FOOD SENSITIVITIES AND INTOLERANCE: FROM TRIGGERS TO TREATMENT (PT. 2)

The below article forms part 2 of a discussion on food sensitivities, in which common causes and food triggers for various types are reviewed.

Part 1 delves into the mechanisms underlying food sensitivities and intolerances, how they are different from allergies, as well as reviewing common risk factors and causes.

3. Lactose Intolerance

Lactose intolerance refers to a condition in which individuals suffer from adverse reactions to dietary lactose. While many with lactose intolerance can generally control their symptoms by avoiding dairy products, lactose is difficult to avoid completely since it is prevalent in a lot of foods and may continue to plague highly intolerant individuals even in the absence of dairy consumption. Lactose intolerance is thought to affect up to 70% of the global population^[1], with those of Northern European and American Indian ancestry having a better tolerance on average.

Symptoms:

• Abdominal pain
• Bloating
• Nausea and vomiting
• Flatulence
• Audible digestive sounds from the gut (i.e., rumbling, gurgling, etc.)
• Fullness

Causes. The enzyme lactase converts lactose into galactose and glucose. Without this conversion, lactose is difficult to absorb and can go on to promote gastrointestinal symptoms upon entering the colon in a similar way to that of FODMAPs. Additionally, lactose can drastically increase short-chain fatty acid production by the gut bacteria, which serves to promote diarrhea when the level exceeds that of absorption. Lactase is produced by the brush border of villi in the long intestine. Production of the enzyme is at its highest point in infancy, after which it declines throughout life. Lactase deficiency can be genetic or a result of intestinal dysfunction induced by damage, aging, gastrointestinal disease, infection, or antibiotics.^[2]

Food Triggers. Those with lactose intolerance may not experience symptoms in response to consuming small amounts of lactose (<12g), especially if spread throughout the day and consumed with other lactose-free foods. The main triggers of lactose intolerance constitute dairy products, with fermented dairy usually being better tolerated. Lactose may also be found in processed foods that include whey protein, curd, milk solids, and milk powder.^[3]

4. Histamine Intolerance

Histamine is a biogenic amine made in the body and commonly found in different foods. It serves several vital roles in many cellular functions, the most pertinent one being the mediation and regulation of allergic immune responses^[4]. Histamine is also involved in maintaining optimal neurotransmission, wakefulness, sleep, digestion and cognition^[5]. Those with histamine intolerance suffer from adverse reactions upon consuming high levels of dietary histamines and related proteins.

Symptoms:

• Itching
• Abdominal pain
• Diarrhea
• Nausea or vomiting
• Sinus symptoms
• Flushing
• Shortness of breath
• Dizziness
• Arrhythmia or increased heart rate

Causes. Histamine intolerance is suspected to be caused by an enzyme deficiency that allows histamine to build up in the system. This results in symptoms when histamine receptors become overly activated.^[6] Histamine is oxidized, deactivated, and eliminated by the enzyme diamine oxidase (DAO). Genetics, alcohol (especially wine and spirits), NSAIDs, and several other pharmaceutical medications can reduce the level of DAO and promote histamine intolerance. As DAO is responsible for metabolizing other biogenic amines, diets high in them can promote histamine intolerance by lowering available DAO.

Food Triggers. Foods high in either histamine or related biogenic amines can serve as triggers in histamine-intolerant individuals. Histamine and other biogenic amines (especially putrescine and cadaverine) are often found in lower quantities in fresh, minimally processed foods, and in higher quantities in preserved, canned, and fermented foods or foods frozen for a long time. Tinned foods, aged cheeses, fermented sausages, seafood, tomato, spinach, aubergine, avocado, alcohol, chocolate, citrus fruits, soy, nuts, and various fruits are often omitted from the diet of a histamine-intolerant person.^[7] As histamine intolerance can present with other gastrointestinal symptoms, other food sensitivities and triggers may co-exist alongside these, such as FODMAPs.

5. Food Chemicals and Additives

Food chemical additives include colorants, stabilizers, preservatives, emulsifiers, binders, fillers, flavor enhancers, and by-products of fermentation or processing. They enhance the shelf-life, palatability, and appearance of foods, medications, and cosmetic products. Over the last several decades, their use has been steadily increasing in popularity among manufacturers. With this, reports of adverse reactions in response to their consumption have also increased. Food additive reactions rarely occur in the general population (estimated at <0.3%); yet seem to affect a larger percentage (approximately 1-7%) of individuals with allergic health conditions, who are perhaps more sensitive.

