Ask the doctor: Chocolate and red wine give me a blocked nose and sore eyes. Could I be intolerant? - Independent.ie

Q: I gave up red wine a few years ago because I was having an allergic reaction. My nose would be blocked and runny and my eyes would be red and sore — like a hay fever reaction. I have found that recently the same thing is happening with chocolate. Could this be the case? Why does this happen and does it mean I have to give up chocolate too?

Dr Grant replies: Food intolerances are not the same as allergies and thankfully do not carry the same health risks. Put simply, food intolerance generally cause gastro- intestinal (GI) symptoms such as excessive intestinal gas, bloating, abdominal pain and diarrhoea, but other symptoms like skin rash/itch or headache may also occur. The amount of food ingested is directly related to the severity of symptoms, and ingestion of the food causes similar symptoms every time there is exposure.

The classic example, when a toddler is exposed to strawberries they may or may not have any symptoms. After further exposure the toddler may develop redness and skin rash/itch around the mouth with a larger amount of strawberries. The toddler likely has an intolerance to strawberries but can continue to be exposed. The proposed theory for this reaction is that strawberries and blueberries contain natural histamine-like (or histamine-releasing compounds) and can cause minor skin eruptions, itching and even urticaria. Examples of other foods that contain relatively high amounts of "biogenic amines" include chocolate, tomato, and banana. Sulphites used to preserve dried fruit, canned goods and wine can trigger reactions.

Adults become intolerant to lactose (the sugar found in milk), casein (the protein found in milk) and gluten (a protein found in grains such as wheat, rye, and barley). On the other hand, food allergies involve the immune system. With immunoglobulin E-mediated food allergies, even trace amounts of the food can cause severe reactions that can be unpredictable and have the potential to progress to life-threatening anaphylaxis.

The symptoms you describe are more upper respiratory symptoms such as nasal congestion, rhinorrhoea and the peri-orbital redness/tenderness which could be a histamine-like reaction. Generally, these symptoms do not occur in isolation with food intolerance, as there is usually an element of skin redness/itch and GI symptoms. Maybe the effect on the skin and GI tract are so mild that you don't even notice them?

As the ingredient list in any given chocolate can be exhaustive, it may be difficult to determine which one is causing your symptoms. It is the same brand and flavour of chocolate you react to? Have you tried buying different varieties and always react regardless? If you have a sensitivity to the cocoa itself, you should notice the same reaction in any chocolate yoghurt or croissant. It could possibly be the amount of chocolate you eat as you may be able to eat small amounts of chocolate without any problems.

Additives in chocolate such as soy lecithin, tyramine, phenylethylamine, theobromine, caffeine, flavourings, or emulsifiers may be what's triggering your symptoms. In large quantities, the particular chocolate you are eating may trigger a reaction in your GI tract or elsewhere in your body.

I suggest you try an elimination diet, quit all forms of chocolate from your diet for two to six weeks then reintroduce a high-quality vegan chocolate like Nobó with only five ingredients, and wait to see if symptoms return. You may find you can tolerate a certain amount of a particular brand of chocolate and you only get symptoms if you go above your threshold or go back to a certain brand.

Intolerance testing can be somewhat inconclusive, so it always advised to see your GP who can recommend if a dietician or further investigation is the next step.

Dr Jennifer Grant is a GP with Beacon HealthCheck