Your immune system is comprised of specialised cells and structures responsible for fighting foreign invaders to your body e.g. pathogenic bacteria, fungi viruses, and also for destroying cells within your body when they become cancerous. Poor nutrition has been shown to result in increased infections, to slow healing from injury and infections, and to increase susceptibility to symptoms and complications from immune system dysfunction. Research shows that immune function often declines as we age, and that this decrease is also related to nutrition and may be slowed or even stopped by maintaining healthy nutrition.

The main components of your immune system are immune cells which include the lymphocytes, or T-cells, which fight invading molecules directly; and the B-cells, which form antibodies that can identify and respond to invading molecules or toxins. The antibodies produced by B-cells can attach to a potentially harmful molecule or to a virus or bacteria, to be removed by other immune cells. Your immune system also includes cells called macrophages and neutrophils, which remove the debris produced by immune cells and damaged tissue at the site of an infection.

The cells of your immune system circulate in the bloodstream or are found in the lymph nodes, which are located throughout your body; they can therefore respond quickly to any invaders that do manage to gain entrance into your body.

Your immune system also includes soluble factors. These molecules recognize when a barrier has been threatened by a foreign invader or toxin, and then try to heal the area of damage and rapidly remove the threat. The immune system also uses soluble factors to communicate to immune cells located further inside the tissue that has been compromised, or into your bloodstream. These messenger soluble factors, called cytokines, call immune cells to the site of damage and activate the cells, bringing them in full force to the infected area and promoting an inflammatory response

Barriers in the body such as the skin, mucus membranes of the respiratory system and the gastro-intestinal tract, keep unwelcome and damaging organisms and molecules from entering your body. Your gastrointestinal tract is like an internal skin: has about 150 times more surface than your outside skin, contains approximately 60% of your entire immune system and is the largest barrier between you and the outside world. The gut has the unique function of keeping out harmful molecules and organisms e.g. harmful bacteria and viruses, whilst allowing in beneficial nutrients, molecules and substances (WHFoods).

Antibiotics, alcohol, non-steroidal anti-inflammatory drugs, oral contraceptive pills, antacids, stress and poor nutrient diet are all associated with inflammation in the gut lining. By supporting gastro-intestinal health you are thereby supporting immune system function.

Factors that support our immune system are:

  • Eating a healthy diet high in fruits, vegetables, and whole grains, and low in saturated fat. Fruit and vegetables provide fibre which can be converted to a food source for beneficial gut bacteria, be used to remove toxic substances from the gut and contain important vitamins such as vitamin C, E, D, A, folate, B6 and B5 which are essential for immune cell production, maturation and function. Vitamin B5 promotes the production and release of antibodies from B-cells. Vitamin B5 deficiency may result in reduced levels of circulating antibodies. Folic acid deficiency may lead to decreased T-cells and can result in reduced efficiency of soluble factors. Vitamin B6 deficiency may impair T-cell functioning and results in a decrease in blood lymphocyte counts. Deficiencies in vitamins B1 and B2 may impair normal antibody response, and low vitamin B12 appears to inhibit phagocytic cells and possibly T-cell function (WHFoods)
  • Adequate protein intake (available from meat, fish, beans, lentils, eggs, nuts, seeds and dairy) is required to provide essential minerals such as zinc, copper, selenium, iron and manganese for the production and function of white blood cells
  • Regular exercise - research suggests that regular exercise boosts the immune system
  • Maintaining a healthy weight is associated with reduced risk of infection
  • Reducing sugar – Research suggests that consuming 75-100mg of sugar (approximately that which is in 2 cans of fizzy drinks) may reduce the ability of white blood cells to fight infection for up to 2 hours; the same has been suggested of saturated fats
  • Stress reduction – Chronic stress presents your body with a steady floods of stress hormones called cortisol and adrenaline. These may suppress the immune system. Chronic stress is also linked to reduced production of white blood cells called secretory IgA which helps to protect mucus membranes in the digestive and respiratory system from infection
  • Adequate omega 3 fatty acid intake from oily fish, nuts and seeds and monounsaturated fats from olive oil support healthy gut membranes
  • Probiotic food intake (from sauerkraut, kefir or yoghurt) or supplementation to support gut health
  • Supplements e.g. garlic, beta-glucans, vitamin D/E/ A/B12/B6 copper, iron, folate, selenium, zinc and probiotics
  • If you drink alcohol, drink only in moderation
  • Get adequate sleep – Lack of sleep can cause an increase of inflammation in the body as the sleep hormone melatonin has an anti-inflammatory action
  • Stopping smoking
  • Healthy aging
  • Food allergies and Intolerances

