This subject is very personal to me. As you may remember I wrote an article about hay fever a few months ago, specifically about treating the symptoms from a natural perspective. However, the question of why some of us experience these symptoms to a greater degree than others has been asked by scientists and hay fever sufferers alike for a long time. Since I wrote that article, more information has come to light which means finding the answer may actually be closer than we think.
Why is it that despite taking anti-histamine tablets and anti-allergy nutrients and herbs, some people are still plagued with streaming eyes, a blocked nose, itchy skin and fits of sneezes? Why do symptoms sometimes worsen after eating certain foods and why do these people also suffer from other symptoms like achy bones, asthma, tiredness, headaches and ‘brain fog’. The answer could be that they have a histamine intolerance.
So what exactly is histamine?
Histamine is a natural substance produced by the body. Most people are aware of its role in the immune system, where it causes an inflammatory response to what your body perceives as an allergen, resulting in hay fever symptoms. However for some people, histamine is either over produced or unable to be broken down properly and it is the histamine buildup that causes prolonged hay fever symptoms as well as other symptoms such as headaches, diarrhoea, asthma and red, itchy skin.
What causes high histamine?
Once histamine is produced in the body, it is either stored or broken down by enzymes. Histamine N-methyltransferase (HMT) is the enzyme which breaks down histamine inside cells, while diamine oxidase (DAO) is the main enzyme used to break down ingested histamine. It is believed that DAO is also responsible for breaking down histamine after it has been released from cells (eg. in the upper respiratory tract). Some people, however, lack one or both of these enzymes, resulting in systemic overload and a histamine intolerance.
DAO is the predominant enzyme that people tend to lack and it is due to a number of reasons including:
- Genetic mutations,
- Certain medications,
- Certain diseases (especially gut related) and
- DAO-blocking foods and beverages (see below).
How to tell if you have a histamine intolerance
First and foremost, if you think you may have a histamine intolerance, ask your GP to test your levels of histamine and DAO. Another option is to simply avoid consuming foods that contain histamine (yes, certain foods contain histamine!), and foods that stimulate the release of histamine from the immune cells. Make note if your symptoms improve or worsen by keeping and food diary.
Foods to avoid
The main culprits are foods which are aged and fermented. These include wine, beer, aged cheeses, vinegars, smoked meats/fish; as well as artificial additives including sulphites and nitrites.
High histamine foods – Avoid consuming:
- Alcohol, especially wine, beer and cider
- Fermented foods such as sauerkraut
- Aged cheeses such as parmesan and blue cheese
- Soy sauce
- Ready made-meals
- Dried fruit
- Products that contain wheat and yeast
- Smoked and processed meat
- Tinned and smoked fish
Foods that stimulate the release of histamine in immune cells – Avoid consuming:
- Tomato and tomato sauces
- Chocolate and cocoa
- Citrus fruit and strawberries
- Dairy yoghurt
- Additives in processed foods including benzoate, sulphites, nitrites,
- glutamate, and food dyes
- Peanuts and walnuts
Foods that block DAO – Avoid consuming:
- Energy drinks
- Black and green tea
There is no cure for histamine intolerance, however research has shown that supplementing with vitamins B6 and high dose vitamin C can help alleviate symptoms. (Always speak to a naturopath or nutritionist before supplementing). Anti-histamines may also help reduce symptoms, however as they only block histamine, and don’t break it down the way DAO does, they only offer temporary relief if any at all.
If you’re currently suffering from a histamine intolerance, it is best to strictly avoid consuming the foods containing it or that promote it. However, once your symptoms clear up you can introduce these foods back into your diet slowly, to find your threshold. Each individual will tolerate certain foods more than others so it’s important to take note of how you’re feeling after you eat these foods. Keep a food diary and learn about how food affects you!
For a more in depth look at Histamine intolerance, have a look at this study published in the American Journal of Clinical Nutrition.