Diet in the irritable bowel syndrome

The relationship between meal regularity with Irritable Bowel Syndrome (IBS) in adults

BACKGROUND

The irregular meal pattern and meal-skipping might be related to irritable bowel syndrome (IBS), however, findings of previous investigations are contradictory. We aimed to examine the relation of meal regularity with IBS in Iranian adult population.

METHODS

Data on 4599 adults who worked in 50 different health centers were used in this cross-sectional study. Dietary habits were measured using a pretested questionnaire. IBS identification was performed through the use of a modified version of Rome III questionnaire.

RESULTS

IBS was prevalent among 18.6% of men and 24.1% of women. After adjustment for potential confounders, those with regular meal pattern, in comparison to those with irregular meals, had 40% lower odds for IBS (OR:0.60, 95%CI: 0.41-0.87). Individuals with regular meals had also 82 lower risk for IBS-Mixed, in comparison to those who had irregular meals (OR:0.18, 0.95%CI: 0.08-0.43). Stratified analysis by gender revealed that women with regular meals, compared with those who did not, had 44% lower risk for IBS (OR: 0.56, 0.95%CI: 0.34-0.91). Normal-weight individuals who had regular meal pattern, compared to those who did not, had 63% lower risks for IBS (OR:0.37, 95%CI: 0.22-0.64). Furthermore, subjects who had regular meal pattern had 53% lower risk for severe symptoms of IBS (OR:0.47, 95%CI: 0.30-0.71).

CONCLUSION

We found that participants with regular meal pattern had reduced odds of IBS, IBS-Mixed and the syndrome severity. Meal regularity was also linked to reduced IBS prevalence in women, and in normal-weight individuals. More prospective studies are needed to affirm these associations.

Effect of Rice, Wheat, and Mung Bean Ingestion on Intestinal Gas Production and Postprandial Gastrointestinal Symptoms in Non-Constipation Irritable Bowel Syndrome Patients

The aim of this study is to evaluate the effect of rice, mung bean, and wheat noodle ingestion on intestinal gas production and postprandial gastrointestinal (GI) symptoms in non-constipation irritable bowel syndrome (IBS) patients. Methods: Twenty patients (13 F, 46 ± 11 y) underwent 8 h breath test studies and GI symptom evaluations after standard rice, wheat, or mung bean noodle meals at 8:00 a.m. in a randomized crossover study with a 1-week washout period. The same meal was ingested at 12:00 p.m. Results: The H₂ and CH₄ concentration in the breath samples were similar at baseline (rice:wheat:mung bean, H₂ = 3.6 ± 0.5:4.1 ± 0.5:4.0 ± 0.7 ppm, CH₄ = 1.3 ± 0.3:2.1 ± 0.4:1.9 ± 0.4 ppm, p > 0.05). Beginning at the fifth hour after breakfast, H₂ and CH₄ concentrations significantly increased after wheat compared to rice and mung bean (8 h AUC H₂ = 4120 ± 2622:2267 ± 1780:2356 ± 1722, AUC CH₄ = 1617 ± 1127:946 ± 664:943 ± 584 ppm-min, respectively) (p < 0.05). Bloating and satiety scores significantly increased after wheat compared to rice (p < 0.05), and increased but did not reach statistical significance compared to mung bean (p > 0.05). A higher bloating score after wheat compared to rice and mung bean was observed clearly after lunch but not after breakfast. Conclusion: Wheat ingestion produced more intestinal gas and more bloating and satiety scores compared to rice and mung bean, especially after lunch. This provides insight into the role of intestinal gas in the development of bloating symptoms in IBS.

Empirically derived dietary habits are associated with irritable bowel syndrome

BACKGROUND/OBJECTIVES

The associations between empirically derived dietary habits and irritable bowel syndrome (IBS) have not been investigated. This study aimed to assess the relationship between empirically derived dietary habits and IBS in a large population of Iranian adults.

SUBJECTS/METHODS

In a cross-sectional study, dietary habits of 4763 adults were assessed in three domains, "meal pattern", "eating rate" and "intra-meal fluid intake". We used latent class analysis to identify classes of dietary habits. IBS was defined based on ROME III criteria.

