Effect of Physical Form of Apples on Gastrointestinal Function and Satiety: a MRI Study

Different physical form of apples had a significant effect on satiety and blood sugar levels which was shown in a 1977 study by Haber and his team (Haber et al.1977).It was suggested that , this effect was due to processing of the apples which modified the bioavailability of carbohydrate and fiber content.However this was not enough to explain the mechanistic effect of the apples. Within the last decade, the role of magenetic resonance imaging has been very promising in understanding gastrointestinal function and physiology. Recent MRI studies have measured changes in gastrointestinal volumes due to the effect of fermentable carbohydrates.

Apple contains fermentable carbohydrates or FODMAPs. They are known to be poorly absorbed in the small and exert an osmotic effect by increasing markedly small bowel water content in the intestinal lumen as demonstrated in imaging studies.(Murray et al 2014 and Placidi et al 2012). A reduction of FODMAPs in the diet of IBS sufferers has been found to alleviate functional gut symptoms demonstrated in several randomised controlled trials.

In order to fully understand the 1977 Haber study, the investigators would like to repeat the study using modern MRI methods in healthy volunteers and measure the volume changes in the stomach, small bowel and colon. In addition appetite and symptoms would also be investigated after ingesting each test meal.

18 healthy volunteers will participate in this 3-way crossover study. They will attend one morning for each study, with the studies separated by approximately 1 week. We will measure breath hydrogen before the test meal, and after that approximately every hour for the next 5 h. We will also scan the subjects at baseline, immediately after the test meal and then approximately every hour for 5 hours postprandially. Subjects will be scanned on a research dedicated 1.5T MRI scanner. At baseline and every time the subjects come out of the MRI scanner we will ask them to rate their feelings of fullness, hunger and appetite as well their gastrointestinal symptoms on 100mm VAS scales. The subjects will be fed three types of Pink Lady apples test meals: whole apple, apple puree and apple juice. The apples will be sourced from supermarkets. The apple juice and apple puree will be prepared for this study by Campden BRI, a world famous food science research institute in Chipping Campden, UK. Each test meal will approximately provide 46g of available carbohydrate; 180kcal

Eligibility Criteria:
Inclusion Criteria:

* Aged 18 or older
* Able to give informed consent

Exclusion Criteria:

* Aversion to the test product
* Unable to eat whole fruit due to poor dentition or other reasons
* Pregnancy and lactation declared by candidate
* History declared by the candidate of pre-existing gastrointestinal disorder that may affect bowel function
* A positive diagnosis of irritable bowel syndrome based on the Rome III criteria questionnaire
* Reported history of previous resection of the oesophagus, stomach or intestine (excluding appendix)
* Intestinal stoma
* Any medical condition potentially compromising participation in the study e.g. diabetes mellitus, respiratory disease limiting ability to lie in the scanner
* Contraindications for MRI scanning i.e. metallic implants, pacemakers, history of metallic foreign body in eye(s) and penetrating eye injury
* Unable to limit alcohol intake to ≤ 35 units/ week and ≤ 8 units per day during trial and to avoid alcohol the day before each study day
* Unable to stop drugs known to alter GI motility including mebeverine, opiates, monoamine oxidase inhibitors, phenothiazines, benzodiazepines, calcium channel antagonists for the duration of the study (Selective serotonin reuptake inhibitors and low dose tricyclic antidepressants will be recorded but will not be an exclusion criteria)
* Antibiotic or prescribed probiotic treatment in the past 8 weeks
* Inability to lie flat or exceed scanner limits of weight \<120kg
* Poor understanding of English language
* Participation in night shift work the week prior to the study day. Night work is defined as working between midnight and 6.00 AM
* Participation in any medical trials for the past 3 months
* Alteration in habitual diet in the last 6 months
* Anyone who in the opinion of the investigator is unlikely to be able to comply with the protocol e.g. cognitive dysfunction, chaotic lifestyle related to substance abuse