Table 1.
Role of specific foods and their contribution to functional dyspepsia symptoms
| Food | Active molecules | Study characteristics | Outcomes measurement | Proposed mechanisms of action | Effects | Ref. |
| Fatty foods | Lipids | Cross-sectional study (4 health subjects); Loxiglumide vs Loxiglumide plus fat | Gastrointestinal contractile activity (manometry) | Increased CCK release | (1) Hypersensitivity to gastrointestinal hormones; (2) Delayed gastric emptying; and (3) Symptoms exacerbation | [27] |
| Randomized crossover study (20 FD patients); Duodenal infusion of saline vs lipid solutions | Gastric volume measurement (gastric barostat) | [28] | ||||
| Almond | Tryptophan | Cross-sectional study (384 FD patients); Symptoms correlation with the intake of 114 different foods | Gastrointestinal symptoms measurement (VAS) | Indirect stimulation of serotoninergic 5-HT1 and 5-HT4 receptors | (1) Improved gastric emptying; and (2) Symptoms improvement | [29] |
| Double-blind RCT over placebo; Tandospirone vs placebo | [33] | |||||
| Pepper and Chili | Capsaicin | Cross-sectional study (121 FD patients); Symptom generation according to TRPV1 genotypes and the intake of spicy food | TRPV1 polymorphisms (on blood samples) | Regulation of TRPV1 receptors | (1) Hyperalgesia (acute administration); and (2) Reduced visceral hypersensitivity (chronic administration) | [35] |
| Randomized crossover study (20 IBS-D patients); Standard meal vs spicy meal vs chili | Gastrointestinal symptoms measurement (VAS) | [36] | ||||
| Double-blind trial over placebo (30 FD patients); Pepper vs placebo | Gastrointestinal symptoms measurement (VAS) | [37] | ||||
| Peppermint and Caraway oil | Cross-over study (6 health subjects); Peppermint caraway oil combination (enteric vs non enteric coated capsules) | Gastroduodenal motility (manometric study) | Allosteric effect on 5-HT3 receptors | (1) Antiemetic, Choleretic and spasmolytic action; and (2) Symptoms improvement | [41] | |
| Randomized, double-blind trial over placebo (96 FD patients); Peppermints caraway oil vs placebo | Gastrointestinal symptoms measurement (VAS) | [44] | ||||
| Ginger | Gingerols and Shogaols | Double-blind trial over placebo (24 health subjects); Ginger vs placebo | Gastric emptying (US) | Inhibition of cholinergic M3 and serotoninergic 5-HT3 receptors | (1) Enhanced gastric emptying; (2) Improved gastric motility; (3) Reduced nausea and vomiting; and (4) educed inflammation | [47] |
| Randomized, double-blind trial over placebo 126 FD patients); inger vs placebo | Gastrointestinal symptoms score (VAS) | [48] | ||||
| RCT over placebo (11 FD patients); inger vs placebo | Gastrointestinal symptoms (VAS) Gastric emptying (US), circulating hormones (GLP-1, motilin and ghrelin) | [50] | ||||
| FODMAPs | FOS, GOS, Lactose, Fructose (excess), Polyols | Randomized crossover study (30 IBS patients and 8 health subjects); LFD vs Australian diet | Gastrointestinal symptoms score (VAS) | Increased intestinal fermentation Increased osmotic load | (1) Abnormal gas production; (2) Luminal water retention and abdominal distension; (3) Symptoms exacerbation; and (4) Enhanced duodenal inflammation | [25] |
5-HT1: 5-hydroxytryptamine subtype 1; 5-HT4: 5-hydroxytryptamine subtype 4; CCK: Cholecystokinin; FD: Functional dyspepsia; FODMAPs: Fermentable oligosaccharides, disaccharides, monosaccharides and polyols; FOS: Fructo-oligosaccharides; GOS: Galacto-oligosaccharides; LFD: Low fodmaps diet; M3: Muscarinic receptor subtype 3; TRPV1: Transient receptor potential vanilloid subtype 1; GLP1: Glucagon-like peptide 1, US: Ultrasound, GI: Gastrointestinal; VAS: Visual analogue scale.