RESULTS

IBS was prevalent in 20.3% (n = 966) of the study population. Two distinct classes of meal patterns: "regular" and "irregular", three classes of eating rates: "moderate", "moderate-to-slow" and "moderate-to-fast" and two classes of fluid ingestion with meals: "moderate" and "heavy intra-meal drinking" were identified. After adjustment for confounders, "heavy intra-meal fluid intake" was protectively associated with IBS (OR = 0.79; 95% CI:0.64-0.96). When potential confounders were considered, "meal pattern" and "eating rate" were not significantly associated with IBS in the whole population. After adjustment for confounders, women with "irregular meal pattern" had a 30% greater risk of having IBS, compared with those with "regular meal pattern" (OR = 1.30; 95% CI:1.02-1.67). Overweight participants with "fast eating rate" were 70% more likely to have IBS, compared to those with "moderate eating rate" (OR = 1.70; 95% CI:1.13-2.55). "Irregular meal pattern" was related to frequency and severity of abdominal pain.

CONCLUSIONS

We found a significant association between heavy intra-meal fluid intake" and IBS. More large-scale prospective studies are needed to affirm this association.

Prevalence of irritable bowel syndrome in caregivers of patients with chronic diseases

BACKGROUND

Caregivers are an at-risk population for psychic and physical diseases such as irritable bowel syndrome (IBS). However, it is not known whether providing care for the chronically ill patient can be considered a risk factor for developing IBS. In this study, our aim was to evaluate the prevalence of IBS according to the Rome II criteria in a group of caregivers.

METHODS

A cross-sectional study was conducted through an evaluation of caregivers of chronically ill patients. Subjects completed questionnaires including the Rome II Modular Questionnaire, the Hospital Anxiety and Depression Scale, the Zarit Caregiver Burden Interview (ZCBI) (an instrument for evaluating the burden experienced by caregivers), and the irritable bowel syndrome quality of life (IBS-QoL) questionnaire.

KEY RESULTS

Ninety-six primary caregivers (mean age was 43.6 ± 13.7 years and 87% were women) were evaluated. The mean length of time providing care was 37.6 months (3-288 months). Forty-seven caregivers (49%) presented with IBS. The caregivers with IBS had higher scores in the global ZCBI score (47 ± 8 vs 28 ± 8, p = 0.001) and on the anxiety and depression scale (p = 0.001) than those that did not have IBS. A total of 72% were diagnosed with caregiver stress syndrome; 42 of them had IBS according to the Rome II questionnaire (60% vs 18%, p = 0.001, relative risk 3.28, 95% CI: 1.4-7.4).

CONCLUSIONS & INFERENCES

Caregivers of chronically ill patients have a high prevalence of IBS, which is associated with depression, anxiety, and poor QoL.

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols: role in irritable bowel syndrome

Irritable bowel syndrome (IBS) was previously left poorly treated despite its high prevalence and cost. Over the past decade, significant research has been conducted providing new dietary strategies for IBS management. The 'low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet' has shown symptom improvement in 68-76% of patients. Randomized, controlled trials have now proven its efficacy. The diet, low in poorly absorbed and fermentable carbohydrates, uses dietary restriction and re-challenge to determine individual tolerance to various short-chain carbohydrates. However there may be potential detrimental effects of the diet in the long term, due to potential changes to the gastrointestinal microbiota. Appropriate dietary education and management of the diet is imperative. Future research should focus on the relevance of changes to the microbiota and ways to liberalize the dietary restrictions.

Binge eating, body mass index, and gastrointestinal symptoms

OBJECTIVE

Symptoms of both gastroesophageal reflux disease (GERD) and irritable bowel syndrome (IBS) are frequently reported by individuals who binge eat. Higher body mass index (BMI) has also been associated with these disorders and with binge eating (BE). However, it is unknown whether BE influences GERD/IBS and how BMI might affect these associations. Thus, we examined the potential associations among BE, GERD, IBS, and BMI.

METHODS

Participants were from the Swedish Twin study of Adults: Genes and Environment (STAGE) and provided information on disordered eating behavior, BMI, gastrointestinal (GI) disorders, and commonly comorbid psychiatric and somatic illnesses. Key features of GERD and IBS were identified to create modified definitions of both disorders that were used as primary outcome variables. Logistic regression models were applied to determine the association between BE and each GERD/IBS both independently and in the context of BMI and other commonly comorbid psychiatric and somatic morbidities.

