You might reach for antihistamines on a regular basis—to quell the runny nose and itchy eyes, or to calm the itching after a mosquito bite. Releasing histamine (a neurotransmitter involved in immune response, which also regulates certain functions in the gut, brain, spinal cord and uterus) is our body’s way of trying to protect itself from invaders, but in the case of hay fever, this immune reaction goes into overdrive.

Now though, in an age where our immune systems have been challenged like never before, histamine issues are increasingly emerging as part of the many Long COVID (post-COVID conditions) symptoms people can experience.

And a low histamine diet could help.

What is histamine? 

Histamine intolerance (more on that below) is a syndrome that occurs when the body is unable to break down histamine sufficiently. And so, as a result, we have too much of it in our bodies. It affects 1-in-100 people, but could affect up to 5% of the population according to the Histamine Intolerance Awareness campaign. It can be genetic, but other facts can trigger sensitivity too.

Abnormally high levels of histamine now appear to be a factor in Long COVID. Doctors have noticed that symptoms of this condition were very similar to many Long COVID symptoms.

“Interestingly, all of my patients with Long COVID also have elevated histamine levels, not just those with histamine intolerance. We’re seeing a multitude of symptoms mainly based around inflammation in various different parts of their bodies. People can experience severe headaches, skin irritations, itchiness, hives, sinusitis, rhinitis, shortness of breath, dizziness and nausea, plus IBS-type symptoms including diarrhea, constipation, bloating and abdominal pain. They can also experience extreme fatigue (ME), brain fog and neurological symptoms such as paints in their feet, face and tingling sensations in the body. This list isn’t exhaustive and varies from person to person,” one doctor said.

By reducing the histamine in people’s diet, doctors have reduced many Long COVID symptoms. This type of diet is difficult to follow, but often people see an improvement very quickly—their itchy skin, fatigue, brain fog and IBS symptoms can all improve. The response depended on how severe their symptoms were — some saw an improvement within a matter of days after reducing the histamine in their diet, but others took a few weeks.

How do you follow a low histamine diet?

A normal, healthy diet contains moderate levels of histamine. Ordinarily, this doesn’t cause a problem. Certain foods such as strawberries, avocado and chocolate (except white chocolate) contain higher levels of histamine.

If you are histamine intolerant, they can trigger any of the range of familiar symptoms, from itchy eyes to rashes. Reducing or eliminating high-histamine foods, under the guidance of a dietician, can help alleviate symptoms, whether you have a histamine intolerance or histamine issues relating to Long COVID.

Below is the list of food you cannot eat because they either have higher levels of histamine or have been reported to release histamine (we’re sorry).

• Alcohol, such as wine and beer
• Fermented foods, such as sauerkraut, kefir and kombucha
• Yeast extract or Marmite
• Foods that contain vinegar, such as pickled vegetables
• Cured/smoked meats, such as bacon and salami
• Shellfish
• Soured foods, such as sourdough bread, sour cream, or buttermilk
• Aged/mature food, including cheeses like Blue, Roquefort and Parmesan
• Nuts and dried fruit (these may contain mold)
• Gluten
• Tomatoes, avocados, spinach, and eggplants
• Most fruits, including citrus (lemon, lime, oranges), papaya, pineapple, plum, kiwi, and banana
• Chocolate and cocoa-based products
• Salty snacks
• Vinegars

Below is the list of food you can eat, thankfully.

• Fresh meat, poultry and fish
• Most fresh herbs and spices
• Dairy milk (assuming you don’t have a dairy intolerance)
• Gluten-free oats
• Eggs
• Dairy substitutes, such as coconut milk
• Gluten-free grains, such as quinoa and rice
• Olive oil

Pretty tough, right? If you’re like us, you’re probably wondering, “Well, what can I eat, then?” Maybe starting to grow your own food could help (and relieve some of the stress).