Adverse food reactions are increasingly common, both in children and adults. 

With up to 20% of the population being affected¹ you are likely to see a lot of them in your clinic. Do you know how to manage food intolerances effectively? This can be crucial to your success as a practitioner. There are two main types of food intolerances; management of each type differs slightly.

Functional Food Intolerances

Functional food intolerances are caused by maldigestion of food due to low levels of gastric secretions² or Small Intestinal Bacterial Overgrowth (SIBO)³.

Improving digestive function with bitters, liver & gall-bladder support, and probiotics is a vital part of managing functional food intolerances.

Lactose, fat and FODMAP intolerance are types of functional intolerances. Maldigestion of these foods has an osmotic effect in the bowel causing diarrhoea, and fermentation of undigested food by gut bacteria causes gas, bloating and cramping pain^2,4 which is often associated with a diagnosis of Irritable Bowel Syndrome (IBS)⁴.

Functional intolerances are best managed by reducing intake of the offending foods initially, with studies finding significant improvement in IBS symptoms with a low FODMAP diet⁵. However long-term dietary restriction can cause health problems. A low FODMAP diet is low in fibre and prebiotics and can contribute to dysbiosis, while long-term avoidance of fats can cause deficiencies in essential fatty acids and fat-soluble vitamins. Therefore it is vital that following the initial removal of the offending foods, significant work is done to improve digestive function so that the food group can be reintroduced and tolerated.

Bitter herbs such as gentian, wormwood and feverfew improve gastric secretions⁶, as does Betaine hydrochloride⁷, which reduces adverse food reactions². Choleretic and cholagogue herbs such as St Mary's Thistle, Globe Artichoke and Dandelion root increase bile and improve fat tolerance⁸. Pancreatic enzymes break down food in the intestine; any unused enzymes are reabsorbed and contribute to the pancreatic enzyme pool, leading to improved digestion even when supplementation is ceased⁹. Gut antimicrobials such as high-berberine phellodendron, oregano and anise oil¹⁰ and probiotic supplements¹¹ may reduce dysbiosis and the subsequent fermentation of foods. After 1-3 months of avoidance, the offending foods should be reintroduced gradually to the point of tolerance.

Non-IgE immune mediated food intolerances

Non-IgE immune mediated food intolerances are caused by the release of IgG and IgA antibodies and inflammatory cytokines in response to food antigens^1,2. 

Reducing inflammation and improving intestinal barrier function is key to managing immune mediated food intolerances.

These inflammatory molecules act as a final 'chemical' barrier when intestinal barrier function is impaired and food antigens are able to cross the gut wall intact¹². This sets off a systemic inflammatory cascade which may present in many ways, from Inflammatory Bowel Disease to atopy, arthritis and autoimmunity¹². Common food triggers include gluten, casein, corn, soy, eggs, yeast, food additives and salicylates.^1,2

Effective management means complete avoidance of the offending foods while improving gut barrier function and reducing intestinal and systemic inflammation. Glutamine, Zinc, Vitamin A and Vitamin D play important roles in the integrity of the gut wall, and deficiency of these nutrients is associated with food allergies and intolerances,^1,12 while supplementing with these nutrients improves intestinal barrier function¹³. Herbs such as turmeric,^14,15 deglycyrrhized licorice¹⁶ and aloe vera¹⁷ reduce inflammation and improve intestinal permeability. 

Causes of Increased Intestinal Permeability¹²

• Nutritional deficiencies
• Dysbiosis, pathogenic enteric bacteria & viruses
• Impaired function & diversity of microbiome
• Toxin exposure
• Poor diet, lack of fibre, inflammatory foods
• Certain medications
• Chronic inflammation- intestinal or systemic

Multi-strain probiotics¹² and Saccharomyces boulardii¹⁸ upregulate tight junction proteins and reduce adherence of pathogenic bacteria. Reintroduction of antigenic foods may be trialled after 6-12 months; if well tolerated, these foods may be included in the diet in small to moderate amounts. If not, continued avoidance may be necessary.