RESULTS

Prevalence estimates for GERD and IBS were higher among women than men (all p-values<.001). Only the association between BE and IBS was significant in both men and women after adjustment for BMI and the psychiatric/somatic morbidities.

CONCLUSION

BE appears to be an important consideration in the presence of IBS symptoms in both men and women, even when considering the impact of BMI and other commonly comorbid conditions. This association underscores the importance of routine assessment of BE in patients presenting with IBS to effectively manage the concurrent presentation of these problems.

Life course study of the etiology of self-reported irritable bowel syndrome in the 1958 British birth cohort

OBJECTIVE

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with unknown etiology. This is the first study to use a life course approach to examine premorbid risk markers for self-reported IBS in a UK birth cohort.

METHODS

Cohort study using the 1958 British birth cohort, which included 98.7% of births in 1 week in England, Wales, and Scotland. The outcome was self-reported IBS by the age of 42 years, classified with onset after 24 years and onset after 34 years. Childhood psychopathology was assessed by the Rutter scales, and adulthood psychopathology was assessed by the Malaise Inventory.

RESULTS

The prevalence of self-reported IBS in this cohort was 8.4% by 42 years (95% confidence interval [CI]=8.2-8.6). In multivariate analyses, being female (odds ratio [OR]=2.00, 95% CI=1.67-2.36), reporting 1 week to 1 month of school absence for ill health at 16 years (OR=1.27, 95% CI=1.03-1.56) and psychopathology at 23 years (OR=1.25, 95% CI=1.01-1.54) and 33 years (OR=2.20, 95% CI=1.74-2.76) were associated with an increased odds for IBS. Prospectively measured childhood adversity showed no significant association.

CONCLUSIONS

This is the first study to show a long-term prospective link between premorbid psychopathology and later self-reported IBS, in agreement with previous findings on chronic fatigue syndrome. There is no evidence that prospective measures of childhood adversity are risk markers for IBS, and there is weak evidence that prospective measures of childhood illness at 16 years are risk markers for IBS, differing to results from the same cohort for psychopathology, chronic fatigue syndrome, and chronic widespread pain. This study also does not replicate the findings of retrospective studies examining the etiology of IBS.

Nutrient intake in patients with irritable bowel syndrome compared with the general population

BACKGROUND

Food and diet are central issues that concern patients with irritable bowel syndrome (IBS). Few studies have thoroughly analyzed dietary intake in IBS. Our aims were to determine the nutrient intake in IBS patients in comparison to the general population, assess nutritional differences between IBS subgroups based on the predominant bowel habit or symptom severity, as well as to evaluate if their nutrient intake meet nutrition recommendations.

METHODS

We included 187 IBS patients (mean 40.2 years; 139 women). They completed a 4-days food registration record, which was compared with an age-, and gender-matched control group (n = 374; 278 women) from a nation-wide dietary survey and with Nordic Nutrient Recommendations.

KEY RESULTS

Daily nutrient intake in IBS patients was similar to the general population and met national nutrients recommendations. Irritable bowel syndrome patients had similar energy distribution from macronutrients compared to the control group, but the protein percentage tended to be higher. Irritable bowel syndrome patients also had significantly higher daily intake of vitamin E, folate, iron, vitamin C, and dietary fibers, as well as lower intake of vitamin A, riboflavin, calcium, and potassium. There was no association between nutrient intake and IBS subtypes or symptom severity.

CONCLUSIONS & INFERENCES

Although many IBS patients state that they avoid food items, this does not seem to influence their intake of nutrients to any large extent. The observed minor differences in nutrient intake indicate a tendency toward higher intake of fruit and vegetables and a lower intake of meat and dairy products in IBS patients.

Review: Management of postprandial diarrhea syndrome

Unexpected, urgent, sometimes painful bowel movements after eating are common complaints among adults. Without a clear etiology, if pain is present and resolves with the movements, this is usually labeled "irritable bowel syndrome-diarrhea" based solely on symptoms. If this symptom-based approach is applied exclusively, it may lead physicians not to consider treatable conditions: celiac disease, or maldigestion due to bile acid malabsorption, pancreatic exocrine insufficiency, or an a-glucosidase (sucrase, glucoamylase, maltase, or isomaltase) deficiency. These conditions can be misdiagnosed as irritable bowel syndrome-diarrhea (or functional diarrhea, if pain is not present). Limited testing is currently available to confirm these conditions (antibody screens for celiac disease; fecal fat as a surrogate marker for pancreatic function). Therefore, empirical treatment with alpha amylase, pancreatic enzymes, or a bile acid-binding agent may simultaneously treat these patients and serve as a surrogate diagnostic test. This review will summarize the current evidence for bile acid malabsorption, and deficiencies of pancreatic enzymes or a-glucosidases as potential causes for postprandial diarrhea, and provide an algorithm for treatment options.

