Do you think something you are eating is making you feel unwell? Sometimes it’s hard to find the answer to this question, because the area of food allergy, intolerance and sensitivity is complex. To be honest, when I study the immune system (which is at the heart of food reactions) I feel as though I’m diving straight into a labyrinth, as covered to some extent in previous articles.
So what happens when the food you eat doesn’t agree with you? What is food sensitivity exactly? And what’s the difference between a food intolerance and sensitivity?
Firstly, a food sensitivity – or intolerance – is very different from a food allergy.
What is a food allergy?
A food allergy results in an immediate immune reaction whereby SAS style immune cells or antibodies (code name: IgE) sweep in and ‘take down’ an invader at lightning speed. The invader in the case of a food allergy is unfortunately an innocent food molecule that’s mistaken for something highly dangerous or toxic. The symptomatic result of an IgE immune response happens quickly; within minutes or hours.
Allergies can be life threatening, making them really alarming for a sufferer and their loved ones. The most extreme IgE reaction is anaphylaxis.
You can have IgE reactions that are not as extreme as anaphylaxis, but still nasty. Symptoms might include vomiting, tingling in the mouth, a rash or hives appearing. Nevertheless, any suspected allergy needs to be followed up with testing, and foods to which you are determined to be allergic must be avoided. Why? Because IgE commandos rarely forget their enemies (no matter how mistaken they are).
What is a food intolerance?
This question is not so straight forward to answer, and it’s not without its controversies. The terms food intolerance and food sensitivity tend to be interchanged, but to me there are stark differences between the two.
A food intolerance relates to an enzyme deficiency.
You need lots of enzymes to help you break down the food you eat into particles microsopic enough to transfer through the barrier wall of your intestines and into your blood supply. You produce different enzymes to break down different substances.
For example, the digestive enzyme lactase helps you break down lactose, the sugar found in dairy products. Likewise, the enzyme diamine oxidase (referred to as DAO) helps you break down histamine in foods (not to mention the histamine that’s naturally produced elsewhere in your body).
In some susceptible people, these enzymes are not produced in large enough quantities for their target to be broken down adequately. Their army has not been supplied with enough kit to get the job done. This can result in symptoms very similar to food sensitivity.
There can be a number of reasons for an enzyme deficiency situation. For some it’s a genetic issue. For others the delicate cells of their gut may be held hostage by rebel forces. In the case of small intestine bacterial overgrowth (often referred to as SIBO), for example, there is evidence to suggest its ability to undermine the production of digestive enzymes. In addition, the gasses produced by certain bacteria of the gut can also give you symptoms. Sometimes an intolerance occurs after a bout of gastrointestinal illness, as often seen in children.
What is a food sensitivity?
A food sensitivity is an immune mediated reaction to a specific food or foods.
However, the immune system mechanism in the case of food sensitivity is different to that of an allergy.
In the case of food sensitivity, the immune response is far slower, and the type of immune cell is different. Rather than flying onto the scene in a blaze of glory like the IgE allergy antibodies do, these soldiers (code name: IgG) perform a stealth operation. The results of their work are not always noticed for a day or two.
Common symptoms of food sensitivity include headache, brain fog, fatigue, low mood, stomach pain, constipation, diarrhoea, bloating and weight gain. These symptoms are not life threatening but are insidious in their nature, having the ability to really impact on your life. And because the impact of a food sensitivity reaction doesn’t happen immediately it can make it hard to pinpoint the culprit food. Remember that a key feature of your immune system function is inflammation. If you have too many IgG immune cells being deployed there is likely to be a knock-on effect in your body, and this can be wide-spread rather than localised. Your IgG forces are the most abundant of all the antibodies in your immune system. The bottom line is that elevated levels of IgG antibodies may be linked to chronic inflammation, and increasingly to autoimmunity too.
However, understanding just why – or even if – IgG antibodies are a problem in chronic (i.e. persisting for a long time or constantly reoccurring) ill health has been hard to untangle, but scientists who study immunology are slowly unpicking the detail and understanding more as each year passes.
Food sensitivities are controversial
While it is now more widely accepted that elevated levels of IgG antibodies to specific foods are linked to a range of health conditions (including IBS, migraine headache and weight gain), some confounding factors have made this area of research really difficult. This is because many people without any health concerns also show as having high IgG antibodies to specific foods when tested. Why are they not feeling unwell?
The answer could lie in the fact that IgG troops are split into different operational task forces. In fact, there are (to date) four different task forces that have been identified. These individual groups all play specific roles in the war against invasion. And they don’t all necessarily go out and start fighting right off the bat. Some of them play a more diplomatic role, and actually help to negotiate tolerance between different sides. We do therefore need a degree of IgG antibody activation to be able to tolerate the food we eat. As such, every single one of us produces IgG antibodies to food. And the increasing in numbers of some of these task forces vs levels of the more aggressive IgE antibodies is understood to be why some children grow out of a juvenile allergy.
The latest research in this fascinating area of immunology points more towards the different groups of IgG antibodies – and the chain reactions from the work of some of these groups – rather than the total number of IgG cells in itself. For example, some IgG groups are able to carry firearms that others don’t possess. A protein called complement is one such form of weaponry. It is complement that is now understood to be a more likely driver for some symptoms, not the IgG antibody in itself, and this is because complement plays a key role in the activation of inflammation.
How do I find out if I have a food sensitivity?
There are tests that measure the blood for IgG markers to specific foods. These tests are not without controversy, and at the moment there is no standardization for IgG food sensitivity testing. Having said that, IgG mediated immune response and it’s impact on health is gaining academic awareness. However, given the emerging information in this area, it seems logical to measure complement proteins in addition to IgG antibodies in order to gain clearer understanding of the big picture. This is the test I am more frequently suggesting in clinic these days – when it’s justified.
Do remember that we all produce IgG antibodies, so testing just because you are curious isn’t a sensible strategy. You don’t want to end up restricting your diet – and vital nutrition – when there was no reason to do so in the first place.
But the story doesn’t end there!
While food sensitivity might be mediating a state of ill health (i.e. preventing you from getting fully better), it’s unlikely to be the root cause of a problem. We need to ask why the food sensitivity occurred in the first place, and if anything can be done about that to really get health back on track and importantly, to stop more sensitivities occurring. I’ll talk more about this in my next post – Could food sensitivitiy be undermining your health? Part 2 (coming soon!)
To finish on a positive note, an IgG soldier is far more forgiving than a hardcore IgE commado. It is certainly willing to forget about the food particle its taken issue with, given enough time apart from it. So, food sensitivity need not be a life sentence in the same way an allergy is, which is very welcome news. As always, it comes back to tackling the root cause of the problem.
What can I do next?
If you suspect food sensitivity is impacting your health do get in touch and we can explore this together. My job is to help identify what could be at the heart of your health condition, then coach you back to optimal health and happiness with lots of lovely, tasty food and some easy to follow lifestyle changes. You can find out a little about my approach to working with clients by reading the interview I gave last year to Amelia Freer. Here is a link to the interview.