Dietary Management

Peanuts and other food items can be a trigger for those with MCAS

People with MCAS find that certain types of foods can help manage their symptoms, such as low–histamine, low FODMaP, gluten-free, sugar-free, lactose-free, low-oxalate, anti-inflammatory, or low-amine diets—or a combination of these. However, not all diets work for everyone, as each person with MCAS is unique—the same foods that affect one person may not affect another.

For example, peanuts, bananas, and cinnamon are listed as high-histamine foods. It’s possible that an MCAS individual could react to peanuts but not to bananas or cinnamon. Or they could react to bananas, but not to peanuts or cinnamon. Or they may not react to any of those, yet they might have an issue with celery, which is considered a low-histamine food, but contains a moderate amount of FODMAPs (in 2 medium stalks), which can affect some people with MCAS or Histamine Intolerance. You may react differently to the same food at different times, depending on factors such as stress, hormone levels, nutrient levels, and more.

It’s essential to work with your healthcare provider to identify your unique trigger foods.

Elimination diets are intended as a temporary tool to help you identify your trigger foods and devise a personalized nutritional plan. Support from a qualified, MCAS-literate healthcare provider is crucial to help you make dietary changes, find what works for you, and support your nutritional needs. In the beginning, they will likely have you keep a daily diary, which can be a nuisance, but is well worth the time and effort to help you get to the root cause of your symptoms.

Foods with high mold content are common triggers for people with MCAS, including peanuts and leftovers. Freshly prepared foods from whole sources are less likely to cause reactions – avoid all packaged and processed foods.

The following lists are general guidelines only. It is not advised to try to navigate this condition on your own. Consult with a licensed MCAS-literate healthcare provider before starting or changing any health, diet, or supplement program.

    • Beets (2 slices max per meal)

    • Broccoli florets (3/4 C max per meal; avoid stalks)

    • Carrots (fresh)

    • Cauliflower (3/4 C max per meal)

    • Cucumber

    • Green beans (15 beans max per meal)

    • Kale

    • Lettuce

    • Parsnips

    • Green bell peppers

    • Radish

    • Russet potatoes (chill after cooking, eat cold)

    • Sweet potatoes (1/2 C max per meal, cubed, steamed)

    • Watercress

    • Zucchini (1/3 C max per meal)

  • Avoid large servings of fruit in one sitting

    • Blueberries (1 C max per meal)

    • Coconut, fresh “meat” (2/3 C max per meal)

    • Pomegranate (1/4 C seeds max per meal)

    Use Cautiously*:

    • Apple

    • Grapes, red and green, fresh & ripe (2-3 grapes max per meal/snack)

    • Peaches, yellow (1/4 C max per meal/snack)

    *Although considered low-histamine foods, these fruits are NOT Low FODMaP, which many people with MCAS do best with. These fruits should be consumed in small amounts, not together.

    • Amaranth

    • Arrowroot

    • Buckwheat

    • Millet

    • Oats, certified gluten-free only

    • Quinoa

    • Rice

  • Eat nuts and seeds in moderation

    • Almonds

    • Chia seeds

    • Flax seeds

    • Hemp seeds

    • Macadamia nuts

  • Use oils in moderation

    • Coconut oil

    • Grapeseed oil

    • Olive oil

    • Water (filtered)

    • Herbal teas (avoid Nettle tea and teas made with restricted spices)

    • Almond milk

    • Coconut milk

    • Coconut water

    • Hemp milk

    • Oat milk, certified gluten-free only

    • Basil

    • Parsley

    • Oregano

    • Thyme

    Mild spices may be used cautiously

  • If needed, try with caution in small amounts:

    • Stevia

    • Maple syrup (100% pure, any grade)

  • A whole-food, plant-based diet that adheres to the principles of a low-histamine and low FODMaP diet, avoiding gluten, added sugars, additives (e.g., MSG), and high glycemic foods, is the recommended dietary choice for a temporary Elimination Diet. However, the following animal products may be used with extreme caution. Freshness is absolutely critical, as histamine levels increase rapidly with age.

    • Fresh meat & poultry*

    • Fresh fish (very high-risk): only use extremely fresh or flash-frozen within 30 minutes of catch; avoid tuna, mackerel, sardines, herring, and anchovies

    • Fresh, unaged dairy, and pasteurized milk and yogurt, per tolerance

    *Poultry has been shown in scientific research to cause urinary tract infections

Foods to focus on

MCAS is a complex condition. While following a whole-food, plant-based diet that adheres to the principles of a low-histamine and low FODMaP diet, avoiding gluten, added sugars, additives (e.g., MSG), and high glycemic foods, is the recommended dietary choice, proving beneficial for most patients, it should be combined with personalized mast cell-mediated therapies in order to achieve symptom remission. Symptoms may get worse before getting better. Work closely with your provider.

