Allergies and Intolerances

allergy

I get so many questions regarding allergies and intolerances, so I decided it was time to write a post about it!

People are often not sure on how to go about getting a proper diagnosis, and there is a lot of self-diagnosing going on. As a dietitian, I recommend as varied a diet as possible, so will always recommend that people seek advice from a qualified professional who uses recognised diagnosis methods to avoid them cutting out foods unnecessarily.

Reactions to foods are common, but most are caused by an intolerance rather than an allergy. Let’s start at the beginning and understand the difference between an allergy and an intolerance.

The difference

A true allergy is defined as “a response of the body’s immune system to a normally harmless substance”. The key word here is IMMUNE system. When someone has a true allergic reaction, this triggers an immune response, or, in other words, the body releases histamine. The release of this histamine will in turn cause a series of reactions which present themselves as symptoms. The presence and nature of these symptoms plays a key part in determining the diagnosis.

An intolerance does not involve the immune system, and therefore does not trigger the release of histamine. An intolerance can be triggered by various things, such as missing crucial enzymes needed to digest foods (as in lactose intolerance), IBS (see my post on irritable bowel syndrome here) or increased sensitivity to naturally occurring substances or food additives.

Symptoms

People who have an intolerance can often consume a small amount of the food and not experience any symptoms, whereas those with allergies can have severe reactions even to small amounts. Allergic reactions can also get progressively worse the more times the person consumes that food.

Allergic reactions are caused by the release of histamine, and generally happen quite soon after the offending food has been consumed. Typical allergic symptoms include; a bumpy, red rash formed around or inside the mouth, tingling or itching around the mouth and throat or swelling of the lips, tongue or throat. In severe cases, people can go into anaphylaxis, which can be life threatening.

Symptoms associated with an intolerance are likely to be less serious than allergic symptoms, take longer to appear* and are often linked to digestive problems. However, this does not mean that they are unimportant. Intolerance symptoms can be debilitating and very uncomfortable for the individual. Typical symptoms include; bloating, abdominal pain and diarrhoea.

*To complicate things a little bit further, there are different types of allergies, IgE and IgG. IgE allergic reactions tend to cause immediate onset of symptoms. However, IgG symptoms can take much longer to develop, sometimes several days. People with allergies often experience a mixture of both types of symptoms. This is why it’s important to get the opinion of a qualified professional so that they can help you determine the nature of your allergy.

Diagnosis

If you think that you, or your child, may have a food allergy or intolerance, the first thing to do is to make an appointment with your GP. When you speak to your GP, they will ask you several questions to help determine the type of reaction you are having. Questions may include what type of symptoms, how long they took to appear, how long they lasted and also whether there is a family history of allergies. Sometimes it helps to begin keeping a food and symptom diary when you suspect an allergy to help you answer these questions!

If your doctor suspects an allergy, there are then a couple of options depending on the symptoms. The best, most accurate diagnosis is likely to come from a combination of your clinical history and the following tests:

Skin-prick test. This is where small amounts of the suspected allergens (foods likely to cause a reaction) are placed into the skin on the forearm. If the skin-prick becomes red, itchy or swollen, this indicates a positive reaction. This test is painless but should be carried out an an allergy centre or doctors clinic, due to it carrying a slight risk of anaphylaxis if your reaction is severe.

Blood test. This involves testing a sample of your blood for presence of certain anti-bodies.

Food elimination. As the name suggests, this is when you cut out the food that you suspect is causing the reaction from your diet. After a period of about 2-6 weeks, the food should then be reintroduced. If the symptoms disappear during the time when you’re not eating the food, and reappear on its reintroduction, then this can be used as a diagnosis. Before starting such a diet, you should seek advice from a dietitian to ensure that you are not losing out on nutrients by eliminating the offending food(s).

Non-evidence based testing. There are some shops that sell kits for allergy testing or outlets that offer testing hair/blood samples for presence of allergens. The principles on which these tests claim to be based are unproven, and research into their effectiveness has found them unreliable.

Unfortunately, tests used for diagnosing food intolerance (with the exception of lactose intolerance) are not always reliable. Some practitioners use IgG blood tests as a result for intolerances, however the evidence is patchy and most allergy specialists consider IgG results unhelpful in isolation.

