Living with irritable bowel syndrome (IBS) can be very difficult. You eat something that seemed perfectly fine last week, and today it sends you rushing to the bathroom or leaves you doubled over with cramping and bloating. If this sounds familiar, you are not alone. IBS affects roughly 10–15% of people worldwide, and diet is one of the most powerful tools we have to manage it.
At Sage Naturopathic Clinic, we work with patients to identify their unique food triggers because IBS is not a one-size-fits-all condition. Three dietary approaches that come up frequently in our practice are the Low FODMAP diet, the low histamine diet, and the low nickel diet. Each targets a different underlying mechanism that can drive IBS symptoms. In this post, we will break down what each diet involves, who it may help, and how to know which approach might be right for you.
What Is IBS and Why Does Diet Matter?
IBS is a functional gastrointestinal disorder characterized by recurring abdominal pain, bloating, and altered bowel habits which can range from diarrhea (IBS-D) to constipation (IBS-C) or a mix of both (IBS-M). Unlike inflammatory bowel disease (IBD), IBS does not cause visible damage to the digestive tract, but it can significantly affect quality of life. The gut-brain axis, gut microbiome imbalances, visceral hypersensitivity, and food sensitivities all play a role in IBS. Diet directly influences each of these factors, which is why a targeted dietary approach can be transformative for many patients.
The Low FODMAP Diet
The Low FODMAP diet is the most well-researched dietary intervention for IBS, with strong evidence supporting its effectiveness in reducing symptoms for up to 75% of patients.
What Are FODMAPs?
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, a group of short-chain carbohydrates that are poorly absorbed in the small intestine. When they reach the large intestine, gut bacteria ferment them rapidly, producing gas and drawing water into the bowel. For people with IBS, this process is especially disruptive.
High FODMAP Foods to Limit
• Wheat and rye (fructans)
• Garlic and onions (fructans)
• Legumes and lentils (galactooligosaccharides)
• Cow’s milk and soft cheeses (lactose)
• Apples, pears, and stone fruits (fructose/sorbitol)
• Mushrooms and cauliflower (polyols)
How It Works
The Low FODMAP diet is typically done in three phases: elimination (2–6 weeks of strict avoidance), reintroduction (systematically testing foods one group at a time), and personalization (building a long-term diet based on your individual tolerances). It is important to work with a clinician or dietitian during this process to ensure nutritional adequacy and to correctly interpret your reactions.
In our clinic, we often see patients who have tried eliminating gluten or dairy on their own with partial results. The Low FODMAP approach offers a more comprehensive and structured framework that identifies specific triggers rather than broad food categories.
The Low Histamine Diet
Histamine is a naturally occurring compound involved in immune responses, digestion, and the nervous system. It is found in many foods and is also produced by gut bacteria. When histamine accumulates, either from too much intake or impaired breakdown, it can trigger a wide range of symptoms. They include digestive upset that closely mimics IBS.
Who Might Benefit?
Histamine intolerance may be a contributing factor in IBS when symptoms include not just bloating and diarrhea, but also headaches, skin flushing, nasal congestion, or heart palpitations after eating. It is often associated with a deficiency in diamine oxidase (DAO), the enzyme responsible for breaking down histamine in the gut.
High Histamine Foods to Reduce
• Aged cheeses (parmesan, cheddar, brie)
• Fermented foods (sauerkraut, kimchi, kombucha, wine, vinegar) • Processed and cured meats (salami, bacon, smoked fish)
• Canned fish (tuna, sardines)
• Tomatoes, spinach, eggplant, and avocado
• Alcohol (especially red wine and beer)
• Leftovers (histamine increases as food ages)
What to Know Before Starting
The low histamine diet is more nuanced than the Low FODMAP diet and lists can vary between sources. It is best used as a diagnostic tool for 4–8 weeks, not as a permanent restrictive diet. Testing DAO enzyme levels and trialling DAO supplementation may also be helpful. If you suspect histamine as a driver of your IBS, speak with a naturopathic doctor to design a safe and effective protocol.