In true food allergy, an abnormal immune system response results in the body making IgE antibodies to fight off a food allergen. However, some people suffer symptoms after eating certain foods even when they are not producing IgE antibodies against them-this may be due to a food intolerance. Food intolerance is much more common than food allergy and can be tested by measuring IgG antibodies to proteins in foods. Testing by CYREX laboratories ( can measure cellular responses to food, and in the case of gluten and dairy proteins can help determine whether the response occurs in the skin, gut or brain and nerve tissues.

The onset of symptoms in food intolerance is usually slower than in food allergy and may be delayed by many hours after eating the offending food. The symptoms may also last for several hours, or several days. Intolerance to several foods or a group of foods is not uncommon, and it can be much more difficult to decide whether food intolerance is the cause of chronic illness, and which foods or substances may be responsible. Common food intolerances are gluten (which includes wheat, barley, oats and rye), dairy and soya.

In allergy, the person cannot usually tolerate even a small amount of the offending food without suffering symptoms, as it only takes a tiny amount to trigger a response from the immune system, which makes it very easy to diagnose. Tests looking for IgE antibody responses to foods are easy to perform and reliable so the diagnosis can usually be readily confirmed. 

With food intolerance, the person can tolerate a reasonable amount of the food, but if they eat too much (or too often) they get symptoms because their body cannot tolerate unlimited amounts.

Common food intolerance symptoms include fatigue, joint pain, dark circles under the eyes, night sweats, foggy brain, anxiety, depression, irritability, headaches, diarrhoea, vomiting, indigestion, bloating, flatulence, irritable bowel, stomach pain, rashes, eczema, and other chronic conditions.

Food intolerance can have a number of different causes:

1. Leaky Gut Syndrome

The lining of the intestines is one cell thick, and when healthy has tight junctions between cells. Contained within the lining are white blood cells of the immune system which act as body guards, deciding which digested food particles may pass through into the blood stream. When inflamed, these cell junctions widen, increasing permeability and allowing unwanted food particles/toxins/harmful bacteria to pass into the blood stream (see figure 1).

White blood cells in the blood stream alert our immune system to destroy these particles so that they do not harm us. White blood cells also remember these substances so that our immune system can respond more quickly to destroy them the next time they appear. When our immune system goes awry our body may start to consider foods as enemy e.g. food intolerances. This can lead to symptoms of intolerance particularly when we have a repetitive diet (e.g. your diet contains lots of dairy or wheat).

By reducing/removing food allergens, gut inflammation and gastro-intestinal permeability, the immune system may revert back to a place of tolerance to certain foods which we were previously intolerant to, and may reduce IBS type symptoms such as bloating, wind, indigestion, pain, diarrhoea and constipation.

2. Enzyme defects

Enzymes are required to help with the breakdown of natural substances found in certain foods.  If these enzymes are missing, or in short supply, then eating the food can cause symptoms because part of the content of the food cannot be properly dealt with by the body. 

In lactose intolerance, for example, the body lacks the enzyme (lactase) that breaks lactose (milk sugar) down into smaller sugars ready for absorption from the gut. Lactose is too large to be absorbed across the gut wall undigested, and its presence in the gut causes gut spasm, pain, bloating, diarrhoea and failure to thrive. Incidentally, these same symptoms can occur in milk allergy, when the body has made antibodies to milk protein, which causes an immune reaction when you drink milk. Hence, you cannot always distinguish allergy from intolerance by symptoms alone without expert help.

Most foods require some enzyme activity in their digestion, and enzyme deficiencies can be an important factor in food intolerance.

3. Pharmacological

Some foods contain naturally occurring chemicals that have an effect on the body, such as caffeine in coffee, tea, and chocolate, or amines in certain cheeses. Some people seem to be more affected than others by these natural substances in the food and experience symptoms which would not occur in others unless they eat far larger quantities of the food.

