Food sensitivity

Introduction

According to a familiar and centuries old saying, “One man’s food is another man’s poison” which simply states that different people can have very different reactions to exactly the same type food. For example, few of us would think twice about munching on peanuts while watching our favourite programme on television, however, for individuals with a sensitivity to peanuts, a mere whiff of just the peanut powder could pose a life threatening situation. Fortunately, few of us will ever have to worry about such extreme reactions to foods, but it may come as a surprise that at least 30% of us will experience one or more episodes of some kind of      food sensitivity during our lifetime. These may cause symptoms with varying degrees of physical discomfort which are often never related to food as their source (Taylor & Hefle, 2001).

Kweon (2001) in his work pointed out that there is increasing evidence that food sensitivities are more common and have a wider and more varied impact on our health than previously realized. Although often equated with food allergies, food sensitivities also include food intolerances which, unlike allergies, are toxic reactions to foods that do not involve the immune system and are often more difficult to diagnose. Many of the symptoms of food sensitivities including vomiting, diarrhoea, blood in the stool, eczema, urticaria (hives), skin rashes, wheezing and runny noses, are associated with an allergic reaction to specific foods. However, food sensitivities may also cause fatigue, gas, bloating, mood swings, nervousness, migraines and eating disorders. These symptoms which are more commonly related to food intolerance are less often associated with the consumption of food. Clinical research is accumulating evidence that the sensitivity to food can also increase the severity of the symptoms of rheumatoid arthritis, asthma and other diseases normally not considered food related.

In addition, Sampson,(1992) stated that food sensitivities include many different types of sensitivities to food which may arise for a wide variety of reasons making it a complex, oftentimes confusing and not easily defined area of study. Diagnosis can also be difficult because symptoms may be delayed for up to two days after a food has been consumed. In general, food sensitivities are the result of toxic responses to food and are divided into two categories: allergic responses; and food intolerances.

A surveillance team of cells determines whether newly introduced molecules pose a threat to your system. New molecules are constantly being introduced into the intestinal tract by the food that we eat. An allergic reaction occurs when your body identifies molecules as potentially harmful and toxic; these molecules are called antigens. The surveillance cells bind to the antigens activating the immune cells to release histamine and other chemicals which then signal the scavenger macrophages to come to the site and destroy them. Allergic reactions involving excessive histamine release can cause anaphylactic reactions (difficulty in breathing) which are responsible for 29,000 people in the United States ending up in the emergency ward each year. When the surveillance immune cells bind to an antigen and send out chemical messengers, they also communicate to other immune cells, the B-cells, which are instructed to make antibodies to the antigen (Nossal, 1993).

What is food sensitivity?

According to Walker-Smith (1994), food sensitivity is the inability to fully digest a food. When your body cannot completely process a food, the result is partially digested proteins and sugars. This happens especially with “Modern Foods” like grains, milk and sugars. Protein breakdown fragments in particular cause trouble because the body does not recognise them as ‘friendly. This sets up inflammation and disrupts bodily functions causing dozens of symptoms if left unattended these symptoms can develop into a disease.

Lichtenstein (1993) defines food sensitivity as an unpleasant reaction to food that is caused by deficiencies or reactions in the digestive tract. Lactose intolerance (caused by an enzyme deficiency) and celiac disease (an autoimmune disorder characterized by the inability to digest wheat, rye, and barley) are among the most common food sensitivities.

American Academy of Allergy, Asthma and Immunology (AAA), pointed out that food sensitivity occurs when a person has difficulty digesting a particular food. This can lead to symptoms such as intestinal gas, abdominal pain or diarrhoea.

Symptoms of food sensitivities

Dominus (2001) in his article published by the New York Times stated that the most common symptoms for food sensitivities include vomiting, diarrhoea, blood in stools, eczema, hives, skin rashes, wheezing and a runny nose. Symptoms can vary depending upon a number of variables including age, the type of allergen (antigen), and the amount of food consumed. It may be difficult to associate the symptoms of an allergic reaction to a particular food because the response time can be highly variable. For example, an allergic response to eating fish will usually occur within minutes after consumption in the form of a rash, hives or asthma or a combination of these symptoms. However, the symptoms of an allergic reaction to cow’s milk may be delayed for 24 to 48 hours after consuming the milk; these symptoms may also be low-grade and last for several days. If this does not make diagnosis difficult enough, reactions to foods made from cow milk may also vary depending on how it was produced and the portion of the milk to which you are allergic. Delayed allergic reactions to foods are difficult to identify without eliminating the food from your diet for at least several weeks and slowly reintroducing it while taking note of any physical, emotional or mental changes as it is being reintroduced.