It is also important to note that none of the allergy tests above are 100% conclusive all of the time. Usually, these tests are used in combination with your clinical history and symptom description. Your GP or doctor will probably have his suspicions upon talking to you, and then the tests will sometimes be used to confirm the diagnosis.

Again, because of the significance of clinical history in diagnosing allergies/intolerances, you can appreciate how important it is to involve a qualified professional.

More information

Allergy UK
NHS Choices
Patient.co.uk
MayoClinic

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How to be a healthy veggie

I’m not vegetarian, but I do enjoy vegetarian food. Every Monday, I experiment with a recipe that typically contains meat and try to make it with lentils, beans or another legume. I support ‘Meat Free Mondays’ for a couple of reasons; I like the taste of legumes and pulses, they’re lower in saturated fats than red meat PLUS I like the challenge of trying to make something where my boyfriend doesn’t notice the meat is ‘missing’!

If you’re thinking about becoming vegetarian or vegan though, it’s more complicated than just cutting meat and animal products from your diet.

First things first, a lot will depend to what degree you cut out meat. Is it just red meat (demi-vegetarian)? No red meat or poultry but you’ll eat fish (piscatarian)? No animals but still eat eggs and dairy (lacto-ovo-vegetarian)? Or no animals or animal products at all (vegan)?
All of these animal products contain nutrients that your body needs, so naturally, if you’re cutting them out then you need to find an alternative source.

Proteins are made up of tiny pieces called amino acids. Amino acids are required by the body to make hormones, enzymes and replace muscle tissue. Some amino acids are essential; the body cannot make them, so they need to be ingested through our diet. Most meats and animal products are called complete proteins, which means that they provide all of the 9 essential amino acids. If still consuming dairy products and eggs, these are valuable sources of protein too – with eggs being a complete protein.
Quinoa and soya beans are also technically complete proteins, although they do not contain as higher levels of these amino acids as animal products do. Therefore, it’s best to mix things up a bit! Quinoa, despite it being a complete protein, is not a rich source, so it should not be the only protein containing food vegetarians eat. Your diet should also contain rich sources, ie; eggs, chic peas, beans and lentils. However, most vegan sources of protein are not complete, meaning that in order to obtain all of the essential amino acids, a couple of protein sources need to be mixed. Legumes (lentils, chic peas, beans etc) are typically low in the essential amino acid called methionine. Grains (rice, cous-cous, brown bread etc), while containing methionine, are insufficient in lysine. By combining legume + grain, vegetarians or vegans can obtain a complete protein. For example; beans on toast, rice and black bean curry, lentil soup and bread or pita bread and hummus. Meat eaters and vegetarians should aim to have 2-3 servings of complete proteins per day.

IronAnother nutrient to be aware of is iron. Women have a higher requirement of iron than men (due to menstruation) and intakes are typically below what is recommended, especially in adolescent girls. Iron found in meat is called haem-iron, and is more readily absorbed than non-haem iron. For this reason, female vegetarians especially, need to ensure that they’re having a couple of sources of non-haem iron daily. Iron can be found in beans and pulses, eggs, fortified breakfast cereals, dark green leafy vegetables (like spinach, broccoli and swiss chard), wholemeal flour, dried apricots and seeds. As I said, these non-haem sources of iron aren’t so easily absorbed by the body, however, there are a few tips than can help enhance absorption. Vitamin C (found in citrus fruits, peppers and sweet potato) helps improve the amount of iron we can obtain from food. So having a glass of orange juice with cereal or some sweet potato in your lentil soup will help up your iron intake. Also, avoid having tea and coffee alongside a meal as they contain tannins and phytates that bind with iron and make it more difficult for the body to absorb.

If vegan, good sources of calcium will be required to replace calcium obtained from dairy (see my nutrient nugget for more info on calcium). Calcium is found in green leafy veg like; kale, broccoli, rocket and watercress, beans, pulses, fish where you eat the bones (tinned mackerel/sardines), almonds, brazil nuts, sesame seeds and dried apricots. Some soya milks and tofu are also fortified with calcium. Vitamin D (obtained from sunlight) enhances calcium absorption, so those at risk of poor vitamin D status should eat a variety of the above foods daily and certain populations may need to consider a vitamin D supplement.

