Evaluating the effect of dietary strategies on gastrointestinal symptoms associated with endometriosis

Participants will be provided with a low Fermentable Oligosaccharide Disaccharide, Monosaccharide and Polyols (FODMAP) diet for a month, and a high FODMAP, or typical Australian diet for a month. They will be randomized to receive which diet first. Participants won't be told that it involves FODMAPs as many will not be naive. By naïve we mean those not familiar with this diet as it is very popular in people with gut symptoms. Both diets are very similar in composition. The control diet is a typical Australian diet. The intervention is the low FODMAP diet. The low FODMAP diet will be similar in design to the typical Australian diet, both being cooked by professional chefs experienced in this area. Examples of meals provided to look like a typical Australian diet in both diets are lasgna, spaghetti Bolognese, where the pasta is either gluten free making it low FODMAP, or normal, which is high FODMAP. there will be no onion or garlic in the low FODMAP diet. Another is a chicken cacciatore, where in one diet there will be no onion, and in the other, onion. Weetbix and bread will be supplied, which is again attainable as being either low or high FODMAP. Drink examples are apple juice,(high FODMAP) vs black currant (low FODMAP). recommended fruit snacks will be either apple, pear, stone fruit (high FODMAP) or berries, bananas, oranges (low) The low FODMAP diet avoids the use of certain fermentable fibres such as onion, garlic, high fructose containing fruits such as apples, pears, and other high fructans containing food. Lactose free milk will be provided, but participants will not know which is which. Their involvement is for 3 months with a 1 week baseline food diary and symptom collection before commencing the first diet. Then follows a month off where they can eat what they want as a wash out period. The second diet will then be brought to them for the 3rd month. A daily food diary will be kept to check for adherence. At the end of the months of study food a questionnaire is completed, and a stool and vaginal swab collected that the participant would have been asked to collect, including instructions and storage. They will be visited at the end of both months to collect the diary, questionnaire and biological samples. The instructions for involvement will be given at recruitment by both the study doctor and the coordinator where prior to consent a detailed description of the study is given. The study coordinator will be in contact at least weekly to check all is OK. The contact number of the dietitian involved will be given for any queries over food as the coordinator is blinded as to what food the participant is eating.