Do I need a food intolerance test?
Most people do not need one. The NHS says that many of the home tests sold for food intolerance have no good evidence behind them, and a result can leave you cutting out foods you did not need to. A better first step is usually to keep a food and symptom diary and talk it through with your GP or a qualified nutrition practitioner, who can help you spot patterns safely.
What the tests can and cannot tell you
Food intolerance means your body struggles with a food, often causing bloating, wind, loose stools or stomach pain a few hours after eating. It is different from an allergy, which involves the immune system and can cause fast, serious reactions. Many tests sold online or in shops, such as hair analysis or some blood tests, are not recommended by the NHS because they do not reliably show which foods are causing you trouble. A positive result can simply show that you have eaten a food, not that it is a problem.
What tends to work better
- A diary. Write down what you eat and drink, and how you feel, for two to four weeks.
- A look for patterns. Do symptoms follow certain foods, big meals, stress or skipped meals?
- A planned, short trial. If a food looks likely, you may try leaving it out for a set time and then bringing it back, ideally with guidance.
- A review. You check whether anything really changed, so you do not stay on a narrow diet for no reason.
Or see someone: find nutritionists near you
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Or by what you would like help with: IBS and gut health
What a nutrition practitioner can do
A nutrition practitioner will go through your diary, your usual meals and your health history, and help you plan a sensible way to test foods without missing out on important nutrients. Many people find that having someone to guide them makes it much less confusing. Note that dietitian is a protected title in the UK, and dietitians must be registered with the HCPC. Other nutrition titles, such as nutritionist, are not protected in the same way, so ask about training and which professional body a person belongs to. The CNHC register covers nutritional therapy among the therapies it lists.
How many sessions might you need?
It varies. Many people book a first longer appointment, then one or two shorter follow-ups a few weeks apart while they try changes and see how they feel. It is fair to ask at the start how many sessions the practitioner expects and what you will be asked to do between them.
Roughly what does it cost?
A first appointment with a private nutrition practitioner in the UK commonly costs from £80, and often more in big cities. Follow-ups are often a little lower. Home test kits are commonly sold from £30, but because their value is doubtful, you may do better putting that money towards a proper consultation. Check what is included and the cancellation terms before you book.
When to see your GP first
Please see your GP before cutting out foods or paying for tests if you have unexplained weight loss, blood in your stool, ongoing diarrhoea or vomiting, constant stomach pain, difficulty swallowing, or symptoms that wake you at night. Also see them if you think you may have coeliac disease, and keep eating gluten until you have been tested, as stopping it first can affect the result. If you get swelling of the lips, face or throat, wheezing or trouble breathing after eating, call 999. If it has happened before, see your GP, who can refer you for allergy testing. A good practitioner will tell you if another route is better first, and nothing here is a reason to change any medical treatment.
More questions
Are food intolerance tests ever worth it?
The NHS does not recommend most of the commercial tests sold for intolerance. Tests for coeliac disease and for allergies are different, and your GP can arrange those where they are needed.
What is the difference between an allergy and an intolerance?
An allergy involves the immune system and can cause fast reactions such as swelling or breathing difficulty. An intolerance usually causes digestive symptoms that are uncomfortable but not dangerous, and often come on later.
Should I cut out gluten or dairy to see what happens?
It is better to speak to your GP first, especially about gluten, because stopping it can affect a coeliac test. For other foods, a planned and time-limited trial with guidance is usually safer than cutting out lots at once.
Can a nutritionist diagnose an intolerance?
A nutrition practitioner can help you spot patterns and plan a careful food trial, but diagnosing a medical condition is for your GP or another health professional.
Can stress make my stomach symptoms worse?
Many people find that stress and irregular eating can make bloating and an unsettled gut worse. Slowing down at meals and finding ways to relax can help you feel more comfortable alongside any food changes.