Fitness & Healthy Lifestyle

Seasonal Allergies & Histamine Intolerance

The sun is out, Spring is in the air & at Natural Nourishment HQ we are feeling good! This time of year however, brings its difficulties for many as with the sunnier weather comes the looming prospect of hay fever season.

The number of adults & children suffering from pollen allergies is rising. For some it means a few sneezes & sniffles, & others it can be a hugely debilitating time. Hay fever & allergies is an area in which nutritional therapy can play a key role, as a preventative measure & to help dampen down already developed symptoms.

For many, antihistamines are a go to option for managing symptoms so let’s start with what histamine actually is, how it can affect health all year round & what we can do about it.

Histamine is a chemical that is produced by our mast cells & is released as part of our immune response. It also naturally occurs in everyday foods & some foods encourage our body to produce higher amounts.

Low levels of histamine in the body is not a problem, in fact it is vital for survival, but it’s when there is a build up that problems occur. For hay fever sufferers, the immune system overreacts to irritants in the air, causing rapid histamine release at a rate faster than their body can remove it, which leads to the typical hay fever symptoms of sneezing, wheezing & runny/itchy eyes & mouths.

Some individuals however can suffer all year round due to a lack of the enzyme diamine oxidase (which breaks down histamine) & this is termed histamine intolerance. In addition to an issue with pollen, those with histamine intolerance may also experience skin rashes/eczema/hives, issues with cold/heat exposure, headaches/migraines, neurological pain, fatigue, brain fog, nasal drip, asthma, digestive issues & food intolerances.

So these 2 situations are obviously very different, histamine intolerance is something that will need much more ongoing & intensive attention to prevent symptoms occurring.

However from a dietary & lifestyle perspective many of the measures used to support those with histamine intolerance will be of benefit for those who suffer with seasonal allergies.

The latter group would just need to start them 3-4 weeks in advance of their normal hay fever onset & continue through their peak allergenic period. They can then stop as the season passes & start again in advance of the next.

At this point we also want to touch on the use of antihistamines. These are there as a last resort to keep you comfortable, & in the case of acute histamine intolerance & mast cell activation syndrome (a different process but 1 that also ends up with excess circulating histamine too) it might be that antihistamines need to be used on occasion to prevent a decline in quality of life.

But all that antihistamines do is patch over your histamine receptors so your circulating levels can’t create a reaction; they have no impact on the levels themselves.

Certain key nutrients however increase histamine breakdown, & we can also lessen histamine influx through our diet which conversely allow your histamine levels to fall. Reworking the internal environment & decreasing symptoms more effectively.


Vitamin & mineral deficiencies – B6, Vitamin D & C & Magnesium are all important for making DAO & managing histamine levels.

Inflammation – high levels of inflammation in the body automatically mean your immune system is overreacting & your body is on high alert to potential allergens. This is one of the first things to address both through diet, lifestyle & supplements.

Hormone imbalances -increased oestrogen can down regulate DAO & progesterone can upregulate it. This explains why some women find they experience worse allergy symptoms at different points in their cycle, peri-menopausal women often suffer more or begin experiencing symptoms which they haven’t before, & Mums-to-be often find their allergies disappear or reduce during pregnancy.

Gut health – an imbalance of the gut microbiome is linked with hay fever, increased allergies & symptoms of histamine intolerance. Food intolerances, digestive complaints such as constipation & diarrhoea, bacterial & parasitic infections all need to be addressed before histamine issues are resolved. A simple stool test can be really useful here & means we can take a really targeted approach to the health of the gut. Often those with chronic allergies test for histamine intolerance instead of assessing gut health, their DAO is often perfectly fine but their microbiome is histaminergic (producing histamine) which is actually the driver for their issues.

Poor liver health & detoxification – if your liver & detoxification pathways are not working optimally then a build up of histamine is only going to have more noticeable effects. This links to both the nutrient deficiencies as these are the cofactors for all liver detox pathways so you could just be spreading your resources too thinly, &/or your gut health – not only could your microbiome be producing more histamine but if transit time is slow, & uptake of nutrients is compromised, then you’ll also be circulating more histamine + other waste back through the body which you then don’t have the resources to remove.