4. Histamine in foods

Some foods contain histamine naturally (e.g. fish/meat that have been stored for too long, aged cheeses, red wine, chocolate, mushrooms, aubergine, spinach, fermented foods). In certain people, this naturally occurring histamine may cause symptoms when the food is eaten e.g. rashes, itchy skin, stomach pains, diarrhoea, vomiting, flushing, nasal congestion, low blood pressure, high blood pressure, irregular heartbeat, difficulty breathing, foggy brain and in severe cases, anaphylaxis.

5. Salicylates in foods

Salicylates are naturally occurring plant chemicals which act as a natural immune hormone and preservative, protecting the plants against diseases, insects, fungi, and harmful bacteria. Salicylates are also created synthetically and can be found in many medicines e.g. aspirin, perfumes and preservatives. Foods naturally contain salicylates e.g. tea, coffee, tomatoes, dried fruit, berries, avocado, many fruits, fruit juices, wine, cider, peppers, mushrooms, peppers, chilli peppers, almonds, pistachio, brazil nuts, mint sweets, liquorice, popcorn, pickled foods. Tolerance to salicylates can vary and those that are sensitive may suffer symptoms if they consume too many salicylate containing foods, see

Symptoms include itchy skin or rashes, eczema, asthma, persistent cough, post-nasal drip, dry eyes, stomach pain/upset, bloating, diarrhoea, constipation fatigue, lethargy, headache, dizziness, sweating, chest pain, racing pulse, low/high blood pressure, aching muscles and joints, breast pain, acne, poorly controlled blood sugar levels, food cravings, weight problems, sleep disturbances, poor concentration, memory loss, depression, anxiety, irritability, panic attacks, hyperactivity and chronic fatigue syndrome.

6. Additives in foods

A wide variety of natural and artificial additives are used in colouring, preserving and processing foods. Some people can suffer symptoms such as asthma, flushing, headache, itchy skin and hives provoked by hypersensitivity to food additives.

Food/symptom diary and elimination diets

Keeping a food diary and recording symptoms (physical, mood and energy levels) helps to recognise links between foods and symptoms. Suspect foods are those which are generally eaten with the most frequency. Suspect food(s) or food groups are then strictly eliminated for a set period of time (preferably avoid holidays and festive periods where you might be tempted) to see whether symptoms reduce or disappear. This requires dedication and planning and should not be performed without the help of a qualified nutritional therapist or dietician to avoid nutritional deficiencies.

The elimination phase is followed by a re-introduction of a singular food and any symptoms are observed. If no symptoms are observed then this food is removed again and another new food is reintroduced until all foods have been reintroduced and observed for reactions.

Prolonged elimination of a food allergen alongside a gut healing protocol may well lead to reintroduction of the food without symptoms. This is known as tolerance, and its maintenance depends on determining the threshold of both frequency and quantity for that person. This requires a careful balance- to not introduce it in too large a quantity or too frequently and in balance with other foods that you may be wishing to reintroduce. Every person is unique and will react differently.

Auto-immune disease (rheumatoid arthritis, coeliac disease, type 1 diabetes, myasthenia gravis, hypothyroidism)

Autoimmunity is the No. 2 cause of chronic illness, according to the American Autoimmune Related Diseases Association. About 5% of the US population has been diagnosed and treated for an autoimmune disease, and another 10% to 20% have early-stage autoimmune symptoms and imbalances. Approximately 75% of these cases are in women and most frequently occur during child-bearing years (AARDA).

The body’s immune response is a marvellous defence system, protecting against foreign invaders and injury, and the body can tell the difference between a non-self and itself. In autoimmune disease, the immune response is faulty and the body’s immune system attacks its own tissues.

An autoimmune disorder may result in damage of body tissues, abnormal growth of an organ and changes in organ function.

Autoimmune diseases can affect nearly every part of the body e.g. blood vessels, connective tissues, endocrine glands (thyroid and pancreas), joints, muscles, red blood cells, skin.

Common autoimmune disorders include coeliac disease, rheumatoid arthritis, multiple sclerosis, Hashimoto’s thyroiditis, chronic inflammatory bowel disease, pernicious anaemia, myasthenia gravis, systemic lupus erythematosus, type 1 diabetes and sjogren syndrome. A person may have more than one autoimmune disorder at the same time e.g. the prevalence of celiac disease in type 1 diabetes is between 5% and 15%, “There’s a correlation between celiac disease and other autoimmune diseases, such as type 1 diabetes, autoimmune thyroid disease, Sjögren’s syndrome, autoimmune liver disease, inflammatory bowel disease, and Addison’s disease…” says Shelley Case, RD.