Causes of food sensitivity

Reactions to chemical components of the diet are more common than true food allergies. They are caused by various organic chemicals occurring naturally in a wide variety of foods, both of animal and vegetable origin more often than to food additives, preservatives, colourings and flavourings, such as sulphites or dyes (Cardinale, Mangini & Berardi, 2008). Both natural and artificial ingredients may cause adverse reactions in sensitive people if consumed in sufficient amount, the degree of sensitivity varying between individuals.

Pharmacological responses to naturally occurring compounds in food, or chemical intolerance, can occur in individuals from both allergic and non-allergic family backgrounds. Symptoms may begin at any age, and may develop quickly or slowly. Triggers may range from a viral infection or illness to environmental chemical exposure. It occurs more commonly in women, which may be because of hormone differences, as many food chemicals mimic hormones.

A deficiency in digestive enzymes can also cause some types of food intolerances. Lactose intolerance is a result of the body not producing sufficient lactase to digest the lactose in milk; dairy foods which are lower in lactose, such as cheese, are less likely to trigger a reaction in this case. Another carbohydrate intolerance caused by enzyme deficiency is hereditary fructose intolerance. Celiac disease, an autoimmune disorder caused by an immune response to the protein gluten, results in gluten intolerance and can lead to temporary lactose intolerance (Heyman, 2006).

According to Raithel, Baenkler and Naegel (2005), most widely distributed naturally occurring food chemical capable of provoking reactions is salicylate, although tartrazine and benzoic acid are well recognised in susceptible individuals. Benzoates and salicylates occur naturally in many different foods, including fruits, juices, vegetables, spices, herbs, nuts, tea, wines, and coffee. Salicylate sensitivity causes reactions to not only aspirin and NSAIDs but also foods in which salicylates naturally occur, such as cherries. Some other natural chemicals which commonly cause reactions and cross reactivity include amines, nitrates, sulphites and some antioxidants. Chemicals involved in aroma and flavour are often suspected. The classification or avoidance of foods based on botanical families bears no relationship to their chemical content and is not relevant in the management of food intolerance.

Salicylate-containing foods include apples, citrus fruits, strawberries, tomatoes, and wine, while reactions to chocolate, cheese, bananas, avocado, tomato or wine point to amines as the likely food chemical. Thus exclusion of single foods does not necessarily identify the chemical responsible as several chemicals can be present in a food; the patient may be sensitive to multiple food chemicals and reaction more likely to occur when foods containing the triggering substance are eaten in a combined quantity that exceeds the patient’s sensitivity thresholds. People with food sensitivities have different sensitivity thresholds, and so more sensitive people will react to smaller amounts of the substance.

Diagnosis of cases of food sensitivities

Diagnosis of food intolerance can include hydrogen breath testing for lactose intolerance and fructose malabsorption, professionally supervised elimination diets, and enzyme-linked immunosorbent assay (ELISA) testing for Immunoglobin G (IgG)-mediated immune responses to specific foods. It is important to be able to distinguish between food allergy, food intolerance, and autoimmune disease in the management of these disorders. Non-(lmmunoglobin E) lgE-mediated intolerance is more chronic, less acute, less obvious in its clinical presentation, and often more difficult to diagnose than allergy, as skin tests and standard immunological studies are not helpful. Elimination diets must remove all poorly tolerated foods, or all foods containing offending compounds. Clinical investigation is generally undertaken only for more serious cases, as for minor complaints which do not significantly limit the person’s lifestyle the cure may be more inconvenient than the problem

The Hemocode Food Intolerance System and Rocky Mountain Analytical Food Allergy Test are invalidated yet heavily marketed examples of ELISA testing of lgG4 to foods. lgG4 against foods indicates that the person has been repeatedly exposed to food proteins recognized as foreign by the immune system. However, its presence should not be considered a factor which induces intolerance. Food- specific IgG4 does not indicate food allergy or intolerance, but rather a normal physiological response of the immune system after exposure to food components. Although elimination of foods based on lgG-4 testing in irritable bowel syndrome (IBS) patients resulted in an improvement in symptoms, the positive effects of food elimination were more likely due to wheat and milk elimination than lgG-4 test-determined factors. The lgG-4 test specificity is questionable as healthy individuals with no symptoms of food intolerance also test positive for lgG-4 to several foods.

