Managing irritable bowel syndrome - Dietary approaches and food intolerance

Irritable bowel syndrome (IBS) is a complex disorder where diet plays a pivotal role in symptom generation for many patients. The aim of this thesis was to explore how diet and self-perceived food intolerance relate to gastrointestinal (GI) symptoms among patients with IBS, and within different manifestations of IBS. In Paper I, reported dietary intake of fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) were characterized among patients with IBS. Intakes varied more between subjects than within, leading to an acceptable precision in diet estimates when data rankings are used. In Paper II cross-sectional data were used to explore how FODMAP intake relates to GI symptoms in IBS patients with different subtypes. Although reported FODMAP intake appeared to be similar between IBS subtypes, only in unsubtyped IBS a strong relationship between excess fructose intake and GI symptom severity was found. NMR metabolomics from serum and urine derived from a randomized controlled dietary trial among patients with IBS in Paper III, did not reveal any consistent pattern in principal component analysis (PCA) regarding reported baseline dietary intake. When evaluating the changes in metabolite concentrations, several metabolites seemed to distinguish responders and non-responders to the dietary modifications. In Paper IV, it was shown that atopic disease is a common IBS comorbidity, but presence of self-reported food intolerance/allergy or atopic disease did not relate to IBS symptom severity. In this analysis, female gender, other somatic symptoms and the number of food items reported to cause GI symptoms were associated with increased IBS symptom severity. In conclusion, both habitual intake of FODMAPs and how one reacts to FODMAP intake seem to vary in this heterogenous patient group. Studies evaluating separate FODMAP components and individual tolerance to these are further warranted

The effect of a phytoestrogen intervention and impact of genetic factors on tumor proliferation markers among Swedish patients with prostate cancer : study protocol for the randomized controlled PRODICA trial

Background: A high intake of phytoestrogens, found in soy, rye, and seeds, is associated with a reduced risk of a prostate cancer diagnosis. Previously, we found that the overall decreased risk of prostate cancer diagnosis in males with a high intake of phytoestrogens was strongly modified by a nucleotide sequence variant in the estrogen receptor-beta (ERβ) gene. However, we do not know if phytoestrogens can inhibit the growth of prostate cancer in males with established diseases. If there is an inhibition or a delay, there is reason to believe that different variants of the ERβ gene will modify the effect. Therefore, we designed an intervention study to investigate the effect of the addition of foods high in phytoestrogens and their interaction with the ERβ genotype on prostate tumor proliferation in patients with prostate cancer. Method: The PRODICA trial is a randomized ongoing intervention study in patients with low- and intermediate-risk prostate cancer with a Gleason score < 8, prostate-specific antigen (PSA) < 20, and scheduled for radical prostatectomy. The study is conducted at Sahlgrenska University Hospital in Gothenburg, Sweden. The intervention consists of a daily intake of soybeans and flaxseeds (~ 200 mg of phytoestrogens) until the surgery, approximately 6 weeks. The aim is to recruit 200 participants. The primary outcome is the difference in the proliferation marker Ki-67 between the intervention and the control groups. The genotype of ERβ will be investigated as an effect-modifying factor. Secondary outcomes include, e.g., concentrations of PSA and steroid hormones in the blood. Discussion: The results of the PRODICA trial will contribute important information on the relevance of increasing the intake of phytoestrogens in patients with prostate cancer who want to make dietary changes to improve the prognosis of their cancer. If genetic factors turn out to influence the effect of the intervention diet, dietary advice can be given to patients who most likely benefit from it. Dietary interventions are cost-effective, non-invasive, and result in few mild side effects. Lastly, the project will provide basic pathophysiological insights which could be relevant to the development of treatment strategies for patients with prostate cancer. Trial registration. ClinicalTrials.gov NCT02759380. Registered on 3 May 2016

Habitual FODMAP Intake in Relation to Symptom Severity and Pattern in Patients with Irritable Bowel Syndrome

Restricting intake of FODMAPs (Fermentable Oligo-, Di-, Monosaccharides and Polyols) is used as treatment for irritable bowel syndrome (IBS). However, whether habitual FODMAP consumption correlates to symptom severity, and if this relationship differs among IBS subtypes, is unclear. The aim was to study the relationship between habitual FODMAP intake and symptom severity. A total of 189 patients with IBS—IBS with constipation (IBS-C) n = 44 (22.3%), IBS with diarrhea (IBS-D) n = 54 (27.4%), mixed IBS (IBS-M) n = 46 (23.4%) and unsubtyped IBS (IBS-U) n = 46 (23.4%)—recorded food intake during four days. Symptom severity was measured with the IBS severity scoring system (IBS-SSS). For FODMAP intake, a lower lactose intake was noted among women with IBS-D, p = 0.009. In women, there was a statistically significant relationship between energy-adjusted FODMAP intake and IBS-SSS (r = 0.21, p = 0.003). This was mainly driven by the subtype IBS-U, where excess fructose intake accounted for 19.9% of explained variance in IBS-SSS (p = 0.007). This study demonstrates small differences in FODMAP intake among IBS patients with different subtypes. Association between IBS symptoms and FODMAP intake was most prominent in unsubtyped IBS. However, patients who are intolerant to certain FODMAPs may already have reduced their FODMAP intake, and this warrants future cohort or experimental studies to uncover

Effects on Serum Hormone Concentrations after a Dietary Phytoestrogen Intervention in Patients with Prostate Cancer: A Randomized Controlled Trial

