Why are Food Intolerances Increasing?

According to a study done from 1991 to 1994, food intolerances affected around 12 percent of the population.¹⁾International prevalences of reported food allergies and intolerances. Comparisons arising from the European Community Respiratory Health Survey (ECRHS) 1991–1994 | European Journal of Clinical Nutrition https://doi.org/10.1038/sj.ejcn.1601159 But more recent surveys suggest that number could be as high as 25 percent today.²⁾Allergy and intolerance | NSW Food Authority

What is a food intolerance?

Food intolerances are adverse reactions to food that are not triggered by the immune system. They are reactions not only to proteins but to other food components as well. Several different mechanisms drive food intolerances. People could be intolerant to foods because they lack certain enzymes. Or intolerances could be due to the disruption of microbes that live in our gut and help us digest specific foods. It is also possible for chemicals in food to have unpleasant or toxic effects on body functions. As for symptoms, they widely vary in onset and severity. Diagnosing intolerances can therefore get tricky. Usually though, diagnosis involves a trial-and-error approach: intake of suspected foods is avoided or reduced for a short period, then reintroduced to assess the body’s response.³⁾Tuck CJ, Biesiekierski JR, Schmid-Grendelmeier P, Pohl D. Food Intolerances. Nutrients. 2019 Jul 22;11(7):1684. doi: 10.3390/nu11071684

Common food intolerances

Probably the most well-known food intolerance is lactose intolerance. It happens when the body does not have enough of the enzyme lactase to break down the sugar lactose in milk and dairy products. Similarly, histamine-intolerant people lack the enzymes for breaking down histamine. Histamine is a chemical found in meat, fish, and fruits like bananas and pineapples. It can also be present in cheese, chocolate, and wine. Intolerance to lactose or histamine results from disturbed gut microbiota, which are the source of the needed enzymes. Taking probiotic supplements, which restore proper gut flora, can help with these particular intolerances.⁴⁾Gargano D, Appanna R, Santonicola A, De Bartolomeis F, Stellato C, Cianferoni A, Casolaro V, Iovino P. Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns. Nutrients. 2021 May 13;13(5):1638. doi: 10.3390/nu13051638⁵⁾Ahn, Sung-Il et al. Effects of probiotics administration on lactose intolerance in adulthood: A meta-analysis. Journal of Dairy Science, Volume 106, Issue 7, 4489 – 4501 https://doi.org/10.3168/jds.2022-22762⁶⁾Smolinska S, Winiarska E, Globinska A, Jutel M. Histamine: A Mediator of Intestinal Disorders-A Review. Metabolites. 2022 Sep 23;12(10):895. doi: 10.3390/metabo12100895

Lactose is actually one of the common FODMAPs, which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. FODMAPs are carbohydrates that occur naturally in a wide range of foods. Other FODMAPs include fructose (for example, in apples, mangoes, and honey), fructans (found in wheat, onion, and garlic), galactans (present in legumes and nuts), and polyols (i.e., sugar alcohols like sorbitol and mannitol found in some fruits and vegetables). FODMAP intolerance happens because these carbohydrates are poorly absorbed into the bloodstream. As a result, they reach the far end of the colon, where they get fermented by bacteria there. These events cause symptoms like bloating, stomach pain, diarrhea, and constipation. Thus, a diet low in FODMAPs can benefit people with such digestive issues.⁷⁾Gargano D, Appanna R, Santonicola A, De Bartolomeis F, Stellato C, Cianferoni A, Casolaro V, Iovino P. Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns. Nutrients. 2021 May 13;13(5):1638. doi: 10.3390/nu13051638

