Hounded by Hay Fever?

Itchy nose and throat, watery eyes and the sniffles? It's likely to be seasonal rhinoconjunctivitis. Otherwise known as 'hay fever', it's triggered by various types of pollen - which can also aggravate symptoms of asthma and cause skin irritation, all linked via the immune IgE response.

Histamine is a natural part of the immune response, making blood vessels more permeable, in order to allow immune cells and fluid into an area of inflammation. When the body tries to expel what it perceives to be harmful substances like pollen, it does so via fluid. This is why you experience watery eyes, and a runny nose. However, too much histamine in the body can have negative effects and aggravate symptoms.

I've had asthma since childhood, but I've been more susceptible to hay fever symptoms over the last few years.

This could be due to levels of diamine oxidase (DAO) and HNMT, two enzymes which help breakdown and clear histamine from the body. Both naturally decline with age and certain prescription dugs can also interfere with levels (1). In addition, we may have genetic modifications which reduce the effect of these enzymes. This can lead to histamine building up in the body, as both breakdown and clearance of it is slower. You can supplement with DAO and HNMT but they won't have any effect unless you're shown, via genetic testing, whether you have a need for either.

Increased symptoms may also be due to climate change: with increased levels of carbon dioxide, scientists are predicting a rise in pollen by over 200% (2), due to higher plant yields and longer growth seasons.

The increased 'sensitivity load' can also be the result of food sensitivities and cross-reactions of certain foods. For example, those sensitive to birch pollen may find their symptoms increase when eating apples, hazelnuts, carrot and celery (3).

But don't reach for the anti-histamines just yet. Anti-histamines work by blocking the effect of histamine, but can make you sleepy, lose concentration, cause stomach upsets and leave a bitter taste in your mouth (4). So, how about trying to reduce your overall histamine load or your inflammatory response to pollen, in the first place?

There are some foods which are naturally high in histamine. Whilst the list isn't definitive for everyone, the main ones are aged cheeses, cured meats, fermented foods, fish which isn't fresh and leftovers. Histamine develops over time and bacteria can produce histamine - but you'll probably notice that this list includes foods which are considered as 'healthy'. So be mindful about which foods you might reduce during the allergy season, as you may also be cutting out other important nutrients contained within them.

Another approach is to increase micronutrients to help moderate inflammation, to reduce your symptoms. Whilst these are naturall