Phytoestrogens have been suggested to have an anti-proliferative role in prostate cancer, potentially by acting through estrogen receptor beta (ERβ) and modulating several hormones. We primarily aimed to investigate the effect of a phytoestrogen intervention on hormone concentrations in blood depending on the ERβ genotype. Patients with low and intermediate-risk prostate cancer, scheduled for radical prostatectomy, were randomized to an intervention group provided with soybeans and flaxseeds (∼200 mg phytoestrogens/d) added to their diet until their surgery, or a control group that was not provided with any food items. Both groups received official dietary recommendations. Blood samples were collected at baseline and endpoint and blood concentrations of different hormones and phytoestrogens were analyzed. The phytoestrogen-rich diet did not affect serum concentrations of testosterone, insulin-like growth factor 1, or sex hormone-binding globulin (SHBG). However, we found a trend of decreased risk of increased serum concentration of estradiol in the intervention group compared to the control group but only in a specific genotype of ERβ (p = 0.058). In conclusion, a high daily intake of phytoestrogen-rich foods has no major effect on hormone concentrations but may lower the concentration of estradiol in patients with prostate cancer with a specific genetic upset of ERβ

Comparison of a web-based food record tool and a food-frequency questionnaire and objective validation using the doubly labelled water technique in a Swedish middle-aged population

Two web-based dietary assessment tools have been developed for use in large-scale studies: the Riksmaten method (4-d food record) and MiniMeal-Q (food-frequency method). The aim of the present study was to examine the ability of these methods to capture energy intake against objectively measured total energy expenditure (TEE) with the doubly labelled water technique (TEEDLW), and to compare reported energy and macronutrient intake. This study was conducted within the pilot study of the Swedish CArdioPulmonary bioImage Study (SCAPIS), which included 1111 randomly selected men and women aged 50–64 years from the Gothenburg general population. Of these, 200 were enrolled in the SCAPIS diet substudy. TEEDLW was measured in a subsample (n 40). Compared with TEEDLW, both methods underestimated energy intake: −2·5 (sd 2·9) MJ with the Riksmaten method; −2·3 (sd 3·6) MJ with MiniMeal-Q. Mean reporting accuracy was 80 and 82 %, respectively. The correlation between reported energy intake and TEEDLW was r 0·4 for the Riksmaten method (P < 0·05) and r 0·28 (non-significant) for MiniMeal-Q. Women reported similar average intake of energy and macronutrients in both methods whereas men reported higher intakes with the Riksmaten method. Energy-adjusted correlations ranged from 0·14 (polyunsaturated fat) to 0·77 (alcohol). Bland–Altman plots showed acceptable agreement for energy and energy-adjusted protein and carbohydrate intake, whereas the agreement for fat intake was poorer. According to energy intake data, both methods displayed similar precision on energy intake reporting. However, MiniMeal-Q was less successful in ranking individuals than the Riksmaten method. The development of methods to achieve limited under-reporting is a major challenge for future research

Carotenoids and alkylresorcinols as objective biomarkers of diet quality when assessing the validity of a web-based food record tool and a food frequency questionnaire in a middle-aged population

BACKGROUND: Recently, two web-based dietary assessment tools were developed; a 4-day food record tool (the Riksmaten method), and a food frequency questionnaire (MiniMeal-Q). The aim of this study was to use objective biomarkers to examine the ability of the two methods to capture habitual dietary intake. METHODS: In total, 200 individuals from the pilot study of the Swedish CArdioPulmonary bioImage Study (SCAPIS) participated. Plasma concentration of carotenoids were determined with high-performance liquid chromatography (HPLC) and used as biomarkers of fruit and vegetable intake. A gas chromatography mass spectrometry (GC-MS) method was used to quantify alkylresorcinol homologues, which were used as biomarkers of whole grain wheat and rye intake. RESULTS: The correlations between energy-adjusted fruit and vegetable intakes and plasma carotenoid concentrations (except lycopene) were stronger amongst women than men (r = 0.46 and r = 0.20 for the Riksmaten method, and r = 0.50 and r = 0.31 for MiniMeal-Q, respectively). For whole grains, the correlations of energy-adjusted intakes and alkylresorcinols were higher using the Riksmaten method (r = 0.30 and r = 0.29 for women and men) than the MiniMeal-Q (r = 0.25 and r = 0.20, respectively). In regression analyses between plasma carotenoids (except lycopene) and reported intake of fruits and vegetables, the R2 were 21.6 % and 5.1 % for women and men by the Riksmaten method, and correspondingly, 18.0 % and 6.6 % by the MiniMeal-Q. In the final full models, adjusted for smoking and BMI, all regression models remained statistically significant. The regression analyses of plasma alkylresorcinols and reported intake of whole grains showed an R2of 9.4 % and 9.7 % for women and men by the Riksmaten method, and correspondingly, 5.3 % and 8.4 % by the MiniMeal-Q. In the final full models, adjusted for smoking and age, all regression models remained statistically significant, except for women in MiniMeal-Q. CONCLUSION: Both dietary assessment methods were able to capture dietary intake based on food groups with a similar precision. Agreements with objective biomarkers ranged from low to moderate, depending on sex and diet quality indicator. While the ability to capture whole grain intake was weak for both methods and sexes, the assessment of vegetable and fruit intake performed in a satisfactory manner for women in both methods