When it comes to chemical intolerances, caffeine is a typical culprit. This substance is present mainly in coffee and tea, as well as in various sodas. People intolerant to caffeine experience negative effects when they consume it even in small amounts. They can get a headache, have a racing heartbeat, feel nervous, or have trouble sleeping. (These symptoms are different from conditions like acid reflux and gastric ulcers, which are worsened by high acid content in coffee.) Likewise, people can be intolerant to salicylates. These chemicals can be found naturally in foods (e.g., strawberries, cereals, and legumes) and in manufactured products (e.g., aspirin and toothpaste). Symptoms of salicylate intolerance usually involve the respiratory tract; they include a stuffy nose, sinus infection, and asthma. In some cases, the skin and the digestive system can be affected too. Symptoms include hives, gas, and abdominal pain. An effective way of dealing with chemical intolerances is to reduce or eliminate intake of the substances that cause them.⁸⁾Tuck CJ, Biesiekierski JR, Schmid-Grendelmeier P, Pohl D. Food Intolerances. Nutrients. 2019 Jul 22;11(7):1684. doi: 10.3390/nu11071684⁹⁾Gargano D, Appanna R, Santonicola A, De Bartolomeis F, Stellato C, Cianferoni A, Casolaro V, Iovino P. Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns. Nutrients. 2021 May 13;13(5):1638. doi: 10.3390/nu13051638¹⁰⁾Smith, Erin, Foxx-Orenstein, Amy, Marks, Lisa A. and Agrwal, Neera. “Food Sensitivity Testing and Elimination Diets in the Management of Irritable Bowel Syndrome” Journal of Osteopathic Medicine, vol. 120, no. 1, 2020, pp. 19-23. https://doi.org/10.7556/jaoa.2020.008

Effects of pesticides, especially glyphosate

Pesticides aim to protect plants from pests, weeds, or diseases. They come in various mixtures, called formulations, and are used worldwide to increase crop yields and improve the perceived quality of agricultural products.¹¹⁾Nicolopoulou-Stamati P, Maipas S, Kotampasi C, Stamatis P, Hens L. Chemical Pesticides and Human Health: The Urgent Need for a New Concept in Agriculture. Front Public Health. 2016 Jul 18;4:148. doi: 10.3389/fpubh.2016.00148¹²⁾Mesnage R, Defarge N, Spiroux de Vendômois J, Séralini GE. Major pesticides are more toxic to human cells than their declared active principles. Biomed Res Int. 2014;2014:179691. doi: 10.1155/2014/179691

Glyphosate is the active ingredient in Roundup®, the world’s most widely used herbicide (a pesticide that kills weeds and grasses). The chemical is also used for drying crops to speed up harvests. These two uses go a long way toward explaining why a lot of grains and legumes contain glyphosate residues. Unfortunately, glyphosate is toxic in several ways. It is made even more harmful by the supposedly inactive ingredients in weed-killing formulations. A study revealed that the Roundup® product was 125 times more toxic than glyphosate alone. On top of that, 8 out of 9 other pesticide formulations were up to a thousand times more harmful than their active ingredients alone.¹³⁾Mesnage R, Defarge N, Spiroux de Vendômois J, Séralini GE. Major pesticides are more toxic to human cells than their declared active principles. Biomed Res Int. 2014;2014:179691. doi: 10.1155/2014/179691

Plants produce the amino acids they need to survive through the shikimate pathway. Glyphosate shuts down this pathway by inhibiting the enzyme EPSP synthase. Glyphosate was initially believed to be safe for humans because the shikimate pathway is not found in mammals. However, it is present in microorganisms, including bacteria in the human gut. Harmful microbes such as E.coli and S. aureus have Class II EPSP synthase. This enzyme variant is more resistant to glyphosate compared to Class I EPSP synthase, which is more prominent in beneficial bacteria like Lactobacillus and Butyricicoccus. This means that glyphosate promotes an overabundance of harmful bacteria in the gut. Such imbalance is linked to inflammation and oxidative stress within the colon. Plus, lower levels of beneficial microbes impair the movement of food through the digestive system. All these negative effects are associated with diarrhea, abdominal pain, irritable bowel syndrome (IBS), and other gastrointestinal issues.¹⁴⁾Samsel A, Seneff S. Glyphosate, pathways to modern diseases III: Manganese, neurological diseases, and associated pathologies. Surg Neurol Int. 2015 Mar 24;6:45. doi: 10.4103/2152-7806.153876.¹⁵⁾Puigbò P, Leino LI, Rainio MJ, Saikkonen K, Saloniemi I, Helander M. Does Glyphosate Affect the Human Microbiota? Life (Basel). 2022 May 9;12(5):707. doi: 10.3390/life12050707¹⁶⁾Barnett JA and Gibson DL (2020) Separating the Empirical Wheat From the Pseudoscientific Chaff: A Critical Review of the Literature Surrounding Glyphosate, Dysbiosis and Wheat-Sensitivity. Front. Microbiol. 11:556729. doi: 10.3389/fmicb.2020.556729

