Life Extension Magazine September 2010
What’s Really Making You Sick?
By Lauren Russel, ND, and Jonathan V. Wright, MD
Inconvenient and Expensive Test Methods
Diagnosis of a food sensitivity depends on many things, including your previous medical history, comprehensive physical examination, oral food challenges, and results of laboratory testing.7,29,30 There are several types of laboratory tests designed to detect food allergies and sensitivities. One of the best known allergy tests measures for food-specific IgE antibodies using a skin prick test, in which the patient is exposed to a variety of foods scratched into the skin and observed for a local allergic reaction. Although fairly accurate for inhalant allergies, the positive predictive accuracy of skin prick tests for food allergens is less than 50% compared to double-blind, placebo-controlled food challenges.31
There are two types of skin testing that may be far more accurate, but they take considerably more time. Performed almost exclusively by physician-members of the American Academy of Environmental Medicine (www.aaem.com), they’re termed “provocation-neutralization” and “serial dilution titration.” In addition to accurate testing, these techniques can help you identify and resolve your food sensitivity issues.
The “radioallergosorbent” test (RAST) and its successor, the “enzyme-linked immunoassay” (ELISA) are both blood tests used to detect food-specific IgE and/or IgG responses. Most commonly, food sensitivities are assessed using the ELISA test to detect IgG4 antibodies to food antigens, a subclass of IgG antibodies. Between 45 and 95 separate foods are measured. Accurate testing requires the patient to eat a wide range of foods within 3 weeks of assessment for IgG4 exposure to be present.
A Cutting-Edge Detection Method
Fortunately, an advance in diagnostic technology is now available that uses a very small amount of your blood to assess your sensitivity to 45 of the most common food antigens. Instead of requiring blood to be drawn from a vein, a small lancet is used to prick the finger so that a few drops of blood can be placed on a blood spot collection card. After the card is allowed to air dry, it is returned to the laboratory for assessment of IgG4 antibodies to food.
Known as the FoodSafe™ test, this is a simple and effective way for you and your doctor to detect the foods your body can’t handle. Each test report comes with a personalized profile showing how you tested against 45 foods most commonly associated with food sensitivities. The report indicates whether the levels of antibodies to the various foods suggest they are “safe” to eat, best to eat in moderation, or foods you should avoid entirely. Results are ranked and reported to you and your doctor as either safe or not safe.
After reviewing your test results, you may wonder what’s left for you to eat, since it’s not uncommon for many of the foods causing you the most trouble to be your favorite foods. Although each person’s plan may vary, more than likely your doctor will ask you to avoid the foods that are considered “unsafe” on your test results. Generally, this means going on an elimination diet for up to 30 days, during which time you avoid the foods that you are most reactive to in your profile. It’s a good idea to also avoid foods that are from the same “family” as those foods you are reactive to. For example, sensitivity to one kind of shellfish may mean that you should avoid other types of shellfish for a certain length of time. For this reason, your doctor may prescribe a diet that contains foods less likely to trigger reactions and allows your body and gastrointestinal tract time to recover from the continuous assault it has unknowingly experienced.
Does this mean you will never be able to eat these foods again? The answer depends on your problem foods and your symptoms. Obviously, if your allergic reaction is life-threatening, you’ll be advised to permanently avoid that food. There are other reasons for life-long avoidance, too, such as gluten intolerance, which makes absorption of many nutrients difficult and good health impossible.
In other cases, you may be able to add a food back into your diet after a period of avoidance, as long as you eat it less frequently. One approach is to avoid the “reactive” foods for a period of time specified by your physician, typically 2 to 4 weeks, and then re-introduce these foods back into your diet to see if you respond to them.32
When avoiding foods during trial periods, eliminate even very small amounts! Reading food labels and understanding the many ways foods are listed as ingredients is important. By avoiding foods for this length of time, your body and immune system have time to recover, and you’ll have a more accurate idea about whether the food can be re-introduced or not, and if so, how often.