Does a self-management program change dietary intake in adults with irritable bowel syndrome?

Making dietary changes such as increasing fiber intake is recommended for the management of irritable bowel syndrome symptoms. Few studies have explored the efficacy of education on compliance with recommendations such as increasing fiber, vegetable, and fruit intake in adults with irritable bowel syndrome. This study examined the effect of a multicomponent self-management intervention that included strategies to enhance fiber, vegetable, and fruit intake. Participants with medically diagnosed irritable bowel syndrome were randomized to usual care or individualized comprehensive self-management, delivered either in-person or by telephone. Since previously published analyses show the two delivery modes to be equally effective, the two intervention groups were combined. Of the 188 individuals randomized, 173 participants (113 in the self-management group and 60 in the usual care group; 23 men, 150 women) provided data on at least one of the three follow-up occasions (3, 6, and 12 months postrandomization). Fiber, vegetable, and fruit intakes were measured using the Food Frequency Questionnaire. Participants in the intervention group demonstrated increases (p < .05) in fiber and fruit intake and a trend in vegetable intake at 6 and 12 months postintervention. Improvement in dietary fiber intake following a self-management intervention for IBS continues to 1 year.

Treatment of irritable bowel syndrome in women

Irritable bowel syndrome (IBS) is a complex clinical process with multiple pathophysiologic mechanisms. There has recently been a shift in the treatment of patients with severe IBS symptoms to disease-modifying therapies as opposed to symptomatic treatment. Because pathophysiologic differences exist between men and women, so does the efficacy of treatment options. These differences could further explain gender-related differences in disease prevalence and treatment response. A brief discussion of the definition, epidemiology, and diagnostic criteria of IBS is followed by a comprehensive review of the current treatment choices and potential future therapeutic options of IBS in women.

Pilot study: a randomised, double blind, placebo controlled trial of pancrealipase for the treatment of postprandial irritable bowel syndrome-diarrhoea

OBJECTIVE: To evaluate the efficacy of pancrealipase (PEZ) compared with placebo in the reduction of postprandial irritable bowel syndrome-diarrhoea (IBS-D). DESIGN: An intention to treat, double blind, randomised, crossover trial comparing PEZ to placebo for reduction of postprandial IBS-D. Patients had to recognise at least two different triggering foods, be willing to consume six baseline 'trigger meals' and again blinded with PEZ and placebo. Patients then chose which drug they preferred for another 25 meals. SETTING: Outpatient internal medicine practice clinic. PATIENTS: 255 patients were screened; 83 met the criteria, including 5 years of symptoms, recognised 'food triggers', no other identifiable cause for the symptoms, either a normal colonoscopy or barium enema while symptomatic and able to discontinue all anticholinergic medications. 69 patients were enrolled, 20 withdrew before randomisation, leaving 49 patients: 14 men, 35 women, mean age 52 years (SD 15.3). Over 60% had experienced symptoms for 11-30 years and 16% for more than 40 years. INTERVENTIONS: After completing six baseline meals, patients were randomised in blocks of four to receive either identical PEZ or a placebo for another six meals, and after a washout period of time received the alternative drug. MAIN OUTCOME MEASURES: The primary analysis was number of patients who chose PEZ over placebo for the extended use. RESULTS: Overall, 30/49 (61%) would have chosen PEZ (p=0.078), with first drug preference for PEZ at 0.002. Among the PEZ subgroup, PEZ use compared with placebo, demonstrated improvement in all symptoms (p≤0.001) for cramping, bloating, borborygami, urge to defecate, global pain and decrease stooling with increase in stool firmness. CONCLUSIONS: PEZ was found in a small group of patients to reduce postprandial IBS-D symptoms and deserves further evaluation.

Are rice and spicy diet good for functional gastrointestinal disorders?