Potential Symptoms:

• Gastrointestinal symptoms including diarrhea and stomach ache
• Headaches and migraines
• Muscle pain or cramps
• Shortness of breath and bronchoconstriction
• Skin rashes
• Hot flashes
• Lack of focus
• Reduced sleep quality

Causes. It is currently unknown what triggers sensitivity toward food additives and chemicals. Many of these compounds have been linked with promoting gut irritation, damage, intestinal permeability, gut dysbiosis, as well as heightened immune reactivity. Despite these findings, there is minimal data on the subject, and results are often contradictory across studies. This may be because food additives are often consumed in very small quantities. Thus, potential adverse effects are not likely to occur in response to any one given food containing them. Experimental studies suggest that they may increase sensitivity towards other dietary components if consumed in large quantities. However, it remains to be seen whether exposures can accumulate across different types of additives or not. A handful of studies have also noted that some additives may lower attention span and promote attention deficit disorder in children.^{[8] [9]}

Food Triggers. It is currently unknown whether food additives and chemicals have a cumulative effect on sensitive individuals or not. Therefore, they may overlap as triggers. Many additives are represented as E-numbers^[10]. However, many E-numbers are safe and not associated with any adverse reactions. Various examples of additives that may trigger an adverse reaction include:

• Glutamate is more likely to trigger an adverse reaction if consumed in high quantities in a free form, as found in larger amounts in processed foods and additives. These include MSG, hydrolyzed proteins and isolates, maltodextrin, and yeast extracts. Soy and several other vegetables, including tomatoes, also contain glutamate in lesser quantities that have been reported to trigger adverse reactions in sensitive individuals.
• Sulfites are used as a preservative in wine and other alcoholic beverages, soft drinks, grape juice, vinegar, dried fruits, fruit bars, lemon juice, sauces, preserved fruits and vegetables, dough, jams and jellies, coconut cream/milk and processed meats. Medications and cosmetic products also may contain sulfites.^[11]
• Colorants can be found in many processed foods, dyes, cosmetics, and medications. They are most often represented by their respective E-numbers. Other colorants that may be listed include tartrazine, carmine (carminic acid, cochineal), and titanium dioxide. Some colorants are natural antioxidants and are not likely to produce adverse reactions.^[12]
• Benzoates are most commonly used in the form of sodium benzoate. Due to adverse reactions, it has largely been replaced in foods with potassium sorbate. However, benzoates are still used mostly in processed foods as a preservative.

Diagnostic Tools

Food sensitivities and intolerances are notoriously difficult to diagnose and often take time. Aside from a physical examination, the following tools may be used to diagnose the patient:

Hydrogen Breath Testing may be used to detect food intolerances and sensitivities resulting from malabsorption or indigestion. Hydrogen is produced in larger quantities in individuals suffering from FODMAP sensitivity, which can also extend toward wheat/gluten and lactose intolerance. This is often used to verify the nature of common gastrointestinal symptoms alongside ELISA tests and an elimination diet.

ELISA Testing (Enzyme-Linked ImmunoSorbent Assay) is the gold standard test used for immunoassays^[13] and is a helpful indicator when diagnosing food sensitivities, intolerances, and allergies. It is able to test antibody levels in response to selective food antigens from blood samples. Active antibody levels found at high enough concentrations point towards a potential food sensitivity. Despite its frequent use, ELISA test results are not accurate enough to pinpoint cross-reactivities between food antigens and antibodies, specifically concerning chemically similar compounds. Other factors can also detract from accuracy. Therefore, food sensitivity diagnosis is often also accompanied by a physical examination and process of elimination.

Elimination Diet. An elimination diet is used as both a diagnostic tool and a treatment option. It refers to a diet that eliminates food triggers in the sensitive individual, usually for 4-6 weeks, before re-introducing the food in an attempt to pinpoint the true cause of the sensitivity. Potentially problematic foods are usually introduced one at a time, every 4-7 days. If the patient experiences a reaction during that time, it is likely that the patient is intolerant to the food and that it should be avoided. Some foods may also only trigger an adverse reaction if consumed in excess and not when consumed in moderation.

