Age & Food Reactivity: Examining the Correlations

 In Bacterial/Viral Infections, Geriatrics

Tolle Causam

Chad Larson, NMD, DC, CCN, CSCS

Over the years, we’ve learned more about the ways our bodies react to specific foods, and even the ways in which specific foods are prepared. We’ve successfully spotlighted common foods and environmental triggers of autoimmune reactions, intolerance, sensitivities, you name it. However, awareness levels are decidedly lower when we shift the focus to how our bodies react to different foods as we enter our “golden years.” We’ve learned a lot, but half the battle is getting the information out there.

As an example, a decrease in the production of the lactose-degrading enzyme, lactase, is very common with aging. In fact, about 65% of the global population has a reduced ability to digest lactose after infancy, according to the National Institutes of Health (NIH).1 Slowing or weakening of contractions in the large intestine, bacterial overgrowth in the small intestine, and slower emptying of the stomach are among other common symptoms associated with changes in digestive function that come with age. Medications and age-related illnesses can also trigger such symptoms.

It is common, as we age, to discover that a food that was once an absolute favorite has now become a significant threat for discomfort. So what is the cause? Because the different causes of digestive tract issues can produce similar symptoms, it can be tricky to get to the root of the problem.

Food Intolerance vs Allergy

Because an aging digestive system can have a harder time digesting certain foods and is also more susceptible to intestinal hyperpermeability,2-5 it is possible to develop food intolerances, sensitivities, and allergies in later adulthood. More than 20% of people in industrialized countries suffer from food allergy or food intolerance.6 Although many of the symptoms mirror each other, food intolerance, food sensitivity, and food allergy are distinct from each other.

Food Intolerance

Food intolerance is a digestive issue rather than immune mediated. Although not life-threatening, intolerance may result in some of the same symptoms caused by food allergy, including bloating, cramping, gas, diarrhea, nausea, joint inflammation, and pain. Other symptoms can include headache, brain fog, nervousness, or irritability. Intolerance to a food is usually due to the lack of an enzyme needed to break down a particular food, eg, deficient lactase in the case of a lactose intolerance. Individuals with gluten sensitivity have difficulty digesting the gluten protein. While enzyme deficiencies vary between individuals, some of the more common food intolerances are to dairy, gluten, eggs, caffeine, peanuts, and corn.

Food Sensitivities

Compared to food allergies and food intolerances, food sensitivities are perhaps the most complicated of these 3 classifications, as it combines many of the nebulous non-immunologic symptoms of food intolerances with the complex immune responses that are typical of food allergies (characterized by delayed IgG and IgA immune responses rather than the faster IgE variety). Testing for food sensitivities is especially important because while symptoms can be less severe or obvious than those of food allergies, the possibility of long-term damage and suffering is a real danger. Celiac disease is one example of this. When individuals with celiac disease ingest gluten, their immune systems respond by attacking the small intestine, ultimately damaging the intestinal tissue. If left untreated, celiac disease can lead to the development of other autoimmune disorders. Celiac disease (and its sequelae) is mediated by IgA and, in some atypical cases, IgG.

Food Allergy

True food allergy, which represents only 2-5% of food intolerances,6 occurs when the immune system mistakes a food antigen as a foreign invader and attacks it. High levels of food-specific immunoglobulin E antibodies are produced, stimulating the release of histamine. The reaction can manifest as hives, swelling, nausea, vomiting, diarrhea, stomach pain, bloating, inflammation, irregular heartbeat, or restricted breathing when life-threatening anaphylaxis occurs. The most common food allergens include milk, wheat, tree nuts, soy, peanuts, and shellfish.

Diagnostic Tips

A food intolerance or food sensitivity can be as problematic as an allergy. The following suggestions are recommended for sorting them out in your patients:

  1. Skin-prick testing and IgE antibody blood tests can help detect allergies, which can be life-saving.
  2. Less is more. Overeating can cause feelings of discomfort, bloating, nausea, and acid reflux. As stomachs empty more slowly and elasticity weakens with age, portions should be reduced accordingly to avoid becoming too full and provoking symptoms of maldigestion.
  3. For identifying food intolerance, an elimination diet can be helpful. However, eliminating foods and slowly reintroducing them back into one’s diet 1 food at a time, although helpful, can also be a long, grueling process that doesn’t always lead to clear results. A high-quality laboratory specializing in functional immunology and autoimmunity can provide a fast and easy way to determine whether a patient has developed an intolerance to specific foods.
  4. Rule out disease. Because of the crossover in symptoms, digestive system issues can easily be mistaken for more serious conditions. For example, what seems like lactose intolerance can in some cases be celiac disease or irritable bowel syndrome. Inflammation and joint pain, which are common symptoms of food allergies and sensitivities, can also be caused by arthritis. Fortunately, there are tests available that can assist with the early detection of connective tissue disorders, as well as monitor the effectiveness of related treatment protocols.


As we age, a variety of immunological insults can accumulate, making us more susceptible to losing tolerance to a whole host of environmental antigens, including dietary proteins. If symptoms persist, testing for food sensitivities can be an important therapeutic opportunity to help individualize a treatment protocol and mitigate risk factors for chronic immune-mediated reactivity, inflammation, and disease.


  1. Genetics Home Reference. Lactose Intolerance. July 9, 2019. National Institute of Health Web site. Accessed July 10, 2019.
  2. Nagpal R, Mainali R, Ahmadi S, et al. Gut microbiome and aging: Physiological and mechanistic insights. Nutr Healthy Aging. 2018;4(4):267-285.
  3. Qi Y, Goel R, Kim S, et al. Intestinal Permeability Biomarker Zonulin is Elevated in Healthy Aging. J Am Med Dir Assoc. 2017;18(9):810.e1-810.e4.
  4. Valentini L, Ramminger S, Haas V, et al. Small intestinal permeability in older adults. Physiol Rep. 2014;2(4):e00281.
  5. Thevaranjan N, Puchta A, Schulz C, et al. Age-Associated Microbial Dysbiosis Promotes Intestinal Permeability, Systemic Inflammation, and Macrophage Dysfunction. Cell Host Microbe. 2017;21(4):455-466.
  6. Zopf Y, Baenkler HW, Silbermann A, et al. The differential diagnosis of food intolerance. Dtsch Arztebl Int. 2009;106(21):359-369.

Chad Larson, NMD, DC, CCN, CSCS, holds a Doctor of Naturopathic Medicine degree from Southwest College of Naturopathic Medicine, and a Doctor of Chiropractic degree from Southern California University of Health Sciences. Dr Larson is an advisor and consultant on the Clinical Consulting Team for Cyrex Laboratories. He is also a certified clinical nutritionist and a certified strength and conditioning specialist. Dr Larson particularly pursues advanced developments in the fields of endocrinology, orthopedics, sports medicine, and environmentally-induced chronic disease.

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