Rice- and chili-containing foods are common in Asia. Studies suggest that rice is completely absorbed in the small bowel, produces little intestinal gas and has a low allergenicity. Several clinical studies have demonstrated that rice-based meals are well tolerated and may improve gastrointestinal symptoms in functional gastrointestinal disorders (FGID). Chili is a spicy ingredient commonly use throughout Asia. The active component of chili is capsaicin. Capsaicin can mediate a painful, burning sensation in the human gut via the transient receptor potential vanilloid-1 (TRPV1). Recently, the TRPV1 expressing sensory fibers have been reported to increase in the gastrointestinal tract of patients with FGID and visceral hypersensitivity. Acute exposure to capsaicin or chili can aggravate abdominal pain and burning in dyspepsia and IBS patients. Whereas, chronic ingestion of natural capsaicin agonist or chili has been shown to decrease dyspeptic and gastroesophageal reflux disease (GERD) symptoms. The high prevalence of spicy food in Asia may modify gastrointestinal burning symptoms in patients with FGID. Studies in Asia demonstrated a low prevalence of heartburn symptoms in GERD patients in several Asian countries. In conclusion rice is well tolerated and should be advocated as the carbohydrate source of choice for patients with FGID. Although, acute chili ingestion can aggravate abdominal pain and burning symptoms in FGID, chronic ingestion of chili was found to improve functional dyspepsia and GERD symptoms in small randomized, controlled studies.

The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review

This review summarizes what is known about the effect of diet on irritable bowel syndrome (IBS) symptoms emphasizing data from randomized, controlled clinical trials. Studies suggest that IBS symptoms in one quarter of patients may be caused or exacerbated by one or more dietary components. Recent studies indicate that a diet restricted in fermentable, poorly absorbed carbohydrates, including fructose, fructans (present in wheat and onions), sorbitol, and other sugar alcohols is beneficial, but confirmatory studies are needed. Despite a long history of enthusiastic use, fiber is marginally beneficial. Insoluble fiber may worsen symptoms. Some patients with IBS, especially those with constipation, will improve with increased intake of soluble fiber. Prebiotic fibers have not been adequately tested. Daily use of peppermint oil is effective in relieving IBS symptoms. The usefulness of probiotics in the form of foods such as live-culture yogurt and buttermilk for IBS symptoms is not established. In clinical practice, it is very difficult to establish that a patient's symptoms result from an adverse reaction to food. A double blind placebo-controlled food challenge is the most reliable method, but it is not suitable for routine clinical use. A modified exclusion diet and stepwise reintroduction of foods or trials of eliminating classes of food may be useful.

New treatments for irritable bowel syndrome in women

The estimated prevalence of irritable bowel syndrome (IBS) in Western countries is 7-15%, with a female:male ratio of 2-2.5:1 in IBS patients who seek healthcare services; however, the female predominance is lower in the general population. IBS has a significant impact on health-related quality of life and is associated with a significant healthcare and economic burden. Management of IBS is comprised of general measures and pharmacologic and nonpharmacologic treatment. However, there are ongoing efforts to find more effective therapeutic approaches. As advancements in the understanding of the pathophysiology of IBS continue to grow, new and effective treatments with novel mechanisms of action that have the potential to improve relief of IBS symptoms over current treatments are likely to be developed. This article provides an overview of current and emerging therapies for IBS and also highlights sex and gender differences in clinical trials and treatment response.

Prebiotics, probiotics, and dietary fiber in gastrointestinal disease

Microecology of the gastrointestinal tract is the physiologic basis for the effect of dietary fiber, prebiotics and probiotics on the host. The ecology consists of the gastrointestinal tract, primarily the intestines, the foods that are fed into the tract, and the flora living within. Within this ecology, normal flora and probiotics, ferment dietary fiber and prebiotics to produce short chain fatty acids and substances that are absorbed and effect the host at the intestinal level and systemically. In this review, we will discuss the effects of prebiotics, probiotics and dietary fiber in gastrointestinal disorders and diseases.

Nutrition and motility disorders

The purpose of this article is to give an overview of the relation between feeding and gastrointestinal symptoms and complaints, and to review different motility disorders that have implications for food intake. We also report the consequences for nutrition state and the evidence-based principles of dietary modification in patients with motility disorders.