Use of GMOs

Genetically modified organisms (GMOs) are plants, animals, or microbes whose DNA has been altered using laboratory-based techniques. Genetically modified (GM) crops are grown on more than 160 million hectares of land in at least 29 countries. Around the world, hundreds of millions of people eat GM foods directly and indirectly.¹⁷⁾Bawa AS, Anilakumar KR. Genetically modified foods: safety, risks and public concerns-a review. J Food Sci Technol. 2013 Dec;50(6):1035-46. doi: 10.1007/s13197-012-0899-1

Although genetic modification is ostensibly done to improve the taste and nutritional value of food, the main use of this technology is to make crops resistant to toxic pesticides. For example, Roundup®-Ready corn, soy, canola, and sugar beets contain a gene that produces a form of EPSP synthase insensitive to glyphosate. This means that farmers can more easily eliminate weeds without killing the crops. However, the weeds have been catching up, becoming more and more resistant to Roundup®, thus requiring greater application of herbicides.¹⁸⁾Samsel A, Seneff S. Glyphosate, pathways to modern diseases III: Manganese, neurological diseases, and associated pathologies. Surg Neurol Int. 2015 Mar 24;6:45. doi: 10.4103/2152-7806.153876.¹⁹⁾Harper D.R. ROUNDUP READY SOYBEANS: AN OVERVIEW OF THE TECHNOLOGY- iastate.edu

Perhaps unsurprisingly, the inserted genes in GMOs can produce novel substances that are either toxins themselves, or that cause unpredictable changes in metabolic processes, both of which pose health hazards. For instance, NK 603, a Roundup®-resistant variety of GM corn, has been found to cause kidney, liver, heart, and bone marrow problems in mice. Consumption of MON 810 and MON 863 — GM corn varieties resistant to insects — has also been linked to kidney and liver dysfunction. MON 863 has even been associated with a rise in blood glucose and triglyceride levels.²⁰⁾Bawa AS, Anilakumar KR. Genetically modified foods: safety, risks and public concerns-a review. J Food Sci Technol. 2013 Dec;50(6):1035-46. doi: 10.1007/s13197-012-0899-1²¹⁾de Vendômois JS, Roullier F, Cellier D, Séralini GE. A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health. Int J Biol Sci 2009; 5(7):706-726. doi:10.7150/ijbs.5.706.

Conclusion

Food intolerances are non-immune-related adverse reactions to food. Diagnosing them can be challenging because they come with symptoms that not only affect multiple systems of the body, but also vary a lot in onset and severity. Once an intolerance is identified, treatment typically involves reducing or eliminating intake of the food trigger.

In the past decades, more and more people have been reporting food intolerances. This trend coincides with the increased use of pesticides and GMOs to boost food supply worldwide. But pesticides, especially those with glyphosate as their active ingredient, have been shown to disrupt the gut microbiome, leading to an inability to properly digest many foods. As for GMOs, they may contain toxins and alter metabolic pathways, resulting in organ damage and impaired functioning. Together, these toxic effects of pesticides and GMOs play an important role in the rise in food intolerances across the population.

Whether or not you have an intolerance, there’s another reason to avoid many of the food culprits mentioned above. Foods that trigger adverse reactions also tend to cause inflammation, a key player in almost every chronic disease. But chronic conditions aren’t a life sentence! A personalized elimination diet can give you permanent relief and drastically increase your performance.