Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In



You Might Not Be Paying Enough Attention to Micronutrients

A look at why nutrient deficiencies can be a problem for endurance athletes—plus four things you can do to find and address them.

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

Many athletes have experienced or had training partners who dealt with anemia, stress fractures, and other illnesses and injuries stemming from nutrient deficiencies. Combined with fad diets, over- and under-supplementation, and confusing nutrition advice, it can be difficult to determine what nutrient requirements you should meet for both health and performance.

It is common to hear about macronutrients—protein, carbohydrates, and fats. But, when it comes to nutrition, micronutrients are just as important. Micronutrients, like vitamins and minerals, make up the foundation for every single process that happens within the human body, including your metabolism, immune system function, hormone production and utilization, and more.

These micronutrients are essential for recovery, performance, and your overall health. Nutrient deficiencies can lead to injuries and illness, which can lead to missed training time or races. More serious issues can take you out for a whole season, like iron deficiency anemia or stress fractures caused by low Vitamin D levels. The reality is athletes require higher amounts of nutrients in order to support the increased stress and strain from training.

You can determine your levels of micronutrients through a simple blood test, although many health care providers will only test for a select few micronutrients. Determining where your micronutrient levels are at will let you know if you have insufficient or suboptimal levels—which is the first step towards addressing those deficiencies.

Using Vitamin D as an example, normal limits for a blood test range from 30 ng/mL to 100 ng/mL. Current research suggests optimal levels are between 50 ng/mL to around 80 ng/mL depending on age, weight, and other lifestyle and genetic factors. Suboptimal levels depend on the athlete, but generally are between 50 ng/mL to 30 ng/mL. An insufficiency in Vitamin D would be below 30 ng/mL. Lastly, a blood test result below 20 ng/mL is considered a deficiency.  

Nutrient deficiencies can be caused by a number of things, including poor gut health leading to an issue with nutrient absorption from supplements and food intake, fad diets or diets that restrict certain food groups, low caloric intake, as a result of relative energy deficiency in sport (RED-S), genetics, or an imbalance from not eating a variety of different types of foods.

Among endurance athletes, common nutrient deficiencies include Vitamin D and Vitamin B, as well as minerals like iron and magnesium. When there are deficiencies and suboptimal levels in B vitamins and iron, we frequently see symptoms like persistent fatigue and bruising. Also, iron and B12 are essential for the formation of red blood cells, which are essential for carrying oxygen and other nutrients to your tissues. In addition, athletes who are getting more frequent colds or the flu throughout training season need to evaluate their nutrient status, as this can be one of the main signs that the immune system, and the body as a whole, is under stress and needs additional support.

Magnesium is one of the most common deficiencies in athletes and can lead to symptoms like muscle cramping. Both magnesium and Vitamin D can also often lead to issues with muscle tissue recovery and bone health—for example causing recurrent stress fractures. 

What can you do?

Ask your physician to order a panel of vitamins and minerals levels, and test yearly for prevention. You can explain that you are an athlete and you want to ensure you have optimal levels for both your health and performance. You can also mention any symptoms you may be having that could be from a nutrient deficiency.

Eat the rainbow and a wide variety of whole foods, including fruits, vegetables, whole grains, legumes, and plant- or animal-based protein. Colorful foods like fruits and vegetables have wide varieties of vitamins and minerals. Seasonal fruits and vegetables can also be great additions. Healthy sources of protein and even organ meats are also fantastic sources of micronutrients.

Work on your gut health. Triathlete has many articles discussing the importance of gut health. Your GI tract is essential for vitamin and mineral absorption through your food. 

Supplement when needed. I always encourage athletes not to over-supplement. Antioxidants are important, but supplementing does not always lead to the best result for athletes. Get a lab test to determine what you specifically need and aim to get your nutrients from a variety of whole foods. Also, athletes who are vegetarian or vegan may need to supplement with iron and B12, which are normally found in animal-based protein.

Micronutrients impact every single process that happens inside your body and they support everything you aim to do through training. Although we generally talk about deficiencies when things go wrong, ensuring an adequate and optimal range of micronutrients can promote better recovery, health, and performance.

Dr. Kirstin Lauritzen DC, MS is a Functional Medicine practitioner in Oregon who specializes in helping athletes prevent nutrient deficiencies, treats chronic illness, and optimize their health, performance and recovery through nutrition and lifestyle changes.