During the “challenge” (re-introduction) phase of the elimination diet trial, your doctor may ask you to re-introduce one food that you were reactive to once every 4 days to see if symptoms recur. If you don’t develop symptoms, then it may be possible to include the food in your diet, but less frequently. If symptoms do recur, then you may have to avoid the food for 6 months or longer.
Rotation diets have been shown to be very effective for treating food sensitivities in some people.33 On the rotation diet, a food is only eaten once every 4 days, allowing the body to clear it between exposures. The rotation diet helps you avoid too much exposure to any one food and gives you a better idea what foods are contributing to your symptoms, in case they recur. If you are more sensitive to certain foods or clear them more slowly from the body, you may need to eat them no more frequently than once every 7-10 days.
Your plan may also include taking omega-3 fatty acids to lessen inflammation, probiotics to replenish gastrointestinal flora, and other products like glutamine that promote intestinal healing.9,34-36 One of the primary benefits of food sensitivity testing is that your doctor can more easily customize your approach based upon your history and test results.
An estimated 45-60% of the general population suffers from serious symptoms and health conditions whose causes cannot be identified. Many of them have no idea that various forms of food sensitivity may be to blame. Reactions to food are the hidden cause behind an extraordinary array of health problems, including headaches and migraines, insomnia, and digestive disorders. An advanced, convenient diagnostic blood test technology called the FoodSafe™ test now enables you and your doctor to zero in on the potential foods behind your health problems and methodically eliminate them—for lifelong relief and optimal health.
If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.
1. Shamberger R. Types of food allergy testing. The Townsend Letter. 2008 Jan;294:71-2.
2. Breneman JC. Basics of Food Allergy. Springfield, Illinois: Charles C. Thomas, Publishers, Ltd.;1978:8.
3. Gaby AR. The role of hidden food allergy/intolerance in chronic disease. Altern Med Rev. 1998 Apr;3(2):90-100.
4. Sicherer SH. Manifestations of food allergy: evaluation and management. Am Fam Physician. 1999 Jan 15;59(2):415-24, 429-30.
5. Volpi N, Maccari F. Serum IgG responses to food antigens in the italian population evaluated by highly sensitive and specific ELISA test. J Immunoassay Immunochem. 2009;30(1):51-69.
6. Parker SL, Sussman GL, Krondl M. Dietary aspects of adverse reactions to foods in adults. CMAJ. 1988 Oct 15;139(8): 711-8.
7. Sicherer SH. Clinical aspects of gastrointestinal food allergy in childhood. Pediatrics. 2003 Jun;111(6 Pt 3):1609-16.
8. Zeiger RS. Food allergen avoidance in the prevention of food allergy in infants and children. Pediatrics. 2003 Jun;111(6 Pt 3):1662-71.
9. Drisko J, Bischoff B, Hall M, McCallum R. Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. J Amer Coll Nutr. 2006 Dec 15;(6):514-22.
10. Baldassarre M, Laneve AM, Grosso R, Laforgia N. Celiac disease: pathogenesis and novel therapeutic strategies. Endo Metab Immune Disord Drug Targets. 2008 Sep;8(3):152-8.
11. Hvatum M, Scott H, Brandtzaeg. Serum IgG subclass antibodies to a variety of food antigens in patients with coeliac disease. Gut. 1992 May;33(5):632-8.
12. Fine K. Early diagnosis of gluten sensitivity: Before the villi are gone. Lecture presented at the Greater Louisville Celiac Sprue Support Group. June, 2003.
13. Available at: http://www.medscape.com/viewarticle/573934. Accessed June 11, 2010.
14. Lieberman S. The Gluten Connection. How Gluten Sensitivity May Be Sabotaging Your Health--And What You Can Do to Take Control Now. New York, NY: Rodale Books; 2006: 86-93.