Diagnosis is made using medical history and cutaneous and serological tests to exclude other causes, but to obtain final confirmation a Double Blind Controlled Food Challenge must be performed. Treatment can involve long-term avoidance, or if possible re-establishing a level of tolerance. The antigen leukocyte cellular antibody test (ALCAT) has been commercially promoted as an alternative, but has not been reliably shown to be of clinical value. (Kitts, Yuan & Joneja, 1997)

Prevention of food sensitivities

There is emerging evidence from studies of cord bloods that both sensitization and the acquisition of tolerance can begin in pregnancy, however the window of main danger for sensitization to foods extends prenatally, remaining most critical during early infancy when the immune system and intestinal tract are still maturing. There is no conclusive evidence to support the restriction of dairy intake in the maternal diet during pregnancy in order to prevent. This is generally not recommended since the drawbacks in terms of loss of nutrition can outweigh the benefits. However, further randomised, controlled trials are required to examine if dietary exclusion by lactating mothers can truly minimize risk to a significant degree and if any reduction in risk is outweighed by deleterious impacts on maternal nutrition.

A Cochrane review has concluded feeding with a soy formula cannot be recommended for prevention of allergy or food intolerance in infants. Further research may be warranted to determine the role of soy formulas for prevention of allergy or food intolerance in infants unable to be breast fed with a strong family history of allergy or cow’s milk protein intolerance. In the case of allergy and celiac disease others recommend a dietary regimen is effective in the prevention of allergic diseases in high-risk infants, particularly in early infancy regarding food allergy and eczema. The most effective dietary regimen is exclusively breastfeeding for at least 4—6 months or, in absence of breast milk, formulas with documented reduced allergenicity for at least the first 4 months, combined with avoidance of solid food and cow’s milk for the first 4 months (Crittenden & Benneft, 2005).

Management of cases of food sensitivities

In line with the views of Clarke and McQueen (1996), individuals can try minor changes of diet to exclude foods causing obvious reactions, and for many this may be adequate without the need for professional assistance. For reasons mentioned above foods causing problems may not be so obvious since food sensitivities may not be noticed for hours or even days after one has digested food. Persons unable to isolate foods and those more sensitive or with disabling symptoms should seek expert medical and dietician help. The dietetic department of a teaching hospital is a good start.

Guidance can also be given to your general practitioner to assist in diagnosis and management. Food elimination diets have been designed to exclude food chemicals likely to cause reactions and foods commonly causing true allergies and those foods where enzyme deficiency causes symptoms. These elimination diets are not everyday diets but intended to isolate problem foods and chemicals. Avoidance of foods with additives is also essential in this process.

Individuals and practitioners need to be aware that during the elimination process patients can display aspects of food addiction, masking, withdrawals, and further sensitization and intolerance. Those foods that an individual considers as ‘must have every day’ are suspect addictions; this includes tea, coffee, chocolate and health foods and drinks, as they all contain food chemicals. Individuals are also unlikely to associate foods causing problems because of masking or where separation of time between eating and symptoms occur. The elimination process can overcome addiction and unmask problem foods so that the patients can associate cause and effect.

It takes around five days of total abstinence to unmask a food or chemical, during the first week on an elimination diet withdrawal symptoms can occur but it takes at least two weeks to remove residual traces, If symptoms have not subsided after six weeks, food intolerance is unlikely to be involved and a normal diet should be restarted. Withdrawals are often associated with a lowering of the threshold for sensitivity which assists in challenge testing, but in this period individuals can be ultra-sensitive even to food smells so care must be taken to avoid all exposures.

After two or more weeks if the symptoms have reduced considerably or gone for at least five days then challenge testing can begin. This can be carried out with selected foods containing only one food chemical, so as to isolate it if reactions occur. In Australia, purified food chemicals in capsule form are available to doctors for patient testing. These are often combined with placebo capsules for control purposes. This type of challenge is more definitive. New challenges should only be given after 48 hours if no reactions occur or after five days of no symptoms if reactions occur.

Once all food chemical sensitivities are identified a dietician can prescribe an appropriate diet for the individual to avoid foods with those chemicals. Lists of suitable foods are available from various hospitals and patient support groups can give local food brand advice. A dietitian will ensure adequate nutrition is achieved with safe foods and supplements if need be.

Over a period of time it is possible for individuals avoiding food chemicals to build up a level of resistance by regular exposure to small amounts in a controlled way, but care must be taken, the aim being to build up a varied diet with adequate composition.

