We all know someone with a “cast-iron” stomach, but most of us know more people with food intolerances. While food allergies are taken quite seriously, food sensitivities are sometimes made light of although their resulting symptoms can be just as painful or debilitating. Initially, GI distress after eating may be written off as food poisoning or vague bellyaches dismissed as anxiety unless someone notices a pattern. While there is testing for food allergies, it is more complicated to pinpoint the source of a food sensitivity, or more likely, sensitivities.
In fact, about 20% of the population of Western countries has some food sensitivity, the most common being lactose intolerance. Reactivity to a food or its components can be transient or chronic. Individual responses are dependent on the amount eaten (dose), combinations with other foods, how often it is eaten, how quickly and thoroughly it is broken down, and whether there have been recent GI infections, antibiotic intake, or other food indiscretions. Genetics, hormonal changes, and how well your liver, kidneys, and pancreas work also influence sensitivities. The gastrointestinal (GI) tract becomes less tolerant as we age and women in particular may notice new food sensitivities during perimenopause.
Recurrent GI symptoms are both confusing and troubling—is it something I ate or is something else going on? It’s best to see your physician to sort out the symptoms, order appropriate tests, and make sure there is no serious disease. If there isn’t a clear medical reason for your discomfort after a work-up, you might seek an in-depth diet evaluation and guidance from a functional medicine physician or registered dietitian/ nutritionist. Take care with online searches. There is a lot of misinformation on the Internet regarding diets from persons with dubious credentials so beware. Many just want to sell you something. (Not me.)
The following list summarizes some food categories associated with GI complaints and I will elaborate on each of these groups in later articles. While it would be nice to be able to blame one or a few foods for GI distress, sometimes discomfort is encountered from swallowing air when wolfing down food or drinking carbonated beverages. Incomplete chewing (eating too fast, painful teeth, or poorly fitting dentures) also leads to air swallowing. So, consider your food habits as well as food choices.
FODMAPs: The term FODMAP is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols, all types of carbohydrates. Fermentable oligosaccharides are sugars strung together to create undigestible “resistant” starches. The remaining terms refer to double and single sugars and sugar alcohols, respectively. Gut fermentation of FODMAPs leads to the production of gas resulting in distension, flatus (AKA farting), abdominal pain, and cramping. Occasionally, fermentation products draw water into the colon and cause diarrhea. FODMAPs can exacerbate irritable bowel disease by aggravating the stretch sensors with gas.
Lectins: A current hot dietary topic, lectins are proteins with a tendency to bind to sugars. Plant lectins cause gut and other adverse bodily reactions in insects and other animals that eat their leaves, fruits, and seeds. The premise is that grains, beans, and other cultivated agricultural products are relatively new (evolutionarily) to humans and our bodies have not evolved to digest them (and their associated lectins) properly. Although the focus is primarily on plant lectins, they are found in most living things and facilitate numerous functions: cell signaling, immune function, and control of cell growth and death in animals and those defensive and protective functions in plants. Lectins are being blamed for not only GI distress, but also obesity, diabetes, and autoimmune diseases.
Gluten: Until unseated by lectins, gluten was the fashionable food to avoid. Gluten is a protein found in wheat, barley, and rye. It is resistant to breakdown by heat or stomach acid and is linked to increased intestinal permeability or “leaky gut”.[1] Decades ago, celiac disease (CD) was the only recognized gluten-related disease, and its prevalence has increased with wheat becoming a dominant food grain worldwide. Individuals with CD cannot eat any amount of gluten-containing grain without suffering serious consequential damage to the lining of the small intestinal.
Non-Gluten Compounds found in Gluten-containing Foods: Not everyone with discomfort after eating wheat, barley and rye has CD. Non-celiac gluten sensitivity (NCGS) is a condition of intolerance to wheat and perhaps other gluten-containing grains when tests for celiac and wheat allergy are negative. Possible causes include wheat germ agglutinin (a lectin), amylase-trypsin inhibitors (ATI) and fructan, the wheat-related FODMAP.[2] [3]
Microbial Transglutaminases: Persons with Celiac Disease should also be aware of an unlabeled compound found in many non-organic foods—microbial transglutaminase (mTG). This compound is immunologically like tissue transglutaminase, the enzyme celiacs develop antibodies to. The ability of transglutaminases to form cross-linkages with proteins has led the food industry to use them in binding together chunks or ground bits of meat or seafood, hence its moniker, “meat glue.” Some examples include surimi (fake crab), chicken nuggets, and deli meats. It’s also used to emulsify, stabilize, and improve elasticity in dairy products and baked goods, including gluten-free creations. Considered a “processing agent” rather than an additive, there is no requirement to be on an ingredient list in the US.
Histamine Intolerance: Histamines are typically associated with allergic reactions like hay fever, beestings, and true food allergies. Exposure to an allergen causes the body to release of histamine from cells in the affected area: skin, nose, throat, heart, blood vessels, respiratory passages, and the GI tract. Histamine Intolerance also causes similar symptoms; however, foods are the source of the histamines rather than the body. These non-allergic reactions can be mild (runny nose and congestion) to moderate (hives, itching, and headaches) to severe (swelling and shortness of breath). GI symptoms include nausea, vomiting, bloating, cramping, and diarrhea. Episodes are often intermittent, so it is difficult to sort out. While some foods contribute to a histamine load, others may facilitate histamine release, and still other foods (or medicines) contain compounds that compete with histamine for the use of a breakdown enzyme, thus keeping histamine levels high.[4] Even not-so-sensitive persons who consume large amounts or combinations of certain histamine-containing or -releasing foods may develop runny nose, nasal congestion, itching, or GI discomfort.