15. Zar S, Kumar D, Benson MJ. Food hypersensitivity and irritable bowel syndrome. Aliment Pharmacol Ther. 2001 Apr;15(4):439-49.
16. Zar S, Mincher L, Benson MJ, Kumar D. Food-specific IgG4 antibody-guided exclusion diet improves symptoms and rectal compliance in irritable bowel syndrome. Scand J Gastroenterol. 2005 Jul;40(7):800-7.
17. Camilleri M, Choi MG. Review article: Irritable bowel syndrome. Aliment Pharmacol Ther. 1997 Feb; 11(1):3-15.
18. Horwitz BJ, Fisher RS. The irritable bowel syndrome. N Eng J Med. 2001 Jun;344(24): 1846-50.
19. Mertz HR. Irritable bowel syndrome. N Eng J Med. 2003 Nov 27;349(22):2136-46.
20. Atkinson W, Sheldon TA, Shaath N, Whorwell PJ. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomized controlled trial. Gut. 2004 Oct;53(10):1459-64.
21. Whorwell P, Lea R. Dietary treatment of the irritable bowel syndrome. Curr Treat Options Gastroenterol. 2004 Aug;7(4):307-16.
22. Whorwell PJ, Bentley KJ, Atkinon W, Sheldon TA. IgG antibodies to foods in IBS. Gut. 2005 Aug;54(8):1204.
23. MacDermott RP. Treatment of irritable bowel syndrome in outpatients with inflammatory bowel disease using a food and beverage intolerance, food and beverage avoidance diet. Inflamm Bowel Dis.2007;13(1):91-6.
24. Yang CH, Li YQ. The therapeutic effects of eliminating allergic foods according to food-specific IgG antibodies in irritable bowel syndrome. Zhonghua Nei Ke Za Zhi. 2007 Aug;46(8):641-3.
25. Isolauri E, Rautava S, Kalliomaki M. Food allergy in irritable bowel syndrome: new facts and old fallacies. Gut. 2004 Oct; 53(10):1391-3.
26. Wilson CW, Kirker JG, Warnes H, O’Malley M. The clinical features of migraine as a manifestation of allergic disease. Postgrad Med J. 1980 Sep;56(659):617-21.
27. Mueller LL.Diagnosing and managing migraine headache. J Am Osteopath Assoc. 2007 Nov;107(10 Suppl 6):ES10-16.
28. Egger J, Carter CM, Wilson J, Turner MW, Soothill JF. Is migraine food allergy? A double-blind controlled trial of oligoantigenic diet treatment. Lancet. 1983 Oct 15; 2(8355):865-9.
29. Mansueto P, Montalto G, Pacor ML, et al. Food allergy in gastroenterologic diseases: Review of literature. World J Gastroenterol. 2006 Dec 28; 12(48):7744-52.
30. Gerez IF, Shek LP, Chng HH, Lee BW. Diagnostic tests for food allergy. Singapore Med J. 2010 Jan;51(1):4-9.
31. Sampson HA. Comparative study of commercial food antigen extracts for the diagnosis of food hypersensitivity. J Allergy Clin Immunol. 1988 Nov;82(5 Pt 1):718-26.
32. Truswell AS. Food sensitivity. Br Med J (Clin Res Ed). 1985 Oct 5;291(6500): 951-5.
33. Rinkel H, Randolph T, Zeller M. Food Allergy. Springfield, IL: Charles C. Thomas Publishers; 1951.
34. Drisko JA, Giles CK, Bischoff BJ. Probiotics in health maintenance and disease prevention. Altern Med Rev. 2003 May;8(2):143-55.
35. Wall R, Ross RP, Fitzgerald GF, Stanton C. Fatty acids from fish: the anti-inflammatory potential of long-chain omega-3 fatty acids. Nutr Rev. 2010 May;68(5):280-9.
36. Miller AL. Therapeutic considerations of L-glutamine: a review of the literature. Altern Med Rev. 1999 Aug;4(4):239-48.