Food intolerances can present themselves through many different symptoms, some more common than others.
Signs and symptoms of a food intolerance
From my experience of living with a dairy intolerance, symptoms included extreme bloating (‘how long til you give birth?’ worthy), stomach cramps, low energy and psoriasis (a skin condition) however other common signs of a food intolerance include:
- Excess gas or flatulence
- Low mood
- Feelings of nausea
- Other symptoms also associated with Irritable Bowel Syndrome (IBS) such as a change in bowel habits and a feeling of not being able to empty your bowels.
Depending on the type of food intolerance someone suffers with, some of these symptoms may be more likely than others. It’s important to remember that there is a significant amount of crossover between symptoms associated with a food intolerance and those of an allergy. One big difference is that an allergy tends to present itself within a couple of hours, whereas signs of a food intolerance can take up to three days to make an appearance. For more information on the difference between a food intolerance and a food allergy, take a look at this post.
When you visit the doctors with the common symptoms of a food intolerance, many will put it down to the catch all term IBS – or Irritable Bowel Syndrome (something I’ve been fobbed off with many times). This isn’t good enough but I understand why it’s done – doctors aren’t trained nutritionists and the symptoms do correlate. If you truly believe your discomfort cannot be IBS, I suggest you avoid the doctors and turn to a specialist instead. This will hopefully save you a lot of time but unfortunately it may cost (unless you get a referral in which case I’ve been told you have to wait a long time).
Common food intolerances
Below are examples of some more common food intolerances. Scroll down to learn more about the specific food intolerance including the signs you should look out for which might indicate you have an intolerance:
- Gluten and wheat intolerance
- Dairy intolerance
- Lactose intolerance
- Egg intolerance
- Oat intolerance
Less common food intolerances
Some less common (or less well known about) food intolerances include:
- Meat intolerance
- Citrus intolerance
- Tomato intolerance
- Nightshade intolerance
Symptoms of a gluten intolerance, wheat intolerance or coeliac disease
I’d say gluten has got to be one of the most common food intolerances (certainly that people recognise). One of the reasons for this might be because of the sheer amount of products gluten is in – from the more obvious such as bread, to the less obvious such as soy sauce, ketchup and mayonnaise. Gluten is also present in wheat so a gluten and wheat intolerance tend to go hand in hand.
Gluten is actually a mixture of two proteins and it’s the body’s inability to digest these proteins that results in an intolerance.
The symptoms of a gluten intolerance (or non-coeliac gluten sensitivity) can be wide-ranging so it’s no surprise that it often takes people many years to formally recognise their discomfort as an intolerance.
Along with the usual IBS-related symptoms (stomach cramps, change in bowel habits, nausea etc.), there are some other more unusual signs which can indicate a sensitivity to gluten:
- ‘Brain fog’: ever felt like you’re on another planet? The inability to think clearly could signal a intolerance to gluten. The difficulty here is knowing what’s normal and what isn’t normal as how many times have you felt like this when you’re tired, hungover or stressed? However, if you attribute the feeling of ‘brain fog’ to consumption of gluten, it might just be worth investigating further.
- Depression and anxiety: the link between junk food and mental health is becoming more widely acknowledged but as far as I’m aware, when diagnosing depression or anxiety, doctors very rarely look to attribute this to a food intolerance. However, research shows that these underlying causes of mental health disorders should not be overlooked with there being a significant link between gluten intolerance (and coeliac disease) and depression and / or anxiety. With the prevalence of mental health disorders on the increase, surely it’s time we stopped reaching straight for the prescription and started to take a more holistic approach?
- Skin problems: eczema, psoriasis and acne could all be side effects of having a gluten intolerance.
- Fatigue: I don’t think anyone could honestly say they spring out of bed every morning without ever thinking they’d rather just stay snuggled up all day. But if you consistently feel exhausted regardless of how many hours of sleep you’ve had, it could indicate gluten or wheat sensitivity.
Symptoms of a dairy intolerance (protein) and lactose intolerance
People often confuse an intolerance of dairy with an intolerance to lactose. Dairy intolerance (what I have) is an intolerance to the proteins in dairy products which means that you should avoid all dairy. Lactose intolerance on the other hand is an intolerance to the sugar in dairy because we’re not able to digest them. I won’t go into this in detail here but if you want to read more about it, take a look at this post.
The signs and symptoms of both kinds of dairy intolerances are very similar. My personal experience has been extreme bloating and stomach discomfort but you may also suffer with some of the following chronic symptoms:
- Low mood
- Skin rashes
If you believe you have an intolerance to dairy, the doctor should also rule out Crohn’s Disease as the symptoms are very similar. Crohn’s Disease is an inflammatory bowel disease and should be treated to avoid causing serious illness. The main difference between the symptoms of Crohn’s Disease and those of a dairy or lactose intolerance is that someone with Crohn’s may also find blood or mucus in faeces. You may also suffer a lack of appetite, anemia and unexplained weight loss.
Symptoms of an egg intolerance
Because the protein in eggs is very similar regardless of what bird it is from – a chicken, goose, duck…you get the jist – if you’re intolerant to one, you’re probably intolerant to them all unfortunately.
Again, the symptoms of an egg intolerance are very similar to those associated with IBS; nausea, vomiting, diarrhoea and stomach pain. However, people do also report having difficulty breathing and skin reactions.
Symptoms of an oat intolerance
An oat intolerance may sometimes be confused with a gluten intolerance for a couple of reasons. The first is that the protein found in oats is actually quite similar to that found in gluten. The second is that oats are often manufactured using the same factory as that used for products containing gluten.
Stomach complaints including bloating, cramping, excessive gas and vomiting are common signs of an oat intolerance, as well as headaches and difficulty breathing.
Symptoms of a meat intolerance
I can’t say I know of anyone who suffers from a meat intolerance (at least no one who would want to admit it to themselves). People can have an intolerance to any kind of meat including beef and chicken. It works in exactly the same way as the intolerances already discussed; the body recognises the proteins in meat as harmful and thus triggers an immune system response resulting in uncomfortable symptoms such as bloating, vomiting, gas and nausea.
Symptoms of a citrus intolerance
Whereas a lot of the intolerances already discussed involve the body’s reaction to proteins in specific food, a citrus intolerance is actually a reaction to the acids in fruits such as lemons, limes, oranges, plums and pineapple.
From my research, a reaction to citrus is more often related to an allergy which can trigger more severe symptoms such as:
- Tingling and itching of the skin
- Swelling of the lips, tongue, face and throat
- Stomach pain
A true allergy to citrus can trigger an Anaphylactic Shock which, if not treated, can be life-threatening.
Symptoms of a tomato intolerance
Tomatoes are part of the Nightshade family of plants which also includes potatoes, peppers and aubergines.
Skin rashes and eczema is a common side effect of having an intolerance to tomatoes or the other Nightshade vegetables. As well as this, other symptoms include stomach bloating, pain, diarrhoea, fatigue and tingling lips.
Again, if these symptoms occur very quickly, you may suffer with a tomato allergy rather than intolerance in which case you should completely cut tomatoes out of your diet.