Food Intolerance: Just fussy eating?? Fad, friend or foe?

We are what we eat and it will affect how we feel. I recently attended a dinner party where each of the 12 guests had at least 1 dietary requirement. This is a relatively new normal, but food intolerance, to some degree, is thought to affect more than half of us.

There can be a lot of confusion surrounding this topic, with labels such as food hypersensitivity, food allergy and food intolerance often being freely interchanged. It is important to make the distinction between a food allergy and a food intolerance because the management can be quite different.

A true food allergy is relatively rare. It affects approximately 1% of the adult population and common allergies include nuts and shellfish. Here, the body sees the proteins found in the culprit food as a threat, and tries to attack it – this is called an immune response.

Symptoms of an allergic reaction usually start immediately (although sometimes a delay of a few hours can occur) and can include tingling in the back of the throat and lips, a rash and vomiting and/or diarrhoea. In more severe cases, it can lead to swelling of the face and breathing difficulties. This is called anaphylaxis and is a medical emergency. The treatment is adrenaline injected in to a muscle as soon as possible, and so once diagnosed, you may be asked to carry an EpiPen with you at all times. You need to avoid this food for the rest of your life.

This attack (or immune response) usually releases an immunoglobulin called IgE and this is what we check for when performing an allergy test. The 2 most common allergy tests are a skin prick test or a blood test known as a radioallergosorbent (RAST) test. Non IgE mediated allergies do exist, but these are more common in children. Speak to your doctor for more information.

An intolerance is different. Your body finds it difficult to break down and digest certain substances in foods but no allergic reaction place. Common intolerances include:

  • Dairy
  • Gluten
  • Wheat
  • Yeast 
  • Alcohol


Gluten free


It can take quite a long time to diagnose an intolerance or identify a trigger food, and there are many reasons behind this. Sometimes your body can tolerate a small amount of the food, but when eaten in larger quantities it can be troublesome. Often, you might just notice that you don’t feel quite right but you can’t quite explain why. You can feel tired and sluggish or notice problems with your skin. You may become constipated or have diarrhoea or a mixture of the two. Commonly, you can feel very bloated and you may find yourself passing more wind, which can be embarrassing.

It is not uncommon for your symptoms to change from day to day, or get worse over time. They can start to have a negative impact on day to day life and overall make you feel quite miserable!

the best place to think

If you are having any of these symptoms, book an appointment with your GP. They will take a full history, and ask questions such as: Have you had any change in your bowel habit? Have you noticed any blood in your stool? Have you had any weight loss? Your GP may also carry out basic investigations such as blood tests and possibly a stool sample to rule out things like coeliac disease, inflammatory bowel disease and even bowel cancer.

If you are given the ‘all clear’ for any specific cause by your doctor, it can take a while to accept there is no magic solution to the very real symptoms that you are having. They will probably advise you to make changes to your diet, and although it may feel like a bit of a cop out, this really is the management.

Your GP may mention the FODMAP diet to you, it stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. Foods containing these short chain carbohydrates are difficult to digest because they attract water and feed gas-generating bacteria inside the intestine, which leads to bloating, flatulence and loose stools. This reaction affects some people more than others. The list of foods to avoid on the FODMAP diet can appear endless, but when done properly, it can make you feel a lot better.

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Your doctor may make other suggestions about what to avoid in your exclusion diet and most often they will recommend a referral to a dietician or nutritionist for support and guidance. It is essential that we ensure you are still getting all the nutrients you need, despite making quite significant changes to your diet. The aim is to exclude a food for a period of time and then re-introduce it slowly and monitor for return of any symptoms.

Can’t I have blood test to check what I am intolerant to?

To be honest, there is no scientific date supporting the accuracy of this test. The most common commercially available tests look at the level of Immunoglobulin G in response to hundreds of different foods and report whether you have a reaction to them. I would advise caution when thinking about getting one, and don’t get one done without consulting a doctor.

That being said, I sympathise fully with sufferers, and being one myself, as a desperate last resort, I paid to have one done. I found my results very interesting (and a little depressing – I couldn’t eat anything I loved!!) Here are my results:


R = Reactive and I should eliminate B = Borderline reaction (may or may not be helpful to eliminate)

There are also lots of other commercially available tests claiming to diagnose food intolerances. Novak Djokovic has famously used kinesiology which uses muscle testing to detect imbalances in the body and he has since cut out gluten amongst other things from his diet. Please speak to your doctor before paying lots of money to get any of these tests done, as the scientific evidence backing these methods is limited.

Food intolerance is real, and it can have a significant effect on people’s lives. If you are having symptoms then the first port of call should be your doctor to rule out any serious illness. Food intolerance tests are expensive, and not entirely backed by science, but some do find the results helpful as a guide. Usually, I find this is because it gives them focus and motivation to control their diet, which really is the key. Make use of a dietician or nutritionist to ensure you stay healthy.