The Low Nickel Diet
Nickel is a trace mineral found naturally in many plant foods. While most people tolerate dietary nickel without issue, some individuals, particularly those with a nickel allergy or systemic nickel sensitivity may experience gastrointestinal symptoms that overlap significantly with IBS, including abdominal pain, bloating, diarrhea, and nausea.
Systemic Nickel Allergy Syndrome (SNAS)
Research has identified a condition called Systemic Nickel Allergy Syndrome (SNAS), where ingested nickel triggers immune-mediated gastrointestinal inflammation. Studies have found that a significant proportion of IBS patients, particularly those who do not respond to the Low
FODMAP diet may have underlying nickel sensitivity. This is an evolving area of research and is not yet widely recognized in mainstream gastroenterology.
High Nickel Foods to Limit
• Whole grains (oats, whole wheat, buckwheat)
• Legumes (lentils, chickpeas, soybeans, peanuts)
• Nuts and seeds (especially sunflower seeds and cashews)
• Chocolate and cocoa products
• Leafy greens (spinach, kale) in large amounts
• Canned foods (nickel can leach from cans)
Is This Diet Right for You?
The low nickel diet is generally considered when other dietary approaches have not provided sufficient relief, or when a patient has a known nickel allergy (such as a contact reaction to jewelry). A skin patch test or an elimination trial under clinical supervision can help determine if nickel is contributing to your symptoms.
How to Choose the Right Approach for You
There is no single IBS diet that works for everyone. In practice, we often see overlapping sensitivities—some patients react to both FODMAPs and high-histamine foods, for example. Here is a simplified overview to help you think about where to start:
• Start with Low FODMAP if: Your primary symptoms are bloating, gas, diarrhea, and/or constipation and you have not yet tried any structured elimination diet. • Consider Low Histamine if: You also experience headaches, skin reactions, flushing, or runny nose alongside gut symptoms, especially after eating fermented or aged foods. • Explore Low Nickel if: You have a known nickel allergy, have not responded well to Low FODMAP, or notice symptoms cluster around whole grains, legumes, and chocolate.
Book a discovery call or initial consultation with Dr. Sanam to learn more.
Dr. Sanam Arora, ND
Naturopathic Doctor at Sage Clinic
References
- Staudacher, H.M., & Whelan, K. (2017). The low FODMAP diet: recent advances in understanding its mechanisms and efficacy in IBS. Gut, 66(8), 1517–1527. https://doi.org/10.1136/gutjnl-2017-313750
- Gibson, P.R., & Shepherd, S.J. (2010). Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach. Journal of Gastroenterology and Hepatology, 25(2), 252–258. https://doi.org/10.1111/j.1440-1746.2009.06149.x 3. Maintz, L., & Novak, N. (2007). Histamine and histamine intolerance. The American Journal of Clinical Nutrition, 85(5), 1185–1196. https://doi.org/10.1093/ajcn/85.5.1185 4. Enko, D., et al. (2018). Concomitant prevalence of low serum diamine oxidase activity and carriage of DAO gene single nucleotide polymorphisms in patients with gastrointestinal complaints. Clinical Biochemistry, 56, 28–34.
https://doi.org/10.1016/j.clinbiochem.2018.04.007
- Borghini, R., et al. (2020). New insights in IBS-like disorders: Pandora’s box has been opened; a review. Gastroenterology & Hepatology from Bed to Bench, 13(2), 85–95. PMID: 32190225
- Sciberras, M., et al. (2019). Dietary nickel intake and gastrointestinal symptoms in irritable bowel syndrome—a controlled study. Nutrients, 11(12), 2878. https://doi.org/10.3390/nu11122878
- Monsbakken, K.W., et al. (2006). Perceived food intolerance in subjects with irritable bowel syndrome—etiology, prevalence and consequences. European Journal of Clinical Nutrition, 60, 667–672. https://doi.org/10.1038/sj.ejcn.1602367