Conclusion

Food sensitivities are adverse reactions that affect a significant number of people in the overall population. The symptoms of any specific type of food sensitivity are manifested only in a small segment of the total population. As a result of the individualistic nature of these illnesses, the public does not tend to view these illnesses as a major health concern. However, food sensitivities are an increasingly important concern to food manufacturers. Consumers with various types of food intolerances must alter their lifestyles on a continuing basis to avoid the offending food or food ingredient. The industry must provide these consumers with the information necessary for them to practice such avoidance effectively. Ingredient labelling statements are the key to implementation of safe and effective avoidance diets. Manufacturers must also be aware that certain processing practices such as the use of shared equipment and the use of re-work can result in undeclared residues of intolerant foods existing in other products. These situations can be hazardous for Food sensitive consumers especially if larger quantities of the intolerant foods are present on an undeclared basis. However, since individuals with food intolerances can usually tolerate some of the offending food in their diets, the practices in the processing environment are much less likely to result in the transfer of hazardous levels of the offending food or food ingredient.

Recommendations

Food sensitivity undoubtedly a very nauseating situation, the best way to get over it is to ensure that you did not get there in the first place. In the light of this, the following recommendations are very necessary:

1. Avoid foods to which you are intolerant and/or allergic. First and foremost, you must know your own body and what foods are toxic to your body. Food sensitivities are very individual. You can be sensitive to a food that no one else in your family or groups of friends finds problematic. It’s part of why we are all individuals, and you should determine for yourself what foods may be causing damage to your body. Many healthcare practitioners are knowledgeable about food sensitivities and, especially if you are experiencing significant symptoms, you should consider talking with your healthcare practitioner about your diet and suspected food sensitivities.
2. Eat organically-grown foods whenever possible. Especially if you suspect food sensitivities, you should avoid foods with pesticides, artificial colourings and preservatives. These synthetic food additives can cause food sensitivities and may promote the intensity of other symptoms you are experiencing. Avoiding these artificial additives is essential in determining the foods to which you are sensitive and in developing a diet that promote your optimal health.
3. Support healthy digestion. One way you can support healthy digestion is to ensure you have adequate amounts of digestive factors. After chewing, the food’s next stop is the stomach, where an adequate amount of stomach acid (hydrochloric acid) is the next necessity. Stomach acid is required for adequate breakdown of proteins, and without proper breakdown, all proteins are potential antigens and toxic food molecules. Low stomach acid (hypochiorhydria) is common, especially in older people since as we age, we make less stomach acid. Research suggests that as many as half of the people over 60 years old have hypochlorhydria. A variety of factors can inhibit sufficient stomach acid production including the pathogenic bacteria, Helicobacter pylon, and frequent use of antacids. Hypochiorhydria is also associated with many diseases, such as asthma, celiac sprue, hepatitis, rheumatoid arthritis, osteoporosis, and diabetes mellitus. Signs of hypochlorhydria include a sense of fullness after eating, bloating, excessive belching, indigestion, multiple food allergies, undigested food in the stool, and peeling and cracked fingernails. In addition to hydrochloric acid, the production of pancreatic enzymes and bicarbonate is also compromised in some people. If necessary, these digestive factors can be replaced with appropriate supplementation. Digestive enzyme support can also be obtained from fresh pineapple or papaya, which contains the enzyme bromelain, and other fresh vegetables and herbs. Processed foods, like canned pineapple, contain little enzyme activity since digestive enzymes are proteins, which are destroyed by heating, such as occurs in the sterilization process.
4. Support the gastrointestinal barrier. The gastrointestinal cell wall is the barrier between potentially toxic food molecules and the inside of your body; therefore, the integrity of this barrier is vital to your health. Support for the mucus that covers the cells in the gastrointestinal tract is very important, especially in the stomach. The mucus layer is one way the stomach and upper small intestine protect themselves against the damaging effects of stomach acid. Alcohol, over-the- counter anti-inflammatory drugs, called NSAIDS (e.g., aspirin), and the pathogenic bacteria, Helicobacter pylon can all reduce the mucous layer, leading to lesions in the stomach and small intestinal tract walls. Choline provides nutritional support for a healthy mucous layer and is found in vegetables such as cauliflower and lettuce. Choline can be obtained from lecithin (phosphatidylcholine) as well, which is high in eggs and soybeans. Some foods also help combat or protect against the damage of Helicobacter pylon; these include catechins found in green tea, some spices such as cinnamon, carotenoids found in vegetables, and vitamin C, found in many fruits and vegetables.

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