Infections – Viruses can often trigger an overactive immune response post infection, & we’ve seen a huge rise in sufferers of mast cell activation syndrome since COVID. Glandular fever, Herpes & H. pylori have all shown to increase the amount of histamine produced by the mast cells too.

Poor methylation – this is 1 form of liver detoxification that keeps the body ticking along as it should. Certain genetic mutations mean you might not be methylating effectively (this can be easily tested for) as do deficiencies in certain vitamins & minerals such as active B vitamins, magnesium, vitamin D & zinc.


A low histamine diet – ideally done for 30 days relatively strictly. After 30 days, we would gradually reintroduce foods to work out how much your body can handle.

Some foods contain high levels of histamine & some promote its release in the body, but below is a list to get you started.

TO AVOID/LIMIT: Tomatoes, peppers, aubergines, mushrooms, avocados, white potatoes, chillies, capiscum derived spices (paprika, cayenne, chilli powder), citrus fruits, spinach, strawberries, bananas, peanuts, coffee, alcohol, chocolate & chocolate products, dried fruit, aged & fermented foods (sauerkraut, kimchi, kombucha, canned food, kefir).

This may seem intense but we’ve got some top tips don’t worry!

  • Where you would usually season with lemon juice turn to a young unfermented vinegar instead.
  • If you’ll struggle without chopped tomatoes then roast carrots & beetroot until tender, then blend with stock to form a lovely replacement.
  • Opt for other berries or cherries over strawberries
  • Choose fresh rather than dried fruit for snacks
  • Try carob instead of cacao for a chocolate hit
  • Switch to swiss chard or parsley instead of spinach
  • Try true tree nuts (almonds, walnuts, hazelnuts etc) & seeds (pumpkin, sunflower, sesame) & their butters instead of peanuts.

TO ADD DAILY: parsley, coriander, raw red onion, broccoli, nettle & tulsi tea, fresh ginger & turmeric, Epsom salt baths.

  • Parsley is a natural antihistamine – try blending with walnuts, nutritional yeast & olive oil to make a lovely pesto, or with peas & butter beans as a dip, or into a smoothie if you have these.
  • Red onions contain high levels of quercetin – a potent mast cell stabiliser. Chop finely or blitz into a food processor then mix into oil for a seasoning, or toss with cucumber, celery, watermelon, & herbs as a salsa.
  • Fresh ginger & turmeric are incredibly useful to balance immune response, we love to add the to smoothies, boil in water to create a tea, or finely grate & mix into tahini or yoghurt to dress cooked vegetables/grains.
  • An organic nettle tea is a great one to be having, we would suggest 2-3 cups of strongly brewed tea per day. You can purchase the AquaSol powdered version, or opt for organic dried nettles to make a loose leaf option. Or a bagged product like that by Clipper.

We entirely understand this is a mental shift & histamine does work within a non-symptomatic range before it produces irritating symptoms. So as we suggest above, try being strict in the short term to get symptoms under control, then gradually increase your intake of the limited foods.

If you are supporting your histamine breakdown with the supplements below at the same time you will most probably find you can include a small amount of a variety of the pro-histamine group without issues.

The limiting factors will be if you have that DAO genetic inefficacy or not, your stress level (as this increases inflammation systemically), exercise intensity (as this encourages histamine release) & the state of your gut health.


Outside of a clinical setting we cannot give accurate dosages but we do list our top suggestions below that you may wish to explore. Any specific questions please do be in touch.

  • Omega-3 is a really effective anti-inflammatory (we love Bare Biology)
  • Quercetin is both a natural antihistamine & reduces inflammation.
  • To support the immune system we recommend Vitamin C, D & Zinc.
  • A methylated B vitamin complex, or a methyl donor complex will aid histamine breakdown.
  • DAO to support the breakdown of food derived histamine is incredibly useful. Take this alongside all meals.
  • If you have diagnosed histamine intolerance this would be suggested ongoing.
  • Probiotics are a funny one when it comes to histamine intolerance & something to be approached with a little caution. Some probiotics can actually aggravate symptoms, for example some Lactobacilli commonly used in the production of fermented dairy products can produce histamine. However there are targeted products that encourage histamine breakdown. Although regularly suggested as being the safest option for someone to self prescribe, in this instance we would actually suggest seeking expert advice before including a probiotic.

Written by Florence de Walden

Associate Nutritional Therapist