About Functional Dyspepsia (FD)

What is Functional Dyspepsia (FD)?

Functional Dyspepsia or Meal-Triggered indigestion is a relatively common and often frustrating condition. About one in six Americans has FD (Functional Dyspepsia)1-3. FD is often described as non-ulcer dyspepsia. FD is an under-diagnosed4 and under-managed condition. FD is a disorder of sensation and movement in the organs of the upper digestive tract where the normal downward pumping and squeezing is altered. The intake and uptake (i.e., digestion and absorption) of food nutrients, can be affected.

What Causes FD?

In the absence of a known cause, it is thought that FD is associated with the disruption in the lining of the gut (gut mucosal barrier) and reversible, localized, often temporary, low-grade immune activation, which can result in the impaired ability to digest and absorb food nutrients5-7. Common triggers are food8, stress9, and the environment10. Food sensitivities, in particular, are commonly associated with FD8. If FD is suspected, consult with a physician about confirming FD and then developing a program to manage it.

What are the Symptoms of FD?

In addition to impacting the intake and uptake (i.e., the digestion and absorption) of food nutrients, FD symptoms are in the upper belly below the ribs and occur at varying times and intensities. They may include the following

  • Abdominal pain
  • Abdominal burning
  • Feeling full before finishing a meal or feeling bloated after a meal
  • Excessive belching
  • Nausea.  

Where do the Symptoms of FD Occur in the Digestive System?

FD occurs in the upper belly, above the navel. In FD, the stomach does not expand normally in response to a meal which means the food eaten backs up in the stomach and in the upper part of the small intestine.

Management Options

Dietary Modifications

Physicians often recommend gradually increasing fiber intake, starting with 2-3 grams per day. Physicians may also recommend exclusionary diets11. Also, NSAIDs are discouraged by physicians. Diet alone may not be practicable in managing FD, but should be part of your overall FD program, implemented with a physician.

Stress Management

Physicians may recommend common stress management tools including regular exercise, taking time to relax, and getting an adequate amount of sleep every night.


Unfortunately, no Rx drugs are approved for FD. Physicians may either prescribe Rx medications off-label or recommend nonprescription products to manage FD.


FDgard product shot

Even before the introduction in 2016 of the modern formulation using SST® (Site-Specific Targeting) technology which is in FDgard®, the combination of caraway oil and peppermint oil (primary component: l-Menthol) had been shown in several randomized, placebo-controlled studies to be effective in the management of FD.12

Physicians now increasingly recommend FDgard®, a medical food specially formulated for the dietary management of FD. FDgard® capsules contain solid-state, triple-coated microspheres of caraway oil and l-Menthol, along with fiber and amino acids (from gelatin protein). Common triggers of FD are food8, stress9, and the environment10. Food sensitivities, in particular, are commonly associated with FD8. That's why physicians are now recommending taking FDgard® 30 to 60 minutes prior to a meal. FDgard® has been shown in a peer-reviewed and published medical journal and in peer-reviewed presentations to be effective in managing FD symptoms§.

Physicians also recommend, in the case a pre-meal dose is missed, that FDgard® can also be taken with or after a meal.

The Distinctive Nutritional Requirements for People Who Have FD

People with FD often do not eat regularly or normally, which may affect their normal intake of nutrients. Also, the uptake (i.e., the digestion of food and the absorption) of nutrients is affected due to disturbances in the GI tract. Vitamin B12 and folate deficiencies are examples of nutritional deficiencies that have been observed in the FD population13.

There is increasing evidence that impaired mucosal defense mechanisms are implicated in the pathogenesis of Functional Gastrointestinal Disorders (FGIDs), including the two most common FGIDs, IBS and FD, allowing immune activation. Specifically, perturbations of GI microbiota, altered mucosal permeability, and abnormal mucosal defense mechanisms have been implicated in the pathogenesis of some FGIDs14-21.

