Relative Energy Deficiency in Sport (RED-S)

Part of the Evidence in Action series by Palmer College of Chiropractic

By Robert Vining, DC, and Breanne Bovee, DC

In 1992, the American College of Sports Medicine (ACSM) encouraged and supported scientific inquiry into and public awareness of a condition that became known as the Female Athlete Triad.1 The hallmark components of the triad include eating disorders, functional hypothalamic amenorrhea and osteoporosis. A person diagnosed with the triad may present with one, two or three component conditions. In high school athletes, the prevalence can be as high as 60% for a single diagnosis, 27% for two, and 16% for all three elements.2 Despite a high prevalence of component conditions, Curry and colleagues reported that physicians lack a widespread knowledge about the triad diagnosis and clinical management options.3

Naming Challenges

The term “Female Athlete Triad” is somewhat misleading because the condition can occur in males, females, athletes and non-athletes.4,5 Also, the “triad” can present as a single condition or two to three co-existing conditions. Perhaps the terminology challenges have contributed to the poor knowledge dissemination among physicians.

A More Comprehensive Name

In 2015, the International Olympic Committee (IOC) introduced a revised term for the condition called Relative Energy Deficiency in Sport (RED-S). RED-S includes a broader scope of related conditions and removes the female emphasis. Disorders arising from RED-S can include: abnormal metabolic rate, menstrual dysfunction, bone disorders such as low mineral density and stress fracture, depressed immunity status, abnormal protein synthesis, cardiovascular dysfunction and compromised psychological health. RED-S can be thought of as a constellation of conditions arising from nutrient deficiency relative to physical activity demands.6

The Question

Given the prevalence of conditions associated with RED-S and the likelihood that doctors of chiropractic will encounter many patients with related conditions, we decided to search the literature to learn more about evidence-based screening tools to help identify RED-S conditions.

Search Strategy

Step 1: First, we searched PubMed by entering “RED-S and screening” in the search bar. This search yielded no studies describing the reliability or validity of screening tools or methods.

Step 2: Next, we searched Google Scholar, again entering “RED-S and screening” into the search field. This search identified an article authored by Mountjoy and colleagues published in the British Journal of Sports Medicine, entitled “The IOC consensus statement: beyond the Female Athlete Triad-Relative Energy Deficiency in Sport.6

Step 3: Because RED-S is such a new term, there hasn’t yet been enough time to test and publish results for screening tools. Therefore, we elected to: A) carefully examine the expert consensus recommendations from the IOC, and B) search for studies evaluating screening tools for the Female Athlete Triad.

Screening Tools

In Google Scholar we searched “female athlete triad screening tools.” We identified two studies developing or testing screening tools. Reference searching within these articles lead us to additional articles and two more screening tools:

  • The Eating Disorder Examination Questionnaire (EDE-Q). The EDE-Q is a self-reported 41 item questionnaire for identifying disordered eating.7
  • A five-question screening tool called “SCOFF” is used to identify disordered eating.8
  • The Low Energy Availability in Females Questionnaire (LEAF-Q) is designed to identify females at risk for low energy availability, abnormal reproductive function, and bone health using a 25 item questionnaire.9
  • The Female Athlete Screening Tool (FAST) is a screening tool for eating disorders in female athletes. It is a self-reported 33 item questionnaire.10

Expert Consensus Recommendations

Because available screening tools are focused only on females and on a small number of potential conditions associated with RED-S, we decided to consider the IOC expert consensus screening recommendations. Though expert recommendations are based on opinions rather than experimental research, in this case they represent the best available evidence. The knowledge on which expert recommendations is based will hopefully increase over time, leading to formal guidelines based on high-quality research. For now, it seems reasonable to seriously consider implementing some or all of the IOC recommendations.

The IOC recommends periodic health evaluation, which should occur at least annually. Screening recommendations are focused on evaluating 1) eating habits, 2) hormonal and metabolic function, 3) body mass density as appropriate for activity, age and ethnicity; and 4) the musculoskeletal system. Additional diagnostic evaluation could include the following items:

  • energy availability by comparing dietary intake to exercise energy expenditure
  • assessment of bone density with dual x-ray absorptiometry, especially for individuals with eating disorders
  • assessment of resting metabolic rate by indirect calorimetry
  • screening for eating disorders

Individuals with high or moderate risk of developing RED-S may require additional diagnostic investigation. High-risk individuals include those identified with anorexia nervosa, other serious medical conditions and those who have experienced extreme weight loss.

Signs of persons with a moderate risk for developing RED-S are:

  • prolonged abnormally low body fat
  • substantial weight loss
  • reduced growth/development in an adolescent
  • abnormal menses
  • abnormal hormone profile in males
  • decreased bone mineral density
  • history of one or more stress fractures
  • low energy availability as determined by nutrient input relative to energy expenditure
  • disordered eating
  • lack of treatment progress

Doctors of chiropractic are well-positioned to identify and engage in appropriate evaluation or referral procedures for the many patients at risk for, or suffering from, RED-S. Becoming familiar with the IOC recommendations can help increase awareness among providers and inform management strategies.


Dr. Vining is associate professor and senior research clinician at the Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa.

Dr. Bovee is a research fellow at the Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, Iowa.

Evidence in Action is a reoccurring series that provides guidance on how to evaluate available evidence and apply it to patient care in the clinic.


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