Why Leftovers Can Be Problematic for Those with MCAS

May 26

Don’t reheat that just yet.

What may seem like a harmless leftover could contribute to a worsening of MCAS (mast cell activation syndrome) symptoms.

Here’s why that leftover you trust could actually be causing you trouble—and ideas to help you stay ahead of it.

Leftovers = Higher Histamine

In people with MCAS, mast cells can become overactive and release too many inflammatory mediators like histamine into the body.

When someone with MCAS eats food high in histamine, they may experience something called histamine overload, which can cause their MCAS symptoms to worsen.

Histamine builds up in foods the longer they’re stored, even in the fridge. Bacteria in leftovers turn amino acids into histamine over time—and reheating the food doesn’t get rid of the histamine.

Common Reactions to Leftovers

Abdominal pain, bloating, or nausea
Itchy skin, warmth, or redness
Headache or migraine
Congestion, cough, or itchy throat

Ideas to Consider for Managing Food

Eating food fresh whenever possible
Freezing food immediately after cooking can help reduce histamine buildup by preserving the food at the histamine level it had when fresh
Tracking food + symptoms in a log can help you better understand your personal triggers
Working with a mast cell-aware dietitian

With MCAS, it’s not just about avoiding certain ingredients—food storage and timing can also be a key part of symptom management!

PMID: 33506573; PMID: 33108461; Mast Cell Action: Diet and MCAS, Implementing a Low Histamine Diet

Disclaimer: This blog post is for informational purposes only and shall not be construed as behavioral health or medical advice. It is not intended or implied to supplement or replace treatment, advice, and/or diagnosis from your own qualified healthcare provider.

Lauren Gould