Food Allergy, Intolerance, and Sensitivity

Good food means good health. But sometimes even good, fresh food can make a person sick. When food causes an allergic reaction, stomach cramps, weight loss, or fatigue, then it’s time to work with a health professional to determine whether an ordinary food may be causing your health problems. This Special Health Report, Food Allergy, Intolerance, and Sensitivity, provides information and advice about the wide range of food-related illnesses and how you can protect yourself and your family.

Food Allergy, Intolerance, and Sensitivity Cover

The Sensitive Gut

When your digestive system is running smoothly, you tend not to think about it. Once trouble begins, your gut — like a squeaky wheel — suddenly demands your attention. This Special Health Report, The Sensitive Gut, covers the major sources of gastrointestinal distress: irritable bowel syndrome, gastric reflux, upset stomach, constipation, diarrhea, and excess gas. It also includes a special Bonus Section describing how…

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Good food means good health. That is the common wisdom. But sometimes even good, fresh food can make a person sick. When fresh strawberries trigger an allergic reaction; when a glass of milk induces stomach cramps; when daily bread induces weight loss and fatigue; then it’s time to work with a health professional to determine whether an ordinary food may be causing your health problems. The most common type of food-related illness by far is caused by food contaminated with infectious microbes. A bowl of cherries can harbor bacteria. A turkey burger can do the same. That’s why this Special Health Report, Food Allergy, Intolerance, and Sensitivity, provides information and advice about the wide range of food-related illnesses — from allergy to food poisoning — and how you can protect yourself and your family.

This report was created by the editors of Harvard Health Publishing in collaboration with Ciaran P. Kelly, M.D., Chief, Blumgart Firm; Director, Celiac Center, Beth Israel Deaconess Medical Center; Professor of Medicine, Harvard Medical School; and Lynda C. Schneider, M.D., Program Director, Allergy, Children's Hospital Boston; Associate Professor of Pediatrics, Harvard Medical School. 44 pages. (2011)

  • The digestive and immune systems
    • The digestion process
  • Contaminated food
    • The microbes among us
    • Poisonous foods
    • If you get sick
  • Food intolerance and sensitivity
    • Lactase deficiency
    • Histamine intolerance
    • Impaired complex carbohydrate digestion
  • Gluten-triggered conditions
    • Celiac disease
    • Gluten sensitivity
  • SPECIAL BONUS SECTION: Ten steps to safer eating
  • Conditions that can be aggravated by foods
    • Migraines
    • Hot flashes
    • Hyperactivity
    • Gout
    • Acid reflux
  • When foods interact with drugs
    • Drugs and meals
    • The cytochrome p450 connection
  • Food allergies
    • Setting the stage for an allergic reaction
    • Why you have food allergies
    • Diagnosing food allergy
    • Reducing the threat of anaphylaxis
    • Living with food allergy
    • Adult-onset food allergies
  • When white blood cells inflame the digestive system
    • Diagnosing EGID
    • Treating EGID
  • Resources
  • Glossary

Gluten sensitivity

Gluten sensitivity, a separate condition from celiac disease, is associated with many of the same symptoms as lactose intolerance — gas, bloating, and diarrhea — but also with additional and more troubling symptoms, including fatigue and dizziness. The condition has baffled clinicians and patients alike for years, because it has been difficult to even imagine how gluten could trigger such a host of seemingly unrelated symptoms. One theory is that gluten sensitivity is part of the “undersea” portion of the “celiac iceberg.” However, recent studies of people who do not to have celiac disease but still develop symptoms when they ingest gluten indicate that gluten sensitivity is separate and distinct from celiac disease.

Symptoms of gluten sensitivity

  • Gas
  • Bloating
  • Abdominal cramps
  • Diarrhea
  • Fatigue
  • Balance problems

In March 2011, a group of researchers in Italy and the United States reported evidence for a potential mechanism to account for gluten sensitivity. Patients with many of the symptoms of celiac disease but no signs of intestinal damage were found to produce an abnormally high number of proteins that play a role in activating inflammation — the immune system’s first line of defense — and an abnormally low number of suppressor T cells, which dampen down inflammation once the “threat” is removed. The inflammatory response, like that brought against the flu virus, can cause fatigue and dizziness. However, because the intestinal villi are not damaged, nutrient absorption isn’t affected.

The new evidence has established gluten sensitivity as a real condition apart from celiac disease, but it hasn’t yet yielded a diagnostic test or new treatment for gluten sensitivity. Thus, gluten sensitivity is still a diagnosis of elimination. Patients in whom celiac disease has been ruled out are asked to eradicate all gluten from their diet. If their symptoms improve, they are deemed gluten sensitive.

Gluten sensitivity can be avoided by excluding all gluten-containing foods and products from your diet. Unlike people with celiac disease, those with gluten sensitivity aren’t risking intestinal injury, defective nutrient absorption and serious complications by eating a little gluten. So if you have gluten sensitivity, you have a little more latitude to experiment than do people with celiac disease. You may want to test whether you can eat foods like soy sauce that have minimal gluten concentrations, or enjoy a bite of cake now and then without repercussions.

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I have a number of the Harvard Health publications, and found this to be one of the most useful to me. Obviously it is not a medical textbook, but for me and my wife it provided us with a clear view of the "basics" on a subject about which there is a great deal of misinformation about, particularly on the Internet. It helped me pin down the nature of a gut problem which has bothered me off and on for more than 60 years, and which had baffled a lot of MDs during that period. I would recommend it to anyone with problems or questions in this area, at least as a basis for further study.
PRO:Handy beginner reference, but only if you have not yet read much on this topic. The writing is suitable for an average adult reading level, so you won't be daunted by a lot of jargon. CON:It may be too basic if you have already been researchng the topic via the internet or other reference books. Most of the information is avbailable for free on reputable websites such as the National library of Medicine and MedlinePlus. Personally I found it redundant, as I already had learned the basics elsewhree, but but for adult or teen total beginners it may be a useful place to start.
I feel that the gluten intolerance section should have more detail. What is in fat free cottage cheese, cream cheese, sour cream etc. that contains gluten. For instance, does 2% fat cottage cheese contain gluten??etc. Thank you, Zoe Veasey
Interesting that carbohydrates, gluten in particular, seem to be the source of distress. Genetic studies suggest that the human species has only recently begun developing the ability to digest starches (and perhaps other carbs?) Since going high fat, low to no carbs, my gas, reflux and weight problems have all disappeared. My endocrinologist suggested there is also data that my joint pains disappeared because of my new diet. Wow! But of course no mainstream medical source can recommend eliminating carbs.