Is there a link between covid and histamine? There is a growing number of people with long-covid, and their symptoms present in some ways similarly to patients with mast-cell-driven inflammation.

Whilst the world still battles with how to get Covid-19 under control we are learning it’s more than just a lung disease, it can affect any of our body systems and organs.

Not everyone will get long-covid, we don’t really yet know why someone experience ongoing problems and others recover quickly, or are asymptomatic.  Some early research is looking into how histamine affects the immune system and whether it may influence symptoms people are experiencing with long-covid. 

What is histamine?

Histamine regulates our immune response, and it is released when we encounter allergens, cytokines, stress hormones, alcohol and hormones.

You can have problems with too much histamine because

1. you can’t get rid of it an impaired ability to degrade it, or
2. from creating too much.

There are two ways histamine can be degraded, and I take a look at these below.

1. By the enzyme DAO (Diamine Oxidase)
2. Methylation by Histamine-N-Methytransferase (HNMT)

Factors affecting breakdown of histamine

The enzyme DAO is created in our gut, by the cells in our mucus lining. (It is also created in the kidneys and placenta of pregnant women) To create DAO, and promote the degrading of histamine, we need certain nutrients including:

• Copper – found in potatoes, sunflower seeds, tofu, salmon. Copper can be affected by taking too much zinc as this may affect absorption. Some medication can also affect copper absorption.
• B6 – needed for many important functions in the body, including creating dopamine, adrenaline and histamine, so can easily be used up by other needs.

Gut health – Because DAO is made in the gut it will also be affected by any inflammation in the intestines. Digestive symptoms are thought to be part of the Covid symptoms and are present in 11-50% of patients presenting at hospital in one study.

Alcohol – inhibits DAO so you may find symptoms of allergies worse after a boozy night.

Histamine and methylation

Methylation is an important biochemical process, which helps us detoxify, regulate gene expression and protein function, as well as create neurotransmitters and hormones.

To support healthy methylation we need vitamins B9, B12 and B6, as well as a host of other factors such as magnesium, and choline.

Women and histamine

Female hormones have a part to play in our histamine response. Oestrogen inhibits DAO, causing more histamine to be in your body when oestrogen is high. Progesterone acts as an anti-histamine by inducing DAO.

So when your oestrogen is higher than progesterone you may find allergic symptoms worse. This could be towards the end of the luteal cycle (end of your cycle), and / or at the start of the follicular phase (beginning of your cycle).

Some women experience more migraines at this time, or an increase in allergic itching, sneezing or congestion.

The histamine bucket

Histamine isn’t bad, we don’t need to get rid of it, but if we have too much we may get symptoms like allergies. You may find it helpful to think of a bucket, and when the bucket is full it overflows causing issues.

A low histamine diet

Not everyone needs to avoid foods that induce or contain histamine, but if you are sensitive you may find it useful to trial a low histamine diet to see how you feel. If you eat a lot of foods high in histamine and experience issues with ongoing inflammation you may benefit from a break from these foods. 

Histamine in food increases over time, and may exacerbate symptoms. These include

• aged cheeses,
• Yoghurt
• Beer
• wine
• smoked fish and meat, processed meats
• fermented foods like kefir or sauerkraut.
• Tinned foods and ready meals may also affect people with a sensitivity to histamine
• artificial colours such as tartrazine, and preservatives such as benzoates and sulphites.

Some foods may affect histamine (but don’t contain it). These include

• Kiwi
• Citrus fruits, oranges, lemons, limes
• Grapes
• Pineapple
• avocado
• Strawberries
• Tomatoes

Other things that might affect histamine are pollen, dust mites or chemicals that trigger histamine.

Supporting your histamine levels

We have more questions than answers at the moment for this virus, so it can be difficult to know how to support your body. Fatigue, brain fog, joint pain, skin conditions and headaches may be related in inflammation in the body. To best support recovery from infection we need to reduce other excessive demands on our body. 

Anyone recovering from an illness can support their immune system with plenty of rest, fresh foods, and healthy proteins.   

• Eat fresh foods, prepared on the day if possible
• Consume fruits rich in vitamin C
• Quercetin may be helpful for the immune system – red apples, grapes, onions, and berries
• Eat a varied diet rich in fibre, protein and vegetables
• Resolve your gut health problems 

Photo by Tim Toomey on Unsplash