Saponins: Saponins are found primarily in plant tissues (leaves, stems, roots, fruits, and seeds). They have a soap-like character and protect plants from herbivores and insects with their unappealing taste and tendency toward gut irritation. Saponins occur in small amounts in many foods, but the greatest amounts are found in chickpeas (garbanzo beans), soybeans, alfalfa sprouts, peanuts, lentils, navy and kidney beans, peas, oats, and quinoa. Because of their foaming and emulsifying qualities, the food industry also uses both natural and synthetic saponins as additives.[5]
Glyphosate: “Factory-farmed” grains and soybeans are often treated with an herbicide called glyphosate to dry them out prior to harvesting. Initially approved to kill weeds in 1974, glyphosate use has grown exponentially and is now the best-selling herbicide worldwide. Glyphosate-based herbicides are usually combined with other (supposedly safe) ingredients to improve solubility, sticking, and absorption and are found under many brand names (such as Roundup®). Its manufacturers claim it is safe for humans with no acute toxic effects, but glyphosate has long-term indirect GI effects because it harms our beneficial intestinal bacteria. Crops treated with glyphosate are used in baked goods, cereals, snacks, cooking oils, vegetarian protein sources, beer, and wine.[6] Depending on the total residues consumed, an individual may develop GI distress.
Additives: To produce some of our favorite ultra-processed foods and mixes, food scientists take refined carbohydrate or protein building blocks and add salt, fat, sugar, high fructose corn syrup, artificial sweeteners, herbs, spices, artificial flavorings, colorants, thickeners, emulsifiers, foaming agents, preservatives, and sometimes vitamins and minerals to create many of our favorite foods. While these additives are labeled GRAS (generally recognized as safe) by the FDA, some have been linked to negative influences on the gut including inflammation and alterations to the protective mucous layer, at least in mice or in the lab.[7] [8] [9]
So, what can you eat??? Your best bet is to consume a little of everything that doesn’t bother you, dine or order out less frequently, and avoid ultra-processed foods. If you can afford it, eat more organic products or at least, those grown with integrated pest management (IPM)techniques. Eat colorful (including white) fruits and vegetables, use herbs and spices, and drink teas to provide beneficial antioxidant and anti-inflammatory phytochemicals for your body and your gut bacteria. Overall, it is worth eating better not only for fewer symptoms of GI distress, but also for better health. Future posts will help guide you.
[1] Karin de Punder and Leo Pruimboom, “The Dietary Intake of Wheat and Other Cereal Grains and Their Role in Inflammation,” Nutrients 5, no. 3 (March 12, 2013): 771–87, https://doi.org/10.3390/nu5030771.
[2] Maria Gloria Mumolo et al., “Is Gluten the Only Culprit for Non-Celiac Gluten/Wheat Sensitivity?,” Nutrients 12, no. 12 (December 10, 2020): E3785, https://doi.org/10.3390/nu12123785.
[3] Feliznando Isidro Cárdenas-Torres et al., “Non-Celiac Gluten Sensitivity: An Update,” Medicina (Kaunas, Lithuania) 57, no. 6 (May 24, 2021): 526, https://doi.org/10.3390/medicina57060526.
[4] Oriol Comas-Basté et al., “Histamine Intolerance: The Current State of the Art,” Biomolecules 10, no. 8 (August 14, 2020): E1181, https://doi.org/10.3390/biom10081181.
[5] Kartik Sharma et al., “Saponins: A Concise Review on Food Related Aspects, Applications and Health Implications,” Food Chemistry Advances 2 (October 1, 2023): 100191, https://doi.org/10.1016/j.focha.2023.100191.
[6] Diogo Soares et al., “Glyphosate Use, Toxicity and Occurrence in Food,” Foods 10, no. 11 (November 12, 2021): 2785, https://doi.org/10.3390/foods10112785.
[7] D. Partridge et al., “Food Additives: Assessing the Impact of Exposure to Permitted Emulsifiers on Bowel and Metabolic Health – Introducing the FADiets Study,” Nutrition Bulletin 44, no. 4 (December 2019): 329–49, https://doi.org/10.1111/nbu.12408.
[8] Federica Laudisi, Carmine Stolfi, and Giovanni Monteleone, “Impact of Food Additives on Gut Homeostasis,” Nutrients 11, no. 10 (October 1, 2019): 2334, https://doi.org/10.3390/nu11102334.
[9] Aaron Lerner and Torsten Matthias, “Changes in Intestinal Tight Junction Permeability Associated with Industrial Food Additives Explain the Rising Incidence of Autoimmune Disease,” Autoimmunity Reviews 14, no. 6 (June 1, 2015): 479–89, https://doi.org/10.1016/j.autrev.2015.01.009.
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