Updated: May 2019
Food sensitivity testing is appealing to patients and health practitioners because it gives specific answers, which provides a sense of control and hope to patients that are struggling with confusion and uncertainty.
Unfortunately, every test gives a different answer. Each company claims their test is the right one, and the others are wrong. I would love to have a valid test that would accurately pinpoint my clients’ food triggers. It would be wonderful to give clients definitive answers and make exact meal plans for them. As an evidence-based health professional, I cannot recommend food sensitivity testing to my clients just because it will make my job easier.
Why does testing often lead to symptom improvement?
There are several reasons why symptoms may improve following a diet based on a non-validated testing method.
- Treatment and placebo effect: Patients often feel better when starting new treatments, because there is a sense of hope.
- Restricting common food triggers: Most testing methods will pinpoint several foods, including common food triggers, such as gluten, milk, tomatoes, etc. If a person is sensitive to gluten, and they get a list of 25 foods to avoid (including gluten), their symptoms would improve because of the gluten restriction, not the other 24 foods.
- Natural fluctuations: Symptoms tend to get better and worse for unknown reasons. People usually seek treatment when their symptoms are bad, and they may have naturally improved without any treatment.
- Healthier Diet: Typically, people have poor diets – skipping meals, processed foods, etc. These habits often improve when they start a new diet plan. The healthier diet, not the restriction, may be the reason for symptom improvement.
Valid laboratory tests
Useful laboratory tests are developed over many years of careful research. The process starts with understanding the pathology of a disease and figuring out what compound could be measured to detect the disease. Research is needed to see if this theory works. In most cases, several universities conduct research and publish their findings in peer reviewed journals, allowing university researchers to learn from each other and develop a strong body of knowledge. Over time, a consensus is hopefully reached about the precise technique to conduct the test and interpret the results. In many cases, the research does not support the theory and the test is not used in clinical practice.
Companies convince patients and practitioners their tests are valid
With clever marketing, companies can make their unresearched tests sound valid. Unfortunately, there are no regulations. The terms “accredited lab” or “awarded patents” are business terms and have no relation to research. Companies will often list several research articles on their website, but the research does not have much to do with the actual test (see examples below). In other cases, the company will list the research that loosely supports their testing method, but completely ignore the research that does not. Finally, companies often report open or non-blinded studies. People usually feel better when they start a new treatment, regardless of the effectiveness of that treatment (placebo effect). Good research studies include a placebo group to counteract this. The treatment is successful if the subjects in the treatment group improve more than the subjects in the placebo group. Open or non-blinded studies only have one group – the treatment group. The results are not meaningful. When companies report this information, it is a “group testimonial,” not a real study.
Why don’t companies validate their tests?
Companies can make a lot of money without the effort of doing research, and a proper research study would probably not support their test. I’m often approached by companies to promote their food sensitivity testing to my clients and colleagues. When I ask companies to provide published research, they usually say that research is too expensive. A basic research study would be inexpensive. People with a certain condition or symptom(s) could be divided into two groups. One group would get their own food sensitivity testing results, and the other group’s results would be mixed up (a subject would get someone else’s results). If the first group, improves significantly more than the second group, there would be objective evidence that the testing method is helpful. I would be happy to promote a testing method if a company could provide any objective evidence that it works.
Different Testing Methods
I’ve listed some brief information about common tests below.