Vitamin B12 is found in animals and animal products. The requirement for this nutrient is small so deficiency is rare but strict vegans should consume a fortified food. For example; yeast extract (marmite), fortified soya products, breakfast cereals and vegetable stocks. Finally, as milk is an important source of iodine, vegans are at risk of low intakes. If this is the case it’s recommended to use iodized salt or take a nutritional supplement.

In order to get all the vitamins and minerals we need, a large variety of fruits and vegetables should be eaten. Think about eating as many different colours as possible! This, alongside beans, lentils, grains and nuts will help ensure your vegetarian or vegan diet is adequate in all nutrients.

IBS – ‘facts and triggers’

First things first, this post is about IBS (irritable bowel syndrome), very different to IBD (inflammatory bowel disease). IBD involves chronic inflammation of sections of the intestines and can require hospitalisation during bad flareups. IBS has no known structural cause and, although it can be inhibiting, symptoms can be improved through making sensible lifestyle and dietary changes.

IBS is quite a common disorder; it is estimated that it could affect up to 25% of the UK population. IBS is thought to be caused through a mixture of psychological and physical factors including; infection, altered gut motility, ‘sensitivity’ to certain foods (I’ll explain this later) and stress.  Many patients who suffer from IBS report symptoms being worse during times of stress, and also recall initial onset to have occurred around the time of a stressful event.

There’s no diagnostic test for IBS, so the first step in diagnosis is excluding presence of more serious conditions, such as IBD. The doctor will then talk through your symptoms with you, and may suspect IBS if you match certain criteria.

Symptoms of IBS differ widely from person to person. Sufferers may experience diarrhoea, constipation (or a mixture of both), bloating, abdominal pain and swelling, wind, urgency to go to the toilet and the feeling of having not been properly. Consequently, the dietary advice varies depending on an individual’s symptoms.

IBS is not a life-threatening condition, but it can cause a significant social impact on those who suffer with it. The good news is that once you’ve learned what foods tend to ‘set it off’, you can work on avoiding these and often improve symptoms. A handy way of doing this is by keeping a food and symptom diary, so you’re able to identify trends in how foods affect your bowel.

As I mentioned earlier, some IBS sufferers can be ‘sensitive’ to certain foods, this is a kind of intolerance whereby specific foods can trigger IBS symptoms. It’s important to stress that these reactions are rarely indicative of food allergy.

Below, I have suggested some things that may help with IBS symptoms. However, because dietary advice will differ so much depending on symptoms, you should also consult a professional for personalised advice. It is important that you don’t cut out too many foods as this will impact the nutritional adequacy of your diet.

  • Eating a healthy diet  This may sound obvious, but you should try to eat as close to the Eatwell Plate recommendations as possible. There’s no need for most IBS sufferers to follow any specific diet. It’s also important to drink plenty of fluids; water can help ease constipation and you’ll be needing to replace increased losses if you’re suffering from diarrhoea.
  • Establishing a regular meal pattern Having some sort of routine is important for preventing feelings of hunger, picking at less healthy foods and can help instill healthy habits. 
  • Stress less! – Heightened emotions such as stress and anxiety can trigger hormonal changes that can affect digestive system mechanisms. Try taking up a new hobby or doing something active to take your mind off what is causing you stress.
  • Prebiotics and Probiotics – Yes, they’re different! Probiotics are live microorganisms that get into the gut and help aid digestion. Prebiotics are non-living substances that encourage the growth of good bacteria in the gut. I think about it as prebiotics being the “food” for probiotics, both of these can be found in certain yoghurt drinks. Although it has not been categorically proven, many patients find that when taken regularly they can help ease IBS symptoms. Remember to always adhere to the manufacturers recommendations.
  • Avoid food triggersTriggers will be different for each person, but some typical ones include; caffeine, alcohol, fizzy drinks, spicy food, sorbitol (artificial sweetener) and fatty foods. Resistant starch found in processed foods can make bloating worse. Resistant starch is also formed when starchy foods (such as potatoes and rice) are reheated. 
  • Fibre – It may be necessary to modify the amount and/or types of fibre in your diet. Recommendations about what to change will be based on your own diet and symptoms, so it’s best to talk fibre through with your own GP or a dietitian.

Please note that this post contains information for the general public, this advice should not replace that given to you by your own doctor or healthcare professional. If you think you may have IBS, make an appointment to go and see your doctor.

More information on IBS provided by NHS Choices is available here.