Good luck with anything you are advised to try – its not easy but it will be worth it!


Sunshine Pills… Yes Please! Why Is Vitamin D So Important?

This week I had my Vitamin D tested. My level was 24nmol/L, which is very low and I am now classed as being Vitamin D deficient. I join approximately half of the UK population, who are also thought to be lacking in this important vitamin. It is essential for good health and healthy, strong bones.

When sunlight hits our skin, Vitamin D is made in the outer layer of our skin called the epidermis. In order for our body to be able to use it, it has to be changed in to an active form by our liver and then our kidneys. The active form of vitamin D is called calcitrol and it has one main role – to help us absorb the right amount of calcium. If we have low levels of Vitamin D, our gut has to work harder to absorb the calcium we need for our bones and this can lead to problems.

Sunlight is the main source of vitamin D. Dietary sources are limited, but small amounts can be found in eggs and oily fish such as salmon, sardines and mackerel. Fortified cereals and margarines also offer part of your recommended daily dose. In some countries, milk is fortified with Vitamin D, but this is not the case in the UK.

Hand with pen drawing the chemical formula of vitamin d

Sunshine is important for Vitamin D, but don’t forget that you need to enjoy your time in the sun safely. Try and avoid the sun during the hottest part of the day (between 11am – 3pm) or maximise your time to 20-30 minutes once or twice a week. Take care to wear a hat and sunglasses, and always use sun protection with a minimum SPF 15 and 4 stars.

In most of Western Europe, especially in the Winter months, the amount of sunshine we get falls far below the levels needed for the body to produce adequate amounts of Vitamin D. This means you are at risk if:

  1. You have darker coloured skin because the body finds it more difficult to make Vitamin D
  2. Your job means you are inside all the time
  3. You are under 5 or over 65 years old
  4. Culturally you have to cover up
  5. You are overweight
  6. You have other health problems, e.g. with your gut, liver or kidney which might affect your body’s ability to make or use the Vitamin D
  7. You are pregnant or breast feeding

With that list – it is not entirely surprising that most of us are low in vitamin D!

In adults, a prolonged low vitamin D level can lead to osteomalacia or ‘soft bones.’ You may feel tired, and develop bone pain especially in the lower back and hips. You might also notice muscle aches and pains or muscle weakness, especially when climbing the stairs or getting up from sitting on the floor. Your joints can also become painful. In extreme cases, it can lead to a change in the shape of your spine and fractures of your bones.

In children, a low Vitamin D can cause rickets, thankfully this is rare. Rickets is a painful condition that affects how bones grow and can cause ‘bow legs’ or ‘knock knees’ to develop. These children are at increased risk of fractures and tend to have poor growth and development.


All children aged between 6 months and 5 years should take a daily supplement of Vitamin D unless they are having more than 500mls of formula milk per day (which is fortified with vitamin D). Pregnant and breast feeding women are also at high risk of deficiency and must take daily supplements. Speak to your doctor or midwife if you have any questions.

Speak To Your Doctor

If you have noticed you are having any of the symptoms of vitamin D deficiency, or you feel you are one of the people at risk, speak to your doctor. They will ask about the symptoms you are having and they may examine you. It is likely they will carry out a blood test checking your Vitamin D level, along with your bone profile and they may also request other tests depending on what you have told them.

Once the results are back, they will discuss them with you. They will review your medical history and any other medications you are on, because in certain circumstances it isn’t safe to take higher doses. Rarely, there can be other reasons why you might have a low Vitamin D level or a low calcium level and if your doctor suspects this they may carry out further investigations.

As a guide a Vitamin D blood level of <30nmol/L is classed as deficient, a level of 30-50nmol/L is insufficient and 50-70nmol/L is considered adequate but ideally levels should be above 70nmol/L.

The most common treatment for a low Vitamin D level is high dose Vitamin D3 tablets – the dose can vary depending on your levels, but I tend to prescribe 50,000 IU once a week for 6 weeks. After ‘topping up’, it is important that you continue taking a maintenance of between 800 IU and 1000 IU otherwise your levels may fall again and any symptoms you had may return.

It is very rare that you can take too much vitamin D, so as long as you are taking your prescribed amounts I wouldn’t worry about overloading yourself.

Other Health Benefits?

There has been a lot in the media suggesting that Vitamin D can help to protect against developing breast and bowel cancer, or high blood pressure and heart disease. It has also been linked to being beneficial in diabetes, multiple sclerosis, dementia and depression. These have all been relatively small studies and no conclusive evidence has been found. It is likely that Vitamin D is protective to a certain degree, but there are many other factors that contribute. It is a small piece of a much larger puzzle.

Vitamin D is extremely important to our general health. Winter is almost upon us, and so my advice would be to speak to your doctor as soon as possible about getting your levels tested. You can then discuss with them the right dose of Vitamin D for you.