References

1. Genuis SJ. Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity. Science of the Total Environment. 2010 Nov 15;408(24):6047-61. DOI: 1016/j.scitotenv.2010.08.047
2. Zopf Y, Baenkler HW, Silbermann A, Hahn EG, Raithel M. The differential diagnosis of food intolerance. Dtsch Arztebl Int. 2009 May 22;106(21):359-69. DOI:  3238/arztebl.2009.0359
3. Van Citters GW, Lin HC. Management of small intestinal bacterial overgrowth. Current gastroenterology reports. 2005 Jul 1;7(4):317-20. DOI:  1111/apt.12479
4. Lomer MC. Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance. Alimentary pharmacology & therapeutics. 2015 Feb 1;41(3):262-75. DOI:10.1111/apt.13041
5. Staudacher HM, Lomer MC, Anderson JL, Barrett JS, Muir JG, Irving PM, Whelan K. Fermentable carbohydrate restriction reduces luminal bifidobacteria and gastrointestinal symptoms in patients with irritable bowel syndrome. The Journal of nutrition. 2012 Aug 1;142(8):1510-8. DOI:3945/jn.112.159285
6. Bone K & Mills S. Principles and Practice of Phytotherapy. 2nd Sydney: Elsevier, 2013 p. 40
7. Thorne Research Inc 2003, "Betaine- Monograph", Alternative Medicine Review, Vol. 8, No. 2, pp. 193-196.
8. Bone K & Mills S. Principles and Practice of Phytotherapy. 2nd Sydney: Elsevier, 2013 pp. 210-11
9. Rothman S, Liebow C, Isenman L. Conservation of digestive enzymes. Physiological reviews. 2002 Jan 1;82(1):1-8. DOI: 1152/physrev.00022.2001
10. Bone K & Mills S. Principles and Practice of Phytotherapy. 2nd Sydney: Elsevier, 2013 p. 201
11. Foster L, Tompkins T, Dahl W. A comprehensive post-market review of studies on a probiotic product containing Lactobacillus helveticus R0052 and Lactobacillus rhamnosus R0011. Beneficial microbes. 2011 Dec 1;2(4):319-34. DOI: 3920/BM2011.0032
12. Bischoff SC, Barbara G, Buurman W, Ockhuizen T, Schulzke JD, Serino M, Tilg H, Watson A, Wells JM. Intestinal permeability-a new target for disease prevention and therapy. BMC gastroenterology. 2014 Nov 18;14(1):189. DOI: 3920/BM2011.0032
13. Lima AA, Anstead GM, Zhang Q, Figueiredo ÍL, Soares AM, Mota R, Lima NL, Guerrant RL, Oriá RB. Effects of glutamine alone or in combination with zinc and vitamin A on growth, intestinal barrier function, stress and satiety-related hormones in Brazilian shantytown children. Clinics. 2014;69(4):225-33. DOI:  6061/clinics/2014(04)02
14. Ma TY, Iwamoto GK, Hoa NT, Akotia V, Pedram A, Boivin MA, Said HM. TNF-alpha-induced increase in intestinal epithelial tight junction permeability requires NF-kappa B activation. American journal of physiology. Gastrointestinal and liver physiology. 2004 Mar;286(3):G367. DOI: 1152/ajpgi.00173.2003
15. Hanai H, Sugimoto K. Curcumin has bright prospects for the treatment of inflammatory bowel disease. Current pharmaceutical design. 2009 Jun 1;15(18):2087-94. DOI: 2174/138161209788489177
16. Raveendra KR, Srinivasa V, Sushma KR, Allan JJ, Goudar KS, Shivaprasad HN, Venkateshwarlu K, Geetharani P, Sushma G, Agarwal A. An extract of Glycyrrhiza glabra (GutGard) alleviates symptoms of functional dyspepsia: a randomized, double-blind, placebo-controlled study. Evidence-Based Complementary and Alternative Medicine. 2011 Jun 16;2012. DOI:  1155/2012/216970
17. Langmead L, Feakins RM, Goldthorpe S, Holt H, Tsironi E, De Silva A, Jewell DP, Rampton DS. Randomized, double‐blind, placebo‐controlled trial of oral aloe vera gel for active ulcerative colitis. Alimentary pharmacology & therapeutics. 2004 Apr 1;19(7):739-47. DOI: 1111/j.1365-2036.2004.01902.x
18. Garcia Vilela E, De Lourdes De Abreu Ferrari M, Oswaldo Da Gama Torres H, Guerra Pinto A, Carolina Carneiro Aguirre A, Paiva Martins F, Marcos Andrade Goulart E, Sales Da Cunha A. Influence of Saccharomyces boulardii on the intestinal permeability of patients with Crohn's disease in remission. Scandinavian journal of gastroenterology. 2008 Jan 1;43(7):842-8. DOI: 1080/00365520801943354