Over 90% of nutrient digestion and absorption takes place in the small intestine22. With FD, this digestive and absorptive process is disrupted in several ways. The bile acid flow is disrupted as part of the cascade of disruption in FGIDs23. Peppermint oil (primary component: l-Menthol) helps restore secretory function such as bile flow24. The German Commission E monograph for peppermint oil lists its use as an anti-spasmodic for bile ducts25. This and other known activities of peppermint oil are helpful in digestion and absorption. The additional anti-spasmodic ingredient, caraway oil, plays an important complementary role in the management of FD8.

Dietary modification alone, as a management strategy, has had mixed success, especially with long-term adherence. Exclusionary diets11 that exclude pro-inflammatory foods such as french fries, sugary sodas, and refined carbohydrates, may help in the short term but also may lead to nutritional imbalances and adherence issues in the long-term. Fiber and relaxation techniques can be helpful, but may not be enough.

Now doctors increasingly use medical foods, such as FDgard®, to help normalize the intake and uptake (i.e., the digestion and absorption) of food nutrients, and to help manage FD symptoms.

FDgard® is specifically formulated to meet the distinctive nutritional requirements of FD that cannot be met with dietary modification alone. FDgard® is designed to supply specially processed, solid-state microspheres of caraway oil and l-Menthol, which help enable proper digestion of food and enhanced absorption of nutrients and to help manage the symptoms of FD. By supporting gut health in the first place, FDgard® may help avoid nutritional issues downstream.


1 Talley, Nicholas J. 2017. “Functional Dyspepsia : Advances in Diagnosis and Therapy.” Gut and Liver 11 (3): 349–57.

2 Voiosu TA, Giurcan R, Voiosu AM, Voiosu MR. Functional dyspepsia today. Maedica - a J Clin Med. 2013;8(1):68-74. doi:10.1097/00001574-200411000-00007.

3 Mahadeva S, Goh KL. Epidemiology of functional dyspepsia: A global perspective. World J Gastroenterol. 2006;12(17):2661-2666. doi:10.3748/wjg.v12.i17.2661.

4 Pleyer, C., H. Bittner, G. R. Locke, R. S. Choung, A. R. Zinsmeister, C. D. Schleck, L. M. Herrick, and N. J. Talley. 2014. “Overdiagnosis of Gastro-Esophageal Reflux Disease and Underdiagnosis of Functional Dyspepsia in a USA Community.” Neurogastroenterology and Motility 26 (8): 1163–71. doi:10.1111/nmo.12377.

5 Talley, NJ, MM Walker, and G Holtmann. 2016. “Functional Dyspepsia.” Curr Opin Gastroenterol 32 (4): 467–73. doi:10.1016/0300-2977(95)00099-9.

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7 Walker, Marjorie M., and Nicholas J. Talley. 2017. “The Role of Duodenal Inflammation in Functional Dyspepsia.” Journal of Clinical Gastroenterology 51 (1): 12–18. doi:10.1097/MCG.0000000000000740.

8 Feinle-Bisset, Christine, and Fernando Azpiroz. 2013. “Dietary and Lifestyle Factors in Functional Dyspepsia.” Nature Reviews Gastroenterology & Hepatology 10 (3). Nature Publishing Group: 150–57. doi:10.1038/nrgastro.2012.246

9 Aro, Pertti, Nicholas J. Talley, Jukka Ronkainen, Tom Storskrubb, Michael Vieth, Sven Erik Johansson, Elisabeth Bolling-Sternevald, and Lars Agréus. 2009. “Anxiety Is Associated With Uninvestigated and Functional Dyspepsia (Rome III Criteria) in a Swedish Population-Based Study.” Gastroenterology 137 (1). AGA Institute American Gastroenterological Association: 94–100. doi:10.1053/j.gastro.2009.03.039.

10 Wildner-Christensen, Mette, Jane Moller Hansen, and Ove B Schaffalitzky De Muckadell. 2006. “Risk Factors for Dyspepsia in a General Population: Non-Steroidal Anti-Inflammatory Drugs, Cigarette Smoking and Unemployment Are More Important than Helicobacter Pylori Infection.” Scandinavian Journal of Gastroenterology 41 (2): 149–54. doi:10.1080/00365520510024070

11 https://www.health.harvard.edu/staying-healthy/foods-that-fight-inflammation

12 Thompson Coon, J, and E Ernst. 2002. “Systematic Review: Herbal Medicinal Products for Non-Ulcer Dyspepsia.” Alimentary Pharmacology & Therapeutics 16 (10): 1689–99. doi:10.1046/j.0269-2813.2002.01339.x.

