Why ‘Relative Energy Deficiency in Sport’ matters to podiatrists

You might be thinking, why and how is the consensus statement on Relative Energy Deficiency in Sport (RED-S) important for me? Trust me, it is!

 

Who are the authors?

The consensus statement was authored by a team of leading experts, who represent a range of qualifications and practitioners. From researchers working in medicine, sports nutrition, physical activity and epidemiology; through to practitioners such as sports physicians, sports dietitians, endocrinologists, and sports scientists.

 

They include: Margo Mountjoy, Kathryn E Ackerman, David M Bailey, Louise M Burke, Naama Constantini, Anthony C Hackney, Ida Aliisa Heikura, Anna Melin, Anne Marte Pensgaard, Trent Stellingwerff, Jorunn Kaiander Sundgot-Borgen, Monica Klungland Torstveit, Astrid Uhrenholdt Jacobsen, Evert Verhagen, Richard Budgett, Lars Engebretsen, and Uğur Erdener.

 

What is the background?

Since the previous version of the RED-S consensus statement in 2018, over 170 additional original research papers have been written to advance the field of RED-S science.

 

Data from these papers was included in the 2023 updated consensus statement, contributing to updated health and performance conceptual models. These models aim to describe the body systems and performance outcomes affected by RED-S.

 

The updated consensus statement also includes a new RED-S clinical assessment tool to facilitate the detection and clinical diagnosis of RED-S, based on accumulated severity and risk stratification.

 

What exactly is REDs science?

The key aetiological factor in RED-S science – which stands for ‘relative energy deficiency in sport’ as a reminder – is low energy availability (LEA).  If you consistently under-fuel to a point where there are insufficient calories to meet essential functions, you are considered to be in a state of low energy availability, or LEA. In this state, the body starts to draw energy from less critical areas, such as bones or the reproductive system, prioritising vital functions like brain activity ^(1,2).

 

RED-S is an extension of LEA. It is considered a syndrome of impaired physiological and/or psychological functioning that is caused by exposure to problematic (prolonged and/or severe) LEA. RED-S is associated with known health and performance consequences, for example bone stress injury or menstrual dysfunction.

 

In simple terms, energy availability can be explained like this:

 

Your body requires a certain amount of energy (basal metabolic rate, or BMR) to maintain essential functions—essentially, to “keep the lights on.” This energy requirement varies from person to person and is influenced by various factors⁽²⁾. On top of this, physical activities, like exercise, increase your energy requirements.

By definition, energy availability refers to the amount of energy remaining for the body to perform its essential physiological functions, after accounting for the energy expended during exercise. It is calculated as the difference between total energy intake and the energy used during exercise, relative to the individual’s fat-free mass (FFM).

 

How easy is it to fall into low energy availability?

It is surprisingly easy to fall into LEA, either unintentionally or intentionally. For example, after a 15 kilometre run, or a busy day on your feet, it might be difficult to refuel adequately.

 

Having an understanding of the risk factors for LEA can help you identify individuals who are at higher risk, in order to refer on appropriately.

 

Low energy availability can be best thought of as a precursor to RED-S. As humans, we go through periods of LEA throughout our life. Missing lunch or breakfast may mean the body uses alternative fuel sources other than the energy just consumed. It is prolonged LEA that can result in RED-S. It is a very complex biological and individual process so please check out the references for more information.

 

At an undergraduate level, podiatrists often receive limited education on nutrition, partly due to time constraints and perceived relevance. However, recent research has demonstrated that nutrition significantly impacts musculoskeletal health, affecting both bone and tendon integrity^(3,4).

 

What is the goal behind the research?

The updated health and performance models, along with the clinical assessment tool, aim to address the following objectives:

1. Enhance clinicians’ understanding of RED-S: Provide insight into how RED-S  affects the health and performance of athletes.
2. Promotion of best practices for prevention and treatment: Offer principles to encourage optimal screening, referral, and management practices amongst clinicians and sports organisations.

 

Recent studies of interest

The below research is critical for clinicians to understand the impact that RED-S can have on patients and their care. REDs can affect many systems throughout the body⁽¹⁾ (bjsports-2023-106994)

• Tendon health: Individuals with elevated HbA1c in the prediabetic range (HbA1c >5.7%) have about a three times higher risk of tendon injury in the lower extremities compared to those with normal HbA1C levels. Hypercholesterolemia (total cholesterol >5 mmol/L) increases the risk of tendon injury in the upper extremities by about 1.5 times, and individuals with metabolic syndrome have about 2.5 times higher risk of tendon injuries in both upper and lower extremities⁽³⁾ (10.1111/sms.13984)

• Bone health: Bone resorption and formation markers are impaired with reduced carbohydrate intake, meaning that without an energy surplus, bone-building capacity is significantly reduced⁽⁵⁾ (10.1002/jbmr.4658)

 

Do you use this approach when carrying out an initial screening?