In Sjögren’s syndrome, your white blood cells attack moisture-producing glands, causing symptoms like dry eyes and dry mouth. In type 1 diabetes, the immune system attacks the insulin-producing cells in the pancreas.

Autoimmune disease triggers

There are many theories about the origins of autoimmune diseases, which include both genetic, dietary and lifestyle choices.


The human leukocyte Antigen (HLA) is associated with most autoimmune diseases.

Environmental factors

Scientists hypothesise that in developed countries autoimmune disease may be linked to cleanliness and decreased exposure to bacteria (the hygiene hypothesis), which causes a skew in the immune system. Other possible triggers include pesticides, hormones and smoking.

Intestinal health and gut bacteria

Research suggests that poor gut health and an imbalance in normal gut bacteria is linked to autoimmune diseases such as rheumatoid arthritis, inflammatory bowel disease, type 1 diabetes and Sjorgrens disease. Many animal and some human studies have shown that probiotic supplementation may re-balance gut bacteria, improve intestinal health and modify immune and anti-inflammatory response and improve tolerance to self.

Gluten triggers
Research suggests that there is a link between coeliac disease and autoimmune disease alongside other environmental triggers. It may be wise to test for gluten sensitivity if you have gastrointestinal symptoms.


Research suggests that some inflammatory processes may enhance the possibility of autoimmune disease in individuals with a genetic predisposition.

Poor nutrient diet

Diets high in refined starches, sugar, saturated fats, and trans fats, and low in fruits, vegetables, whole grains, and omega-3 fatty acids appeared to stimulate an inflammatory reaction. A diet low in Vitamin D, Omega 3 fatty acids and antioxidants (from fruit and vegetables) have been linked to autoimmune disease. Vitamin D from foods, sunlight and supplementation may help to reduce inflammatory chemicals and regulate white blood cells which can predispose the body towards an inflammatory response. Dietary and supplementation of omega 3 fatty acids may be helpful in some autoimmune disease e.g. rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus.

Potential tests to diagnose an auto-immune disease

Standard hospital tests may include:

  • Antinuclear antibody tests
  • Autoantibody tests
  • Complete blood count (CBC)
  • Comprehensive metabolic panel
  • C-reactive protein (CRP) levels
  • Erythrocyte sedimentation rate (ESR) levels
  •  Urinalysis

Complementary tests may include:

  • Comprehensive stool test to help assess levels of helpful and potentially harmful bacteria
  • Cyrex laboratories offers a blood test which screens for antibodies for multiple cells, tissues and organs e.g. thyroid, pancreas, liver, muscle, connective tissues, bones, intestinal tissue, brain and nerve cells to assist in the early detection and monitoring of autoimmune conditions

Dietary strategies for managing autoimmune disease

Nutritional intervention in autoimmune diseases usually emphasises managing pain, reducing inflammation/disease progression/tissue damage and modifying the immune system.

Research suggests that antioxidant/anti-inflammatory foods and nutrients may be beneficial in AID. A diet rich in whole foods, fruit and vegetables, low in sugar, and high in omega 3 fats quality protein from lean meat, fish, nuts, seeds, beans and lentils. Tea, dark chocolate, spices and herbs, and red wine in moderation are all rich in antioxidants.

Drugs typically used in autoimmune disorders are steroids, non-steroidal anti-inflammatory drugs, disease modifying drugs (DMARDS) and biologics such as anti-TNFs; which may cause side-effects such as nausea, vomiting, stomach and intestinal lining irritation and inflammation, and interact with folic acid and vitamin B12. Inflammation of the intestinal lining may have the undesired effect of increasing inflammatory cytokine production from intestinal cells and increase permeability of the intestinal lining. Many medications may have a detrimental effect on beneficial gut bacteria and increase harmful bacteria. Because of the increased permeability of the gut lining gut bacteria inflammatory chemicals may then cross into the blood stream and circulate to joints, the brain and nervous tissues and cause inflammation there.

Whatever your genetic background, family history of autoimmune disease and current condition I would strive to support you to optimise your diet and lifestyle to maximise your health and reduce disease expression.