What are Mast Cells and What is Mast Cell Activation Syndrome?

Mast cells are cells in your immune system that fight infections. Mast Cell Activation Syndrome occurs when these cells do not work properly. Mast cells release histamine, which are chemical messengers that the body uses to detect potential issues. These immune cells lead to allergic reactions or infections by producing itchy skin, watery eyes, runny noses, or tightened airways, among other symptoms. In MCAS, histamine release occurs in the wrong amounts at the incorrect times. Histamines normally help the body by triggering reactions to eliminate the source of the issue. However, dysfunctional mast cells can produce histamines when they’re not needed, which can interfere with daily functioning. If you are experiencing symptoms, talking to a medical doctor and a dietitian can help you come up with a treatment plan to increase your quality of life.

Why is a Balanced Diet Important if You Have Mast Cell Activation Syndrome?

Histamines are produced by mast cells but are also naturally found in food. Some foods contain higher levels of histamines, which can trigger symptoms. Other foods can trigger histamine release, which can worsen symptoms. Those who do not experience mast cell activation syndrome can incorporate those foods into a healthy diet. Those with MCAS may need to pay extra attention to their diet in order to reduce symptom triggers.

Dietary histamines and mast cell-derived histamines are the same compounds, but how they interact with the body is different. Since the body uses enzymes to break down histamines, reduced enzyme function can interfere with the metabolism of histamines and exacerbate symptoms. For those with MCAS, histamine-rich foods can increase the histamine burden in their body. Therefore, reducing the amount of histamine-containing foods you eat can be one strategy to try if you are seeking to improve symptoms. Completely eliminating histamines is impossible, but you and your dietitian can work together to reduce your intake of high-histamine foods and reduce MCAS food triggers. 

An RDN may recommend 2-6 weeks of following a low-histamine diet, then recommend reintroducing high-histamine foods. If there is a significant difference in symptoms when you eliminate or reintroduce high-histamine foods, you may be histamine intolerant. If you do not notice symptom relief when high-histamine foods are removed, then you may not be histamine intolerant. Alternatively, if symptoms worsen when you reintroduce high-histamine foods, you may have histamine intolerance. It is best practice to be monitored by a healthcare provider when following elimination diets so they can guide you to participate safely and rule out any other possible MCAS triggers.

What Are the Most Common Mast Cell Triggers for MCAS Patients?

Although mast cell activation symptom onset can seem random, many patients experience common triggers that can include sudden temperature changes, fatigue, stress, exercise, certain foods, alcohol, medication, venoms, infections, and sunlight. Your dietitian will work with you to ensure that you sleep adequately, exercise safely and tolerably, consume low-histamine foods, reduce alcohol consumption, and possibly recommend other adjustments. Additionally, your dietitian will provide you with social support to adhere to nutrition recommendations when making dietary changes.

What is a Low-Histamine Diet?

A low-histamine diet focuses on reducing the intake of foods that either contain high amounts of histamine or trigger its release in the body. You may experience fewer or less intense symptoms on a low-histamine diet. This dietary approach is a foundational strategy in mast cell activation syndrome management and creating a pathway to improved health. Keeping a food journal that includes the foods you eat and the subsequent signs and symptoms is key to identifying which and how many symptoms have improved or worsened with dietary changes. 

What are Histamine Releasing Foods and How Do They Relate to Your Immune System?

Some of the highest histamine foods include aged and fermented foods such as cheese, yogurt, processed meats, alcohol, sauerkraut, food additives, soy, fish, fruits such as strawberries and cherries, and vegetables including spinach and tomatoes. Selecting fresh foods and fresh meat is important because histamine levels increase the longer food sits. As food ages or if it is stored improperly, bacteria can break down proteins in the food, which can trigger a histamine release. There are also some foods that do not have histamines but do trigger the release of histamine from mast cells.

Frozen foods tend to be lower in dietary histamine because they are frozen quickly after harvest, which prevents bacteria from thriving. Canned and fermented foods tend to be higher in histamine due to the higher potential for bacterial growth. Although bacterial growth is slowed down in the canning process, the canning process does not eliminate bacteria, and certain bacteria can still grow. Try to buy and eat fresh produce within a few days to ensure you are consuming foods in the freshest form possible. Many find that avoiding leftover foods can also help reduce dietary histamine intake. Working with a dietitian can help ensure that you are getting the adequate nutrition you need to thrive while avoiding dietary triggers.

Conclusion

Managing Mast Cell Activation Syndrome involves being knowledgeable about your unique triggers. While more research needs to be conducted on MCAS, many of those with MCAS find a low histamine diet helpful. A registered dietitian nutritionist can help assess your nutrition and develop a personalized plan to reduce histamine-containing foods while still consuming balanced meals. A dietitian will help ensure you eat specific foods that are safe, effective, and nutritionally adequate. With the right guidance, you can implement the appropriate steps to improve your quality of life and make lifestyle choices to help you manage your mast cell activation syndrome.

Sources

TMS for a Cure. (n.d.). Symptoms and triggers of mast cell activation syndrome. Retrieved December 8, 2024, from https://tmsforacure.org/signs-symptoms-triggers/symptoms-and-triggers-of-mast-cell-activation/

American Academy of Allergy, Asthma, and Immunology. (n.d.). Mast cell activation syndrome. Retrieved December 8, 2024, from https://www.aaaai.org/conditions-treatments/related-conditions/mcas

Johns Hopkins Medicine. (n.d.). Chronic fatigue syndrome: Low histamine diet. Retrieved December 8, 2024, from https://www.hopkinsmedicine.org/-/media/johns-hopkins-childrens-center/documents/specialties/adolescent-medicine/cfs-low-histamine-diet.pdf

Blanchard, E., & Mote, M. (2017). Mast cell activation syndrome and histamine intolerance: A diagnostic challenge. The Journal of Allergy and Clinical Immunology, 140(4), 1157-1164. https://doi.org/10.1016/j.jaci.2017.07.042