Yes, this research has significantly changed my initial screening process and understanding of contributing factors to the complaints we see regularly in the clinic.

 

My approach involves the initial screening of risk and RED-S potential involvement. If I identify a person may be at risk, I am able to suggest talking with a qualified professional.

 

We know that musculoskeletal conditions are multifactorial and may have a nutritional component. This approach simplifies a complex topic, allowing us to screen effectively.

 

While we don’t provide nutritional advice, we can identify symptoms or signs that warrant an appropriate referral.

 

What do you feel is of particular interest for podiatrists in this context?

Podiatrists need to understand the wide-ranging impacts of RED-S. Several common symptoms and their relevance include:

 

• Impaired bone health: Energy imbalance can significantly affect bone remodelling, even with the best rehabilitation and conditioning efforts. This may increase the risk of fractures if not addressed^(1,4).

• Neurocognitive function and mental health issues: Depression, exercise dependence/addiction, and disordered eating behaviours can be associated with RED-S⁽⁶⁾. Patients experiencing persistent pain may find it challenging to engage with treatment plans if their mood is affected.

• Sleep and recovery: Poor sleep is associated with persistent pain and injury, and RED-S can impact sleep quality⁽⁷⁾.

• Decreased muscle strength, recovery, and endurance performance: These issues can significantly affect athletic performance and day-to-day activities⁽⁸⁾.

 

By screening for RED-S and understanding its potential impact, we can educate and help our patients more effectively, to manage their health.  This knowledge also encourages collaborative work with other health professionals to potentially improve treatment outcomes.

 

Any other parts of this research that you found interesting?

I found the diagnostic criteria and classification particularly interesting. Based on their guidelines, athletes may need to stop participating in sports if they have a severe presentation of RED-S. The seriousness of RED-S and its impact on multiple bodily systems cannot be overstated. It’s a reminder that RED-S can affect anyone, regardless of body size or weight.

 

How can podiatrists use this knowledge immediately?

The screening is important for two main reasons.

 

Firstly, if someone has answered these questions indicating they may be at risk of RED-S, they will likely need input and help from a qualified health professional. Think of it like in the diabetes world, if someone is identified (with TBI) as being at high risk of vascular complications, we would clearly refer them to the appropriate health professional. The same guidelines can apply. As you have seen, RED-S can have a multitude of effects on the body and may need further input.

 

Secondly, RED-S can have a direct effect on our treatment plan. To put it simply, if someone has RED-S and you’re trying to rehab a stress fracture, the bone is not able to physically remodel because of the energy deficit. It is pretty important we address that.

 

Podiatrists can begin by integrating some clear screening questions and signs into their practice. For example:

• Look for signs such as over-exercising, eating disorders, weight changes, and anaemia.
• Ask about gastrointestinal symptoms, both daily and during.
• Inquire about conditions that may result in malabsorption (coeliac disease).
• Question if they have had recent blood work results and if so, was anything abnormal such as cholesterol or iron/ferritin.

 

There are some interesting screening questions in LEAF, with other examples below. As a precursor for context, these questions may feel uncomfortable asking.

 

I often explain the following before asking, ‘I need to ask you some questions about your systemic health because it can have a significant impact on your injury and treatment plan. It may sound a little odd as I am a podiatrist and if you don’t feel comfortable answering, that is okay. We need to ask them so we can get a holistic view of this injury’.

 

In my career, I haven’t had someone refuse to answer. People want to know how we can help and we need to know these answers. I understand in some cases it is more important (such as stress fracture v Achilles tendinopathy)

• If they identify as a person who menstruates, query whether menstruation did not begin by 15 years of age? Or whether they have experienced prolonged amenorrhoea?
  • Amenorrhoea is more than three missed periods. History of 1 low-risk bone stress injury within the previous 2 years and absence of <6 months from training due to BSI in the previous 2 years
• Has there been a reduced or low libido/sex drive (especially in males) and decreased morning erections (emerging)
• Does the patient have a low BMI or recent change in BMI?
• Do they participate in a weight-sensitive or leanness sport such as running or triathlon?
• Have they increased their hours of exercise per week, to seven hours or more?
• Do they show signs of exercise dependence/addiction?

 

Contact Blake Withers

Instagram: @BlakeWithers.Sportspodiatrist

Contact Dr Rebecca Haslam who contributed to this article (and who Blake recommends following).

Instagram: @Nutrient Nation