13 Rasool, Shahid, Shahab Abid, Mohammad Perwaiz Iqbal, Naseema Mehboobali, Ghulam Haider, and Wasim Jafri. 2012. “Relationship between Vitamin B12, Folate and Homocysteine Levels and H. Pylori Infection in Patients with Functional Dyspepsia: A Cross-Section Study.” BMC Research Notes 5 (1): 206. doi:10.1186/1756-0500-5-206.

14 Bischoff, Stephan C, Giovanni Barbara, Wim Buurman, Theo Ockhuizen, Jörg-Dieter Schulzke, Matteo Serino, Herbert Tilg, Alastair Watson, and Jerry M Wells. 2014. “Intestinal Permeability – a New Target for Disease Prevention and Therapy.” BMC Gastroenterology 14 (1): 189. doi:10.1186/s12876-014-0189-7.

15 Kindt, S., A. Tertychnyy, G. De Hertogh, K. Geboes, and J. Tack. 2009. “Intestinal Immune Activation in Presumed Post-Infectious Functional Dyspepsia.” Neurogastroenterology and Motility 21 (8): 832–38. doi:10.1111/j.1365-2982.2009.01299.x

16 Kassinen A, Krogius-Kurikka L, Makivuokko H, et al., The fecal microbiota of irritable bowel syndrome patients differs significantly from that of healthy subject. Gastroenterology 2007; 133:24-33.

17 Annahazi A, Ferrier L, Bezirard V, et al. Luminal cysteine-proteases degrade colonic tight junction structure and are responsible for abdominal pain in constipation-predominant IBS. Am J Gastroenterol 2013; 108:1322-31.

18 Lee H, Park JH, Park DI, et al. Mucosal mast cell count is associated with intestinal permeability in patients with diarrhea predominant irritable bowel syndrome. Neurogastroenterol Motil 2013; 19:244-50.

19 Matricon J, Meleine M, Gelot A, et al. Review article: associations between immune activation, intestinal permeability and the irritable bowel syndrome. Aliment Pharmacol Ther 2012; 36:1009-31.

20 Vanheel H, Vicario M, Vanuytsel T, et al. Impaired duodenal mucosal integrity and low-grade inflammation in functional dyspepsia. Gut 63 2014: 262-271; doi:10.1136/gutjnl-2012-303857.

21 Martinez C, Lobo B, Pigrau M, et al. Diarrhoea-predominant irritable bowel syndrome: an organic disorder with structural abnormalities in the jejunal epithelial barrier. Gut 2012; 62:1160-8.

22 Dr. Ananya Mandal MD. What Does the Small Intestine Do? https://www.news-medical.net/health/What-Does-the-Small-Intestine-Do.aspx.

23 Kamath, P.S. et al., abnormal gallbladder motility in irritable bowel syndrome: evidence for target-organ defect. Am J Physiol 260:G815-G819, 1991.

24 Zong, L. et al., Preliminary experimental research on the mechanism of liver bile secretion stimulated by peppermint oil. J Dig Dis. 2011 Aug: 12(4):295-301.

25 Balakrishnan, A., Therapeutic uses of peppermint—A review. J Pharm Sci & Res. Vol. 7(7), 2015, 474-476.

26 Chey WD, Lacy BE, Cash BD, Epstein M, et al. A Novel, Duodenal-Release Formulation of a Combination of Caraway Oil and L-Menthol for the Treatment of Functional Dyspepsia: A Randomized Controlled Trial. Clin Transl Gastroenterol. 2019;10(4) (FDRESTTM, Functional Dyspepsia Response Evaluation and Safety Trial)

27 FDACTTM, Functional Dyspepsia Adherence and Compliance Trial, a peer-reviewed and presented patient-reported outcomes study by Dr. Chey (ACG 2017).