Feeling tired after eating with Mast Cell Activation Syndrome (MCAS) is a common issue and can happen for several reasons related to mast cell overactivity. Here’s why it might be happening and what you can do about it:
Possible Reasons for Fatigue After Eating with MCAS
1. Histamine and Other Mast Cell Mediators
- When you eat, mast cells in the gut may become overactive and release histamine, prostaglandins, and cytokines, which can trigger fatigue, brain fog, dizziness, and weakness.
- Certain high-histamine or triggering foods (like fermented foods, alcohol, processed meats, and aged cheeses) may worsen this reaction.
2. Postprandial Hypotension (Low Blood Pressure After Eating)
- Blood is redirected to the digestive system after meals, and in MCAS, mast cell mediators like histamine and prostaglandins can cause blood vessels to dilate, leading to a drop in blood pressure.
- Symptoms: Fatigue, dizziness, lightheadedness, feeling faint after meals.
- This can be worse if meals are high in carbohydrates, as they cause a bigger shift in blood flow.
3. Reactive Hypoglycemia (Blood Sugar Drop After Eating)
- Some people with MCAS experience blood sugar fluctuations, where blood sugar spikes after eating, then crashes.
- This can happen due to dysregulation of insulin and cortisol, often linked to inflammation and mast cell activation.
- Symptoms: Fatigue, shakiness, brain fog, anxiety, sweating, hunger shortly after eating.
4. Food Sensitivities & Immune Activation
- MCAS often comes with food sensitivities that can trigger inflammation and an immune response, leading to fatigue.
- Common culprits: Gluten, dairy, high-histamine foods, FODMAPs, food additives (like MSG or artificial sweeteners).
- Even if you don’t have a traditional allergy, your immune system may still react, draining your energy.
5. Gut Dysbiosis & Leaky Gut
- Many people with MCAS have gut issues like leaky gut, SIBO (small intestinal bacterial overgrowth), or dysbiosis, which can lead to improper digestion and immune activation.
- If undigested food particles or bacteria trigger an immune response, fatigue and inflammation can result.
6. Mitochondrial Dysfunction & Inflammation
- MCAS-related inflammation can disrupt mitochondrial function, reducing your body’s ability to produce energy (ATP).
- This can lead to chronic fatigue, especially after eating when digestion requires energy.
What Can Help?
✅ Track Your Triggers – Keep a food diary to identify which foods make you tired.
✅ Eat Smaller, Balanced Meals – Avoid large, high-carb meals that can worsen blood sugar swings and blood pressure drops.
✅ Try a Low-Histamine Diet – Focus on fresh, whole foods and avoid fermented, aged, and processed foods.
✅ Stay Hydrated & Add Electrolytes – Helps stabilize blood pressure and energy levels.
✅ Support Digestion – Digestive enzymes and probiotics (if tolerated) may help reduce gut-related mast cell activation.
✅ Stabilize Mast Cells – Medications or supplements like quercetin, DAO enzyme, cromolyn sodium, or H1/H2 antihistamines may help.
✅ Balance Blood Sugar – Pair carbs with protein and healthy fats to prevent crashes.
✅ Consider LDN (Low-Dose Naltrexone) – Some people with MCAS find LDN helps reduce fatigue by regulating inflammation and immune function.
For more on MCAS and fatigue check out this post – https://mcashub.com/mcas-and-fatigue/
To Us! Love and Health!
