary from day to day, week to week, and throughout the season for athletes. Eating meals and fueling workouts or races should also be cycled according to how hard or easy it is. Energy intake should also always be adjusted post-injury or during illness to ensure adequate healing and preserved body composition with reduced physical activity/mobility. 

Focusing on a variety of whole foods, beverages or eating patterns involved in the immune, inflammatory and injury processes of athletes, including but not limited to dairy products(Hint: check out this training table handout I made in partnership with the California Milk Advisory Board on the performance and recovery benefits of dairy products that you can use with your athletes), whole fruit, tart cherry juice, beetroot juice or even the Mediterranean diet. A whole foods foundation that includes lean proteins, fiber-rich whole grains, fruits, vegetables, dairy, and healthy fats such as nuts and seeds is the best approach for your athletes. 

It’s important to note that athletes don’t consume “nutrients,” they consume combinations of whole foods and beverages as part of their meals and snacks. That’s why research and nutrition education has shifted to focus on how the benefits of foods and beverages, specifically dairy products, can be greater than the individual nutrients they contain. This is known as the “dairy matrix.” Nutrients and bioactive compounds in dairy products combine to produce an overall effect on health and chronic disease prevention as well as optimizing athletic activity. Studies show that the dairy matrix has benefits beyond the individual supplementation of the same nutrients and has positive effects on bone mass density, bone metabolism and muscle health

When you talk to your athletes about nutrition, use the dairy matrix concept to remind them that eating whole foods, such as dairy products, is an important way to establish practical eating habits, while optimizing their health, performance and recovery. In order to help put this research into practice for yourself and your athletes, check out these useful resources:

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Nutrition Misperceptions and the Immune, Inflammatory and Injury Process of Athletes 

I get questions all the time from my athletes as well as members of the performance staff on nutrition misperceptions and their relationship to injury, immune function or inflammation. Here are the top four misperceptions I typical hear and how to address them with your athletes:

1. Misperception #1: Eating dairy products weakens immune function. 

Help your athletes realize that eating a balanced diet with a variety of foods to get essential nutrients is important to help maintain a healthy immune function. All dairy products can fit into a healthy, balanced diet and provide nutrients implicated in immune function, like vitamin A, vitamin D, zinc and protein. Yogurt is also full of probiotics, which can help contribute to normal immune system functioning. Avoiding milk and other dairy foods is not recommended to improve immune function. 

2. Misperception #2: Eating dairy products causes inflammation.

In fact, the current scientific evidence suggests the opposite may be true. When we talk about dairy or any other foods in the context of inflammation, we are talking about low-grade chronic inflammation, which can be related to untreated injury, nutrient deficits or overtraining and can lead to changes in the immune system. Studies show that eating the recommended amounts of dairy foods as part of a nutrient-rich, balanced eating plan is not linked to increased chronic inflammation. In fact, several clinical studies have shown that dietary patterns that include dairy foods (milk, cheese and yogurt) are associated with either improved (e.g., anti-inflammatory) or no effects on markers of chronic inflammation. For your athletes, it’s important to let them know that combating chronic inflammation involves more than individual nutrients or foods. 

3. Misperception #3: Eating dairy increases the risk of bone fracture.

The opposite may be true. Some studies indicate that adequate calcium, protein and vitamin D intakes from dairy products are strongly correlated with lower incidence of stress fractures in athletes, including female cross-country runners. A greater intake of calcium from dairy products may also be beneficial for bone mineral density and thus protective against stress fractures. Keep in mind, going dairy-free could unintentionally be counter-effective for proactive injury prevention. 

4. Misperception #4: Athletes who are lactose intolerant can’t have any dairy products. 

Before eliminating dairy, encourage athletes to be properly tested for lactose intolerance by a doctor, as many other conditions can result in similar symptoms. If you are working with an athlete who is lactose intolerant, let them know it is an individual condition and there are plenty of low- or lactose-free options available (check out slide eight in this sports nutrition presentation) to help keep real dairy in the diet to maximize their immune, inflammatory and injury process. Options include natural hard cheeses (e.g. Cheddar, Monterey), yogurt and other low or lactose-free cow’s milk products.

Implementing Evidence-Based Sports Nutrition Programs and the Immune, Inflammatory and Injury Process of Athletes

Helping your athletes achieve their performance goals without illness or fatigue from training-induced or psychosocial subclinical immune, inflammatory and injury dysfunction takes a team. Facilitate the coordinated involvement of the sport performance staff (e.g., dietitians), coaches, and athletes to set your players up for success with their nutrition.

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When I asked my colleague Dustin about how others can do this effectively for their programs, he let me know it’s best to, “Provide a structured plan for your athletes to follow and help assist with the process. Putting nutritional reminders on their treatment sheet is one way to help remind them and track compliance. Adding foods and beverages like milk or yogurt to their post workout shake can help kick start the recovery process as well by providing carbohydrates, protein and fluids.”

Here are some additional action steps that Dustin and I use daily with our players at the 49ers in the context of their inflammatory, immune and injury processes:

  • Pre-Treatment - Educate athletes on timing and importance of nutrition and any pre-rehabilitation supplementation they might need. 
  • Post-Treatment - Create a treatment sheet that ensures the athlete consumes post-workout/rehab nutrition at the end of their treatment. 
  • Long-Term Rehabilitation - Schedule meetings with a sports dietitian, if available, to monitor and track progress. Schedule weekly weigh-ins to track weight and track monthly or quarterly body composition. Coordinate with a sports dietitian on a nutrition plan to help prevent muscle atrophy through research-based guidelines. 
  • Ongoing- Establish and implement a nutrition program based on current resources to optimize athlete performance, recovery, and rehabilitation results. 


Hopefully, you now have the knowledge and tools to understand the role nutrition plays in the immune, inflammatory and injury process of your athletes and can begin to implement evidence-based programs to better their performance and recovery.  


Article credit:

Martin Kier
Martin Kier

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