Possible Treatment Options

Treatment options for food intolerances and sensitivities generally involve dietary interventions that limit exposure and control for symptoms.

Food Avoidance and Rechallenge. As explained above, the elimination diet is often used as a diagnostic and therapeutic option. Diets that either restrict or avoid the consumption of offending foods often show great improvement in symptoms.^[14] Sticking to a healthy diet plan devoid of highly refined and unhealthy foods often improves the efficacy of an elimination diet. Once the real offenders have been ascertained, the patient’s diet can easily be modified to reduce or avoid the source of the problem. It is important for patients with food intolerances to undertake an elimination diet with the help of a trained dietician or nutritionist who can accurately assess the situation, pinpoint problematic foods and help prevent malnourishment during the process.

Oral Immunotherapy is an experimental treatment option that attempts to desensitize the patient to food allergens by incrementally increasing the patient’s consumption of the allergen. Patients with immune-mediated food sensitivities may benefit from this form of therapy. However, it is contraindicated for those with food intolerances and digestive symptoms. Despite some studies showing success, there are many reports of adverse reactions occurring in response to oral immunotherapy, particularly with dose escalation.^[15] Minor forms of this therapy are often incorporated into a treatment plan for a patient with food sensitivities in order to ascertain optimal tolerance and dose maintenance of an offending food. This therapy should not be attempted without the guidance of a trained physician.

Pharmacological Interventions. Patients with severe symptoms who are not responding to dietary interventions may benefit from the following pharmaceutical solutions:

• Antihistamines are a class of medication capable of blocking the action of histamine, often by inhibiting histamine receptors. As histamine is a main mediator of allergic reactions, antihistamines can often help to improve symptoms in those with severe food sensitivities and allergies. Individuals with histamine intolerance may also experience symptom relief from antihistamine use. However, as they do not lower excessive histamine levels, a diet low in histamine is often recommended.
• Digestive Enzymes. Depending on the individual, digestive enzymes may be prescribed to promote better breakdown of lactose and dietary proteins, including gluten and histamine^[16]. In patients with gastrointestinal disease, digestive enzymes may help to ameliorate sensitivities to foods induced through severe indigestion. Food containing digestive enzymes, such as papain in papaya^[17], can also serve to enhance digestive function and has been associated with lessening symptom severity in cases of allergy.

Supplementation that may be complementary in treating food sensitivities and intolerance include:

• Probiotic supplementation has been shown to alleviate symptoms in almost every case of food sensitivity and intolerance. Patients often present with gut dysbiosis or lowered microbial diversity, which probiotics (in combination with sufficient prebiotic substrates in the diet) can help to improve. Bacteria that are commonly found in abundance include proteolytic bacteria, while those lacking are generally strains of the lactobacillus and Bifidobacterium species. Those with histamine intolerance or FODMAP sensitivity may have difficulty in consuming conventional probiotic foods as these are traditionally high in histamine and/or lactose. A diverse probiotic supplement is advisable.
• Vitamin A supplementation may prove useful in improving oral tolerance towards food antigens due to its effect on the immune cells that line the gut. Retinoic acid, in particular, is known to lower immune reactivity and is stored by both gut microbes and immune cells along the gut and in the liver for this purpose. Deficiencies in vitamin A can exacerbate symptoms by enhancing immune reactivity.

Improving Digestive Health. For many types of intolerances and food sensitivities, low levels of digestive enzymes, as well as incomplete digestion, are often contributing factors. While supplementation of probiotics and digestive enzymes can help to reduce symptoms, maintaining optimal digestive health may serve to ameliorate sensitivities in the long run. Enhancing digestive health includes eating a balanced, nutritious diet and consuming foods in a way that supports metabolism.

Intermittent Fasting is a form of caloric restriction that may help to improve symptoms of food sensitivities through reprogramming the metabolism, improving the gut microbial profile, and giving the gut an opportunity to regenerate any damage that may be aiding the problem.

Conclusion

Food intolerances and sensitivities are known to affect people with gastrointestinal and autoimmune diseases more frequently than the general population. They are more prevalent than food allergies. Common underlying mechanisms pertain to compromised digestive health, increased intestinal permeability, and gut dysbiosis, all of which lead to adverse immune and digestive reactions toward sensitive food components. Therapy involves tailoring the diet for optimal tolerance towards foods, improving digestive health, and keeping immune reactions contained.

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