Nutritional care of the patient with constipation

Chronic constipation is defined as a symptom-based disorder based on the presence for at least 3 months in the last year of unsatisfactory defecation characterized by infrequent stools, difficult stool passage, or both. On the other hand, the presence of clinically important abdominal discomfort or pain associated with constipation defines irritable bowel syndrome (IBS) with constipation. Intake of dietary fibre and bulking agents (psyllium) may be effective in alleviating chronic constipation in patients without slow colonic transit or disordered constipation. On the other hand, fibre may improve stool consistency in patients with IBS with constipation, but it is considered to be not effective in improving abdominal pain, distension or bloating. Probiotics may be effective in relieving constipation; however, the effect of lactic acid bacteria ingestion may be dependent on the bacterial strain used and the population being studied. Lactulose, which is a substrate for lactic acid bacteria (prebiotic), is effective to treat patients with chronic constipation.

The value of a general therapeutic approach in subjects with irritable bowel syndrome

BACKGROUND

The general therapeutic approach is the cornerstone in the management of irritable bowel syndrome, but the effect is poorly documented.

AIM

To evaluate the effect of the general therapeutic approach for irritable bowel syndrome.

METHODS

Subjects with irritable bowel syndrome identified in a public screening were included. Scores for abdominal symptom (range 0-12), musculoskeletal pain and mood disorders were calculated. After exclusion of other disorders, a doctor presented irritable bowel syndrome as a positive diagnosis, gave information, reassurance and lifestyle advice, but no pharmacotherapy. A dietician gave dietary advice. There was a follow-up after 6 months.

RESULTS

Sixty-five persons (females/males: 44/21) with mean age 49 years (range 31-76) were included, 31 (48%) were recommended dietary changes. Twenty subjects (31%) had satisfactory relief of symptoms after 6 months. The scores for abdominal symptom was reduced from 3.1 to 2.2 (P = 0.007), the reduction was 2.2 in the diarrhoea-predominant group given advice compared with 0.4 in the other subjects (P = 0.035). Previous consultations for the complaints, visits for psychiatric disorders, and presence of mood disorders were predictors of persistent complaints.

CONCLUSIONS

There was a significant relief of symptoms after 6 months, those with psychological co-morbidity responded less well. The effect of dietary advice was only seen in those with diarrhoea-predominant irritable bowel syndrome.

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L-Lysine acts like a partial serotonin receptor 4 antagonist and inhibits serotonin-mediated intestinal pathologies and anxiety in rats

The purpose of this investigation was to determine whether a nutritionally essential amino acid, l-lysine, acts like a serotonin receptor 4 (5-HT4) antagonist, and if l-lysine is beneficial in animal models of serotonin (5-HT)-induced anxiety, diarrhea, ileum contractions, and tachycardia and in stress-induced fecal excretion. The radioligand-binding assay was used to test the binding of l-lysine to various 5-HT receptors. The effects of l-lysine on 5-HT-induced contractions of isolated guinea pig ileum were studied in vitro. The effects of oral administration of l-lysine on diarrhea, stress-induced fecal excretion, and 5-HT-induced corticosterone release, tachycardia, and anxiety (an elevated plus maze paradigm) were studied in rats in vivo. l-Lysine (0.8 mmol/dl) inhibited (9.17%) binding of 5-HT to the 5-HT4 receptor, without any effect on 5-HT1A,2A,2B,2C,3 binding. l-Lysine (0.07 and 0.7 mmol/dl) blocked 5-HT-induced contractions of an isolated guinea pig ileum in vitro (P < 0.05 and P < 0.01). Orally applied l-lysine (1 g/kg of body weight) inhibited (P < 0.12) diarrhea triggered by coadministration of restraint stress and 5-hydroxytryptophane (10 mg/kg of body weight), and significantly blocked anxiety induced by the 5-HT4 receptor agonist (3.0 mmol/liter) in rats in vivo. No effects of l-lysine or the 5-HT4 receptor agonist on plasma corticosterone and heart rate were recorded. l-Lysine may be a partial 5-HT4 receptor antagonist and suppresses 5-HT4 receptor-mediated intestinal pathologies and anxiety in rats. An increase in nutritional load of l-lysine might be a useful tool in treating stress-induced anxiety and 5-HT-related diarrhea-type intestinal dysfunctions.