    • Avocado

    • Eggplant

    • Mushrooms (some)

    • Olives

    • Spinach

    • Squash

    • Tomatoes

    Also consider avoiding Low FODMaP Diet veggies:

    • Artichoke

    • Asparagus

    • Brussels sprouts

    • Broccoli stalks

    • Cabbage

    • Garlic

    • Onion

    • Peas

    • Leaks

    • Citrus: lemon, lime, orange, grapefruit

    • Banana

    • Cherries

    • Dried fruit (including fruit sugars, like date sugar)

    • Guava

    • Kiwi

    • Papaya

    • Pears

    • Pineapple

    • Plums

    • Raspberries

    • Strawberries

    • Fruit juice

    Also consider these Low FODMap Diet fruits:

    • Apples

    • Peaches

    • Mango

    • Watermelon

    • Nectarines

    • Prunes

    • Lychee

    • Beans, all

    • Chickpeas

    • Lentils

    • Peanuts

    • Soybeans (including tofu, tempeh, soy milk, and soy sauce)

    • Peas

    • Walnuts

    • Cashews

  • Avoid breads, cereals, crackers, pasta, and biscuits; avoid wheat and rye.

    • All alcohol

    • Fermented drinks (e.g., Kombucha)

    • Soda pop and sugary drinks

    • Energy drinks

    • Commercially packaged fruit juices

    • Nettle tea and teas made with triggering spices

    • Chili powder

    • Cinnamon

    • Cloves

    • Red pepper

  • Avoid all sugary foods, including high-fructose corn syrup and honey, as well as sweeteners that end in “ol”: sorbitol, mannitol, xylitol, malitol (beware of sugarless gum and anything that is artificially sweetened).

    A peer-reviewed study (Nagai et al., 2012, European Journal of Pharmacology) demonstrated that high glucose directly activates human mast cells. β-hexosaminidase is a marker of mast cell degranulation - when mast cells degranulate, they release histamine.

    • Sauerkraut

    • Kimchi

    • Pickles

    • Olives

    • Kombucha

    • Miso

    • Tempeh

    • Sourdough bread

    • Vinegar, all types

    • Soy sauce

    • Vinegar, all types

    • Ketchup

    • Mustard

    • Mayonnaise

    • Honey

    • Any condiments containing restricted ingredients

    • Cocoa

    • Carob

    • Chocolate

    • Sugar

    • Dairy: milk and milk products, including sour cream, buttermilk, kefir, and yogurt

    • All cheese, including cottage cheese

    • All processed/cured meats (deli meat, sausage, hot dogs, jerky, salami, ham)

    • All canned fish

    • All shellfish

    • High-histamine fish (tuna, mackerel, sardines, anchovies, herring)

    • Meat & poultry that is not absolutely fresh

  • Avoid all leftovers. When preparing fresh foods, store any unused portions in the freezer. Anything stored in the refrigerator should be eaten within 24 hours. Reheating food can be risky.

Foods to avoid

IMPORTANT CONSIDERATIONS

  • Avoid any food items you know you are allergic to.

  • Any foods that have previously caused MCAS reactions can be slowly reintroduced after a strict avoidance period of up to 8 weeks.

  • You may tolerate a food from one brand or manufacturer but not another. Staying brand-consistent can help you manage your symptoms.

  • Use sweeteners minimally. If a sweetener is necessary, consider trying 100% pure maple syrup (any grade), which has a low glucose index (GI) and minimal blood sugar spike. Monitor symptoms carefully and document them in your daily diary.

  • If you can tolerate taking a multi-vitamin-mineral supplement, it’s a good idea to do so to avoid the risk of becoming nutrient-deficient. Certain nutrient deficiencies can cause severe symptoms and gravely impact your body’s immune system. It’s crucial to get enough B12, folate, zinc, magnesium, and vitamin D, among others. Vitamin D is foundational and must be at an optimal level to achieve symptom remission.

  • Histamine intolerance and MCAS are complex conditions; individual tolerance can vary significantly. Even low-histamine foods can cause reactions in some individuals. Always assert caution and work closely with your MCAS-literate healthcare provider.