How does "the triad" impact ARFID?

The triad refers to three health conditions that commonly co-occur amongst neurodivergent people:

1. Postural Orthostatic Tachycardia Syndrome (POTS)

2. Mast Cell Activation Syndrome (MCAS)

3. Ehlers Danlos Syndrome (EDS), more commonly hypermobile Ehlers Danlos (hEDS)

These conditions can occur individually, but regularly co-occur. One study (with a large sample size of 37, 665) found that almost 1 in 3 participants with MCAS also had a diagnosis of hEDS (Monaco et al., 2022). Another study found that those with POTS and EDS are much more likely to have MCAS than those without (31% versus 2%) (Wang et al., 2021).

These conditions individually can impact on eating in a number of ways.

MCAS

In MCAS we often see gut symptoms like bloating, nausea, diarrhoea, pain and reflux which can be triggered by eating. Some people experience allergic type reactions (more rarely anaphylaxis), which can create a lot of fear and confusion around food. Food may also trigger full-body symptoms like rashes, hives, anxiety, insomnia and brain fog.

Adverse food reactions can lead to fear around eating and can limit the number of safe foods available. Food restriction can be a strategy to avoid illness, physical discomfort or pain. Over time, fear around food, nutrient deficiencies and gut microbiome changes can enforce restriction by reducing tolerance to other foods.

Histamine itself in MCAS can contribute to this pattern. The chronic release of histamine from mast cells is linked to anxiety and nervous system dysregulation, which can not only increase fear around food but can impair digestive processes. When we are in a state dominated by the sympathetic nervous system (fight or flight mode), our digestion is impaired as resources are sent elsewhere in the body to respond to immediate threats. We can see reduced digestive secretions and dysregulated timing of digestive processes.

POTS

A key feature of POTS is dysautonomia; the dysfunction of the autonomic (automatic) nervous system that controls blood pressure, heart rate, digestion, body temperature, sweating and more. Dysautonomia commonly causes gut symptoms like diarrhoea, constipation, bloating, pain, reflux, nausea and vomiting. These symptoms can impact on appetite, fullness, can create fear around food and lead to increased food restriction.

hEDS

hEDS is often described purely as a connective tissue disorder, but more recently is being acknowledged as a multi-system disorder with significant impacts on the immune system (particularly mast cells). Connective tissue differences in hEDS are often linked to gut dysmotility (i.e. altered co-ordination and movement of the gut when processing food) which might look like delayed stomach emptying, low appetite, early fullness, reflux, bloating, diarrhoea or constipation. Dysmotility can cause an overgrowth of microbes in the gut (often in the small intestine), leading to more gut symptoms.

Connective tissue differences may also increase the likelihood of:

· weak lower oesophageal sphincter tone (allowing stomach acid to enter the oesophagus)

· hiatal hernia (the upper end of the stomach pushes through the diaphragm into the chest) which can contribute to reflux

· abdominal hernias (commonly around the belly button) which may cause discomfort, pain or pressure

· pelvic floor or rectal prolapse, often causing constipation

The gut symptoms linked to these connective tissue differences often increase fear around food and can create a huge barrier to eating.

Eating Challenges

These conditions individually and when they overlap can make eating feel unpredictable, exhausting and unsafe. Fatigue, digestive symptoms, food reactions and the effort involved in planning, sourcing and preparing meals can all make eating harder. The fear and overwhelm of unpredictable symptoms can create a cycle of restriction, driving or worsening ARFID.

When MCAS, POTS and/or hEDS are contributing to ARFID, supports often need to address both the eating difficulty and the physical symptoms driving it. This might look like:

· Reducing digestive symptoms and reactions to food through MCAS, POTS and hEDS support

· Addressing nutrient deficiencies

· Nervous system regulation to support a sense of safety

· Respecting sensory differences and boundaries

Digestive and whole body symptoms related to food are very real and restriction is an understandable way to cope with these symptoms. Everyone deserves ARFID care that is neuroaffirming, respects autonomy, is compassionate and addresses these underlying health factors.

References:

Monaco A, Choi D, Uzun S, Maitland A, Riley B. Association of mast-cell-related conditions with hypermobile syndromes: a review of the literature. Immunol Res. 2022 Aug;70(4):419-431. doi: 10.1007/s12026-022-09280-1. Epub 2022 Apr 21. PMID: 35449490; PMCID: PMC9022617.

Wang E, Ganti T, Vaou E, Hohler A. The relationship between mast cell activation syndrome, postural tachycardia syndrome, and Ehlers-Danlos syndrome. Allergy Asthma Proc. 2021 May 1;42(3):243-246. doi: 10.2500/aap.2021.42.210022. PMID: 33980338.

Written by Sam Jeffrey (he/him), a neurodivergent (AuDHD) naturopath based on Whadjuk Noongar land and a proud queer, trans man. He is deeply committed to creating healthcare spaces where neurodivergent, queer and trans folks feel safe, respected and genuinely understood.

This article is intended as general advice only and does not replace medical advice. It is recommended that you seek personalised advice specific to your individual needs.